ZSHALL(1) - phpMan

ZSHALL(1) General Commands Manual ZSHALL(1)

NAME
zshall - the Z shell meta-man page

OVERVIEW
Because zsh contains many features, the zsh manual has been split into a number of sec-
tions. This manual page includes all the separate manual pages in the following order:

zsh Zsh overview
zshroadmap Informal introduction to the manual
zshmisc Anything not fitting into the other sections
zshexpn Zsh command and parameter expansion
zshparam Zsh parameters
zshoptions Zsh options
zshbuiltins Zsh built-in functions
zshzle Zsh command line editing
zshcompwid Zsh completion widgets
zshcompsys Zsh completion system
zshcompctl Zsh completion control
zshmodules Zsh loadable modules
zshcalsys Zsh built-in calendar functions
zshtcpsys Zsh built-in TCP functions
zshzftpsys Zsh built-in FTP client
zshcontrib Additional zsh functions and utilities

DESCRIPTION
Zsh is a UNIX command interpreter (shell) usable as an interactive login shell and as a
shell script command processor. Of the standard shells, zsh most closely resembles ksh
but includes many enhancements. It does not provide compatibility with POSIX or other
shells in its default operating mode: see the section Compatibility below.

Zsh has command line editing, builtin spelling correction, programmable command comple-
tion, shell functions (with autoloading), a history mechanism, and a host of other fea-
tures.

AUTHOR
Zsh was originally written by Paul Falstad <pf AT zsh.org>. Zsh is now maintained by the
members of the zsh-workers mailing list <zsh-workers AT zsh.org>. The development is cur-
rently coordinated by Peter Stephenson <pws AT zsh.org>. The coordinator can be contacted at
<coordinator AT zsh.org>, but matters relating to the code should generally go to the mailing
list.

AVAILABILITY
Zsh is available from the following HTTP and anonymous FTP site.

ftp://ftp.zsh.org/pub/
https://www.zsh.org/pub/
)

The up-to-date source code is available via Git from Sourceforge. See https://source-
forge.net/projects/zsh/ for details. A summary of instructions for the archive can be
found at http://zsh.sourceforge.net/.

MAILING LISTS
Zsh has 3 mailing lists:

<zsh-announce AT zsh.org>
Announcements about releases, major changes in the shell and the monthly posting of
the Zsh FAQ. (moderated)

<zsh-users AT zsh.org>
User discussions.

<zsh-workers AT zsh.org>
Hacking, development, bug reports and patches.

To subscribe or unsubscribe, send mail to the associated administrative address for the
mailing list.

<zsh-announce-subscribe AT zsh.org>
<zsh-users-subscribe AT zsh.org>
<zsh-workers-subscribe AT zsh.org>
<zsh-announce-unsubscribe AT zsh.org>
<zsh-users-unsubscribe AT zsh.org>
<zsh-workers-unsubscribe AT zsh.org>

YOU ONLY NEED TO JOIN ONE OF THE MAILING LISTS AS THEY ARE NESTED. All submissions to
zsh-announce are automatically forwarded to zsh-users. All submissions to zsh-users are
automatically forwarded to zsh-workers.

If you have problems subscribing/unsubscribing to any of the mailing lists, send mail to
<listmaster AT zsh.org>. The mailing lists are maintained by Karsten Thygesen
<karthy AT kom.dk>.

The mailing lists are archived; the archives can be accessed via the administrative ad-
dresses listed above. There is also a hypertext archive, maintained by Geoff Wing
<gcw AT zsh.org>, available at https://www.zsh.org/mla/.

THE ZSH FAQ
Zsh has a list of Frequently Asked Questions (FAQ), maintained by Peter Stephenson
<pws AT zsh.org>. It is regularly posted to the newsgroup comp.unix.shell and the zsh-an-
nounce mailing list. The latest version can be found at any of the Zsh FTP sites, or at
http://www.zsh.org/FAQ/. The contact address for FAQ-related matters is <faqmas-
ter AT zsh.org>.

THE ZSH WEB PAGE
Zsh has a web page which is located at https://www.zsh.org/. This is maintained by
Karsten Thygesen <karthy AT zsh.org>, of SunSITE Denmark. The contact address for web-re-
lated matters is <webmaster AT zsh.org>.

THE ZSH USERGUIDE
A userguide is currently in preparation. It is intended to complement the manual, with
explanations and hints on issues where the manual can be cabbalistic, hierographic, or
downright mystifying (for example, the word `hierographic' does not exist). It can be
viewed in its current state at http://zsh.sourceforge.net/Guide/. At the time of writing,
chapters dealing with startup files and their contents and the new completion system were
essentially complete.

INVOCATION
The following flags are interpreted by the shell when invoked to determine where the shell
will read commands from:

-c Take the first argument as a command to execute, rather than reading commands from
a script or standard input. If any further arguments are given, the first one is
assigned to $0, rather than being used as a positional parameter.

-i Force shell to be interactive. It is still possible to specify a script to exe-
cute.

-s Force shell to read commands from the standard input. If the -s flag is not
present and an argument is given, the first argument is taken to be the pathname of
a script to execute.

If there are any remaining arguments after option processing, and neither of the options
-c or -s was supplied, the first argument is taken as the file name of a script containing
shell commands to be executed. If the option PATH_SCRIPT is set, and the file name does
not contain a directory path (i.e. there is no `/' in the name), first the current direc-
tory and then the command path given by the variable PATH are searched for the script. If
the option is not set or the file name contains a `/' it is used directly.

After the first one or two arguments have been appropriated as described above, the re-
maining arguments are assigned to the positional parameters.

For further options, which are common to invocation and the set builtin, see zshop-
tions(1).

The long option `--emulate' followed (in a separate word) by an emulation mode may be
passed to the shell. The emulation modes are those described for the emulate builtin, see
zshbuiltins(1). The `--emulate' option must precede any other options (which might other-
wise be overridden), but following options are honoured, so may be used to modify the re-
quested emulation mode. Note that certain extra steps are taken to ensure a smooth emula-
tion when this option is used compared with the emulate command within the shell: for ex-
ample, variables that conflict with POSIX usage such as path are not defined within the
shell.

Options may be specified by name using the -o option. -o acts like a single-letter op-
tion, but takes a following string as the option name. For example,

zsh -x -o shwordsplit scr

runs the script scr, setting the XTRACE option by the corresponding letter `-x' and the
SH_WORD_SPLIT option by name. Options may be turned off by name by using +o instead of
-o. -o can be stacked up with preceding single-letter options, so for example `-xo
shwordsplit' or `-xoshwordsplit' is equivalent to `-x -o shwordsplit'.

Options may also be specified by name in GNU long option style, `--option-name'. When
this is done, `-' characters in the option name are permitted: they are translated into
`_', and thus ignored. So, for example, `zsh --sh-word-split' invokes zsh with the
SH_WORD_SPLIT option turned on. Like other option syntaxes, options can be turned off by
replacing the initial `-' with a `+'; thus `+-sh-word-split' is equivalent to
`--no-sh-word-split'. Unlike other option syntaxes, GNU-style long options cannot be
stacked with any other options, so for example `-x-shwordsplit' is an error, rather than
being treated like `-x --shwordsplit'.

The special GNU-style option `--version' is handled; it sends to standard output the
shell's version information, then exits successfully. `--help' is also handled; it sends
to standard output a list of options that can be used when invoking the shell, then exits
successfully.

Option processing may be finished, allowing following arguments that start with `-' or `+'
to be treated as normal arguments, in two ways. Firstly, a lone `-' (or `+') as an argu-
ment by itself ends option processing. Secondly, a special option `--' (or `+-'), which
may be specified on its own (which is the standard POSIX usage) or may be stacked with
preceding options (so `-x-' is equivalent to `-x --'). Options are not permitted to be
stacked after `--' (so `-x-f' is an error), but note the GNU-style option form discussed
above, where `--shwordsplit' is permitted and does not end option processing.

Except when the sh/ksh emulation single-letter options are in effect, the option `-b' (or
`+b') ends option processing. `-b' is like `--', except that further single-letter op-
tions can be stacked after the `-b' and will take effect as normal.

COMPATIBILITY
Zsh tries to emulate sh or ksh when it is invoked as sh or ksh respectively; more pre-
cisely, it looks at the first letter of the name by which it was invoked, excluding any
initial `r' (assumed to stand for `restricted'), and if that is `b', `s' or `k' it will
emulate sh or ksh. Furthermore, if invoked as su (which happens on certain systems when
the shell is executed by the su command), the shell will try to find an alternative name
from the SHELL environment variable and perform emulation based on that.

In sh and ksh compatibility modes the following parameters are not special and not ini-
tialized by the shell: ARGC, argv, cdpath, fignore, fpath, HISTCHARS, mailpath, MANPATH,
manpath, path, prompt, PROMPT, PROMPT2, PROMPT3, PROMPT4, psvar, status, watch.

The usual zsh startup/shutdown scripts are not executed. Login shells source /etc/profile
followed by $HOME/.profile. If the ENV environment variable is set on invocation, $ENV is
sourced after the profile scripts. The value of ENV is subjected to parameter expansion,
command substitution, and arithmetic expansion before being interpreted as a pathname.
Note that the PRIVILEGED option also affects the execution of startup files.

The following options are set if the shell is invoked as sh or ksh: NO_BAD_PATTERN,
NO_BANG_HIST, NO_BG_NICE, NO_EQUALS, NO_FUNCTION_ARGZERO, GLOB_SUBST, NO_GLOBAL_EXPORT,
NO_HUP, INTERACTIVE_COMMENTS, KSH_ARRAYS, NO_MULTIOS, NO_NOMATCH, NO_NOTIFY,
POSIX_BUILTINS, NO_PROMPT_PERCENT, RM_STAR_SILENT, SH_FILE_EXPANSION, SH_GLOB, SH_OP-
TION_LETTERS, SH_WORD_SPLIT. Additionally the BSD_ECHO and IGNORE_BRACES options are set
if zsh is invoked as sh. Also, the KSH_OPTION_PRINT, LOCAL_OPTIONS, PROMPT_BANG,
PROMPT_SUBST and SINGLE_LINE_ZLE options are set if zsh is invoked as ksh.

RESTRICTED SHELL
When the basename of the command used to invoke zsh starts with the letter `r' or the `-r'
command line option is supplied at invocation, the shell becomes restricted. Emulation
mode is determined after stripping the letter `r' from the invocation name. The following
are disabled in restricted mode:

o changing directories with the cd builtin

o changing or unsetting the EGID, EUID, GID, HISTFILE, HISTSIZE, IFS, LD_AOUT_LI-
BRARY_PATH, LD_AOUT_PRELOAD, LD_LIBRARY_PATH, LD_PRELOAD, MODULE_PATH, module_path,
PATH, path, SHELL, UID and USERNAME parameters

o specifying command names containing /

o specifying command pathnames using hash

o redirecting output to files

o using the exec builtin command to replace the shell with another command

o using jobs -Z to overwrite the shell process' argument and environment space

o using the ARGV0 parameter to override argv[0] for external commands

o turning off restricted mode with set +r or unsetopt RESTRICTED

These restrictions are enforced after processing the startup files. The startup files
should set up PATH to point to a directory of commands which can be safely invoked in the
restricted environment. They may also add further restrictions by disabling selected
builtins.

Restricted mode can also be activated any time by setting the RESTRICTED option. This im-
mediately enables all the restrictions described above even if the shell still has not
processed all startup files.

A shell Restricted Mode is an outdated way to restrict what users may do: modern systems
have better, safer and more reliable ways to confine user actions, such as chroot jails,
containers and zones.

A restricted shell is very difficult to implement safely. The feature may be removed in a
future version of zsh.

It is important to realise that the restrictions only apply to the shell, not to the com-
mands it runs (except for some shell builtins). While a restricted shell can only run the
restricted list of commands accessible via the predefined `PATH' variable, it does not
prevent those commands from running any other command.

As an example, if `env' is among the list of allowed commands, then it allows the user to
run any command as `env' is not a shell builtin command and can run arbitrary executables.

So when implementing a restricted shell framework it is important to be fully aware of
what actions each of the allowed commands or features (which may be regarded as modules)
can perform.

Many commands can have their behaviour affected by environment variables. Except for the
few listed above, zsh does not restrict the setting of environment variables.

If a `perl', `python', `bash', or other general purpose interpreted script it treated as a
restricted command, the user can work around the restriction by setting specially crafted
`PERL5LIB', `PYTHONPATH', `BASHENV' (etc.) environment variables. On GNU systems, any com-
mand can be made to run arbitrary code when performing character set conversion (including
zsh itself) by setting a `GCONV_PATH' environment variable. Those are only a few exam-
ples.

Bear in mind that, contrary to some other shells, `readonly' is not a security feature in
zsh as it can be undone and so cannot be used to mitigate the above.

A restricted shell only works if the allowed commands are few and carefully written so as
not to grant more access to users than intended. It is also important to restrict what
zsh module the user may load as some of them, such as `zsh/system', `zsh/mapfile' and
`zsh/files', allow bypassing most of the restrictions.

STARTUP/SHUTDOWN FILES
Commands are first read from /etc/zsh/zshenv; this cannot be overridden. Subsequent be-
haviour is modified by the RCS and GLOBAL_RCS options; the former affects all startup
files, while the second only affects global startup files (those shown here with an path
starting with a /). If one of the options is unset at any point, any subsequent startup
file(s) of the corresponding type will not be read. It is also possible for a file in
$ZDOTDIR to re-enable GLOBAL_RCS. Both RCS and GLOBAL_RCS are set by default.

Commands are then read from $ZDOTDIR/.zshenv. If the shell is a login shell, commands are
read from /etc/zsh/zprofile and then $ZDOTDIR/.zprofile. Then, if the shell is interac-
tive, commands are read from /etc/zsh/zshrc and then $ZDOTDIR/.zshrc. Finally, if the
shell is a login shell, /etc/zsh/zlogin and $ZDOTDIR/.zlogin are read.

When a login shell exits, the files $ZDOTDIR/.zlogout and then /etc/zsh/zlogout are read.
This happens with either an explicit exit via the exit or logout commands, or an implicit
exit by reading end-of-file from the terminal. However, if the shell terminates due to
exec'ing another process, the logout files are not read. These are also affected by the
RCS and GLOBAL_RCS options. Note also that the RCS option affects the saving of history
files, i.e. if RCS is unset when the shell exits, no history file will be saved.

If ZDOTDIR is unset, HOME is used instead. Files listed above as being in /etc may be in
another directory, depending on the installation.

As /etc/zsh/zshenv is run for all instances of zsh, it is important that it be kept as
small as possible. In particular, it is a good idea to put code that does not need to be
run for every single shell behind a test of the form `if [[ -o rcs ]]; then ...' so that
it will not be executed when zsh is invoked with the `-f' option.

Any of these files may be pre-compiled with the zcompile builtin command (see zsh-
builtins(1)). If a compiled file exists (named for the original file plus the .zwc exten-
sion) and it is newer than the original file, the compiled file will be used instead.

ZSHROADMAP(1) General Commands Manual ZSHROADMAP(1)

NAME
zshroadmap - informal introduction to the zsh manual The Zsh Manual, like the shell it-
self, is large and often complicated. This section of the manual provides some pointers
to areas of the shell that are likely to be of particular interest to new users, and indi-
cates where in the rest of the manual the documentation is to be found.

WHEN THE SHELL STARTS
When it starts, the shell reads commands from various files. These can be created or
edited to customize the shell. See the section Startup/Shutdown Files in zsh(1).

If no personal initialization files exist for the current user, a function is run to help
you change some of the most common settings. It won't appear if your administrator has
disabled the zsh/newuser module. The function is designed to be self-explanatory. You
can run it by hand with `autoload -Uz zsh-newuser-install; zsh-newuser-install -f'. See
also the section User Configuration Functions in zshcontrib(1).

INTERACTIVE USE
Interaction with the shell uses the builtin Zsh Line Editor, ZLE. This is described in
detail in zshzle(1).

The first decision a user must make is whether to use the Emacs or Vi editing mode as the
keys for editing are substantially different. Emacs editing mode is probably more natural
for beginners and can be selected explicitly with the command bindkey -e.

A history mechanism for retrieving previously typed lines (most simply with the Up or Down
arrow keys) is available; note that, unlike other shells, zsh will not save these lines
when the shell exits unless you set appropriate variables, and the number of history lines
retained by default is quite small (30 lines). See the description of the shell variables
(referred to in the documentation as parameters) HISTFILE, HISTSIZE and SAVEHIST in zsh-
param(1). Note that it's currently only possible to read and write files saving history
when the shell is interactive, i.e. it does not work from scripts.

The shell now supports the UTF-8 character set (and also others if supported by the oper-
ating system). This is (mostly) handled transparently by the shell, but the degree of
support in terminal emulators is variable. There is some discussion of this in the shell
FAQ, http://www.zsh.org/FAQ/. Note in particular that for combining characters to be han-
dled the option COMBINING_CHARS needs to be set. Because the shell is now more sensitive
to the definition of the character set, note that if you are upgrading from an older ver-
sion of the shell you should ensure that the appropriate variable, either LANG (to affect
all aspects of the shell's operation) or LC_CTYPE (to affect only the handling of charac-
ter sets) is set to an appropriate value. This is true even if you are using a sin-
gle-byte character set including extensions of ASCII such as ISO-8859-1 or ISO-8859-15.
See the description of LC_CTYPE in zshparam(1).

Completion
Completion is a feature present in many shells. It allows the user to type only a part
(usually the prefix) of a word and have the shell fill in the rest. The completion system
in zsh is programmable. For example, the shell can be set to complete email addresses in
arguments to the mail command from your ~/.abook/addressbook; usernames, hostnames, and
even remote paths in arguments to scp, and so on. Anything that can be written in or
glued together with zsh can be the source of what the line editor offers as possible com-
pletions.

Zsh has two completion systems, an old, so called compctl completion (named after the
builtin command that serves as its complete and only user interface), and a new one, re-
ferred to as compsys, organized as library of builtin and user-defined functions. The two
systems differ in their interface for specifying the completion behavior. The new system
is more customizable and is supplied with completions for many commonly used commands; it
is therefore to be preferred.

The completion system must be enabled explicitly when the shell starts. For more informa-
tion see zshcompsys(1).

Extending the line editor
Apart from completion, the line editor is highly extensible by means of shell functions.
Some useful functions are provided with the shell; they provide facilities such as:

insert-composed-char
composing characters not found on the keyboard

match-words-by-style
configuring what the line editor considers a word when moving or deleting by word

history-beginning-search-backward-end, etc.
alternative ways of searching the shell history

replace-string, replace-pattern
functions for replacing strings or patterns globally in the command line

edit-command-line
edit the command line with an external editor.

See the section `ZLE Functions' in zshcontrib(1) for descriptions of these.

OPTIONS
The shell has a large number of options for changing its behaviour. These cover all as-
pects of the shell; browsing the full documentation is the only good way to become ac-
quainted with the many possibilities. See zshoptions(1).

PATTERN MATCHING
The shell has a rich set of patterns which are available for file matching (described in
the documentation as `filename generation' and also known for historical reasons as `glob-
bing') and for use when programming. These are described in the section `Filename Genera-
tion' in zshexpn(1).

Of particular interest are the following patterns that are not commonly supported by other
systems of pattern matching:

** for matching over multiple directories

| for matching either of two alternatives

~, ^ the ability to exclude patterns from matching when the EXTENDED_GLOB option is set

(...) glob qualifiers, included in parentheses at the end of the pattern, which select
files by type (such as directories) or attribute (such as size).

GENERAL COMMENTS ON SYNTAX
Although the syntax of zsh is in ways similar to the Korn shell, and therefore more re-
motely to the original UNIX shell, the Bourne shell, its default behaviour does not en-
tirely correspond to those shells. General shell syntax is introduced in the section
`Shell Grammar' in zshmisc(1).

One commonly encountered difference is that variables substituted onto the command line
are not split into words. See the description of the shell option SH_WORD_SPLIT in the
section `Parameter Expansion' in zshexpn(1). In zsh, you can either explicitly request
the splitting (e.g. ${=foo}) or use an array when you want a variable to expand to more
than one word. See the section `Array Parameters' in zshparam(1).

PROGRAMMING
The most convenient way of adding enhancements to the shell is typically by writing a
shell function and arranging for it to be autoloaded. Functions are described in the sec-
tion `Functions' in zshmisc(1). Users changing from the C shell and its relatives should
notice that aliases are less used in zsh as they don't perform argument substitution, only
simple text replacement.

A few general functions, other than those for the line editor described above, are pro-
vided with the shell and are described in zshcontrib(1). Features include:

promptinit
a prompt theme system for changing prompts easily, see the section `Prompt Themes'

zsh-mime-setup
a MIME-handling system which dispatches commands according to the suffix of a file
as done by graphical file managers

zcalc a calculator

zargs a version of xargs that makes the find command redundant

zmv a command for renaming files by means of shell patterns.

ZSHMISC(1) General Commands Manual ZSHMISC(1)

NAME
zshmisc - everything and then some

SIMPLE COMMANDS & PIPELINES
A simple command is a sequence of optional parameter assignments followed by blank-sepa-
rated words, with optional redirections interspersed. For a description of assignment,
see the beginning of zshparam(1).

The first word is the command to be executed, and the remaining words, if any, are argu-
ments to the command. If a command name is given, the parameter assignments modify the
environment of the command when it is executed. The value of a simple command is its exit
status, or 128 plus the signal number if terminated by a signal. For example,

echo foo

is a simple command with arguments.

A pipeline is either a simple command, or a sequence of two or more simple commands where
each command is separated from the next by `|' or `|&'. Where commands are separated by
`|', the standard output of the first command is connected to the standard input of the
next. `|&' is shorthand for `2>&1 |', which connects both the standard output and the
standard error of the command to the standard input of the next. The value of a pipeline
is the value of the last command, unless the pipeline is preceded by `!' in which case the
value is the logical inverse of the value of the last command. For example,

echo foo | sed 's/foo/bar/'

is a pipeline, where the output (`foo' plus a newline) of the first command will be passed
to the input of the second.

If a pipeline is preceded by `coproc', it is executed as a coprocess; a two-way pipe is
established between it and the parent shell. The shell can read from or write to the co-
process by means of the `>&p' and `<&p' redirection operators or with `print -p' and `read
-p'. A pipeline cannot be preceded by both `coproc' and `!'. If job control is active,
the coprocess can be treated in other than input and output as an ordinary background job.

A sublist is either a single pipeline, or a sequence of two or more pipelines separated by
`&&' or `||'. If two pipelines are separated by `&&', the second pipeline is executed
only if the first succeeds (returns a zero status). If two pipelines are separated by
`||', the second is executed only if the first fails (returns a nonzero status). Both op-
erators have equal precedence and are left associative. The value of the sublist is the
value of the last pipeline executed. For example,

dmesg | grep panic && print yes

is a sublist consisting of two pipelines, the second just a simple command which will be
executed if and only if the grep command returns a zero status. If it does not, the value
of the sublist is that return status, else it is the status returned by the print (almost
certainly zero).

A list is a sequence of zero or more sublists, in which each sublist is terminated by `;',
`&', `&|', `&!', or a newline. This terminator may optionally be omitted from the last
sublist in the list when the list appears as a complex command inside `(...)' or `{...}'.
When a sublist is terminated by `;' or newline, the shell waits for it to finish before
executing the next sublist. If a sublist is terminated by a `&', `&|', or `&!', the shell
executes the last pipeline in it in the background, and does not wait for it to finish
(note the difference from other shells which execute the whole sublist in the background).
A backgrounded pipeline returns a status of zero.

More generally, a list can be seen as a set of any shell commands whatsoever, including
the complex commands below; this is implied wherever the word `list' appears in later de-
scriptions. For example, the commands in a shell function form a special sort of list.

PRECOMMAND MODIFIERS
A simple command may be preceded by a precommand modifier, which will alter how the com-
mand is interpreted. These modifiers are shell builtin commands with the exception of no-
correct which is a reserved word.

- The command is executed with a `-' prepended to its argv[0] string.

builtin
The command word is taken to be the name of a builtin command, rather than a shell
function or external command.

command [ -pvV ]
The command word is taken to be the name of an external command, rather than a
shell function or builtin. If the POSIX_BUILTINS option is set, builtins will
also be executed but certain special properties of them are suppressed. The -p flag
causes a default path to be searched instead of that in $path. With the -v flag,
command is similar to whence and with -V, it is equivalent to whence -v.

exec [ -cl ] [ -a argv0 ]
The following command together with any arguments is run in place of the current
process, rather than as a sub-process. The shell does not fork and is replaced.
The shell does not invoke TRAPEXIT, nor does it source zlogout files. The options
are provided for compatibility with other shells.

The -c option clears the environment.

The -l option is equivalent to the - precommand modifier, to treat the replacement
command as a login shell; the command is executed with a - prepended to its argv[0]
string. This flag has no effect if used together with the -a option.

The -a option is used to specify explicitly the argv[0] string (the name of the
command as seen by the process itself) to be used by the replacement command and is
directly equivalent to setting a value for the ARGV0 environment variable.

nocorrect
Spelling correction is not done on any of the words. This must appear before any
other precommand modifier, as it is interpreted immediately, before any parsing is
done. It has no effect in non-interactive shells.

noglob Filename generation (globbing) is not performed on any of the words.

COMPLEX COMMANDS
A complex command in zsh is one of the following:

if list then list [ elif list then list ] ... [ else list ] fi
The if list is executed, and if it returns a zero exit status, the then list is ex-
ecuted. Otherwise, the elif list is executed and if its status is zero, the then
list is executed. If each elif list returns nonzero status, the else list is exe-
cuted.

for name ... [ in word ... ] term do list done
Expand the list of words, and set the parameter name to each of them in turn, exe-
cuting list each time. If the `in word' is omitted, use the positional parameters
instead of the words.

The term consists of one or more newline or ; which terminate the words, and are
optional when the `in word' is omitted.

More than one parameter name can appear before the list of words. If N names are
given, then on each execution of the loop the next N words are assigned to the cor-
responding parameters. If there are more names than remaining words, the remaining
parameters are each set to the empty string. Execution of the loop ends when there
is no remaining word to assign to the first name. It is only possible for in to
appear as the first name in the list, else it will be treated as marking the end of
the list.

for (( [expr1] ; [expr2] ; [expr3] )) do list done
The arithmetic expression expr1 is evaluated first (see the section `Arithmetic
Evaluation'). The arithmetic expression expr2 is repeatedly evaluated until it
evaluates to zero and when non-zero, list is executed and the arithmetic expression
expr3 evaluated. If any expression is omitted, then it behaves as if it evaluated
to 1.

while list do list done
Execute the do list as long as the while list returns a zero exit status.

until list do list done
Execute the do list as long as until list returns a nonzero exit status.

repeat word do list done
word is expanded and treated as an arithmetic expression, which must evaluate to a
number n. list is then executed n times.

The repeat syntax is disabled by default when the shell starts in a mode emulating
another shell. It can be enabled with the command `enable -r repeat'

case word in [ [(] pattern [ | pattern ] ... ) list (;;|;&|;|) ] ... esac
Execute the list associated with the first pattern that matches word, if any. The
form of the patterns is the same as that used for filename generation. See the
section `Filename Generation'.

Note further that, unless the SH_GLOB option is set, the whole pattern with alter-
natives is treated by the shell as equivalent to a group of patterns within paren-
theses, although white space may appear about the parentheses and the vertical bar
and will be stripped from the pattern at those points. White space may appear
elsewhere in the pattern; this is not stripped. If the SH_GLOB option is set, so
that an opening parenthesis can be unambiguously treated as part of the case syn-
tax, the expression is parsed into separate words and these are treated as strict
alternatives (as in other shells).

If the list that is executed is terminated with ;& rather than ;;, the following
list is also executed. The rule for the terminator of the following list ;;, ;& or
;| is applied unless the esac is reached.

If the list that is executed is terminated with ;| the shell continues to scan the
patterns looking for the next match, executing the corresponding list, and applying
the rule for the corresponding terminator ;;, ;& or ;|. Note that word is not
re-expanded; all applicable patterns are tested with the same word.

select name [ in word ... term ] do list done
where term is one or more newline or ; to terminate the words. Print the set of
words, each preceded by a number. If the in word is omitted, use the positional
parameters. The PROMPT3 prompt is printed and a line is read from the line editor
if the shell is interactive and that is active, or else standard input. If this
line consists of the number of one of the listed words, then the parameter name is
set to the word corresponding to this number. If this line is empty, the selection
list is printed again. Otherwise, the value of the parameter name is set to null.
The contents of the line read from standard input is saved in the parameter REPLY.
list is executed for each selection until a break or end-of-file is encountered.

( list )
Execute list in a subshell. Traps set by the trap builtin are reset to their de-
fault values while executing list.

{ list }
Execute list.

{ try-list } always { always-list }
First execute try-list. Regardless of errors, or break or continue commands en-
countered within try-list, execute always-list. Execution then continues from the
result of the execution of try-list; in other words, any error, or break or con-
tinue command is treated in the normal way, as if always-list were not present.
The two chunks of code are referred to as the `try block' and the `always block'.

Optional newlines or semicolons may appear after the always; note, however, that
they may not appear between the preceding closing brace and the always.

An `error' in this context is a condition such as a syntax error which causes the
shell to abort execution of the current function, script, or list. Syntax errors
encountered while the shell is parsing the code do not cause the always-list to be
executed. For example, an erroneously constructed if block in try-list would cause
the shell to abort during parsing, so that always-list would not be executed, while
an erroneous substitution such as ${*foo*} would cause a run-time error, after
which always-list would be executed.

An error condition can be tested and reset with the special integer variable
TRY_BLOCK_ERROR. Outside an always-list the value is irrelevant, but it is ini-
tialised to -1. Inside always-list, the value is 1 if an error occurred in the
try-list, else 0. If TRY_BLOCK_ERROR is set to 0 during the always-list, the error
condition caused by the try-list is reset, and shell execution continues normally
after the end of always-list. Altering the value during the try-list is not useful
(unless this forms part of an enclosing always block).

Regardless of TRY_BLOCK_ERROR, after the end of always-list the normal shell status
$? is the value returned from try-list. This will be non-zero if there was an er-
ror, even if TRY_BLOCK_ERROR was set to zero.

The following executes the given code, ignoring any errors it causes. This is an
alternative to the usual convention of protecting code by executing it in a sub-
shell.

{
# code which may cause an error
} always {
# This code is executed regardless of the error.
(( TRY_BLOCK_ERROR = 0 ))
}
# The error condition has been reset.

When a try block occurs outside of any function, a return or a exit encountered in
try-list does not cause the execution of always-list. Instead, the shell exits im-
mediately after any EXIT trap has been executed. Otherwise, a return command en-
countered in try-list will cause the execution of always-list, just like break and
continue.

function word ... [ () ] [ term ] { list }
word ... () [ term ] { list }
word ... () [ term ] command
where term is one or more newline or ;. Define a function which is referenced by
any one of word. Normally, only one word is provided; multiple words are usually
only useful for setting traps. The body of the function is the list between the {
and }. See the section `Functions'.

If the option SH_GLOB is set for compatibility with other shells, then whitespace
may appear between the left and right parentheses when there is a single word;
otherwise, the parentheses will be treated as forming a globbing pattern in that
case.

In any of the forms above, a redirection may appear outside the function body, for
example

func() { ... } 2>&1

The redirection is stored with the function and applied whenever the function is
executed. Any variables in the redirection are expanded at the point the function
is executed, but outside the function scope.

time [ pipeline ]
The pipeline is executed, and timing statistics are reported on the standard error
in the form specified by the TIMEFMT parameter. If pipeline is omitted, print sta-
tistics about the shell process and its children.

[[ exp ]]
Evaluates the conditional expression exp and return a zero exit status if it is
true. See the section `Conditional Expressions' for a description of exp.

ALTERNATE FORMS FOR COMPLEX COMMANDS
Many of zsh's complex commands have alternate forms. These are non-standard and are
likely not to be obvious even to seasoned shell programmers; they should not be used any-
where that portability of shell code is a concern.

The short versions below only work if sublist is of the form `{ list }' or if the
SHORT_LOOPS option is set. For the if, while and until commands, in both these cases the
test part of the loop must also be suitably delimited, such as by `[[ ... ]]' or `(( ...
))', else the end of the test will not be recognized. For the for, repeat, case and se-
lect commands no such special form for the arguments is necessary, but the other condition
(the special form of sublist or use of the SHORT_LOOPS option) still applies.

if list { list } [ elif list { list } ] ... [ else { list } ]
An alternate form of if. The rules mean that

if [[ -o ignorebraces ]] {
print yes
}

works, but

if true { # Does not work!
print yes
}

does not, since the test is not suitably delimited.

if list sublist
A short form of the alternate if. The same limitations on the form of list apply
as for the previous form.

for name ... ( word ... ) sublist
A short form of for.

for name ... [ in word ... ] term sublist
where term is at least one newline or ;. Another short form of for.

for (( [expr1] ; [expr2] ; [expr3] )) sublist
A short form of the arithmetic for command.

foreach name ... ( word ... ) list end
Another form of for.

while list { list }
An alternative form of while. Note the limitations on the form of list mentioned
above.

until list { list }
An alternative form of until. Note the limitations on the form of list mentioned
above.

repeat word sublist
This is a short form of repeat.

case word { [ [(] pattern [ | pattern ] ... ) list (;;|;&|;|) ] ... }
An alternative form of case.

select name [ in word ... term ] sublist
where term is at least one newline or ;. A short form of select.

function word ... [ () ] [ term ] sublist
This is a short form of function.

RESERVED WORDS
The following words are recognized as reserved words when used as the first word of a com-
mand unless quoted or disabled using disable -r:

do done esac then elif else fi for case if while function repeat time until select coproc
nocorrect foreach end ! [[ { } declare export float integer local readonly typeset

Additionally, `}' is recognized in any position if neither the IGNORE_BRACES option nor
the IGNORE_CLOSE_BRACES option is set.

ERRORS
Certain errors are treated as fatal by the shell: in an interactive shell, they cause con-
trol to return to the command line, and in a non-interactive shell they cause the shell to
be aborted. In older versions of zsh, a non-interactive shell running a script would not
abort completely, but would resume execution at the next command to be read from the
script, skipping the remainder of any functions or shell constructs such as loops or con-
ditions; this somewhat illogical behaviour can be recovered by setting the option CON-
TINUE_ON_ERROR.

Fatal errors found in non-interactive shells include:

o Failure to parse shell options passed when invoking the shell

o Failure to change options with the set builtin

o Parse errors of all sorts, including failures to parse mathematical expressions

o Failures to set or modify variable behaviour with typeset, local, declare, export,
integer, float

o Execution of incorrectly positioned loop control structures (continue, break)

o Attempts to use regular expression with no regular expression module available

o Disallowed operations when the RESTRICTED options is set

o Failure to create a pipe needed for a pipeline

o Failure to create a multio

o Failure to autoload a module needed for a declared shell feature

o Errors creating command or process substitutions

o Syntax errors in glob qualifiers

o File generation errors where not caught by the option BAD_PATTERN

o All bad patterns used for matching within case statements

o File generation failures where not caused by NO_MATCH or similar options

o All file generation errors where the pattern was used to create a multio

o Memory errors where detected by the shell

o Invalid subscripts to shell variables

o Attempts to assign read-only variables

o Logical errors with variables such as assignment to the wrong type

o Use of invalid variable names

o Errors in variable substitution syntax

o Failure to convert characters in $'...' expressions

If the POSIX_BUILTINS option is set, more errors associated with shell builtin commands
are treated as fatal, as specified by the POSIX standard.

COMMENTS
In non-interactive shells, or in interactive shells with the INTERACTIVE_COMMENTS option
set, a word beginning with the third character of the histchars parameter (`#' by default)
causes that word and all the following characters up to a newline to be ignored.

ALIASING
Every eligible word in the shell input is checked to see if there is an alias defined for
it. If so, it is replaced by the text of the alias if it is in command position (if it
could be the first word of a simple command), or if the alias is global. If the replace-
ment text ends with a space, the next word in the shell input is always eligible for pur-
poses of alias expansion. An alias is defined using the alias builtin; global aliases may
be defined using the -g option to that builtin.

A word is defined as:

o Any plain string or glob pattern

o Any quoted string, using any quoting method (note that the quotes must be part of
the alias definition for this to be eligible)

o Any parameter reference or command substitution

o Any series of the foregoing, concatenated without whitespace or other tokens be-
tween them

o Any reserved word (case, do, else, etc.)

o With global aliasing, any command separator, any redirection operator, and `(' or
`)' when not part of a glob pattern

Alias expansion is done on the shell input before any other expansion except history ex-
pansion. Therefore, if an alias is defined for the word foo, alias expansion may be
avoided by quoting part of the word, e.g. \foo. Any form of quoting works, although there
is nothing to prevent an alias being defined for the quoted form such as \foo as well.

When POSIX_ALIASES is set, only plain unquoted strings are eligible for aliasing. The
alias builtin does not reject ineligible aliases, but they are not expanded.

For use with completion, which would remove an initial backslash followed by a character
that isn't special, it may be more convenient to quote the word by starting with a single
quote, i.e. 'foo; completion will automatically add the trailing single quote.

Alias difficulties
Although aliases can be used in ways that bend normal shell syntax, not every string of
non-white-space characters can be used as an alias.

Any set of characters not listed as a word above is not a word, hence no attempt is made
to expand it as an alias, no matter how it is defined (i.e. via the builtin or the special
parameter aliases described in the section THE ZSH/PARAMETER MODULE in zshmodules(1)).
However, as noted in the case of POSIX_ALIASES above, the shell does not attempt to deduce
whether the string corresponds to a word at the time the alias is created.

For example, an expression containing an = at the start of a command line is an assignment
and cannot be expanded as an alias; a lone = is not an assignment but can only be set as
an alias using the parameter, as otherwise the = is taken part of the syntax of the
builtin command.

It is not presently possible to alias the `((' token that introduces arithmetic expres-
sions, because until a full statement has been parsed, it cannot be distinguished from two
consecutive `(' tokens introducing nested subshells. Also, if a separator such as && is
aliased, \&& turns into the two tokens \& and &, each of which may have been aliased sepa-
rately. Similarly for \<<, \>|, etc.

There is a commonly encountered problem with aliases illustrated by the following code:

alias echobar='echo bar'; echobar

This prints a message that the command echobar could not be found. This happens because
aliases are expanded when the code is read in; the entire line is read in one go, so that
when echobar is executed it is too late to expand the newly defined alias. This is often
a problem in shell scripts, functions, and code executed with `source' or `.'. Conse-
quently, use of functions rather than aliases is recommended in non-interactive code.

Note also the unhelpful interaction of aliases and function definitions:

alias func='noglob func'
func() {
echo Do something with $*
}

Because aliases are expanded in function definitions, this causes the following command to
be executed:

noglob func() {
echo Do something with $*
}

which defines noglob as well as func as functions with the body given. To avoid this, ei-
ther quote the name func or use the alternative function definition form `function func'.
Ensuring the alias is defined after the function works but is problematic if the code
fragment might be re-executed.

QUOTING
A character may be quoted (that is, made to stand for itself) by preceding it with a `\'.
`\' followed by a newline is ignored.

A string enclosed between `$'' and `'' is processed the same way as the string arguments
of the print builtin, and the resulting string is considered to be entirely quoted. A
literal `'' character can be included in the string by using the `\'' escape.

All characters enclosed between a pair of single quotes ('') that is not preceded by a `$'
are quoted. A single quote cannot appear within single quotes unless the option RC_QUOTES
is set, in which case a pair of single quotes are turned into a single quote. For exam-
ple,

print ''''

outputs nothing apart from a newline if RC_QUOTES is not set, but one single quote if it
is set.

Inside double quotes (""), parameter and command substitution occur, and `\' quotes the
characters `\', ``', `"', `$', and the first character of $histchars (default `!').

REDIRECTION
If a command is followed by & and job control is not active, then the default standard in-
put for the command is the empty file /dev/null. Otherwise, the environment for the exe-
cution of a command contains the file descriptors of the invoking shell as modified by in-
put/output specifications.

The following may appear anywhere in a simple command or may precede or follow a complex
command. Expansion occurs before word or digit is used except as noted below. If the re-
sult of substitution on word produces more than one filename, redirection occurs for each
separate filename in turn.

< word Open file word for reading as standard input. It is an error to open a file in
this fashion if it does not exist.

<> word
Open file word for reading and writing as standard input. If the file does not ex-
ist then it is created.

> word Open file word for writing as standard output. If the file does not exist then it
is created. If the file exists, and the CLOBBER option is unset, this causes an
error; otherwise, it is truncated to zero length.

>| word
>! word
Same as >, except that the file is truncated to zero length if it exists, regard-
less of CLOBBER.

>> word
Open file word for writing in append mode as standard output. If the file does not
exist, and the CLOBBER and APPEND_CREATE options are both unset, this causes an er-
ror; otherwise, the file is created.

>>| word
>>! word
Same as >>, except that the file is created if it does not exist, regardless of
CLOBBER and APPEND_CREATE.

<<[-] word
The shell input is read up to a line that is the same as word, or to an
end-of-file. No parameter expansion, command substitution or filename generation
is performed on word. The resulting document, called a here-document, becomes the
standard input.

If any character of word is quoted with single or double quotes or a `\', no inter-
pretation is placed upon the characters of the document. Otherwise, parameter and
command substitution occurs, `\' followed by a newline is removed, and `\' must be
used to quote the characters `\', `$', ``' and the first character of word.

Note that word itself does not undergo shell expansion. Backquotes in word do not
have their usual effect; instead they behave similarly to double quotes, except
that the backquotes themselves are passed through unchanged. (This information is
given for completeness and it is not recommended that backquotes be used.) Quotes
in the form $'...' have their standard effect of expanding backslashed references
to special characters.

If <<- is used, then all leading tabs are stripped from word and from the document.

<<< word
Perform shell expansion on word and pass the result to standard input. This is
known as a here-string. Compare the use of word in here-documents above, where
word does not undergo shell expansion.

<& number
>& number
The standard input/output is duplicated from file descriptor number (see dup2(2)).

<& -
>& - Close the standard input/output.

<& p
>& p The input/output from/to the coprocess is moved to the standard input/output.

>& word
&> word
(Except where `>& word' matches one of the above syntaxes; `&>' can always be used
to avoid this ambiguity.) Redirects both standard output and standard error (file
descriptor 2) in the manner of `> word'. Note that this does not have the same ef-
fect as `> word 2>&1' in the presence of multios (see the section below).

>&| word
>&! word
&>| word
&>! word
Redirects both standard output and standard error (file descriptor 2) in the manner
of `>| word'.

>>& word
&>> word
Redirects both standard output and standard error (file descriptor 2) in the manner
of `>> word'.

>>&| word
>>&! word
&>>| word
&>>! word
Redirects both standard output and standard error (file descriptor 2) in the manner
of `>>| word'.

If one of the above is preceded by a digit, then the file descriptor referred to is that
specified by the digit instead of the default 0 or 1. The order in which redirections are
specified is significant. The shell evaluates each redirection in terms of the (file de-
scriptor, file) association at the time of evaluation. For example:

... 1>fname 2>&1

first associates file descriptor 1 with file fname. It then associates file descriptor 2
with the file associated with file descriptor 1 (that is, fname). If the order of redi-
rections were reversed, file descriptor 2 would be associated with the terminal (assuming
file descriptor 1 had been) and then file descriptor 1 would be associated with file
fname.

The `|&' command separator described in Simple Commands & Pipelines in zshmisc(1) is a
shorthand for `2>&1 |'.

The various forms of process substitution, `<(list)', and `=(list)' for input and
`>(list)' for output, are often used together with redirection. For example, if word in
an output redirection is of the form `>(list)' then the output is piped to the command
represented by list. See Process Substitution in zshexpn(1).

OPENING FILE DESCRIPTORS USING PARAMETERS
When the shell is parsing arguments to a command, and the shell option IGNORE_BRACES is
not set, a different form of redirection is allowed: instead of a digit before the opera-
tor there is a valid shell identifier enclosed in braces. The shell will open a new file
descriptor that is guaranteed to be at least 10 and set the parameter named by the identi-
fier to the file descriptor opened. No whitespace is allowed between the closing brace
and the redirection character. For example:

... {myfd}>&1

This opens a new file descriptor that is a duplicate of file descriptor 1 and sets the pa-
rameter myfd to the number of the file descriptor, which will be at least 10. The new
file descriptor can be written to using the syntax >&$myfd. The file descriptor remains
open in subshells and forked external executables.

The syntax {varid}>&-, for example {myfd}>&-, may be used to close a file descriptor
opened in this fashion. Note that the parameter given by varid must previously be set to
a file descriptor in this case.

It is an error to open or close a file descriptor in this fashion when the parameter is
readonly. However, it is not an error to read or write a file descriptor using <&$param
or >&$param if param is readonly.

If the option CLOBBER is unset, it is an error to open a file descriptor using a parameter
that is already set to an open file descriptor previously allocated by this mechanism.
Unsetting the parameter before using it for allocating a file descriptor avoids the error.

Note that this mechanism merely allocates or closes a file descriptor; it does not perform
any redirections from or to it. It is usually convenient to allocate a file descriptor
prior to use as an argument to exec. The syntax does not in any case work when used
around complex commands such as parenthesised subshells or loops, where the opening brace
is interpreted as part of a command list to be executed in the current shell.

The following shows a typical sequence of allocation, use, and closing of a file descrip-
tor:

integer myfd
exec {myfd}>~/logs/mylogfile.txt
print This is a log message. >&$myfd
exec {myfd}>&-

Note that the expansion of the variable in the expression >&$myfd occurs at the point the
redirection is opened. This is after the expansion of command arguments and after any
redirections to the left on the command line have been processed.

MULTIOS
If the user tries to open a file descriptor for writing more than once, the shell opens
the file descriptor as a pipe to a process that copies its input to all the specified out-
puts, similar to tee, provided the MULTIOS option is set, as it is by default. Thus:

date >foo >bar

writes the date to two files, named `foo' and `bar'. Note that a pipe is an implicit re-
direction; thus

date >foo | cat

writes the date to the file `foo', and also pipes it to cat.

Note that the shell opens all the files to be used in the multio process immediately, not
at the point they are about to be written.

Note also that redirections are always expanded in order. This happens regardless of the
setting of the MULTIOS option, but with the option in effect there are additional conse-
quences. For example, the meaning of the expression >&1 will change after a previous redi-
rection:

date >&1 >output

In the case above, the >&1 refers to the standard output at the start of the line; the re-
sult is similar to the tee command. However, consider:

date >output >&1

As redirections are evaluated in order, when the >&1 is encountered the standard output is
set to the file output and another copy of the output is therefore sent to that file.
This is unlikely to be what is intended.

If the MULTIOS option is set, the word after a redirection operator is also subjected to
filename generation (globbing). Thus

: > *

will truncate all files in the current directory, assuming there's at least one. (Without
the MULTIOS option, it would create an empty file called `*'.) Similarly, you can do

echo exit 0 >> *.sh

If the user tries to open a file descriptor for reading more than once, the shell opens
the file descriptor as a pipe to a process that copies all the specified inputs to its
output in the order specified, provided the MULTIOS option is set. It should be noted
that each file is opened immediately, not at the point where it is about to be read: this
behaviour differs from cat, so if strictly standard behaviour is needed, cat should be
used instead.

Thus

sort <foo <fubar

or even

sort <f{oo,ubar}

is equivalent to `cat foo fubar | sort'.

Expansion of the redirection argument occurs at the point the redirection is opened, at
the point described above for the expansion of the variable in >&$myfd.

Note that a pipe is an implicit redirection; thus

cat bar | sort <foo

is equivalent to `cat bar foo | sort' (note the order of the inputs).

If the MULTIOS option is unset, each redirection replaces the previous redirection for
that file descriptor. However, all files redirected to are actually opened, so

echo Hello > bar > baz

when MULTIOS is unset will truncate `bar', and write `Hello' into `baz'.

There is a problem when an output multio is attached to an external program. A simple ex-
ample shows this:

cat file >file1 >file2
cat file1 file2

Here, it is possible that the second `cat' will not display the full contents of file1 and
file2 (i.e. the original contents of file repeated twice).

The reason for this is that the multios are spawned after the cat process is forked from
the parent shell, so the parent shell does not wait for the multios to finish writing
data. This means the command as shown can exit before file1 and file2 are completely
written. As a workaround, it is possible to run the cat process as part of a job in the
current shell:

{ cat file } >file >file2

Here, the {...} job will pause to wait for both files to be written.

REDIRECTIONS WITH NO COMMAND
When a simple command consists of one or more redirection operators and zero or more pa-
rameter assignments, but no command name, zsh can behave in several ways.

If the parameter NULLCMD is not set or the option CSH_NULLCMD is set, an error is caused.
This is the csh behavior and CSH_NULLCMD is set by default when emulating csh.

If the option SH_NULLCMD is set, the builtin `:' is inserted as a command with the given
redirections. This is the default when emulating sh or ksh.

Otherwise, if the parameter NULLCMD is set, its value will be used as a command with the
given redirections. If both NULLCMD and READNULLCMD are set, then the value of the latter
will be used instead of that of the former when the redirection is an input. The default
for NULLCMD is `cat' and for READNULLCMD is `more'. Thus

< file

shows the contents of file on standard output, with paging if that is a terminal. NULLCMD
and READNULLCMD may refer to shell functions.

COMMAND EXECUTION
If a command name contains no slashes, the shell attempts to locate it. If there exists a
shell function by that name, the function is invoked as described in the section `Func-
tions'. If there exists a shell builtin by that name, the builtin is invoked.

Otherwise, the shell searches each element of $path for a directory containing an exe-
cutable file by that name. If the search is unsuccessful, the shell prints an error mes-
sage and returns a nonzero exit status.

If execution fails because the file is not in executable format, and the file is not a di-
rectory, it is assumed to be a shell script. /bin/sh is spawned to execute it. If the
program is a file beginning with `#!', the remainder of the first line specifies an inter-
preter for the program. The shell will execute the specified interpreter on operating
systems that do not handle this executable format in the kernel.

If no external command is found but a function command_not_found_handler exists the shell
executes this function with all command line arguments. The return status of the function
becomes the status of the command. If the function wishes to mimic the behaviour of the
shell when the command is not found, it should print the message `command not found: cmd'
to standard error and return status 127. Note that the handler is executed in a subshell
forked to execute an external command, hence changes to directories, shell parameters,
etc. have no effect on the main shell.

FUNCTIONS
Shell functions are defined with the function reserved word or the special syntax `func-
name ()'. Shell functions are read in and stored internally. Alias names are resolved
when the function is read. Functions are executed like commands with the arguments passed
as positional parameters. (See the section `Command Execution'.)

Functions execute in the same process as the caller and share all files and present work-
ing directory with the caller. A trap on EXIT set inside a function is executed after the
function completes in the environment of the caller.

The return builtin is used to return from function calls.

Function identifiers can be listed with the functions builtin. Functions can be undefined
with the unfunction builtin.

AUTOLOADING FUNCTIONS
A function can be marked as undefined using the autoload builtin (or `functions -u' or
`typeset -fu'). Such a function has no body. When the function is first executed, the
shell searches for its definition using the elements of the fpath variable. Thus to de-
fine functions for autoloading, a typical sequence is:

fpath=(~/myfuncs $fpath)
autoload myfunc1 myfunc2 ...

The usual alias expansion during reading will be suppressed if the autoload builtin or its
equivalent is given the option -U. This is recommended for the use of functions supplied
with the zsh distribution. Note that for functions precompiled with the zcompile builtin
command the flag -U must be provided when the .zwc file is created, as the corresponding
information is compiled into the latter.

For each element in fpath, the shell looks for three possible files, the newest of which
is used to load the definition for the function:

element.zwc
A file created with the zcompile builtin command, which is expected to contain the
definitions for all functions in the directory named element. The file is treated
in the same manner as a directory containing files for functions and is searched
for the definition of the function. If the definition is not found, the search
for a definition proceeds with the other two possibilities described below.

If element already includes a .zwc extension (i.e. the extension was explicitly
given by the user), element is searched for the definition of the function without
comparing its age to that of other files; in fact, there does not need to be any
directory named element without the suffix. Thus including an element such as
`/usr/local/funcs.zwc' in fpath will speed up the search for functions, with the
disadvantage that functions included must be explicitly recompiled by hand before
the shell notices any changes.

element/function.zwc
A file created with zcompile, which is expected to contain the definition for func-
tion. It may include other function definitions as well, but those are neither
loaded nor executed; a file found in this way is searched only for the definition
of function.

element/function
A file of zsh command text, taken to be the definition for function.

In summary, the order of searching is, first, in the parents of directories in fpath for
the newer of either a compiled directory or a directory in fpath; second, if more than one
of these contains a definition for the function that is sought, the leftmost in the fpath
is chosen; and third, within a directory, the newer of either a compiled function or an
ordinary function definition is used.

If the KSH_AUTOLOAD option is set, or the file contains only a simple definition of the
function, the file's contents will be executed. This will normally define the function in
question, but may also perform initialization, which is executed in the context of the
function execution, and may therefore define local parameters. It is an error if the
function is not defined by loading the file.

Otherwise, the function body (with no surrounding `funcname() {...}') is taken to be the
complete contents of the file. This form allows the file to be used directly as an exe-
cutable shell script. If processing of the file results in the function being re-defined,
the function itself is not re-executed. To force the shell to perform initialization and
then call the function defined, the file should contain initialization code (which will be
executed then discarded) in addition to a complete function definition (which will be re-
tained for subsequent calls to the function), and a call to the shell function, including
any arguments, at the end.

For example, suppose the autoload file func contains

func() { print This is func; }
print func is initialized

then `func; func' with KSH_AUTOLOAD set will produce both messages on the first call, but
only the message `This is func' on the second and subsequent calls. Without KSH_AUTOLOAD
set, it will produce the initialization message on the first call, and the other message
on the second and subsequent calls.

It is also possible to create a function that is not marked as autoloaded, but which loads
its own definition by searching fpath, by using `autoload -X' within a shell function.
For example, the following are equivalent:

myfunc() {
autoload -X
}
myfunc args...

and

unfunction myfunc # if myfunc was defined
autoload myfunc
myfunc args...

In fact, the functions command outputs `builtin autoload -X' as the body of an autoloaded
function. This is done so that

eval "$(functions)"

produces a reasonable result. A true autoloaded function can be identified by the pres-
ence of the comment `# undefined' in the body, because all comments are discarded from de-
fined functions.

To load the definition of an autoloaded function myfunc without executing myfunc, use:

autoload +X myfunc

ANONYMOUS FUNCTIONS
If no name is given for a function, it is `anonymous' and is handled specially. Either
form of function definition may be used: a `()' with no preceding name, or a `function'
with an immediately following open brace. The function is executed immediately at the
point of definition and is not stored for future use. The function name is set to
`(anon)'.

Arguments to the function may be specified as words following the closing brace defining
the function, hence if there are none no arguments (other than $0) are set. This is a
difference from the way other functions are parsed: normal function definitions may be
followed by certain keywords such as `else' or `fi', which will be treated as arguments to
anonymous functions, so that a newline or semicolon is needed to force keyword interpreta-
tion.

Note also that the argument list of any enclosing script or function is hidden (as would
be the case for any other function called at this point).

Redirections may be applied to the anonymous function in the same manner as to a cur-
rent-shell structure enclosed in braces. The main use of anonymous functions is to pro-
vide a scope for local variables. This is particularly convenient in start-up files as
these do not provide their own local variable scope.

For example,

variable=outside
function {
local variable=inside
print "I am $variable with arguments $*"
} this and that
print "I am $variable"

outputs the following:

I am inside with arguments this and that
I am outside

Note that function definitions with arguments that expand to nothing, for example `name=;
function $name { ... }', are not treated as anonymous functions. Instead, they are
treated as normal function definitions where the definition is silently discarded.

SPECIAL FUNCTIONS
Certain functions, if defined, have special meaning to the shell.

Hook Functions
For the functions below, it is possible to define an array that has the same name as the
function with `_functions' appended. Any element in such an array is taken as the name of
a function to execute; it is executed in the same context and with the same arguments as
the basic function. For example, if $chpwd_functions is an array containing the values
`mychpwd', `chpwd_save_dirstack', then the shell attempts to execute the functions `ch-
pwd', `mychpwd' and `chpwd_save_dirstack', in that order. Any function that does not ex-
ist is silently ignored. A function found by this mechanism is referred to elsewhere as a
`hook function'. An error in any function causes subsequent functions not to be run.
Note further that an error in a precmd hook causes an immediately following periodic func-
tion not to run (though it may run at the next opportunity).

chpwd Executed whenever the current working directory is changed.

periodic
If the parameter PERIOD is set, this function is executed every $PERIOD seconds,
just before a prompt. Note that if multiple functions are defined using the array
periodic_functions only one period is applied to the complete set of functions, and
the scheduled time is not reset if the list of functions is altered. Hence the set
of functions is always called together.

precmd Executed before each prompt. Note that precommand functions are not re-executed
simply because the command line is redrawn, as happens, for example, when a notifi-
cation about an exiting job is displayed.

preexec
Executed just after a command has been read and is about to be executed. If the
history mechanism is active (regardless of whether the line was discarded from the
history buffer), the string that the user typed is passed as the first argument,
otherwise it is an empty string. The actual command that will be executed (includ-
ing expanded aliases) is passed in two different forms: the second argument is a
single-line, size-limited version of the command (with things like function bodies
elided); the third argument contains the full text that is being executed.

zshaddhistory
Executed when a history line has been read interactively, but before it is exe-
cuted. The sole argument is the complete history line (so that any terminating
newline will still be present).

If any of the hook functions returns status 1 (or any non-zero value other than 2,
though this is not guaranteed for future versions of the shell) the history line
will not be saved, although it lingers in the history until the next line is exe-
cuted, allowing you to reuse or edit it immediately.

If any of the hook functions returns status 2 the history line will be saved on the
internal history list, but not written to the history file. In case of a conflict,
the first non-zero status value is taken.

A hook function may call `fc -p ...' to switch the history context so that the his-
tory is saved in a different file from the that in the global HISTFILE parameter.
This is handled specially: the history context is automatically restored after the
processing of the history line is finished.

The following example function works with one of the options INC_APPEND_HISTORY or
SHARE_HISTORY set, in order that the line is written out immediately after the his-
tory entry is added. It first adds the history line to the normal history with the
newline stripped, which is usually the correct behaviour. Then it switches the
history context so that the line will be written to a history file in the current
directory.

zshaddhistory() {
print -sr -- ${1%%$'\n'}
fc -p .zsh_local_history
}

zshexit
Executed at the point where the main shell is about to exit normally. This is not
called by exiting subshells, nor when the exec precommand modifier is used before
an external command. Also, unlike TRAPEXIT, it is not called when functions exit.

Trap Functions
The functions below are treated specially but do not have corresponding hook arrays.

TRAPNAL
If defined and non-null, this function will be executed whenever the shell catches
a signal SIGNAL, where NAL is a signal name as specified for the kill builtin. The
signal number will be passed as the first parameter to the function.

If a function of this form is defined and null, the shell and processes spawned by
it will ignore SIGNAL.

The return status from the function is handled specially. If it is zero, the sig-
nal is assumed to have been handled, and execution continues normally. Otherwise,
the shell will behave as interrupted except that the return status of the trap is
retained.

Programs terminated by uncaught signals typically return the status 128 plus the
signal number. Hence the following causes the handler for SIGINT to print a mes-
sage, then mimic the usual effect of the signal.

TRAPINT() {
print "Caught SIGINT, aborting."
return $(( 128 + $1 ))
}

The functions TRAPZERR, TRAPDEBUG and TRAPEXIT are never executed inside other
traps.

TRAPDEBUG
If the option DEBUG_BEFORE_CMD is set (as it is by default), executed before each
command; otherwise executed after each command. See the description of the trap
builtin in zshbuiltins(1) for details of additional features provided in debug
traps.

TRAPEXIT
Executed when the shell exits, or when the current function exits if defined inside
a function. The value of $? at the start of execution is the exit status of the
shell or the return status of the function exiting.

TRAPZERR
Executed whenever a command has a non-zero exit status. However, the function is
not executed if the command occurred in a sublist followed by `&&' or `||'; only
the final command in a sublist of this type causes the trap to be executed. The
function TRAPERR acts the same as TRAPZERR on systems where there is no SIGERR
(this is the usual case).

The functions beginning `TRAP' may alternatively be defined with the trap builtin: this
may be preferable for some uses. Setting a trap with one form removes any trap of the
other form for the same signal; removing a trap in either form removes all traps for the
same signal. The forms

TRAPNAL() {
# code
}

('function traps') and

trap '
# code
' NAL

('list traps') are equivalent in most ways, the exceptions being the following:

o Function traps have all the properties of normal functions, appearing in the list
of functions and being called with their own function context rather than the con-
text where the trap was triggered.

o The return status from function traps is special, whereas a return from a list trap
causes the surrounding context to return with the given status.

o Function traps are not reset within subshells, in accordance with zsh behaviour;
list traps are reset, in accordance with POSIX behaviour.

JOBS
If the MONITOR option is set, an interactive shell associates a job with each pipeline.
It keeps a table of current jobs, printed by the jobs command, and assigns them small in-
teger numbers. When a job is started asynchronously with `&', the shell prints a line to
standard error which looks like:

[1] 1234

indicating that the job which was started asynchronously was job number 1 and had one
(top-level) process, whose process ID was 1234.

If a job is started with `&|' or `&!', then that job is immediately disowned. After
startup, it does not have a place in the job table, and is not subject to the job control
features described here.

If you are running a job and wish to do something else you may hit the key ^Z (control-Z)
which sends a TSTP signal to the current job: this key may be redefined by the susp op-
tion of the external stty command. The shell will then normally indicate that the job has
been `suspended', and print another prompt. You can then manipulate the state of this
job, putting it in the background with the bg command, or run some other commands and then
eventually bring the job back into the foreground with the foreground command fg. A ^Z
takes effect immediately and is like an interrupt in that pending output and unread input
are discarded when it is typed.

A job being run in the background will suspend if it tries to read from the terminal.

Note that if the job running in the foreground is a shell function, then suspending it
will have the effect of causing the shell to fork. This is necessary to separate the
function's state from that of the parent shell performing the job control, so that the
latter can return to the command line prompt. As a result, even if fg is used to continue
the job the function will no longer be part of the parent shell, and any variables set by
the function will not be visible in the parent shell. Thus the behaviour is different
from the case where the function was never suspended. Zsh is different from many other
shells in this regard.

One additional side effect is that use of disown with a job created by suspending shell
code in this fashion is delayed: the job can only be disowned once any process started
from the parent shell has terminated. At that point, the disowned job disappears silently
from the job list.

The same behaviour is found when the shell is executing code as the right hand side of a
pipeline or any complex shell construct such as if, for, etc., in order that the entire
block of code can be managed as a single job. Background jobs are normally allowed to
produce output, but this can be disabled by giving the command `stty tostop'. If you set
this tty option, then background jobs will suspend when they try to produce output like
they do when they try to read input.

When a command is suspended and continued later with the fg or wait builtins, zsh restores
tty modes that were in effect when it was suspended. This (intentionally) does not apply
if the command is continued via `kill -CONT', nor when it is continued with bg.

There are several ways to refer to jobs in the shell. A job can be referred to by the
process ID of any process of the job or by one of the following:

%number
The job with the given number.
%string
The last job whose command line begins with string.
%?string
The last job whose command line contains string.
%% Current job.
%+ Equivalent to `%%'.
%- Previous job.

The shell learns immediately whenever a process changes state. It normally informs you
whenever a job becomes blocked so that no further progress is possible. If the NOTIFY op-
tion is not set, it waits until just before it prints a prompt before it informs you. All
such notifications are sent directly to the terminal, not to the standard output or stan-
dard error.

When the monitor mode is on, each background job that completes triggers any trap set for
CHLD.

When you try to leave the shell while jobs are running or suspended, you will be warned
that `You have suspended (running) jobs'. You may use the jobs command to see what they
are. If you do this or immediately try to exit again, the shell will not warn you a sec-
ond time; the suspended jobs will be terminated, and the running jobs will be sent a
SIGHUP signal, if the HUP option is set.

To avoid having the shell terminate the running jobs, either use the nohup command (see
nohup(1)) or the disown builtin.

SIGNALS
The INT and QUIT signals for an invoked command are ignored if the command is followed by
`&' and the MONITOR option is not active. The shell itself always ignores the QUIT sig-
nal. Otherwise, signals have the values inherited by the shell from its parent (but see
the TRAPNAL special functions in the section `Functions').

Certain jobs are run asynchronously by the shell other than those explicitly put into the
background; even in cases where the shell would usually wait for such jobs, an explicit
exit command or exit due to the option ERR_EXIT will cause the shell to exit without wait-
ing. Examples of such asynchronous jobs are process substitution, see the section PROCESS
SUBSTITUTION in the zshexpn(1) manual page, and the handler processes for multios, see the
section MULTIOS in the zshmisc(1) manual page.

ARITHMETIC EVALUATION
The shell can perform integer and floating point arithmetic, either using the builtin let,
or via a substitution of the form $((...)). For integers, the shell is usually compiled
to use 8-byte precision where this is available, otherwise precision is 4 bytes. This can
be tested, for example, by giving the command `print - $(( 12345678901 ))'; if the number
appears unchanged, the precision is at least 8 bytes. Floating point arithmetic always
uses the `double' type with whatever corresponding precision is provided by the compiler
and the library.

The let builtin command takes arithmetic expressions as arguments; each is evaluated sepa-
rately. Since many of the arithmetic operators, as well as spaces, require quoting, an
alternative form is provided: for any command which begins with a `((', all the characters
until a matching `))' are treated as a quoted expression and arithmetic expansion per-
formed as for an argument of let. More precisely, `((...))' is equivalent to `let "..."'.
The return status is 0 if the arithmetic value of the expression is non-zero, 1 if it is
zero, and 2 if an error occurred.

For example, the following statement

(( val = 2 + 1 ))

is equivalent to

let "val = 2 + 1"

both assigning the value 3 to the shell variable val and returning a zero status.

Integers can be in bases other than 10. A leading `0x' or `0X' denotes hexadecimal and a
leading `0b' or `0B' binary. Integers may also be of the form `base#n', where base is a
decimal number between two and thirty-six representing the arithmetic base and n is a num-
ber in that base (for example, `16#ff' is 255 in hexadecimal). The base# may also be
omitted, in which case base 10 is used. For backwards compatibility the form `[base]n' is
also accepted.

An integer expression or a base given in the form `base#n' may contain underscores (`_')
after the leading digit for visual guidance; these are ignored in computation. Examples
are 1_000_000 or 0xffff_ffff which are equivalent to 1000000 and 0xffffffff respectively.

It is also possible to specify a base to be used for output in the form `[#base]', for ex-
ample `[#16]'. This is used when outputting arithmetical substitutions or when assigning
to scalar parameters, but an explicitly defined integer or floating point parameter will
not be affected. If an integer variable is implicitly defined by an arithmetic expres-
sion, any base specified in this way will be set as the variable's output arithmetic base
as if the option `-i base' to the typeset builtin had been used. The expression has no
precedence and if it occurs more than once in a mathematical expression, the last encoun-
tered is used. For clarity it is recommended that it appear at the beginning of an ex-
pression. As an example:

typeset -i 16 y
print $(( [#8] x = 32, y = 32 ))
print $x $y

outputs first `8#40', the rightmost value in the given output base, and then `8#40 16#20',
because y has been explicitly declared to have output base 16, while x (assuming it does
not already exist) is implicitly typed by the arithmetic evaluation, where it acquires the
output base 8.

The base may be replaced or followed by an underscore, which may itself be followed by a
positive integer (if it is missing the value 3 is used). This indicates that underscores
should be inserted into the output string, grouping the number for visual clarity. The
following integer specifies the number of digits to group together. For example:

setopt cbases
print $(( [#16_4] 65536 ** 2 ))

outputs `0x1_0000_0000'.

The feature can be used with floating point numbers, in which case the base must be omit-
ted; grouping is away from the decimal point. For example,

zmodload zsh/mathfunc
print $(( [#_] sqrt(1e7) ))

outputs `3_162.277_660_168_379_5' (the number of decimal places shown may vary).

If the C_BASES option is set, hexadecimal numbers are output in the standard C format, for
example `0xFF' instead of the usual `16#FF'. If the option OCTAL_ZEROES is also set (it
is not by default), octal numbers will be treated similarly and hence appear as `077' in-
stead of `8#77'. This option has no effect on the output of bases other than hexadecimal
and octal, and these formats are always understood on input.

When an output base is specified using the `[#base]' syntax, an appropriate base prefix
will be output if necessary, so that the value output is valid syntax for input. If the #
is doubled, for example `[##16]', then no base prefix is output.

Floating point constants are recognized by the presence of a decimal point or an exponent.
The decimal point may be the first character of the constant, but the exponent character e
or E may not, as it will be taken for a parameter name. All numeric parts (before and af-
ter the decimal point and in the exponent) may contain underscores after the leading digit
for visual guidance; these are ignored in computation.

An arithmetic expression uses nearly the same syntax and associativity of expressions as
in C.

In the native mode of operation, the following operators are supported (listed in decreas-
ing order of precedence):

+ - ! ~ ++ --
unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement
<< >> bitwise shift left, right
& bitwise AND
^ bitwise XOR
| bitwise OR
** exponentiation
* / % multiplication, division, modulus (remainder)
+ - addition, subtraction
< > <= >=
comparison
== != equality and inequality
&& logical AND
|| ^^ logical OR, XOR
? : ternary operator
= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
assignment
, comma operator

The operators `&&', `||', `&&=', and `||=' are short-circuiting, and only one of the lat-
ter two expressions in a ternary operator is evaluated. Note the precedence of the bit-
wise AND, OR, and XOR operators.

With the option C_PRECEDENCES the precedences (but no other properties) of the operators
are altered to be the same as those in most other languages that support the relevant op-
erators:

+ - ! ~ ++ --
unary plus/minus, logical NOT, complement, {pre,post}{in,de}crement
** exponentiation
* / % multiplication, division, modulus (remainder)
+ - addition, subtraction
<< >> bitwise shift left, right
< > <= >=
comparison
== != equality and inequality
& bitwise AND
^ bitwise XOR
| bitwise OR
&& logical AND
^^ logical XOR
|| logical OR
? : ternary operator
= += -= *= /= %= &= ^= |= <<= >>= &&= ||= ^^= **=
assignment
, comma operator

Note the precedence of exponentiation in both cases is below that of unary operators,
hence `-3**2' evaluates as `9', not `-9'. Use parentheses where necessary: `-(3**2)'.
This is for compatibility with other shells.

Mathematical functions can be called with the syntax `func(args)', where the function de-
cides if the args is used as a string or a comma-separated list of arithmetic expressions.
The shell currently defines no mathematical functions by default, but the module zsh/math-
func may be loaded with the zmodload builtin to provide standard floating point mathemati-
cal functions.

An expression of the form `##x' where x is any character sequence such as `a', `^A', or
`\M-\C-x' gives the value of this character and an expression of the form `#name' gives
the value of the first character of the contents of the parameter name. Character values
are according to the character set used in the current locale; for multibyte character
handling the option MULTIBYTE must be set. Note that this form is different from
`$#name', a standard parameter substitution which gives the length of the parameter name.
`#\' is accepted instead of `##', but its use is deprecated.

Named parameters and subscripted arrays can be referenced by name within an arithmetic ex-
pression without using the parameter expansion syntax. For example,

((val2 = val1 * 2))

assigns twice the value of $val1 to the parameter named val2.

An internal integer representation of a named parameter can be specified with the integer
builtin. Arithmetic evaluation is performed on the value of each assignment to a named
parameter declared integer in this manner. Assigning a floating point number to an inte-
ger results in rounding towards zero.

Likewise, floating point numbers can be declared with the float builtin; there are two
types, differing only in their output format, as described for the typeset builtin. The
output format can be bypassed by using arithmetic substitution instead of the parameter
substitution, i.e. `${float}' uses the defined format, but `$((float))' uses a generic
floating point format.

Promotion of integer to floating point values is performed where necessary. In addition,
if any operator which requires an integer (`&', `|', `^', `<<', `>>' and their equivalents
with assignment) is given a floating point argument, it will be silently rounded towards
zero except for `~' which rounds down.

Users should beware that, in common with many other programming languages but not software
designed for calculation, the evaluation of an expression in zsh is taken a term at a time
and promotion of integers to floating point does not occur in terms only containing inte-
gers. A typical result of this is that a division such as 6/8 is truncated, in this being
rounded towards 0. The FORCE_FLOAT shell option can be used in scripts or functions where
floating point evaluation is required throughout.

Scalar variables can hold integer or floating point values at different times; there is no
memory of the numeric type in this case.

If a variable is first assigned in a numeric context without previously being declared, it
will be implicitly typed as integer or float and retain that type either until the type is
explicitly changed or until the end of the scope. This can have unforeseen consequences.
For example, in the loop

for (( f = 0; f < 1; f += 0.1 )); do
# use $f
done

if f has not already been declared, the first assignment will cause it to be created as an
integer, and consequently the operation `f += 0.1' will always cause the result to be
truncated to zero, so that the loop will fail. A simple fix would be to turn the initial-
ization into `f = 0.0'. It is therefore best to declare numeric variables with explicit
types.

CONDITIONAL EXPRESSIONS
A conditional expression is used with the [[ compound command to test attributes of files
and to compare strings. Each expression can be constructed from one or more of the fol-
lowing unary or binary expressions:

-a file
true if file exists.

-b file
true if file exists and is a block special file.

-c file
true if file exists and is a character special file.

-d file
true if file exists and is a directory.

-e file
true if file exists.

-f file
true if file exists and is a regular file.

-g file
true if file exists and has its setgid bit set.

-h file
true if file exists and is a symbolic link.

-k file
true if file exists and has its sticky bit set.

-n string
true if length of string is non-zero.

-o option
true if option named option is on. option may be a single character, in which case
it is a single letter option name. (See the section `Specifying Options'.)

When no option named option exists, and the POSIX_BUILTINS option hasn't been set,
return 3 with a warning. If that option is set, return 1 with no warning.

-p file
true if file exists and is a FIFO special file (named pipe).

-r file
true if file exists and is readable by current process.

-s file
true if file exists and has size greater than zero.

-t fd true if file descriptor number fd is open and associated with a terminal device.
(note: fd is not optional)

-u file
true if file exists and has its setuid bit set.

-v varname
true if shell variable varname is set.

-w file
true if file exists and is writable by current process.

-x file
true if file exists and is executable by current process. If file exists and is a
directory, then the current process has permission to search in the directory.

-z string
true if length of string is zero.

-L file
true if file exists and is a symbolic link.

-O file
true if file exists and is owned by the effective user ID of this process.

-G file
true if file exists and its group matches the effective group ID of this process.

-S file
true if file exists and is a socket.

-N file
true if file exists and its access time is not newer than its modification time.

file1 -nt file2
true if file1 exists and is newer than file2.

file1 -ot file2
true if file1 exists and is older than file2.

file1 -ef file2
true if file1 and file2 exist and refer to the same file.

string = pattern
string == pattern
true if string matches pattern. The two forms are exactly equivalent. The `='
form is the traditional shell syntax (and hence the only one generally used with
the test and [ builtins); the `==' form provides compatibility with other sorts of
computer language.

string != pattern
true if string does not match pattern.

string =~ regexp
true if string matches the regular expression regexp. If the option RE_MATCH_PCRE
is set regexp is tested as a PCRE regular expression using the zsh/pcre module,
else it is tested as a POSIX extended regular expression using the zsh/regex mod-
ule. Upon successful match, some variables will be updated; no variables are
changed if the matching fails.

If the option BASH_REMATCH is not set the scalar parameter MATCH is set to the sub-
string that matched the pattern and the integer parameters MBEGIN and MEND to the
index of the start and end, respectively, of the match in string, such that if
string is contained in variable var the expression `${var[$MBEGIN,$MEND]}' is iden-
tical to `$MATCH'. The setting of the option KSH_ARRAYS is respected. Likewise,
the array match is set to the substrings that matched parenthesised subexpressions
and the arrays mbegin and mend to the indices of the start and end positions, re-
spectively, of the substrings within string. The arrays are not set if there were
no parenthesised subexpressions. For example, if the string `a short string' is
matched against the regular expression `s(...)t', then (assuming the option KSH_AR-
RAYS is not set) MATCH, MBEGIN and MEND are `short', 3 and 7, respectively, while
match, mbegin and mend are single entry arrays containing the strings `hor', `4'
and `6', respectively.

If the option BASH_REMATCH is set the array BASH_REMATCH is set to the substring
that matched the pattern followed by the substrings that matched parenthesised sub-
expressions within the pattern.

string1 < string2
true if string1 comes before string2 based on ASCII value of their characters.

string1 > string2
true if string1 comes after string2 based on ASCII value of their characters.

exp1 -eq exp2
true if exp1 is numerically equal to exp2. Note that for purely numeric compar-
isons use of the ((...)) builtin described in the section `ARITHMETIC EVALUATION'
is more convenient than conditional expressions.

exp1 -ne exp2
true if exp1 is numerically not equal to exp2.

exp1 -lt exp2
true if exp1 is numerically less than exp2.

exp1 -gt exp2
true if exp1 is numerically greater than exp2.

exp1 -le exp2
true if exp1 is numerically less than or equal to exp2.

exp1 -ge exp2
true if exp1 is numerically greater than or equal to exp2.

( exp )
true if exp is true.

! exp true if exp is false.

exp1 && exp2
true if exp1 and exp2 are both true.

exp1 || exp2
true if either exp1 or exp2 is true.

For compatibility, if there is a single argument that is not syntactically significant,
typically a variable, the condition is treated as a test for whether the expression ex-
pands as a string of non-zero length. In other words, [[ $var ]] is the same as [[ -n
$var ]]. It is recommended that the second, explicit, form be used where possible.

Normal shell expansion is performed on the file, string and pattern arguments, but the re-
sult of each expansion is constrained to be a single word, similar to the effect of double
quotes.

Filename generation is not performed on any form of argument to conditions. However, it
can be forced in any case where normal shell expansion is valid and when the option EX-
TENDED_GLOB is in effect by using an explicit glob qualifier of the form (#q) at the end
of the string. A normal glob qualifier expression may appear between the `q' and the
closing parenthesis; if none appears the expression has no effect beyond causing filename
generation. The results of filename generation are joined together to form a single word,
as with the results of other forms of expansion.

This special use of filename generation is only available with the [[ syntax. If the con-
dition occurs within the [ or test builtin commands then globbing occurs instead as part
of normal command line expansion before the condition is evaluated. In this case it may
generate multiple words which are likely to confuse the syntax of the test command.

For example,

[[ -n file*(#qN) ]]

produces status zero if and only if there is at least one file in the current directory
beginning with the string `file'. The globbing qualifier N ensures that the expression is
empty if there is no matching file.

Pattern metacharacters are active for the pattern arguments; the patterns are the same as
those used for filename generation, see zshexpn(1), but there is no special behaviour of
`/' nor initial dots, and no glob qualifiers are allowed.

In each of the above expressions, if file is of the form `/dev/fd/n', where n is an inte-
ger, then the test applied to the open file whose descriptor number is n, even if the un-
derlying system does not support the /dev/fd directory.

In the forms which do numeric comparison, the expressions exp undergo arithmetic expansion
as if they were enclosed in $((...)).

For example, the following:

[[ ( -f foo || -f bar ) && $report = y* ]] && print File exists.

tests if either file foo or file bar exists, and if so, if the value of the parameter re-
port begins with `y'; if the complete condition is true, the message `File exists.' is
printed.

EXPANSION OF PROMPT SEQUENCES
Prompt sequences undergo a special form of expansion. This type of expansion is also
available using the -P option to the print builtin.

If the PROMPT_SUBST option is set, the prompt string is first subjected to parameter ex-
pansion, command substitution and arithmetic expansion. See zshexpn(1).

Certain escape sequences may be recognised in the prompt string.

If the PROMPT_BANG option is set, a `!' in the prompt is replaced by the current history
event number. A literal `!' may then be represented as `!!'.

If the PROMPT_PERCENT option is set, certain escape sequences that start with `%' are ex-
panded. Many escapes are followed by a single character, although some of these take an
optional integer argument that should appear between the `%' and the next character of the
sequence. More complicated escape sequences are available to provide conditional expan-
sion.

SIMPLE PROMPT ESCAPES
Special characters
%% A `%'.

%) A `)'.

Login information
%l The line (tty) the user is logged in on, without `/dev/' prefix. If the name
starts with `/dev/tty', that prefix is stripped.

%M The full machine hostname.

%m The hostname up to the first `.'. An integer may follow the `%' to specify how
many components of the hostname are desired. With a negative integer, trailing
components of the hostname are shown.

%n $USERNAME.

%y The line (tty) the user is logged in on, without `/dev/' prefix. This does not
treat `/dev/tty' names specially.

Shell state
%# A `#' if the shell is running with privileges, a `%' if not. Equivalent to
`%(!.#.%%)'. The definition of `privileged', for these purposes, is that either
the effective user ID is zero, or, if POSIX.1e capabilities are supported, that at
least one capability is raised in either the Effective or Inheritable capability
vectors.

%? The return status of the last command executed just before the prompt.

%_ The status of the parser, i.e. the shell constructs (like `if' and `for') that have
been started on the command line. If given an integer number that many strings will
be printed; zero or negative or no integer means print as many as there are. This
is most useful in prompts PS2 for continuation lines and PS4 for debugging with the
XTRACE option; in the latter case it will also work non-interactively.

%^ The status of the parser in reverse. This is the same as `%_' other than the order
of strings. It is often used in RPS2.

%d
%/ Current working directory. If an integer follows the `%', it specifies a number of
trailing components of the current working directory to show; zero means the whole
path. A negative integer specifies leading components, i.e. %-1d specifies the
first component.

%~ As %d and %/, but if the current working directory starts with $HOME, that part is
replaced by a `~'. Furthermore, if it has a named directory as its prefix, that
part is replaced by a `~' followed by the name of the directory, but only if the
result is shorter than the full path; see Dynamic and Static named directories in
zshexpn(1).

%e Evaluation depth of the current sourced file, shell function, or eval. This is in-
cremented or decremented every time the value of %N is set or reverted to a previ-
ous value, respectively. This is most useful for debugging as part of $PS4.

%h
%! Current history event number.

%i The line number currently being executed in the script, sourced file, or shell
function given by %N. This is most useful for debugging as part of $PS4.

%I The line number currently being executed in the file %x. This is similar to %i,
but the line number is always a line number in the file where the code was defined,
even if the code is a shell function.

%j The number of jobs.

%L The current value of $SHLVL.

%N The name of the script, sourced file, or shell function that zsh is currently exe-
cuting, whichever was started most recently. If there is none, this is equivalent
to the parameter $0. An integer may follow the `%' to specify a number of trailing
path components to show; zero means the full path. A negative integer specifies
leading components.

%x The name of the file containing the source code currently being executed. This be-
haves as %N except that function and eval command names are not shown, instead the
file where they were defined.

%c
%.
%C Trailing component of the current working directory. An integer may follow the `%'
to get more than one component. Unless `%C' is used, tilde contraction is per-
formed first. These are deprecated as %c and %C are equivalent to %1~ and %1/, re-
spectively, while explicit positive integers have the same effect as for the latter
two sequences.

Date and time
%D The date in yy-mm-dd format.

%T Current time of day, in 24-hour format.

%t
%@ Current time of day, in 12-hour, am/pm format.

%* Current time of day in 24-hour format, with seconds.

%w The date in day-dd format.

%W The date in mm/dd/yy format.

%D{string}
string is formatted using the strftime function. See strftime(3) for more details.
Various zsh extensions provide numbers with no leading zero or space if the number
is a single digit:

%f a day of the month
%K the hour of the day on the 24-hour clock
%L the hour of the day on the 12-hour clock

In addition, if the system supports the POSIX gettimeofday system call, %. provides
decimal fractions of a second since the epoch with leading zeroes. By default
three decimal places are provided, but a number of digits up to 9 may be given fol-
lowing the %; hence %6. outputs microseconds, and %9. outputs nanoseconds. (The
latter requires a nanosecond-precision clock_gettime; systems lacking this will re-
turn a value multiplied by the appropriate power of 10.) A typical example of this
is the format `%D{%H:%M:%S.%.}'.

The GNU extension %N is handled as a synonym for %9..

Additionally, the GNU extension that a `-' between the % and the format character
causes a leading zero or space to be stripped is handled directly by the shell for
the format characters d, f, H, k, l, m, M, S and y; any other format characters are
provided to the system's strftime(3) with any leading `-' present, so the handling
is system dependent. Further GNU (or other) extensions are also passed to strf-
time(3) and may work if the system supports them.

Visual effects
%B (%b)
Start (stop) boldface mode.

%E Clear to end of line.

%U (%u)
Start (stop) underline mode.

%S (%s)
Start (stop) standout mode.

%F (%f)
Start (stop) using a different foreground colour, if supported by the terminal.
The colour may be specified two ways: either as a numeric argument, as normal, or
by a sequence in braces following the %F, for example %F{red}. In the latter case
the values allowed are as described for the fg zle_highlight attribute; see Charac-
ter Highlighting in zshzle(1). This means that numeric colours are allowed in the
second format also.

%K (%k)
Start (stop) using a different bacKground colour. The syntax is identical to that
for %F and %f.

%{...%}
Include a string as a literal escape sequence. The string within the braces should
not change the cursor position. Brace pairs can nest.

A positive numeric argument between the % and the { is treated as described for %G
below.

%G Within a %{...%} sequence, include a `glitch': that is, assume that a single char-
acter width will be output. This is useful when outputting characters that other-
wise cannot be correctly handled by the shell, such as the alternate character set
on some terminals. The characters in question can be included within a %{...%} se-
quence together with the appropriate number of %G sequences to indicate the correct
width. An integer between the `%' and `G' indicates a character width other than
one. Hence %{seq%2G%} outputs seq and assumes it takes up the width of two stan-
dard characters.

Multiple uses of %G accumulate in the obvious fashion; the position of the %G is
unimportant. Negative integers are not handled.

Note that when prompt truncation is in use it is advisable to divide up output into
single characters within each %{...%} group so that the correct truncation point
can be found.

CONDITIONAL SUBSTRINGS IN PROMPTS
%v The value of the first element of the psvar array parameter. Following the `%'
with an integer gives that element of the array. Negative integers count from the
end of the array.

%(x.true-text.false-text)
Specifies a ternary expression. The character following the x is arbitrary; the
same character is used to separate the text for the `true' result from that for the
`false' result. This separator may not appear in the true-text, except as part of
a %-escape sequence. A `)' may appear in the false-text as `%)'. true-text and
false-text may both contain arbitrarily-nested escape sequences, including further
ternary expressions.

The left parenthesis may be preceded or followed by a positive integer n, which de-
faults to zero. A negative integer will be multiplied by -1, except as noted below
for `l'. The test character x may be any of the following:

! True if the shell is running with privileges.
# True if the effective uid of the current process is n.
? True if the exit status of the last command was n.
_ True if at least n shell constructs were started.
C
/ True if the current absolute path has at least n elements relative to the
root directory, hence / is counted as 0 elements.
c
.
~ True if the current path, with prefix replacement, has at least n elements
relative to the root directory, hence / is counted as 0 elements.
D True if the month is equal to n (January = 0).
d True if the day of the month is equal to n.
e True if the evaluation depth is at least n.
g True if the effective gid of the current process is n.
j True if the number of jobs is at least n.
L True if the SHLVL parameter is at least n.
l True if at least n characters have already been printed on the current line.
When n is negative, true if at least abs(n) characters remain before the op-
posite margin (thus the left margin for RPROMPT).
S True if the SECONDS parameter is at least n.
T True if the time in hours is equal to n.
t True if the time in minutes is equal to n.
v True if the array psvar has at least n elements.
V True if element n of the array psvar is set and non-empty.
w True if the day of the week is equal to n (Sunday = 0).

%<string<
%>string>
%[xstring]
Specifies truncation behaviour for the remainder of the prompt string. The third,
deprecated, form is equivalent to `%xstringx', i.e. x may be `<' or `>'. The
string will be displayed in place of the truncated portion of any string; note this
does not undergo prompt expansion.

The numeric argument, which in the third form may appear immediately after the `[',
specifies the maximum permitted length of the various strings that can be displayed
in the prompt. In the first two forms, this numeric argument may be negative, in
which case the truncation length is determined by subtracting the absolute value of
the numeric argument from the number of character positions remaining on the cur-
rent prompt line. If this results in a zero or negative length, a length of 1 is
used. In other words, a negative argument arranges that after truncation at least
n characters remain before the right margin (left margin for RPROMPT).

The forms with `<' truncate at the left of the string, and the forms with `>' trun-
cate at the right of the string. For example, if the current directory is
`/home/pike', the prompt `%8<..<%/' will expand to `..e/pike'. In this string, the
terminating character (`<', `>' or `]'), or in fact any character, may be quoted by
a preceding `\'; note when using print -P, however, that this must be doubled as
the string is also subject to standard print processing, in addition to any back-
slashes removed by a double quoted string: the worst case is therefore `print -P
"%<\\\\<<..."'.

If the string is longer than the specified truncation length, it will appear in
full, completely replacing the truncated string.

The part of the prompt string to be truncated runs to the end of the string, or to
the end of the next enclosing group of the `%(' construct, or to the next trunca-
tion encountered at the same grouping level (i.e. truncations inside a `%(' are
separate), which ever comes first. In particular, a truncation with argument zero
(e.g., `%<<') marks the end of the range of the string to be truncated while turn-
ing off truncation from there on. For example, the prompt `%10<...<%~%<<%# ' will
print a truncated representation of the current directory, followed by a `%' or
`#', followed by a space. Without the `%<<', those two characters would be in-
cluded in the string to be truncated. Note that `%-0<<' is not equivalent to `%<<'
but specifies that the prompt is truncated at the right margin.

Truncation applies only within each individual line of the prompt, as delimited by
embedded newlines (if any). If the total length of any line of the prompt after
truncation is greater than the terminal width, or if the part to be truncated con-
tains embedded newlines, truncation behavior is undefined and may change in a fu-
ture version of the shell. Use `%-n(l.true-text.false-text)' to remove parts of
the prompt when the available space is less than n.

ZSHEXPN(1) General Commands Manual ZSHEXPN(1)

NAME
zshexpn - zsh expansion and substitution

DESCRIPTION
The following types of expansions are performed in the indicated order in five steps:

History Expansion
This is performed only in interactive shells.

Alias Expansion
Aliases are expanded immediately before the command line is parsed as explained un-
der Aliasing in zshmisc(1).

Process Substitution
Parameter Expansion
Command Substitution
Arithmetic Expansion
Brace Expansion
These five are performed in left-to-right fashion. On each argument, any of the
five steps that are needed are performed one after the other. Hence, for example,
all the parts of parameter expansion are completed before command substitution is
started. After these expansions, all unquoted occurrences of the characters
`\',`'' and `"' are removed.

Filename Expansion
If the SH_FILE_EXPANSION option is set, the order of expansion is modified for com-
patibility with sh and ksh. In that case filename expansion is performed immedi-
ately after alias expansion, preceding the set of five expansions mentioned above.

Filename Generation
This expansion, commonly referred to as globbing, is always done last.

The following sections explain the types of expansion in detail.

HISTORY EXPANSION
History expansion allows you to use words from previous command lines in the command line
you are typing. This simplifies spelling corrections and the repetition of complicated
commands or arguments.

Immediately before execution, each command is saved in the history list, the size of which
is controlled by the HISTSIZE parameter. The one most recent command is always retained
in any case. Each saved command in the history list is called a history event and is as-
signed a number, beginning with 1 (one) when the shell starts up. The history number that
you may see in your prompt (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)) is the number
that is to be assigned to the next command.

Overview
A history expansion begins with the first character of the histchars parameter, which is
`!' by default, and may occur anywhere on the command line, including inside double quotes
(but not inside single quotes '...' or C-style quotes $'...' nor when escaped with a back-
slash).

The first character is followed by an optional event designator (see the section `Event
Designators') and then an optional word designator (the section `Word Designators'); if
neither of these designators is present, no history expansion occurs.

Input lines containing history expansions are echoed after being expanded, but before any
other expansions take place and before the command is executed. It is this expanded form
that is recorded as the history event for later references.

History expansions do not nest.

By default, a history reference with no event designator refers to the same event as any
preceding history reference on that command line; if it is the only history reference in a
command, it refers to the previous command. However, if the option CSH_JUNKIE_HISTORY is
set, then every history reference with no event specification always refers to the previ-
ous command.

For example, `!' is the event designator for the previous command, so `!!:1' always refers
to the first word of the previous command, and `!!$' always refers to the last word of the
previous command. With CSH_JUNKIE_HISTORY set, then `!:1' and `!$' function in the same
manner as `!!:1' and `!!$', respectively. Conversely, if CSH_JUNKIE_HISTORY is unset,
then `!:1' and `!$' refer to the first and last words, respectively, of the same event
referenced by the nearest other history reference preceding them on the current command
line, or to the previous command if there is no preceding reference.

The character sequence `^foo^bar' (where `^' is actually the second character of the
histchars parameter) repeats the last command, replacing the string foo with bar. More
precisely, the sequence `^foo^bar^' is synonymous with `!!:s^foo^bar^', hence other modi-
fiers (see the section `Modifiers') may follow the final `^'. In particular,
`^foo^bar^:G' performs a global substitution.

If the shell encounters the character sequence `!"' in the input, the history mechanism is
temporarily disabled until the current list (see zshmisc(1)) is fully parsed. The `!"' is
removed from the input, and any subsequent `!' characters have no special significance.

A less convenient but more comprehensible form of command history support is provided by
the fc builtin.

Event Designators
An event designator is a reference to a command-line entry in the history list. In the
list below, remember that the initial `!' in each item may be changed to another character
by setting the histchars parameter.

! Start a history expansion, except when followed by a blank, newline, `=' or `('.
If followed immediately by a word designator (see the section `Word Designators'),
this forms a history reference with no event designator (see the section `Over-
view').

!! Refer to the previous command. By itself, this expansion repeats the previous com-
mand.

!n Refer to command-line n.

!-n Refer to the current command-line minus n.

!str Refer to the most recent command starting with str.

!?str[?]
Refer to the most recent command containing str. The trailing `?' is necessary if
this reference is to be followed by a modifier or followed by any text that is not
to be considered part of str.

!# Refer to the current command line typed in so far. The line is treated as if it
were complete up to and including the word before the one with the `!#' reference.

!{...} Insulate a history reference from adjacent characters (if necessary).

Word Designators
A word designator indicates which word or words of a given command line are to be included
in a history reference. A `:' usually separates the event specification from the word
designator. It may be omitted only if the word designator begins with a `^', `$', `*',
`-' or `%'. Word designators include:

0 The first input word (command).
n The nth argument.
^ The first argument. That is, 1.
$ The last argument.
% The word matched by (the most recent) ?str search.
x-y A range of words; x defaults to 0.
* All the arguments, or a null value if there are none.
x* Abbreviates `x-$'.
x- Like `x*' but omitting word $.

Note that a `%' word designator works only when used in one of `!%', `!:%' or `!?str?:%',
and only when used after a !? expansion (possibly in an earlier command). Anything else
results in an error, although the error may not be the most obvious one.

Modifiers
After the optional word designator, you can add a sequence of one or more of the following
modifiers, each preceded by a `:'. These modifiers also work on the result of filename
generation and parameter expansion, except where noted.

a Turn a file name into an absolute path: prepends the current directory, if neces-
sary; remove `.' path segments; and remove `..' path segments and the segments that
immediately precede them.

This transformation is agnostic about what is in the filesystem, i.e. is on the
logical, not the physical directory. It takes place in the same manner as when
changing directories when neither of the options CHASE_DOTS or CHASE_LINKS is set.
For example, `/before/here/../after' is always transformed to `/before/after', re-
gardless of whether `/before/here' exists or what kind of object (dir, file, sym-
link, etc.) it is.

A Turn a file name into an absolute path as the `a' modifier does, and then pass the
result through the realpath(3) library function to resolve symbolic links.

Note: on systems that do not have a realpath(3) library function, symbolic links
are not resolved, so on those systems `a' and `A' are equivalent.

Note: foo:A and realpath(foo) are different on some inputs. For realpath(foo) se-
mantics, see the `P` modifier.

c Resolve a command name into an absolute path by searching the command path given by
the PATH variable. This does not work for commands containing directory parts.
Note also that this does not usually work as a glob qualifier unless a file of the
same name is found in the current directory.

e Remove all but the part of the filename extension following the `.'; see the defi-
nition of the filename extension in the description of the r modifier below. Note
that according to that definition the result will be empty if the string ends with
a `.'.

h [ digits ]
Remove a trailing pathname component, shortening the path by one directory level:
this is the `head' of the pathname. This works like `dirname'. If the h is fol-
lowed immediately (with no spaces or other separator) by any number of decimal dig-
its, and the value of the resulting number is non-zero, that number of leading com-
ponents is preserved instead of the final component being removed. In an absolute
path the leading `/' is the first component, so, for example, if
var=/my/path/to/something, then ${var:h3} substitutes /my/path. Consecutive `/'s
are treated the same as a single `/'. In parameter substitution, digits may only
be used if the expression is in braces, so for example the short form substitution
$var:h2 is treated as ${var:h}2, not as ${var:h2}. No restriction applies to the
use of digits in history substitution or globbing qualifiers. If more components
are requested than are present, the entire path is substituted (so this does not
trigger a `failed modifier' error in history expansion).

l Convert the words to all lowercase.

p Print the new command but do not execute it. Only works with history expansion.

P Turn a file name into an absolute path, like realpath(3). The resulting path will
be absolute, have neither `.' nor `..' components, and refer to the same directory
entry as the input filename.

Unlike realpath(3), non-existent trailing components are permitted and preserved.

q Quote the substituted words, escaping further substitutions. Works with history
expansion and parameter expansion, though for parameters it is only useful if the
resulting text is to be re-evaluated such as by eval.

Q Remove one level of quotes from the substituted words.

r Remove a filename extension leaving the root name. Strings with no filename exten-
sion are not altered. A filename extension is a `.' followed by any number of
characters (including zero) that are neither `.' nor `/' and that continue to the
end of the string. For example, the extension of `foo.orig.c' is `.c', and
`dir.c/foo' has no extension.

s/l/r[/]
Substitute r for l as described below. The substitution is done only for the first
string that matches l. For arrays and for filename generation, this applies to
each word of the expanded text. See below for further notes on substitutions.

The forms `gs/l/r' and `s/l/r/:G' perform global substitution, i.e. substitute ev-
ery occurrence of r for l. Note that the g or :G must appear in exactly the posi-
tion shown.

See further notes on this form of substitution below.

& Repeat the previous s substitution. Like s, may be preceded immediately by a g.
In parameter expansion the & must appear inside braces, and in filename generation
it must be quoted with a backslash.

t [ digits ]
Remove all leading pathname components, leaving the final component (tail). This
works like `basename'. Any trailing slashes are first removed. Decimal digits are
handled as described above for (h), but in this case that number of trailing compo-
nents is preserved instead of the default 1; 0 is treated the same as 1.

u Convert the words to all uppercase.

x Like q, but break into words at whitespace. Does not work with parameter expan-
sion.

The s/l/r/ substitution works as follows. By default the left-hand side of substitutions
are not patterns, but character strings. Any character can be used as the delimiter in
place of `/'. A backslash quotes the delimiter character. The character `&', in the
right-hand-side r, is replaced by the text from the left-hand-side l. The `&' can be
quoted with a backslash. A null l uses the previous string either from the previous l or
from the contextual scan string s from `!?s'. You can omit the rightmost delimiter if a
newline immediately follows r; the rightmost `?' in a context scan can similarly be omit-
ted. Note the same record of the last l and r is maintained across all forms of expan-
sion.

Note that if a `&' is used within glob qualifiers an extra backslash is needed as a & is a
special character in this case.

Also note that the order of expansions affects the interpretation of l and r. When used
in a history expansion, which occurs before any other expansions, l and r are treated as
literal strings (except as explained for HIST_SUBST_PATTERN below). When used in parame-
ter expansion, the replacement of r into the parameter's value is done first, and then any
additional process, parameter, command, arithmetic, or brace references are applied, which
may evaluate those substitutions and expansions more than once if l appears more than once
in the starting value. When used in a glob qualifier, any substitutions or expansions are
performed once at the time the qualifier is parsed, even before the `:s' expression itself
is divided into l and r sides.

If the option HIST_SUBST_PATTERN is set, l is treated as a pattern of the usual form de-
scribed in the section FILENAME GENERATION below. This can be used in all the places
where modifiers are available; note, however, that in globbing qualifiers parameter sub-
stitution has already taken place, so parameters in the replacement string should be
quoted to ensure they are replaced at the correct time. Note also that complicated pat-
terns used in globbing qualifiers may need the extended glob qualifier notation
(#q:s/.../.../) in order for the shell to recognize the expression as a glob qualifier.
Further, note that bad patterns in the substitution are not subject to the NO_BAD_PATTERN
option so will cause an error.

When HIST_SUBST_PATTERN is set, l may start with a # to indicate that the pattern must
match at the start of the string to be substituted, and a % may appear at the start or af-
ter an # to indicate that the pattern must match at the end of the string to be substi-
tuted. The % or # may be quoted with two backslashes.

For example, the following piece of filename generation code with the EXTENDED_GLOB op-
tion:

print -r -- *.c(#q:s/#%(#b)s(*).c/'S${match[1]}.C'/)

takes the expansion of *.c and applies the glob qualifiers in the (#q...) expression,
which consists of a substitution modifier anchored to the start and end of each word (#%).
This turns on backreferences ((#b)), so that the parenthesised subexpression is available
in the replacement string as ${match[1]}. The replacement string is quoted so that the
parameter is not substituted before the start of filename generation.

The following f, F, w and W modifiers work only with parameter expansion and filename gen-
eration. They are listed here to provide a single point of reference for all modifiers.

f Repeats the immediately (without a colon) following modifier until the resulting
word doesn't change any more.

F:expr:
Like f, but repeats only n times if the expression expr evaluates to n. Any char-
acter can be used instead of the `:'; if `(', `[', or `{' is used as the opening
delimiter, the closing delimiter should be ')', `]', or `}', respectively.

w Makes the immediately following modifier work on each word in the string.

W:sep: Like w but words are considered to be the parts of the string that are separated by
sep. Any character can be used instead of the `:'; opening parentheses are handled
specially, see above.

PROCESS SUBSTITUTION
Each part of a command argument that takes the form `<(list)', `>(list)' or `=(list)' is
subject to process substitution. The expression may be preceded or followed by other
strings except that, to prevent clashes with commonly occurring strings and patterns, the
last form must occur at the start of a command argument, and the forms are only expanded
when first parsing command or assignment arguments. Process substitutions may be used
following redirection operators; in this case, the substitution must appear with no trail-
ing string.

Note that `<<(list)' is not a special syntax; it is equivalent to `< <(list)', redirecting
standard input from the result of process substitution. Hence all the following documen-
tation applies. The second form (with the space) is recommended for clarity.

In the case of the < or > forms, the shell runs the commands in list as a subprocess of
the job executing the shell command line. If the system supports the /dev/fd mechanism,
the command argument is the name of the device file corresponding to a file descriptor;
otherwise, if the system supports named pipes (FIFOs), the command argument will be a
named pipe. If the form with > is selected then writing on this special file will provide
input for list. If < is used, then the file passed as an argument will be connected to
the output of the list process. For example,

paste <(cut -f1 file1) <(cut -f3 file2) |
tee >(process1) >(process2) >/dev/null

cuts fields 1 and 3 from the files file1 and file2 respectively, pastes the results to-
gether, and sends it to the processes process1 and process2.

If =(...) is used instead of <(...), then the file passed as an argument will be the name
of a temporary file containing the output of the list process. This may be used instead
of the < form for a program that expects to lseek (see lseek(2)) on the input file.

There is an optimisation for substitutions of the form =(<<<arg), where arg is a sin-
gle-word argument to the here-string redirection <<<. This form produces a file name con-
taining the value of arg after any substitutions have been performed. This is handled en-
tirely within the current shell. This is effectively the reverse of the special form
$(<arg) which treats arg as a file name and replaces it with the file's contents.

The = form is useful as both the /dev/fd and the named pipe implementation of <(...) have
drawbacks. In the former case, some programmes may automatically close the file descrip-
tor in question before examining the file on the command line, particularly if this is
necessary for security reasons such as when the programme is running setuid. In the sec-
ond case, if the programme does not actually open the file, the subshell attempting to
read from or write to the pipe will (in a typical implementation, different operating sys-
tems may have different behaviour) block for ever and have to be killed explicitly. In
both cases, the shell actually supplies the information using a pipe, so that programmes
that expect to lseek (see lseek(2)) on the file will not work.

Also note that the previous example can be more compactly and efficiently written (pro-
vided the MULTIOS option is set) as:

paste <(cut -f1 file1) <(cut -f3 file2) \
> >(process1) > >(process2)

The shell uses pipes instead of FIFOs to implement the latter two process substitutions in
the above example.

There is an additional problem with >(process); when this is attached to an external com-
mand, the parent shell does not wait for process to finish and hence an immediately fol-
lowing command cannot rely on the results being complete. The problem and solution are
the same as described in the section MULTIOS in zshmisc(1). Hence in a simplified version
of the example above:

paste <(cut -f1 file1) <(cut -f3 file2) > >(process)

(note that no MULTIOS are involved), process will be run asynchronously as far as the par-
ent shell is concerned. The workaround is:

{ paste <(cut -f1 file1) <(cut -f3 file2) } > >(process)

The extra processes here are spawned from the parent shell which will wait for their com-
pletion.

Another problem arises any time a job with a substitution that requires a temporary file
is disowned by the shell, including the case where `&!' or `&|' appears at the end of a
command containing a substitution. In that case the temporary file will not be cleaned up
as the shell no longer has any memory of the job. A workaround is to use a subshell, for
example,

(mycmd =(myoutput)) &!

as the forked subshell will wait for the command to finish then remove the temporary file.

A general workaround to ensure a process substitution endures for an appropriate length of
time is to pass it as a parameter to an anonymous shell function (a piece of shell code
that is run immediately with function scope). For example, this code:

() {
print File $1:
cat $1
} =(print This be the verse)

outputs something resembling the following

File /tmp/zsh6nU0kS:
This be the verse

The temporary file created by the process substitution will be deleted when the function
exits.

PARAMETER EXPANSION
The character `$' is used to introduce parameter expansions. See zshparam(1) for a de-
scription of parameters, including arrays, associative arrays, and subscript notation to
access individual array elements.

Note in particular the fact that words of unquoted parameters are not automatically split
on whitespace unless the option SH_WORD_SPLIT is set; see references to this option below
for more details. This is an important difference from other shells. However, as in
other shells, null words are elided from unquoted parameters' expansions.

With default options, after the assignments:

array=("first word" "" "third word")
scalar="only word"

then $array substitutes two words, `first word' and `third word', and $scalar substitutes
a single word `only word'. Note that second element of array was elided. Scalar parame-
ters can be elided too if their value is null (empty). To avoid elision, use quoting as
follows: "$scalar" for scalars and "${array[@]}" or "${(@)array}" for arrays. (The last
two forms are equivalent.)

Parameter expansions can involve flags, as in `${(@kv)aliases}', and other operators, such
as `${PREFIX:-"/usr/local"}'. Parameter expansions can also be nested. These topics will
be introduced below. The full rules are complicated and are noted at the end.

In the expansions discussed below that require a pattern, the form of the pattern is the
same as that used for filename generation; see the section `Filename Generation'. Note
that these patterns, along with the replacement text of any substitutions, are themselves
subject to parameter expansion, command substitution, and arithmetic expansion. In addi-
tion to the following operations, the colon modifiers described in the section `Modifiers'
in the section `History Expansion' can be applied: for example, ${i:s/foo/bar/} performs
string substitution on the expansion of parameter $i.

In the following descriptions, `word' refers to a single word substituted on the command
line, not necessarily a space delimited word.

${name}
The value, if any, of the parameter name is substituted. The braces are required
if the expansion is to be followed by a letter, digit, or underscore that is not to
be interpreted as part of name. In addition, more complicated forms of substitu-
tion usually require the braces to be present; exceptions, which only apply if the
option KSH_ARRAYS is not set, are a single subscript or any colon modifiers appear-
ing after the name, or any of the characters `^', `=', `~', `#' or `+' appearing
before the name, all of which work with or without braces.

If name is an array parameter, and the KSH_ARRAYS option is not set, then the value
of each element of name is substituted, one element per word. Otherwise, the ex-
pansion results in one word only; with KSH_ARRAYS, this is the first element of an
array. No field splitting is done on the result unless the SH_WORD_SPLIT option is
set. See also the flags = and s:string:.

${+name}
If name is the name of a set parameter `1' is substituted, otherwise `0' is substi-
tuted.

${name-word}
${name:-word}
If name is set, or in the second form is non-null, then substitute its value; oth-
erwise substitute word. In the second form name may be omitted, in which case word
is always substituted.

${name+word}
${name:+word}
If name is set, or in the second form is non-null, then substitute word; otherwise
substitute nothing.

${name=word}
${name:=word}
${name::=word}
In the first form, if name is unset then set it to word; in the second form, if
name is unset or null then set it to word; and in the third form, unconditionally
set name to word. In all forms, the value of the parameter is then substituted.

${name?word}
${name:?word}
In the first form, if name is set, or in the second form if name is both set and
non-null, then substitute its value; otherwise, print word and exit from the shell.
Interactive shells instead return to the prompt. If word is omitted, then a stan-
dard message is printed.

In any of the above expressions that test a variable and substitute an alternate word,
note that you can use standard shell quoting in the word value to selectively override the
splitting done by the SH_WORD_SPLIT option and the = flag, but not splitting by the
s:string: flag.

In the following expressions, when name is an array and the substitution is not quoted, or
if the `(@)' flag or the name[@] syntax is used, matching and replacement is performed on
each array element separately.

${name#pattern}
${name##pattern}
If the pattern matches the beginning of the value of name, then substitute the
value of name with the matched portion deleted; otherwise, just substitute the
value of name. In the first form, the smallest matching pattern is preferred; in
the second form, the largest matching pattern is preferred.

${name%pattern}
${name%%pattern}
If the pattern matches the end of the value of name, then substitute the value of
name with the matched portion deleted; otherwise, just substitute the value of
name. In the first form, the smallest matching pattern is preferred; in the second
form, the largest matching pattern is preferred.

${name:#pattern}
If the pattern matches the value of name, then substitute the empty string; other-
wise, just substitute the value of name. If name is an array the matching array
elements are removed (use the `(M)' flag to remove the non-matched elements).

${name:|arrayname}
If arrayname is the name (N.B., not contents) of an array variable, then any ele-
ments contained in arrayname are removed from the substitution of name. If the
substitution is scalar, either because name is a scalar variable or the expression
is quoted, the elements of arrayname are instead tested against the entire expres-
sion.

${name:*arrayname}
Similar to the preceding substitution, but in the opposite sense, so that entries
present in both the original substitution and as elements of arrayname are retained
and others removed.

${name:^arrayname}
${name:^^arrayname}
Zips two arrays, such that the output array is twice as long as the shortest (long-
est for `:^^') of name and arrayname, with the elements alternatingly being picked
from them. For `:^', if one of the input arrays is longer, the output will stop
when the end of the shorter array is reached. Thus,

a=(1 2 3 4); b=(a b); print ${a:^b}

will output `1 a 2 b'. For `:^^', then the input is repeated until all of the
longer array has been used up and the above will output `1 a 2 b 3 a 4 b'.

Either or both inputs may be a scalar, they will be treated as an array of length 1
with the scalar as the only element. If either array is empty, the other array is
output with no extra elements inserted.

Currently the following code will output `a b' and `1' as two separate elements,
which can be unexpected. The second print provides a workaround which should con-
tinue to work if this is changed.

a=(a b); b=(1 2); print -l "${a:^b}"; print -l "${${a:^b}}"

${name:offset}
${name:offset:length}
This syntax gives effects similar to parameter subscripting in the form
$name[start,end], but is compatible with other shells; note that both offset and
length are interpreted differently from the components of a subscript.

If offset is non-negative, then if the variable name is a scalar substitute the
contents starting offset characters from the first character of the string, and if
name is an array substitute elements starting offset elements from the first ele-
ment. If length is given, substitute that many characters or elements, otherwise
the entire rest of the scalar or array.

A positive offset is always treated as the offset of a character or element in name
from the first character or element of the array (this is different from native zsh
subscript notation). Hence 0 refers to the first character or element regardless
of the setting of the option KSH_ARRAYS.

A negative offset counts backwards from the end of the scalar or array, so that -1
corresponds to the last character or element, and so on.

When positive, length counts from the offset position toward the end of the scalar
or array. When negative, length counts back from the end. If this results in a
position smaller than offset, a diagnostic is printed and nothing is substituted.

The option MULTIBYTE is obeyed, i.e. the offset and length count multibyte charac-
ters where appropriate.

offset and length undergo the same set of shell substitutions as for scalar assign-
ment; in addition, they are then subject to arithmetic evaluation. Hence, for ex-
ample

print ${foo:3}
print ${foo: 1 + 2}
print ${foo:$(( 1 + 2))}
print ${foo:$(echo 1 + 2)}

all have the same effect, extracting the string starting at the fourth character of
$foo if the substitution would otherwise return a scalar, or the array starting at
the fourth element if $foo would return an array. Note that with the option
KSH_ARRAYS $foo always returns a scalar (regardless of the use of the offset syn-
tax) and a form such as ${foo[*]:3} is required to extract elements of an array
named foo.

If offset is negative, the - may not appear immediately after the : as this indi-
cates the ${name:-word} form of substitution. Instead, a space may be inserted be-
fore the -. Furthermore, neither offset nor length may begin with an alphabetic
character or & as these are used to indicate history-style modifiers. To substi-
tute a value from a variable, the recommended approach is to precede it with a $ as
this signifies the intention (parameter substitution can easily be rendered unread-
able); however, as arithmetic substitution is performed, the expression ${var:
offs} does work, retrieving the offset from $offs.

For further compatibility with other shells there is a special case for array off-
set 0. This usually accesses the first element of the array. However, if the sub-
stitution refers to the positional parameter array, e.g. $@ or $*, then offset 0
instead refers to $0, offset 1 refers to $1, and so on. In other words, the posi-
tional parameter array is effectively extended by prepending $0. Hence ${*:0:1}
substitutes $0 and ${*:1:1} substitutes $1.

${name/pattern/repl}
${name//pattern/repl}
${name:/pattern/repl}
Replace the longest possible match of pattern in the expansion of parameter name by
string repl. The first form replaces just the first occurrence, the second form
all occurrences, and the third form replaces only if pattern matches the entire
string. Both pattern and repl are subject to double-quoted substitution, so that
expressions like ${name/$opat/$npat} will work, but obey the usual rule that pat-
tern characters in $opat are not treated specially unless either the option
GLOB_SUBST is set, or $opat is instead substituted as ${~opat}.

The pattern may begin with a `#', in which case the pattern must match at the start
of the string, or `%', in which case it must match at the end of the string, or
`#%' in which case the pattern must match the entire string. The repl may be an
empty string, in which case the final `/' may also be omitted. To quote the final
`/' in other cases it should be preceded by a single backslash; this is not neces-
sary if the `/' occurs inside a substituted parameter. Note also that the `#', `%'
and `#% are not active if they occur inside a substituted parameter, even at the
start.

If, after quoting rules apply, ${name} expands to an array, the replacements act on
each element individually. Note also the effect of the I and S parameter expansion
flags below; however, the flags M, R, B, E and N are not useful.

For example,

foo="twinkle twinkle little star" sub="t*e" rep="spy"
print ${foo//${~sub}/$rep}
print ${(S)foo//${~sub}/$rep}

Here, the `~' ensures that the text of $sub is treated as a pattern rather than a
plain string. In the first case, the longest match for t*e is substituted and the
result is `spy star', while in the second case, the shortest matches are taken and
the result is `spy spy lispy star'.

${#spec}
If spec is one of the above substitutions, substitute the length in characters of
the result instead of the result itself. If spec is an array expression, substi-
tute the number of elements of the result. This has the side-effect that joining
is skipped even in quoted forms, which may affect other sub-expressions in spec.
Note that `^', `=', and `~', below, must appear to the left of `#' when these forms
are combined.

If the option POSIX_IDENTIFIERS is not set, and spec is a simple name, then the
braces are optional; this is true even for special parameters so e.g. $#- and $#*
take the length of the string $- and the array $* respectively. If POSIX_IDENTI-
FIERS is set, then braces are required for the # to be treated in this fashion.

${^spec}
Turn on the RC_EXPAND_PARAM option for the evaluation of spec; if the `^' is dou-
bled, turn it off. When this option is set, array expansions of the form
foo${xx}bar, where the parameter xx is set to (a b c), are substituted with
`fooabar foobbar foocbar' instead of the default `fooa b cbar'. Note that an empty
array will therefore cause all arguments to be removed.

Internally, each such expansion is converted into the equivalent list for brace ex-
pansion. E.g., ${^var} becomes {$var[1],$var[2],...}, and is processed as de-
scribed in the section `Brace Expansion' below: note, however, the expansion hap-
pens immediately, with any explicit brace expansion happening later. If word
splitting is also in effect the $var[N] may themselves be split into different list
elements.

${=spec}
Perform word splitting using the rules for SH_WORD_SPLIT during the evaluation of
spec, but regardless of whether the parameter appears in double quotes; if the `='
is doubled, turn it off. This forces parameter expansions to be split into sepa-
rate words before substitution, using IFS as a delimiter. This is done by default
in most other shells.

Note that splitting is applied to word in the assignment forms of spec before the
assignment to name is performed. This affects the result of array assignments with
the A flag.

${~spec}
Turn on the GLOB_SUBST option for the evaluation of spec; if the `~' is doubled,
turn it off. When this option is set, the string resulting from the expansion will
be interpreted as a pattern anywhere that is possible, such as in filename expan-
sion and filename generation and pattern-matching contexts like the right hand side
of the `=' and `!=' operators in conditions.

In nested substitutions, note that the effect of the ~ applies to the result of the
current level of substitution. A surrounding pattern operation on the result may
cancel it. Hence, for example, if the parameter foo is set to *, ${~foo//\*/*.c}
is substituted by the pattern *.c, which may be expanded by filename generation,
but ${${~foo}//\*/*.c} substitutes to the string *.c, which will not be further ex-
panded.

If a ${...} type parameter expression or a $(...) type command substitution is used in
place of name above, it is expanded first and the result is used as if it were the value
of name. Thus it is possible to perform nested operations: ${${foo#head}%tail} substi-
tutes the value of $foo with both `head' and `tail' deleted. The form with $(...) is of-
ten useful in combination with the flags described next; see the examples below. Each
name or nested ${...} in a parameter expansion may also be followed by a subscript expres-
sion as described in Array Parameters in zshparam(1).

Note that double quotes may appear around nested expressions, in which case only the part
inside is treated as quoted; for example, ${(f)"$(foo)"} quotes the result of $(foo), but
the flag `(f)' (see below) is applied using the rules for unquoted expansions. Note fur-
ther that quotes are themselves nested in this context; for example, in "${(@f)"$(foo)"}",
there are two sets of quotes, one surrounding the whole expression, the other (redundant)
surrounding the $(foo) as before.

Parameter Expansion Flags
If the opening brace is directly followed by an opening parenthesis, the string up to the
matching closing parenthesis will be taken as a list of flags. In cases where repeating a
flag is meaningful, the repetitions need not be consecutive; for example, `(q%q%q)' means
the same thing as the more readable `(%%qqq)'. The following flags are supported:

# Evaluate the resulting words as numeric expressions and output the characters cor-
responding to the resulting integer. Note that this form is entirely distinct from
use of the # without parentheses.

If the MULTIBYTE option is set and the number is greater than 127 (i.e. not an
ASCII character) it is treated as a Unicode character.

% Expand all % escapes in the resulting words in the same way as in prompts (see EX-
PANSION OF PROMPT SEQUENCES in zshmisc(1)). If this flag is given twice, full
prompt expansion is done on the resulting words, depending on the setting of the
PROMPT_PERCENT, PROMPT_SUBST and PROMPT_BANG options.

@ In double quotes, array elements are put into separate words. E.g., `"${(@)foo}"'
is equivalent to `"${foo[@]}"' and `"${(@)foo[1,2]}"' is the same as `"$foo[1]"
"$foo[2]"'. This is distinct from field splitting by the f, s or z flags, which
still applies within each array element.

A Convert the substitution into an array expression, even if it otherwise would be
scalar. This has lower precedence than subscripting, so one level of nested expan-
sion is required in order that subscripts apply to array elements. Thus
${${(A)name}[1]} yields the full value of name when name is scalar.

This assigns an array parameter with `${...=...}', `${...:=...}' or `${...::=...}'.
If this flag is repeated (as in `AA'), assigns an associative array parameter. As-
signment is made before sorting or padding; if field splitting is active, the word
part is split before assignment. The name part may be a subscripted range for or-
dinary arrays; when assigning an associative array, the word part must be converted
to an array, for example by using `${(AA)=name=...}' to activate field splitting.

Surrounding context such as additional nesting or use of the value in a scalar as-
signment may cause the array to be joined back into a single string again.

a Sort in array index order; when combined with `O' sort in reverse array index or-
der. Note that `a' is therefore equivalent to the default but `Oa' is useful for
obtaining an array's elements in reverse order.

b Quote with backslashes only characters that are special to pattern matching. This
is useful when the contents of the variable are to be tested using GLOB_SUBST, in-
cluding the ${~...} switch.

Quoting using one of the q family of flags does not work for this purpose since
quotes are not stripped from non-pattern characters by GLOB_SUBST. In other words,

pattern=${(q)str}
[[ $str = ${~pattern} ]]

works if $str is `a*b' but not if it is `a b', whereas

pattern=${(b)str}
[[ $str = ${~pattern} ]]

is always true for any possible value of $str.

c With ${#name}, count the total number of characters in an array, as if the elements
were concatenated with spaces between them. This is not a true join of the array,
so other expressions used with this flag may have an effect on the elements of the
array before it is counted.

C Capitalize the resulting words. `Words' in this case refers to sequences of al-
phanumeric characters separated by non-alphanumerics, not to words that result from
field splitting.

D Assume the string or array elements contain directories and attempt to substitute
the leading part of these by names. The remainder of the path (the whole of it if
the leading part was not substituted) is then quoted so that the whole string can
be used as a shell argument. This is the reverse of `~' substitution: see the
section FILENAME EXPANSION below.

e Perform single word shell expansions, namely parameter expansion, command substitu-
tion and arithmetic expansion, on the result. Such expansions can be nested but too
deep recursion may have unpredictable effects.

f Split the result of the expansion at newlines. This is a shorthand for `ps:\n:'.

F Join the words of arrays together using newline as a separator. This is a short-
hand for `pj:\n:'.

g:opts:
Process escape sequences like the echo builtin when no options are given (g::).
With the o option, octal escapes don't take a leading zero. With the c option, se-
quences like `^X' are also processed. With the e option, processes `\M-t' and sim-
ilar sequences like the print builtin. With both of the o and e options, behaves
like the print builtin except that in none of these modes is `\c' interpreted.

i Sort case-insensitively. May be combined with `n' or `O'.

k If name refers to an associative array, substitute the keys (element names) rather
than the values of the elements. Used with subscripts (including ordinary arrays),
force indices or keys to be substituted even if the subscript form refers to val-
ues. However, this flag may not be combined with subscript ranges. With the
KSH_ARRAYS option a subscript `[*]' or `[@]' is needed to operate on the whole ar-
ray, as usual.

L Convert all letters in the result to lower case.

n Sort decimal integers numerically; if the first differing characters of two test
strings are not digits, sorting is lexical. Integers with more initial zeroes are
sorted before those with fewer or none. Hence the array `foo1 foo02 foo2 foo3
foo20 foo23' is sorted into the order shown. May be combined with `i' or `O'.

o Sort the resulting words in ascending order; if this appears on its own the sorting
is lexical and case-sensitive (unless the locale renders it case-insensitive).
Sorting in ascending order is the default for other forms of sorting, so this is
ignored if combined with `a', `i' or `n'.

O Sort the resulting words in descending order; `O' without `a', `i' or `n' sorts in
reverse lexical order. May be combined with `a', `i' or `n' to reverse the order
of sorting.

P This forces the value of the parameter name to be interpreted as a further parame-
ter name, whose value will be used where appropriate. Note that flags set with one
of the typeset family of commands (in particular case transformations) are not ap-
plied to the value of name used in this fashion.

If used with a nested parameter or command substitution, the result of that will be
taken as a parameter name in the same way. For example, if you have `foo=bar' and
`bar=baz', the strings ${(P)foo}, ${(P)${foo}}, and ${(P)$(echo bar)} will be ex-
panded to `baz'.

Likewise, if the reference is itself nested, the expression with the flag is
treated as if it were directly replaced by the parameter name. It is an error if
this nested substitution produces an array with more than one word. For example,
if `name=assoc' where the parameter assoc is an associative array, then
`${${(P)name}[elt]}' refers to the element of the associative subscripted `elt'.

q Quote characters that are special to the shell in the resulting words with back-
slashes; unprintable or invalid characters are quoted using the $'\NNN' form, with
separate quotes for each octet.

If this flag is given twice, the resulting words are quoted in single quotes and if
it is given three times, the words are quoted in double quotes; in these forms no
special handling of unprintable or invalid characters is attempted. If the flag is
given four times, the words are quoted in single quotes preceded by a $. Note that
in all three of these forms quoting is done unconditionally, even if this does not
change the way the resulting string would be interpreted by the shell.

If a q- is given (only a single q may appear), a minimal form of single quoting is
used that only quotes the string if needed to protect special characters. Typi-
cally this form gives the most readable output.

If a q+ is given, an extended form of minimal quoting is used that causes unprint-
able characters to be rendered using $'...'. This quoting is similar to that used
by the output of values by the typeset family of commands.

Q Remove one level of quotes from the resulting words.

t Use a string describing the type of the parameter where the value of the parameter
would usually appear. This string consists of keywords separated by hyphens (`-').
The first keyword in the string describes the main type, it can be one of `scalar',
`array', `integer', `float' or `association'. The other keywords describe the type
in more detail:

local for local parameters

left for left justified parameters

right_blanks
for right justified parameters with leading blanks

right_zeros
for right justified parameters with leading zeros

lower for parameters whose value is converted to all lower case when it is ex-
panded

upper for parameters whose value is converted to all upper case when it is ex-
panded

readonly
for readonly parameters

tag for tagged parameters

export for exported parameters

unique for arrays which keep only the first occurrence of duplicated values

hide for parameters with the `hide' flag

hideval
for parameters with the `hideval' flag

special
for special parameters defined by the shell

u Expand only the first occurrence of each unique word.

U Convert all letters in the result to upper case.

v Used with k, substitute (as two consecutive words) both the key and the value of
each associative array element. Used with subscripts, force values to be substi-
tuted even if the subscript form refers to indices or keys.

V Make any special characters in the resulting words visible.

w With ${#name}, count words in arrays or strings; the s flag may be used to set a
word delimiter.

W Similar to w with the difference that empty words between repeated delimiters are
also counted.

X With this flag, parsing errors occurring with the Q, e and # flags or the pattern
matching forms such as `${name#pattern}' are reported. Without the flag, errors
are silently ignored.

z Split the result of the expansion into words using shell parsing to find the words,
i.e. taking into account any quoting in the value. Comments are not treated spe-
cially but as ordinary strings, similar to interactive shells with the INTERAC-
TIVE_COMMENTS option unset (however, see the Z flag below for related options)

Note that this is done very late, even later than the `(s)' flag. So to access sin-
gle words in the result use nested expansions as in `${${(z)foo}[2]}'. Likewise, to
remove the quotes in the resulting words use `${(Q)${(z)foo}}'.

0 Split the result of the expansion on null bytes. This is a shorthand for `ps:\0:'.

The following flags (except p) are followed by one or more arguments as shown. Any char-
acter, or the matching pairs `(...)', `{...}', `[...]', or `<...>', may be used in place
of a colon as delimiters, but note that when a flag takes more than one argument, a
matched pair of delimiters must surround each argument.

p Recognize the same escape sequences as the print builtin in string arguments to any
of the flags described below that follow this argument.

Alternatively, with this option string arguments may be in the form $var in which
case the value of the variable is substituted. Note this form is strict; the
string argument does not undergo general parameter expansion.

For example,

sep=:
val=a:b:c
print ${(ps.$sep.)val}

splits the variable on a :.

~ Strings inserted into the expansion by any of the flags below are to be treated as
patterns. This applies to the string arguments of flags that follow ~ within the
same set of parentheses. Compare with ~ outside parentheses, which forces the en-
tire substituted string to be treated as a pattern. Hence, for example,

[[ "?" = ${(~j.|.)array} ]]

treats `|' as a pattern and succeeds if and only if $array contains the string `?'
as an element. The ~ may be repeated to toggle the behaviour; its effect only
lasts to the end of the parenthesised group.

j:string:
Join the words of arrays together using string as a separator. Note that this oc-
curs before field splitting by the s:string: flag or the SH_WORD_SPLIT option.

l:expr::string1::string2:
Pad the resulting words on the left. Each word will be truncated if required and
placed in a field expr characters wide.

The arguments :string1: and :string2: are optional; neither, the first, or both may
be given. Note that the same pairs of delimiters must be used for each of the
three arguments. The space to the left will be filled with string1 (concatenated
as often as needed) or spaces if string1 is not given. If both string1 and string2
are given, string2 is inserted once directly to the left of each word, truncated if
necessary, before string1 is used to produce any remaining padding.

If either of string1 or string2 is present but empty, i.e. there are two delimiters
together at that point, the first character of $IFS is used instead.

If the MULTIBYTE option is in effect, the flag m may also be given, in which case
widths will be used for the calculation of padding; otherwise individual multibyte
characters are treated as occupying one unit of width.

If the MULTIBYTE option is not in effect, each byte in the string is treated as oc-
cupying one unit of width.

Control characters are always assumed to be one unit wide; this allows the mecha-
nism to be used for generating repetitions of control characters.

m Only useful together with one of the flags l or r or with the # length operator
when the MULTIBYTE option is in effect. Use the character width reported by the
system in calculating how much of the string it occupies or the overall length of
the string. Most printable characters have a width of one unit, however certain
Asian character sets and certain special effects use wider characters; combining
characters have zero width. Non-printable characters are arbitrarily counted as
zero width; how they would actually be displayed will vary.

If the m is repeated, the character either counts zero (if it has zero width), else
one. For printable character strings this has the effect of counting the number of
glyphs (visibly separate characters), except for the case where combining charac-
ters themselves have non-zero width (true in certain alphabets).

r:expr::string1::string2:
As l, but pad the words on the right and insert string2 immediately to the right of
the string to be padded.

Left and right padding may be used together. In this case the strategy is to apply
left padding to the first half width of each of the resulting words, and right pad-
ding to the second half. If the string to be padded has odd width the extra pad-
ding is applied on the left.

s:string:
Force field splitting at the separator string. Note that a string of two or more
characters means that all of them must match in sequence; this differs from the
treatment of two or more characters in the IFS parameter. See also the = flag and
the SH_WORD_SPLIT option. An empty string may also be given in which case every
character will be a separate element.

For historical reasons, the usual behaviour that empty array elements are retained
inside double quotes is disabled for arrays generated by splitting; hence the fol-
lowing:

line="one::three"
print -l "${(s.:.)line}"

produces two lines of output for one and three and elides the empty field. To
override this behaviour, supply the `(@)' flag as well, i.e. "${(@s.:.)line}".

Z:opts:
As z but takes a combination of option letters between a following pair of delim-
iter characters. With no options the effect is identical to z. (Z+c+) causes com-
ments to be parsed as a string and retained; any field in the resulting array be-
ginning with an unquoted comment character is a comment. (Z+C+) causes comments to
be parsed and removed. The rule for comments is standard: anything between a word
starting with the third character of $HISTCHARS, default #, up to the next newline
is a comment. (Z+n+) causes unquoted newlines to be treated as ordinary white-
space, else they are treated as if they are shell code delimiters and converted to
semicolons. Options are combined within the same set of delimiters, e.g. (Z+Cn+).

_:flags:
The underscore (_) flag is reserved for future use. As of this revision of zsh,
there are no valid flags; anything following an underscore, other than an empty
pair of delimiters, is treated as an error, and the flag itself has no effect.

The following flags are meaningful with the ${...#...} or ${...%...} forms. The S and I
flags may also be used with the ${.../...} forms.

S With # or ##, search for the match that starts closest to the start of the string
(a `substring match'). Of all matches at a particular position, # selects the
shortest and ## the longest:

% str="aXbXc"
% echo ${(S)str#X*}
abXc
% echo ${(S)str##X*}
a
%

With % or %%, search for the match that starts closest to the end of the string:

% str="aXbXc"
% echo ${(S)str%X*}
aXbc
% echo ${(S)str%%X*}
aXb
%

(Note that % and %% don't search for the match that ends closest to the end of the
string, as one might expect.)

With substitution via ${.../...} or ${...//...}, specifies non-greedy matching,
i.e. that the shortest instead of the longest match should be replaced:

% str="abab"
% echo ${str/*b/_}
_
% echo ${(S)str/*b/_}
_ab
%

I:expr:
Search the exprth match (where expr evaluates to a number). This only applies when
searching for substrings, either with the S flag, or with ${.../...} (only the ex-
prth match is substituted) or ${...//...} (all matches from the exprth on are sub-
stituted). The default is to take the first match.

The exprth match is counted such that there is either one or zero matches from each
starting position in the string, although for global substitution matches overlap-
ping previous replacements are ignored. With the ${...%...} and ${...%%...} forms,
the starting position for the match moves backwards from the end as the index in-
creases, while with the other forms it moves forward from the start.

Hence with the string
which switch is the right switch for Ipswich?
substitutions of the form ${(SI:N:)string#w*ch} as N increases from 1 will match
and remove `which', `witch', `witch' and `wich'; the form using `##' will match and
remove `which switch is the right switch for Ipswich', `witch is the right switch
for Ipswich', `witch for Ipswich' and `wich'. The form using `%' will remove the
same matches as for `#', but in reverse order, and the form using `%%' will remove
the same matches as for `##' in reverse order.

B Include the index of the beginning of the match in the result.

E Include the index one character past the end of the match in the result (note this
is inconsistent with other uses of parameter index).

M Include the matched portion in the result.

N Include the length of the match in the result.

R Include the unmatched portion in the result (the Rest).

Rules
Here is a summary of the rules for substitution; this assumes that braces are present
around the substitution, i.e. ${...}. Some particular examples are given below. Note
that the Zsh Development Group accepts no responsibility for any brain damage which may
occur during the reading of the following rules.

1. Nested substitution
If multiple nested ${...} forms are present, substitution is performed from the in-
side outwards. At each level, the substitution takes account of whether the cur-
rent value is a scalar or an array, whether the whole substitution is in double
quotes, and what flags are supplied to the current level of substitution, just as
if the nested substitution were the outermost. The flags are not propagated up to
enclosing substitutions; the nested substitution will return either a scalar or an
array as determined by the flags, possibly adjusted for quoting. All the following
steps take place where applicable at all levels of substitution.

Note that, unless the `(P)' flag is present, the flags and any subscripts apply di-
rectly to the value of the nested substitution; for example, the expansion
${${foo}} behaves exactly the same as ${foo}. When the `(P)' flag is present in a
nested substitution, the other substitution rules are applied to the value before
it is interpreted as a name, so ${${(P)foo}} may differ from ${(P)foo}.

At each nested level of substitution, the substituted words undergo all forms of
single-word substitution (i.e. not filename generation), including command substi-
tution, arithmetic expansion and filename expansion (i.e. leading ~ and =). Thus,
for example, ${${:-=cat}:h} expands to the directory where the cat program resides.
(Explanation: the internal substitution has no parameter but a default value =cat,
which is expanded by filename expansion to a full path; the outer substitution then
applies the modifier :h and takes the directory part of the path.)

2. Internal parameter flags
Any parameter flags set by one of the typeset family of commands, in particular the
-L, -R, -Z, -u and -l options for padding and capitalization, are applied directly
to the parameter value. Note these flags are options to the command, e.g. `typeset
-Z'; they are not the same as the flags used within parameter substitutions.

At the outermost level of substitution, the `(P)' flag (rule 4.) ignores these
transformations and uses the unmodified value of the parameter as the name to be
replaced. This is usually the desired behavior because padding may make the value
syntactically illegal as a parameter name, but if capitalization changes are de-
sired, use the ${${(P)foo}} form (rule 25.).

3. Parameter subscripting
If the value is a raw parameter reference with a subscript, such as ${var[3]}, the
effect of subscripting is applied directly to the parameter. Subscripts are evalu-
ated left to right; subsequent subscripts apply to the scalar or array value
yielded by the previous subscript. Thus if var is an array, ${var[1][2]} is the
second character of the first word, but ${var[2,4][2]} is the entire third word
(the second word of the range of words two through four of the original array).
Any number of subscripts may appear. Flags such as `(k)' and `(v)' which alter the
result of subscripting are applied.

4. Parameter name replacement
At the outermost level of nesting only, the `(P)' flag is applied. This treats the
value so far as a parameter name (which may include a subscript expression) and re-
places that with the corresponding value. This replacement occurs later if the
`(P)' flag appears in a nested substitution.

If the value so far names a parameter that has internal flags (rule 2.), those in-
ternal flags are applied to the new value after replacement.

5. Double-quoted joining
If the value after this process is an array, and the substitution appears in double
quotes, and neither an `(@)' flag nor a `#' length operator is present at the cur-
rent level, then words of the value are joined with the first character of the pa-
rameter $IFS, by default a space, between each word (single word arrays are not
modified). If the `(j)' flag is present, that is used for joining instead of $IFS.

6. Nested subscripting
Any remaining subscripts (i.e. of a nested substitution) are evaluated at this
point, based on whether the value is an array or a scalar. As with 3., multiple
subscripts can appear. Note that ${foo[2,4][2]} is thus equivalent to
${${foo[2,4]}[2]} and also to "${${(@)foo[2,4]}[2]}" (the nested substitution re-
turns an array in both cases), but not to "${${foo[2,4]}[2]}" (the nested substitu-
tion returns a scalar because of the quotes).

7. Modifiers
Any modifiers, as specified by a trailing `#', `%', `/' (possibly doubled) or by a
set of modifiers of the form `:...' (see the section `Modifiers' in the section
`History Expansion'), are applied to the words of the value at this level.

8. Character evaluation
Any `(#)' flag is applied, evaluating the result so far numerically as a character.

9. Length
Any initial `#' modifier, i.e. in the form ${#var}, is used to evaluate the length
of the expression so far.

10. Forced joining
If the `(j)' flag is present, or no `(j)' flag is present but the string is to be
split as given by rule 11., and joining did not take place at rule 5., any words in
the value are joined together using the given string or the first character of $IFS
if none. Note that the `(F)' flag implicitly supplies a string for joining in this
manner.

11. Simple word splitting
If one of the `(s)' or `(f)' flags are present, or the `=' specifier was present
(e.g. ${=var}), the word is split on occurrences of the specified string, or (for =
with neither of the two flags present) any of the characters in $IFS.

If no `(s)', `(f)' or `=' was given, but the word is not quoted and the option
SH_WORD_SPLIT is set, the word is split on occurrences of any of the characters in
$IFS. Note this step, too, takes place at all levels of a nested substitution.

12. Case modification
Any case modification from one of the flags `(L)', `(U)' or `(C)' is applied.

13. Escape sequence replacement
First any replacements from the `(g)' flag are performed, then any prompt-style
formatting from the `(%)' family of flags is applied.

14. Quote application
Any quoting or unquoting using `(q)' and `(Q)' and related flags is applied.

15. Directory naming
Any directory name substitution using `(D)' flag is applied.

16. Visibility enhancement
Any modifications to make characters visible using the `(V)' flag are applied.

17. Lexical word splitting
If the '(z)' flag or one of the forms of the '(Z)' flag is present, the word is
split as if it were a shell command line, so that quotation marks and other
metacharacters are used to decide what constitutes a word. Note this form of
splitting is entirely distinct from that described by rule 11.: it does not use
$IFS, and does not cause forced joining.

18. Uniqueness
If the result is an array and the `(u)' flag was present, duplicate elements are
removed from the array.

19. Ordering
If the result is still an array and one of the `(o)' or `(O)' flags was present,
the array is reordered.

20. RC_EXPAND_PARAM
At this point the decision is made whether any resulting array elements are to be
combined element by element with surrounding text, as given by either the RC_EX-
PAND_PARAM option or the `^' flag.

21. Re-evaluation
Any `(e)' flag is applied to the value, forcing it to be re-examined for new param-
eter substitutions, but also for command and arithmetic substitutions.

22. Padding
Any padding of the value by the `(l.fill.)' or `(r.fill.)' flags is applied.

23. Semantic joining
In contexts where expansion semantics requires a single word to result, all words
are rejoined with the first character of IFS between. So in `${(P)${(f)lines}}'
the value of ${lines} is split at newlines, but then must be joined again before
the `(P)' flag can be applied.

If a single word is not required, this rule is skipped.

24. Empty argument removal
If the substitution does not appear in double quotes, any resulting zero-length ar-
gument, whether from a scalar or an element of an array, is elided from the list of
arguments inserted into the command line.

Strictly speaking, the removal happens later as the same happens with other forms
of substitution; the point to note here is simply that it occurs after any of the
above parameter operations.

25. Nested parameter name replacement
If the `(P)' flag is present and rule 4. has not applied, the value so far is
treated as a parameter name (which may include a subscript expression) and replaced
with the corresponding value, with internal flags (rule 2.) applied to the new
value.

Examples
The flag f is useful to split a double-quoted substitution line by line. For example,
${(f)"$(<file)"} substitutes the contents of file divided so that each line is an element
of the resulting array. Compare this with the effect of $(<file) alone, which divides the
file up by words, or the same inside double quotes, which makes the entire content of the
file a single string.

The following illustrates the rules for nested parameter expansions. Suppose that $foo
contains the array (bar baz):

"${(@)${foo}[1]}"
This produces the result b. First, the inner substitution "${foo}", which has no
array (@) flag, produces a single word result "bar baz". The outer substitution
"${(@)...[1]}" detects that this is a scalar, so that (despite the `(@)' flag) the
subscript picks the first character.

"${${(@)foo}[1]}"
This produces the result `bar'. In this case, the inner substitution "${(@)foo}"
produces the array `(bar baz)'. The outer substitution "${...[1]}" detects that
this is an array and picks the first word. This is similar to the simple case
"${foo[1]}".

As an example of the rules for word splitting and joining, suppose $foo contains the array
`(ax1 bx1)'. Then

${(s/x/)foo}
produces the words `a', `1 b' and `1'.

${(j/x/s/x/)foo}
produces `a', `1', `b' and `1'.

${(s/x/)foo%%1*}
produces `a' and ` b' (note the extra space). As substitution occurs before either
joining or splitting, the operation first generates the modified array (ax bx),
which is joined to give "ax bx", and then split to give `a', ` b' and `'. The fi-
nal empty string will then be elided, as it is not in double quotes.

COMMAND SUBSTITUTION
A command enclosed in parentheses preceded by a dollar sign, like `$(...)', or quoted with
grave accents, like ``...`', is replaced with its standard output, with any trailing new-
lines deleted. If the substitution is not enclosed in double quotes, the output is broken
into words using the IFS parameter.

The substitution `$(cat foo)' may be replaced by the faster `$(<foo)'. In this case foo
undergoes single word shell expansions (parameter expansion, command substitution and
arithmetic expansion), but not filename generation.

If the option GLOB_SUBST is set, the result of any unquoted command substitution, includ-
ing the special form just mentioned, is eligible for filename generation.

ARITHMETIC EXPANSION
A string of the form `$[exp]' or `$((exp))' is substituted with the value of the arith-
metic expression exp. exp is subjected to parameter expansion, command substitution and
arithmetic expansion before it is evaluated. See the section `Arithmetic Evaluation'.

BRACE EXPANSION
A string of the form `foo{xx,yy,zz}bar' is expanded to the individual words `fooxxbar',
`fooyybar' and `foozzbar'. Left-to-right order is preserved. This construct may be
nested. Commas may be quoted in order to include them literally in a word.

An expression of the form `{n1..n2}', where n1 and n2 are integers, is expanded to every
number between n1 and n2 inclusive. If either number begins with a zero, all the result-
ing numbers will be padded with leading zeroes to that minimum width, but for negative
numbers the - character is also included in the width. If the numbers are in decreasing
order the resulting sequence will also be in decreasing order.

An expression of the form `{n1..n2..n3}', where n1, n2, and n3 are integers, is expanded
as above, but only every n3th number starting from n1 is output. If n3 is negative the
numbers are output in reverse order, this is slightly different from simply swapping n1
and n2 in the case that the step n3 doesn't evenly divide the range. Zero padding can be
specified in any of the three numbers, specifying it in the third can be useful to pad for
example `{-99..100..01}' which is not possible to specify by putting a 0 on either of the
first two numbers (i.e. pad to two characters).

An expression of the form `{c1..c2}', where c1 and c2 are single characters (which may be
multibyte characters), is expanded to every character in the range from c1 to c2 in what-
ever character sequence is used internally. For characters with code points below 128
this is US ASCII (this is the only case most users will need). If any intervening charac-
ter is not printable, appropriate quotation is used to render it printable. If the char-
acter sequence is reversed, the output is in reverse order, e.g. `{d..a}' is substituted
as `d c b a'.

If a brace expression matches none of the above forms, it is left unchanged, unless the
option BRACE_CCL (an abbreviation for `brace character class') is set. In that case, it
is expanded to a list of the individual characters between the braces sorted into the or-
der of the characters in the ASCII character set (multibyte characters are not currently
handled). The syntax is similar to a [...] expression in filename generation: `-' is
treated specially to denote a range of characters, but `^' or `!' as the first character
is treated normally. For example, `{abcdef0-9}' expands to 16 words 0 1 2 3 4 5 6 7 8 9 a
b c d e f.

Note that brace expansion is not part of filename generation (globbing); an expression
such as */{foo,bar} is split into two separate words */foo and */bar before filename gen-
eration takes place. In particular, note that this is liable to produce a `no match' er-
ror if either of the two expressions does not match; this is to be contrasted with
*/(foo|bar), which is treated as a single pattern but otherwise has similar effects.

To combine brace expansion with array expansion, see the ${^spec} form described in the
section Parameter Expansion above.

FILENAME EXPANSION
Each word is checked to see if it begins with an unquoted `~'. If it does, then the word
up to a `/', or the end of the word if there is no `/', is checked to see if it can be
substituted in one of the ways described here. If so, then the `~' and the checked por-
tion are replaced with the appropriate substitute value.

A `~' by itself is replaced by the value of $HOME. A `~' followed by a `+' or a `-' is
replaced by current or previous working directory, respectively.

A `~' followed by a number is replaced by the directory at that position in the directory
stack. `~0' is equivalent to `~+', and `~1' is the top of the stack. `~+' followed by a
number is replaced by the directory at that position in the directory stack. `~+0' is
equivalent to `~+', and `~+1' is the top of the stack. `~-' followed by a number is re-
placed by the directory that many positions from the bottom of the stack. `~-0' is the
bottom of the stack. The PUSHD_MINUS option exchanges the effects of `~+' and `~-' where
they are followed by a number.

Dynamic named directories
If the function zsh_directory_name exists, or the shell variable zsh_directory_name_func-
tions exists and contains an array of function names, then the functions are used to im-
plement dynamic directory naming. The functions are tried in order until one returns sta-
tus zero, so it is important that functions test whether they can handle the case in ques-
tion and return an appropriate status.

A `~' followed by a string namstr in unquoted square brackets is treated specially as a
dynamic directory name. Note that the first unquoted closing square bracket always termi-
nates namstr. The shell function is passed two arguments: the string n (for name) and
namstr. It should either set the array reply to a single element which is the directory
corresponding to the name and return status zero (executing an assignment as the last
statement is usually sufficient), or it should return status non-zero. In the former case
the element of reply is used as the directory; in the latter case the substitution is
deemed to have failed. If all functions fail and the option NOMATCH is set, an error re-
sults.

The functions defined as above are also used to see if a directory can be turned into a
name, for example when printing the directory stack or when expanding %~ in prompts. In
this case each function is passed two arguments: the string d (for directory) and the can-
didate for dynamic naming. The function should either return non-zero status, if the di-
rectory cannot be named by the function, or it should set the array reply to consist of
two elements: the first is the dynamic name for the directory (as would appear within
`~[...]'), and the second is the prefix length of the directory to be replaced. For exam-
ple, if the trial directory is /home/myname/src/zsh and the dynamic name for /home/my-
name/src (which has 16 characters) is s, then the function sets

reply=(s 16)

The directory name so returned is compared with possible static names for parts of the di-
rectory path, as described below; it is used if the prefix length matched (16 in the exam-
ple) is longer than that matched by any static name.

It is not a requirement that a function implements both n and d calls; for example, it
might be appropriate for certain dynamic forms of expansion not to be contracted to names.
In that case any call with the first argument d should cause a non-zero status to be re-
turned.

The completion system calls `zsh_directory_name c' followed by equivalent calls to ele-
ments of the array zsh_directory_name_functions, if it exists, in order to complete dy-
namic names for directories. The code for this should be as for any other completion
function as described in zshcompsys(1).

As a working example, here is a function that expands any dynamic names beginning with the
string p: to directories below /home/pws/perforce. In this simple case a static name for
the directory would be just as effective.

zsh_directory_name() {
emulate -L zsh
setopt extendedglob
local -a match mbegin mend
if [[ $1 = d ]]; then
# turn the directory into a name
if [[ $2 = (#b)(/home/pws/perforce/)([^/]##)* ]]; then
typeset -ga reply
reply=(p:$match[2] $(( ${#match[1]} + ${#match[2]} )) )
else
return 1
fi
elif [[ $1 = n ]]; then
# turn the name into a directory
[[ $2 != (#b)p:(?*) ]] && return 1
typeset -ga reply
reply=(/home/pws/perforce/$match[1])
elif [[ $1 = c ]]; then
# complete names
local expl
local -a dirs
dirs=(/home/pws/perforce/*(/:t))
dirs=(p:${^dirs})
_wanted dynamic-dirs expl 'dynamic directory' compadd -S\] -a dirs
return
else
return 1
fi
return 0
}

Static named directories
A `~' followed by anything not already covered consisting of any number of alphanumeric
characters or underscore (`_'), hyphen (`-'), or dot (`.') is looked up as a named direc-
tory, and replaced by the value of that named directory if found. Named directories are
typically home directories for users on the system. They may also be defined if the text
after the `~' is the name of a string shell parameter whose value begins with a `/'. Note
that trailing slashes will be removed from the path to the directory (though the original
parameter is not modified).

It is also possible to define directory names using the -d option to the hash builtin.

When the shell prints a path (e.g. when expanding %~ in prompts or when printing the di-
rectory stack), the path is checked to see if it has a named directory as its prefix. If
so, then the prefix portion is replaced with a `~' followed by the name of the directory.
The shorter of the two ways of referring to the directory is used, i.e. either the direc-
tory name or the full path; the name is used if they are the same length. The parameters
$PWD and $OLDPWD are never abbreviated in this fashion.

`=' expansion
If a word begins with an unquoted `=' and the EQUALS option is set, the remainder of the
word is taken as the name of a command. If a command exists by that name, the word is re-
placed by the full pathname of the command.

Notes
Filename expansion is performed on the right hand side of a parameter assignment, includ-
ing those appearing after commands of the typeset family. In this case, the right hand
side will be treated as a colon-separated list in the manner of the PATH parameter, so
that a `~' or an `=' following a `:' is eligible for expansion. All such behaviour can be
disabled by quoting the `~', the `=', or the whole expression (but not simply the colon);
the EQUALS option is also respected.

If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in the form `identi-
fier=expression' becomes eligible for file expansion as described in the previous para-
graph. Quoting the first `=' also inhibits this.

FILENAME GENERATION
If a word contains an unquoted instance of one of the characters `*', `(', `|', `<', `[',
or `?', it is regarded as a pattern for filename generation, unless the GLOB option is un-
set. If the EXTENDED_GLOB option is set, the `^' and `#' characters also denote a pat-
tern; otherwise they are not treated specially by the shell.

The word is replaced with a list of sorted filenames that match the pattern. If no match-
ing pattern is found, the shell gives an error message, unless the NULL_GLOB option is
set, in which case the word is deleted; or unless the NOMATCH option is unset, in which
case the word is left unchanged.

In filename generation, the character `/' must be matched explicitly; also, a `.' must be
matched explicitly at the beginning of a pattern or after a `/', unless the GLOB_DOTS op-
tion is set. No filename generation pattern matches the files `.' or `..'. In other in-
stances of pattern matching, the `/' and `.' are not treated specially.

Glob Operators
* Matches any string, including the null string.

? Matches any character.

[...] Matches any of the enclosed characters. Ranges of characters can be specified by
separating two characters by a `-'. A `-' or `]' may be matched by including it as
the first character in the list. There are also several named classes of charac-
ters, in the form `[:name:]' with the following meanings. The first set use the
macros provided by the operating system to test for the given character combina-
tions, including any modifications due to local language settings, see ctype(3):

[:alnum:]
The character is alphanumeric

[:alpha:]
The character is alphabetic

[:ascii:]
The character is 7-bit, i.e. is a single-byte character without the top bit
set.

[:blank:]
The character is a blank character

[:cntrl:]
The character is a control character

[:digit:]
The character is a decimal digit

[:graph:]
The character is a printable character other than whitespace

[:lower:]
The character is a lowercase letter

[:print:]
The character is printable

[:punct:]
The character is printable but neither alphanumeric nor whitespace

[:space:]
The character is whitespace

[:upper:]
The character is an uppercase letter

[:xdigit:]
The character is a hexadecimal digit

Another set of named classes is handled internally by the shell and is not sensi-
tive to the locale:

[:IDENT:]
The character is allowed to form part of a shell identifier, such as a pa-
rameter name

[:IFS:]
The character is used as an input field separator, i.e. is contained in the
IFS parameter

[:IFSSPACE:]
The character is an IFS white space character; see the documentation for IFS
in the zshparam(1) manual page.

[:INCOMPLETE:]
Matches a byte that starts an incomplete multibyte character. Note that
there may be a sequence of more than one bytes that taken together form the
prefix of a multibyte character. To test for a potentially incomplete byte
sequence, use the pattern `[[:INCOMPLETE:]]*'. This will never match a se-
quence starting with a valid multibyte character.

[:INVALID:]
Matches a byte that does not start a valid multibyte character. Note this
may be a continuation byte of an incomplete multibyte character as any part
of a multibyte string consisting of invalid and incomplete multibyte charac-
ters is treated as single bytes.

[:WORD:]
The character is treated as part of a word; this test is sensitive to the
value of the WORDCHARS parameter

Note that the square brackets are additional to those enclosing the whole set of
characters, so to test for a single alphanumeric character you need `[[:alnum:]]'.
Named character sets can be used alongside other types, e.g. `[[:alpha:]0-9]'.

[^...]
[!...] Like [...], except that it matches any character which is not in the given set.

<[x]-[y]>
Matches any number in the range x to y, inclusive. Either of the numbers may be
omitted to make the range open-ended; hence `<->' matches any number. To match in-
dividual digits, the [...] form is more efficient.

Be careful when using other wildcards adjacent to patterns of this form; for exam-
ple, <0-9>* will actually match any number whatsoever at the start of the string,
since the `<0-9>' will match the first digit, and the `*' will match any others.
This is a trap for the unwary, but is in fact an inevitable consequence of the rule
that the longest possible match always succeeds. Expressions such as
`<0-9>[^[:digit:]]*' can be used instead.

(...) Matches the enclosed pattern. This is used for grouping. If the KSH_GLOB option
is set, then a `@', `*', `+', `?' or `!' immediately preceding the `(' is treated
specially, as detailed below. The option SH_GLOB prevents bare parentheses from be-
ing used in this way, though the KSH_GLOB option is still available.

Note that grouping cannot extend over multiple directories: it is an error to have
a `/' within a group (this only applies for patterns used in filename generation).
There is one exception: a group of the form (pat/)# appearing as a complete path
segment can match a sequence of directories. For example, foo/(a*/)#bar matches
foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.

x|y Matches either x or y. This operator has lower precedence than any other. The `|'
character must be within parentheses, to avoid interpretation as a pipeline. The
alternatives are tried in order from left to right.

^x (Requires EXTENDED_GLOB to be set.) Matches anything except the pattern x. This
has a higher precedence than `/', so `^foo/bar' will search directories in `.' ex-
cept `./foo' for a file named `bar'.

x~y (Requires EXTENDED_GLOB to be set.) Match anything that matches the pattern x but
does not match y. This has lower precedence than any operator except `|', so
`*/*~foo/bar' will search for all files in all directories in `.' and then exclude
`foo/bar' if there was such a match. Multiple patterns can be excluded by
`foo~bar~baz'. In the exclusion pattern (y), `/' and `.' are not treated specially
the way they usually are in globbing.

x# (Requires EXTENDED_GLOB to be set.) Matches zero or more occurrences of the pat-
tern x. This operator has high precedence; `12#' is equivalent to `1(2#)', rather
than `(12)#'. It is an error for an unquoted `#' to follow something which cannot
be repeated; this includes an empty string, a pattern already followed by `##', or
parentheses when part of a KSH_GLOB pattern (for example, `!(foo)#' is invalid and
must be replaced by `*(!(foo))').

x## (Requires EXTENDED_GLOB to be set.) Matches one or more occurrences of the pattern
x. This operator has high precedence; `12##' is equivalent to `1(2##)', rather
than `(12)##'. No more than two active `#' characters may appear together. (Note
the potential clash with glob qualifiers in the form `1(2##)' which should there-
fore be avoided.)

ksh-like Glob Operators
If the KSH_GLOB option is set, the effects of parentheses can be modified by a preceding
`@', `*', `+', `?' or `!'. This character need not be unquoted to have special effects,
but the `(' must be.

@(...) Match the pattern in the parentheses. (Like `(...)'.)

*(...) Match any number of occurrences. (Like `(...)#', except that recursive directory
searching is not supported.)

+(...) Match at least one occurrence. (Like `(...)##', except that recursive directory
searching is not supported.)

?(...) Match zero or one occurrence. (Like `(|...)'.)

!(...) Match anything but the expression in parentheses. (Like `(^(...))'.)

Precedence
The precedence of the operators given above is (highest) `^', `/', `~', `|' (lowest); the
remaining operators are simply treated from left to right as part of a string, with `#'
and `##' applying to the shortest possible preceding unit (i.e. a character, `?', `[...]',
`<...>', or a parenthesised expression). As mentioned above, a `/' used as a directory
separator may not appear inside parentheses, while a `|' must do so; in patterns used in
other contexts than filename generation (for example, in case statements and tests within
`[[...]]'), a `/' is not special; and `/' is also not special after a `~' appearing out-
side parentheses in a filename pattern.

Globbing Flags
There are various flags which affect any text to their right up to the end of the enclos-
ing group or to the end of the pattern; they require the EXTENDED_GLOB option. All take
the form (#X) where X may have one of the following forms:

i Case insensitive: upper or lower case characters in the pattern match upper or
lower case characters.

l Lower case characters in the pattern match upper or lower case characters; upper
case characters in the pattern still only match upper case characters.

I Case sensitive: locally negates the effect of i or l from that point on.

b Activate backreferences for parenthesised groups in the pattern; this does not work
in filename generation. When a pattern with a set of active parentheses is
matched, the strings matched by the groups are stored in the array $match, the in-
dices of the beginning of the matched parentheses in the array $mbegin, and the in-
dices of the end in the array $mend, with the first element of each array corre-
sponding to the first parenthesised group, and so on. These arrays are not other-
wise special to the shell. The indices use the same convention as does parameter
substitution, so that elements of $mend and $mbegin may be used in subscripts; the
KSH_ARRAYS option is respected. Sets of globbing flags are not considered paren-
thesised groups; only the first nine active parentheses can be referenced.

For example,

foo="a_string_with_a_message"
if [[ $foo = (a|an)_(#b)(*) ]]; then
print ${foo[$mbegin[1],$mend[1]]}
fi

prints `string_with_a_message'. Note that the first set of parentheses is before
the (#b) and does not create a backreference.

Backreferences work with all forms of pattern matching other than filename genera-
tion, but note that when performing matches on an entire array, such as ${ar-
ray#pattern}, or a global substitution, such as ${param//pat/repl}, only the data
for the last match remains available. In the case of global replacements this may
still be useful. See the example for the m flag below.

The numbering of backreferences strictly follows the order of the opening parenthe-
ses from left to right in the pattern string, although sets of parentheses may be
nested. There are special rules for parentheses followed by `#' or `##'. Only the
last match of the parenthesis is remembered: for example, in `[[ abab = (#b)([ab])#
]]', only the final `b' is stored in match[1]. Thus extra parentheses may be nec-
essary to match the complete segment: for example, use `X((ab|cd)#)Y' to match a
whole string of either `ab' or `cd' between `X' and `Y', using the value of
$match[1] rather than $match[2].

If the match fails none of the parameters is altered, so in some cases it may be
necessary to initialise them beforehand. If some of the backreferences fail to
match -- which happens if they are in an alternate branch which fails to match, or
if they are followed by # and matched zero times -- then the matched string is set
to the empty string, and the start and end indices are set to -1.

Pattern matching with backreferences is slightly slower than without.

B Deactivate backreferences, negating the effect of the b flag from that point on.

cN,M The flag (#cN,M) can be used anywhere that the # or ## operators can be used except
in the expressions `(*/)#' and `(*/)##' in filename generation, where `/' has spe-
cial meaning; it cannot be combined with other globbing flags and a bad pattern er-
ror occurs if it is misplaced. It is equivalent to the form {N,M} in regular ex-
pressions. The previous character or group is required to match between N and M
times, inclusive. The form (#cN) requires exactly N matches; (#c,M) is equivalent
to specifying N as 0; (#cN,) specifies that there is no maximum limit on the number
of matches.

m Set references to the match data for the entire string matched; this is similar to
backreferencing and does not work in filename generation. The flag must be in ef-
fect at the end of the pattern, i.e. not local to a group. The parameters $MATCH,
$MBEGIN and $MEND will be set to the string matched and to the indices of the be-
ginning and end of the string, respectively. This is most useful in parameter sub-
stitutions, as otherwise the string matched is obvious.

For example,

arr=(veldt jynx grimps waqf zho buck)
print ${arr//(#m)[aeiou]/${(U)MATCH}}

forces all the matches (i.e. all vowels) into uppercase, printing `vEldt jynx
grImps wAqf zhO bUck'.

Unlike backreferences, there is no speed penalty for using match references, other
than the extra substitutions required for the replacement strings in cases such as
the example shown.

M Deactivate the m flag, hence no references to match data will be created.

anum Approximate matching: num errors are allowed in the string matched by the pattern.
The rules for this are described in the next subsection.

s, e Unlike the other flags, these have only a local effect, and each must appear on its
own: `(#s)' and `(#e)' are the only valid forms. The `(#s)' flag succeeds only at
the start of the test string, and the `(#e)' flag succeeds only at the end of the
test string; they correspond to `^' and `$' in standard regular expressions. They
are useful for matching path segments in patterns other than those in filename gen-
eration (where path segments are in any case treated separately). For example,
`*((#s)|/)test((#e)|/)*' matches a path segment `test' in any of the following
strings: test, test/at/start, at/end/test, in/test/middle.

Another use is in parameter substitution; for example `${array/(#s)A*Z(#e)}' will
remove only elements of an array which match the complete pattern `A*Z'. There are
other ways of performing many operations of this type, however the combination of
the substitution operations `/' and `//' with the `(#s)' and `(#e)' flags provides
a single simple and memorable method.

Note that assertions of the form `(^(#s))' also work, i.e. match anywhere except at
the start of the string, although this actually means `anything except a
zero-length portion at the start of the string'; you need to use `(""~(#s))' to
match a zero-length portion of the string not at the start.

q A `q' and everything up to the closing parenthesis of the globbing flags are ig-
nored by the pattern matching code. This is intended to support the use of glob
qualifiers, see below. The result is that the pattern `(#b)(*).c(#q.)' can be used
both for globbing and for matching against a string. In the former case, the
`(#q.)' will be treated as a glob qualifier and the `(#b)' will not be useful,
while in the latter case the `(#b)' is useful for backreferences and the `(#q.)'
will be ignored. Note that colon modifiers in the glob qualifiers are also not ap-
plied in ordinary pattern matching.

u Respect the current locale in determining the presence of multibyte characters in a
pattern, provided the shell was compiled with MULTIBYTE_SUPPORT. This overrides
the MULTIBYTE option; the default behaviour is taken from the option. Compare U.
(Mnemonic: typically multibyte characters are from Unicode in the UTF-8 encoding,
although any extension of ASCII supported by the system library may be used.)

U All characters are considered to be a single byte long. The opposite of u. This
overrides the MULTIBYTE option.

For example, the test string fooxx can be matched by the pattern (#i)FOOXX, but not by
(#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X. The string (#ia2)readme specifies case-insensi-
tive matching of readme with up to two errors.

When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB must be set and the
left parenthesis should be preceded by @. Note also that the flags do not affect letters
inside [...] groups, in other words (#i)[a-z] still matches only lowercase letters. Fi-
nally, note that when examining whole paths case-insensitively every directory must be
searched for all files which match, so that a pattern of the form (#i)/foo/bar/... is po-
tentially slow.

Approximate Matching
When matching approximately, the shell keeps a count of the errors found, which cannot ex-
ceed the number specified in the (#anum) flags. Four types of error are recognised:

1. Different characters, as in fooxbar and fooybar.

2. Transposition of characters, as in banana and abnana.

3. A character missing in the target string, as with the pattern road and target
string rod.

4. An extra character appearing in the target string, as with stove and strove.

Thus, the pattern (#a3)abcd matches dcba, with the errors occurring by using the first
rule twice and the second once, grouping the string as [d][cb][a] and [a][bc][d].

Non-literal parts of the pattern must match exactly, including characters in character
ranges: hence (#a1)??? matches strings of length four, by applying rule 4 to an empty
part of the pattern, but not strings of length two, since all the ? must match. Other
characters which must match exactly are initial dots in filenames (unless the GLOB_DOTS
option is set), and all slashes in filenames, so that a/bc is two errors from ab/c (the
slash cannot be transposed with another character). Similarly, errors are counted sepa-
rately for non-contiguous strings in the pattern, so that (ab|cd)ef is two errors from
aebf.

When using exclusion via the ~ operator, approximate matching is treated entirely sepa-
rately for the excluded part and must be activated separately. Thus, (#a1)README~READ_ME
matches READ.ME but not READ_ME, as the trailing READ_ME is matched without approximation.
However, (#a1)README~(#a1)READ_ME does not match any pattern of the form READ?ME as all
such forms are now excluded.

Apart from exclusions, there is only one overall error count; however, the maximum errors
allowed may be altered locally, and this can be delimited by grouping. For example,
(#a1)cat((#a0)dog)fox allows one error in total, which may not occur in the dog section,
and the pattern (#a1)cat(#a0)dog(#a1)fox is equivalent. Note that the point at which an
error is first found is the crucial one for establishing whether to use approximation; for
example, (#a1)abc(#a0)xyz will not match abcdxyz, because the error occurs at the `x',
where approximation is turned off.

Entire path segments may be matched approximately, so that `(#a1)/foo/d/is/avail-
able/at/the/bar' allows one error in any path segment. This is much less efficient than
without the (#a1), however, since every directory in the path must be scanned for a possi-
ble approximate match. It is best to place the (#a1) after any path segments which are
known to be correct.

Recursive Globbing
A pathname component of the form `(foo/)#' matches a path consisting of zero or more di-
rectories matching the pattern foo.

As a shorthand, `**/' is equivalent to `(*/)#'; note that this therefore matches files in
the current directory as well as subdirectories. Thus:

ls -ld -- (*/)#bar

ls -ld -- **/bar

does a recursive directory search for files named `bar' (potentially including the file
`bar' in the current directory). This form does not follow symbolic links; the alterna-
tive form `***/' does, but is otherwise identical. Neither of these can be combined with
other forms of globbing within the same path segment; in that case, the `*' operators re-
vert to their usual effect.

Even shorter forms are available when the option GLOB_STAR_SHORT is set. In that case if
no / immediately follows a ** or *** they are treated as if both a / plus a further * are
present. Hence:

setopt GLOBSTARSHORT
ls -ld -- **.c

is equivalent to

ls -ld -- **/*.c

Glob Qualifiers
Patterns used for filename generation may end in a list of qualifiers enclosed in paren-
theses. The qualifiers specify which filenames that otherwise match the given pattern
will be inserted in the argument list.

If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses containing no `|'
or `(' characters (or `~' if it is special) is taken as a set of glob qualifiers. A glob
subexpression that would normally be taken as glob qualifiers, for example `(^x)', can be
forced to be treated as part of the glob pattern by doubling the parentheses, in this case
producing `((^x))'.

If the option EXTENDED_GLOB is set, a different syntax for glob qualifiers is available,
namely `(#qx)' where x is any of the same glob qualifiers used in the other format. The
qualifiers must still appear at the end of the pattern. However, with this syntax multi-
ple glob qualifiers may be chained together. They are treated as a logical AND of the in-
dividual sets of flags. Also, as the syntax is unambiguous, the expression will be
treated as glob qualifiers just as long any parentheses contained within it are balanced;
appearance of `|', `(' or `~' does not negate the effect. Note that qualifiers will be
recognised in this form even if a bare glob qualifier exists at the end of the pattern,
for example `*(#q*)(.)' will recognise executable regular files if both options are set;
however, mixed syntax should probably be avoided for the sake of clarity. Note that
within conditions using the `[[' form the presence of a parenthesised expression (#q...)
at the end of a string indicates that globbing should be performed; the expression may in-
clude glob qualifiers, but it is also valid if it is simply (#q). This does not apply to
the right hand side of pattern match operators as the syntax already has special signifi-
cance.

A qualifier may be any one of the following:

/ directories

F `full' (i.e. non-empty) directories. Note that the opposite sense (^F) expands to
empty directories and all non-directories. Use (/^F) for empty directories.

. plain files

@ symbolic links

= sockets

p named pipes (FIFOs)

* executable plain files (0100 or 0010 or 0001)

% device files (character or block special)

%b block special files

%c character special files

r owner-readable files (0400)

w owner-writable files (0200)

x owner-executable files (0100)

A group-readable files (0040)

I group-writable files (0020)

E group-executable files (0010)

R world-readable files (0004)

W world-writable files (0002)

X world-executable files (0001)

s setuid files (04000)

S setgid files (02000)

t files with the sticky bit (01000)

fspec files with access rights matching spec. This spec may be a octal number optionally
preceded by a `=', a `+', or a `-'. If none of these characters is given, the be-
havior is the same as for `='. The octal number describes the mode bits to be ex-
pected, if combined with a `=', the value given must match the file-modes exactly,
with a `+', at least the bits in the given number must be set in the file-modes,
and with a `-', the bits in the number must not be set. Giving a `?' instead of a
octal digit anywhere in the number ensures that the corresponding bits in the
file-modes are not checked, this is only useful in combination with `='.

If the qualifier `f' is followed by any other character anything up to the next
matching character (`[', `{', and `<' match `]', `}', and `>' respectively, any
other character matches itself) is taken as a list of comma-separated sub-specs.
Each sub-spec may be either an octal number as described above or a list of any of
the characters `u', `g', `o', and `a', followed by a `=', a `+', or a `-', followed
by a list of any of the characters `r', `w', `x', `s', and `t', or an octal digit.
The first list of characters specify which access rights are to be checked. If a
`u' is given, those for the owner of the file are used, if a `g' is given, those of
the group are checked, a `o' means to test those of other users, and the `a' says
to test all three groups. The `=', `+', and `-' again says how the modes are to be
checked and have the same meaning as described for the first form above. The second
list of characters finally says which access rights are to be expected: `r' for
read access, `w' for write access, `x' for the right to execute the file (or to
search a directory), `s' for the setuid and setgid bits, and `t' for the sticky
bit.

Thus, `*(f70?)' gives the files for which the owner has read, write, and execute
permission, and for which other group members have no rights, independent of the
permissions for other users. The pattern `*(f-100)' gives all files for which the
owner does not have execute permission, and `*(f:gu+w,o-rx:)' gives the files for
which the owner and the other members of the group have at least write permission,
and for which other users don't have read or execute permission.

estring
+cmd The string will be executed as shell code. The filename will be included in the
list if and only if the code returns a zero status (usually the status of the last
command).

In the first form, the first character after the `e' will be used as a separator
and anything up to the next matching separator will be taken as the string; `[',
`{', and `<' match `]', `}', and `>', respectively, while any other character
matches itself. Note that expansions must be quoted in the string to prevent them
from being expanded before globbing is done. string is then executed as shell
code. The string globqual is appended to the array zsh_eval_context the duration
of execution.

During the execution of string the filename currently being tested is available in
the parameter REPLY; the parameter may be altered to a string to be inserted into
the list instead of the original filename. In addition, the parameter reply may be
set to an array or a string, which overrides the value of REPLY. If set to an ar-
ray, the latter is inserted into the command line word by word.

For example, suppose a directory contains a single file `lonely'. Then the expres-
sion `*(e:'reply=(${REPLY}{1,2})':)' will cause the words `lonely1' and `lonely2'
to be inserted into the command line. Note the quoting of string.

The form +cmd has the same effect, but no delimiters appear around cmd. Instead,
cmd is taken as the longest sequence of characters following the + that are al-
phanumeric or underscore. Typically cmd will be the name of a shell function that
contains the appropriate test. For example,

nt() { [[ $REPLY -nt $NTREF ]] }
NTREF=reffile
ls -ld -- *(+nt)

lists all files in the directory that have been modified more recently than ref-
file.

ddev files on the device dev

l[-|+]ct
files having a link count less than ct (-), greater than ct (+), or equal to ct

U files owned by the effective user ID

G files owned by the effective group ID

uid files owned by user ID id if that is a number. Otherwise, id specifies a user
name: the character after the `u' will be taken as a separator and the string be-
tween it and the next matching separator will be taken as a user name. The start-
ing separators `[', `{', and `<' match the final separators `]', `}', and `>', re-
spectively; any other character matches itself. The selected files are those owned
by this user. For example, `u:foo:' or `u[foo]' selects files owned by user `foo'.

gid like uid but with group IDs or names

a[Mwhms][-|+]n
files accessed exactly n days ago. Files accessed within the last n days are se-
lected using a negative value for n (-n). Files accessed more than n days ago are
selected by a positive n value (+n). Optional unit specifiers `M', `w', `h', `m'
or `s' (e.g. `ah5') cause the check to be performed with months (of 30 days),
weeks, hours, minutes or seconds instead of days, respectively. An explicit `d'
for days is also allowed.

Any fractional part of the difference between the access time and the current part
in the appropriate units is ignored in the comparison. For instance, `echo
*(ah-5)' would echo files accessed within the last five hours, while `echo *(ah+5)'
would echo files accessed at least six hours ago, as times strictly between five
and six hours are treated as five hours.

m[Mwhms][-|+]n
like the file access qualifier, except that it uses the file modification time.

c[Mwhms][-|+]n
like the file access qualifier, except that it uses the file inode change time.

L[+|-]n
files less than n bytes (-), more than n bytes (+), or exactly n bytes in length.

If this flag is directly followed by a size specifier `k' (`K'), `m' (`M'), or `p'
(`P') (e.g. `Lk-50') the check is performed with kilobytes, megabytes, or blocks
(of 512 bytes) instead. (On some systems additional specifiers are available for
gigabytes, `g' or `G', and terabytes, `t' or `T'.) If a size specifier is used a
file is regarded as "exactly" the size if the file size rounded up to the next unit
is equal to the test size. Hence `*(Lm1)' matches files from 1 byte up to 1
Megabyte inclusive. Note also that the set of files "less than" the test size only
includes files that would not match the equality test; hence `*(Lm-1)' only matches
files of zero size.

^ negates all qualifiers following it

- toggles between making the qualifiers work on symbolic links (the default) and the
files they point to

M sets the MARK_DIRS option for the current pattern

T appends a trailing qualifier mark to the filenames, analogous to the LIST_TYPES op-
tion, for the current pattern (overrides M)

N sets the NULL_GLOB option for the current pattern

D sets the GLOB_DOTS option for the current pattern

n sets the NUMERIC_GLOB_SORT option for the current pattern

Yn enables short-circuit mode: the pattern will expand to at most n filenames. If
more than n matches exist, only the first n matches in directory traversal order
will be considered.

Implies oN when no oc qualifier is used.

oc specifies how the names of the files should be sorted. If c is n they are sorted by
name; if it is L they are sorted depending on the size (length) of the files; if l
they are sorted by the number of links; if a, m, or c they are sorted by the time
of the last access, modification, or inode change respectively; if d, files in sub-
directories appear before those in the current directory at each level of the
search -- this is best combined with other criteria, for example `odon' to sort on
names for files within the same directory; if N, no sorting is performed. Note
that a, m, and c compare the age against the current time, hence the first name in
the list is the youngest file. Also note that the modifiers ^ and - are used, so
`*(^-oL)' gives a list of all files sorted by file size in descending order, fol-
lowing any symbolic links. Unless oN is used, multiple order specifiers may occur
to resolve ties.

The default sorting is n (by name) unless the Y glob qualifier is used, in which
case it is N (unsorted).

oe and o+ are special cases; they are each followed by shell code, delimited as for
the e glob qualifier and the + glob qualifier respectively (see above). The code
is executed for each matched file with the parameter REPLY set to the name of the
file on entry and globsort appended to zsh_eval_context. The code should modify
the parameter REPLY in some fashion. On return, the value of the parameter is used
instead of the file name as the string on which to sort. Unlike other sort opera-
tors, oe and o+ may be repeated, but note that the maximum number of sort operators
of any kind that may appear in any glob expression is 12.

Oc like `o', but sorts in descending order; i.e. `*(^oc)' is the same as `*(Oc)' and
`*(^Oc)' is the same as `*(oc)'; `Od' puts files in the current directory before
those in subdirectories at each level of the search.

[beg[,end]]
specifies which of the matched filenames should be included in the returned list.
The syntax is the same as for array subscripts. beg and the optional end may be
mathematical expressions. As in parameter subscripting they may be negative to make
them count from the last match backward. E.g.: `*(-OL[1,3])' gives a list of the
names of the three largest files.

Pstring
The string will be prepended to each glob match as a separate word. string is de-
limited in the same way as arguments to the e glob qualifier described above. The
qualifier can be repeated; the words are prepended separately so that the resulting
command line contains the words in the same order they were given in the list of
glob qualifiers.

A typical use for this is to prepend an option before all occurrences of a file
name; for example, the pattern `*(P:-f:)' produces the command line arguments `-f
file1 -f file2 ...'

If the modifier ^ is active, then string will be appended instead of prepended.
Prepending and appending is done independently so both can be used on the same glob
expression; for example by writing `*(P:foo:^P:bar:^P:baz:)' which produces the
command line arguments `foo baz file1 bar ...'

More than one of these lists can be combined, separated by commas. The whole list matches
if at least one of the sublists matches (they are `or'ed, the qualifiers in the sublists
are `and'ed). Some qualifiers, however, affect all matches generated, independent of the
sublist in which they are given. These are the qualifiers `M', `T', `N', `D', `n', `o',
`O' and the subscripts given in brackets (`[...]').

If a `:' appears in a qualifier list, the remainder of the expression in parenthesis is
interpreted as a modifier (see the section `Modifiers' in the section `History Expan-
sion'). Each modifier must be introduced by a separate `:'. Note also that the result
after modification does not have to be an existing file. The name of any existing file
can be followed by a modifier of the form `(:...)' even if no actual filename generation
is performed, although note that the presence of the parentheses causes the entire expres-
sion to be subjected to any global pattern matching options such as NULL_GLOB. Thus:

ls -ld -- *(-/)

lists all directories and symbolic links that point to directories, and

ls -ld -- *(-@)

lists all broken symbolic links, and

ls -ld -- *(%W)

lists all world-writable device files in the current directory, and

ls -ld -- *(W,X)

lists all files in the current directory that are world-writable or world-executable, and

print -rC1 /tmp/foo*(u0^@:t)

outputs the basename of all root-owned files beginning with the string `foo' in /tmp, ig-
noring symlinks, and

ls -ld -- *.*~(lex|parse).[ch](^D^l1)

lists all files having a link count of one whose names contain a dot (but not those start-
ing with a dot, since GLOB_DOTS is explicitly switched off) except for lex.c, lex.h,
parse.c and parse.h.

print -rC1 b*.pro(#q:s/pro/shmo/)(#q.:s/builtin/shmiltin/)

demonstrates how colon modifiers and other qualifiers may be chained together. The ordi-
nary qualifier `.' is applied first, then the colon modifiers in order from left to right.
So if EXTENDED_GLOB is set and the base pattern matches the regular file builtin.pro, the
shell will print `shmiltin.shmo'.

ZSHPARAM(1) General Commands Manual ZSHPARAM(1)

NAME
zshparam - zsh parameters

DESCRIPTION
A parameter has a name, a value, and a number of attributes. A name may be any sequence
of alphanumeric characters and underscores, or the single characters `*', `@', `#', `?',
`-', `$', or `!'. A parameter whose name begins with an alphanumeric or underscore is
also referred to as a variable.

The attributes of a parameter determine the type of its value, often referred to as the
parameter type or variable type, and also control other processing that may be applied to
the value when it is referenced. The value type may be a scalar (a string, an integer, or
a floating point number), an array (indexed numerically), or an associative array (an un-
ordered set of name-value pairs, indexed by name, also referred to as a hash).

Named scalar parameters may have the exported, -x, attribute, to copy them into the
process environment, which is then passed from the shell to any new processes that it
starts. Exported parameters are called environment variables. The shell also imports en-
vironment variables at startup time and automatically marks the corresponding parameters
as exported. Some environment variables are not imported for reasons of security or be-
cause they would interfere with the correct operation of other shell features.

Parameters may also be special, that is, they have a predetermined meaning to the shell.
Special parameters cannot have their type changed or their readonly attribute turned off,
and if a special parameter is unset, then later recreated, the special properties will be
retained.

To declare the type of a parameter, or to assign a string or numeric value to a scalar pa-
rameter, use the typeset builtin.

The value of a scalar parameter may also be assigned by writing:

name=value

In scalar assignment, value is expanded as a single string, in which the elements of ar-
rays are joined together; filename expansion is not performed unless the option GLOB_AS-
SIGN is set.

When the integer attribute, -i, or a floating point attribute, -E or -F, is set for name,
the value is subject to arithmetic evaluation. Furthermore, by replacing `=' with `+=', a
parameter can be incremented or appended to. See the section `Array Parameters' and
Arithmetic Evaluation (in zshmisc(1)) for additional forms of assignment.

Note that assignment may implicitly change the attributes of a parameter. For example,
assigning a number to a variable in arithmetic evaluation may change its type to integer
or float, and with GLOB_ASSIGN assigning a pattern to a variable may change its type to an
array.

To reference the value of a parameter, write `$name' or `${name}'. See Parameter Expan-
sion in zshexpn(1) for complete details. That section also explains the effect of the
difference between scalar and array assignment on parameter expansion.

ARRAY PARAMETERS
To assign an array value, write one of:

set -A name value ...
name=(value ...)
name=([key]=value ...)

If no parameter name exists, an ordinary array parameter is created. If the parameter
name exists and is a scalar, it is replaced by a new array.

In the third form, key is an expression that will be evaluated in arithmetic context (in
its simplest form, an integer) that gives the index of the element to be assigned with
value. In this form any elements not explicitly mentioned that come before the largest
index to which a value is assigned are assigned an empty string. The indices may be in
any order. Note that this syntax is strict: [ and ]= must not be quoted, and key may not
consist of the unquoted string ]=, but is otherwise treated as a simple string. The en-
hanced forms of subscript expression that may be used when directly subscripting a vari-
able name, described in the section Array Subscripts below, are not available.

The syntaxes with and without the explicit key may be mixed. An implicit key is deduced
by incrementing the index from the previously assigned element. Note that it is not
treated as an error if latter assignments in this form overwrite earlier assignments.

For example, assuming the option KSH_ARRAYS is not set, the following:

array=(one [3]=three four)

causes the array variable array to contain four elements one, an empty string, three and
four, in that order.

In the forms where only value is specified, full command line expansion is performed.

In the [key]=value form, both key and value undergo all forms of expansion allowed for
single word shell expansions (this does not include filename generation); these are as
performed by the parameter expansion flag (e) as described in zshexpn(1). Nested paren-
theses may surround value and are included as part of the value, which is joined into a
plain string; this differs from ksh which allows the values themselves to be arrays. A
future version of zsh may support that. To cause the brackets to be interpreted as a
character class for filename generation, and therefore to treat the resulting list of
files as a set of values, quote the equal sign using any form of quoting. Example:

name=([a-z]'='*)

To append to an array without changing the existing values, use one of the following:

name+=(value ...)
name+=([key]=value ...)

In the second form key may specify an existing index as well as an index off the end of
the old array; any existing value is overwritten by value. Also, it is possible to use
[key]+=value to append to the existing value at that index.

Within the parentheses on the right hand side of either form of the assignment, newlines
and semicolons are treated the same as white space, separating individual values. Any
consecutive sequence of such characters has the same effect.

Ordinary array parameters may also be explicitly declared with:

typeset -a name

Associative arrays must be declared before assignment, by using:

typeset -A name

When name refers to an associative array, the list in an assignment is interpreted as al-
ternating keys and values:

set -A name key value ...
name=(key value ...)
name=([key]=value ...)

Note that only one of the two syntaxes above may be used in any given assignment; the
forms may not be mixed. This is unlike the case of numerically indexed arrays.

Every key must have a value in this case. Note that this assigns to the entire array,
deleting any elements that do not appear in the list. The append syntax may also be used
with an associative array:

name+=(key value ...)
name+=([key]=value ...)

This adds a new key/value pair if the key is not already present, and replaces the value
for the existing key if it is. In the second form it is also possible to use [key]+=value
to append to the existing value at that key. Expansion is performed identically to the
corresponding forms for normal arrays, as described above.

To create an empty array (including associative arrays), use one of:

set -A name
name=()

Array Subscripts
Individual elements of an array may be selected using a subscript. A subscript of the
form `[exp]' selects the single element exp, where exp is an arithmetic expression which
will be subject to arithmetic expansion as if it were surrounded by `$((...))'. The ele-
ments are numbered beginning with 1, unless the KSH_ARRAYS option is set in which case
they are numbered from zero.

Subscripts may be used inside braces used to delimit a parameter name, thus `${foo[2]}' is
equivalent to `$foo[2]'. If the KSH_ARRAYS option is set, the braced form is the only one
that works, as bracketed expressions otherwise are not treated as subscripts.

If the KSH_ARRAYS option is not set, then by default accesses to an array element with a
subscript that evaluates to zero return an empty string, while an attempt to write such an
element is treated as an error. For backward compatibility the KSH_ZERO_SUBSCRIPT option
can be set to cause subscript values 0 and 1 to be equivalent; see the description of the
option in zshoptions(1).

The same subscripting syntax is used for associative arrays, except that no arithmetic ex-
pansion is applied to exp. However, the parsing rules for arithmetic expressions still
apply, which affects the way that certain special characters must be protected from inter-
pretation. See Subscript Parsing below for details.

A subscript of the form `[*]' or `[@]' evaluates to all elements of an array; there is no
difference between the two except when they appear within double quotes. `"$foo[*]"'
evaluates to `"$foo[1] $foo[2] ..."', whereas `"$foo[@]"' evaluates to `"$foo[1]"
"$foo[2]" ...'. For associative arrays, `[*]' or `[@]' evaluate to all the values, in no
particular order. Note that this does not substitute the keys; see the documentation for
the `k' flag under Parameter Expansion Flags in zshexpn(1) for complete details. When an
array parameter is referenced as `$name' (with no subscript) it evaluates to `$name[*]',
unless the KSH_ARRAYS option is set in which case it evaluates to `${name[0]}' (for an as-
sociative array, this means the value of the key `0', which may not exist even if there
are values for other keys).

A subscript of the form `[exp1,exp2]' selects all elements in the range exp1 to exp2, in-
clusive. (Associative arrays are unordered, and so do not support ranges.) If one of the
subscripts evaluates to a negative number, say -n, then the nth element from the end of
the array is used. Thus `$foo[-3]' is the third element from the end of the array foo,
and `$foo[1,-1]' is the same as `$foo[*]'.

Subscripting may also be performed on non-array values, in which case the subscripts spec-
ify a substring to be extracted. For example, if FOO is set to `foobar', then `echo
$FOO[2,5]' prints `ooba'. Note that some forms of subscripting described below perform
pattern matching, and in that case the substring extends from the start of the match of
the first subscript to the end of the match of the second subscript. For example,

string="abcdefghijklm"
print ${string[(r)d?,(r)h?]}

prints `defghi'. This is an obvious generalisation of the rule for single-character
matches. For a single subscript, only a single character is referenced (not the range of
characters covered by the match).

Note that in substring operations the second subscript is handled differently by the r and
R subscript flags: the former takes the shortest match as the length and the latter the
longest match. Hence in the former case a * at the end is redundant while in the latter
case it matches the whole remainder of the string. This does not affect the result of the
single subscript case as here the length of the match is irrelevant.

Array Element Assignment
A subscript may be used on the left side of an assignment like so:

name[exp]=value

In this form of assignment the element or range specified by exp is replaced by the ex-
pression on the right side. An array (but not an associative array) may be created by as-
signment to a range or element. Arrays do not nest, so assigning a parenthesized list of
values to an element or range changes the number of elements in the array, shifting the
other elements to accommodate the new values. (This is not supported for associative ar-
rays.)

This syntax also works as an argument to the typeset command:

typeset "name[exp]"=value

The value may not be a parenthesized list in this case; only single-element assignments
may be made with typeset. Note that quotes are necessary in this case to prevent the
brackets from being interpreted as filename generation operators. The noglob precommand
modifier could be used instead.

To delete an element of an ordinary array, assign `()' to that element. To delete an ele-
ment of an associative array, use the unset command:

unset "name[exp]"

Subscript Flags
If the opening bracket, or the comma in a range, in any subscript expression is directly
followed by an opening parenthesis, the string up to the matching closing one is consid-
ered to be a list of flags, as in `name[(flags)exp]'.

The flags s, n and b take an argument; the delimiter is shown below as `:', but any char-
acter, or the matching pairs `(...)', `{...}', `[...]', or `<...>', may be used, but note
that `<...>' can only be used if the subscript is inside a double quoted expression or a
parameter substitution enclosed in braces as otherwise the expression is interpreted as a
redirection.

The flags currently understood are:

w If the parameter subscripted is a scalar then this flag makes subscripting work on
words instead of characters. The default word separator is whitespace. When com-
bined with the i or I flag, the effect is to produce the index of the first charac-
ter of the first/last word which matches the given pattern; note that a failed
match in this case always yields 0.

s:string:
This gives the string that separates words (for use with the w flag). The delim-
iter character : is arbitrary; see above.

p Recognize the same escape sequences as the print builtin in the string argument of
a subsequent `s' flag.

f If the parameter subscripted is a scalar then this flag makes subscripting work on
lines instead of characters, i.e. with elements separated by newlines. This is a
shorthand for `pws:\n:'.

r Reverse subscripting: if this flag is given, the exp is taken as a pattern and the
result is the first matching array element, substring or word (if the parameter is
an array, if it is a scalar, or if it is a scalar and the `w' flag is given, re-
spectively). The subscript used is the number of the matching element, so that
pairs of subscripts such as `$foo[(r)??,3]' and `$foo[(r)??,(r)f*]' are possible if
the parameter is not an associative array. If the parameter is an associative ar-
ray, only the value part of each pair is compared to the pattern, and the result is
that value.

If a search through an ordinary array failed, the search sets the subscript to one
past the end of the array, and hence ${array[(r)pattern]} will substitute the empty
string. Thus the success of a search can be tested by using the (i) flag, for ex-
ample (assuming the option KSH_ARRAYS is not in effect):

[[ ${array[(i)pattern]} -le ${#array} ]]

If KSH_ARRAYS is in effect, the -le should be replaced by -lt.

R Like `r', but gives the last match. For associative arrays, gives all possible
matches. May be used for assigning to ordinary array elements, but not for assign-
ing to associative arrays. On failure, for normal arrays this has the effect of
returning the element corresponding to subscript 0; this is empty unless one of the
options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in effect.

Note that in subscripts with both `r' and `R' pattern characters are active even if
they were substituted for a parameter (regardless of the setting of GLOB_SUBST
which controls this feature in normal pattern matching). The flag `e' can be added
to inhibit pattern matching. As this flag does not inhibit other forms of substi-
tution, care is still required; using a parameter to hold the key has the desired
effect:

key2='original key'
print ${array[(Re)$key2]}

i Like `r', but gives the index of the match instead; this may not be combined with a
second argument. On the left side of an assignment, behaves like `r'. For asso-
ciative arrays, the key part of each pair is compared to the pattern, and the first
matching key found is the result. On failure substitutes the length of the array
plus one, as discussed under the description of `r', or the empty string for an as-
sociative array.

I Like `i', but gives the index of the last match, or all possible matching keys in
an associative array. On failure substitutes 0, or the empty string for an asso-
ciative array. This flag is best when testing for values or keys that do not ex-
ist.

k If used in a subscript on an associative array, this flag causes the keys to be in-
terpreted as patterns, and returns the value for the first key found where exp is
matched by the key. Note this could be any such key as no ordering of associative
arrays is defined. This flag does not work on the left side of an assignment to an
associative array element. If used on another type of parameter, this behaves like
`r'.

K On an associative array this is like `k' but returns all values where exp is
matched by the keys. On other types of parameters this has the same effect as `R'.

n:expr:
If combined with `r', `R', `i' or `I', makes them give the nth or nth last match
(if expr evaluates to n). This flag is ignored when the array is associative. The
delimiter character : is arbitrary; see above.

b:expr:
If combined with `r', `R', `i' or `I', makes them begin at the nth or nth last ele-
ment, word, or character (if expr evaluates to n). This flag is ignored when the
array is associative. The delimiter character : is arbitrary; see above.

e This flag causes any pattern matching that would be performed on the subscript to
use plain string matching instead. Hence `${array[(re)*]}' matches only the array
element whose value is *. Note that other forms of substitution such as parameter
substitution are not inhibited.

This flag can also be used to force * or @ to be interpreted as a single key rather
than as a reference to all values. It may be used for either purpose on the left
side of an assignment.

See Parameter Expansion Flags (zshexpn(1)) for additional ways to manipulate the results
of array subscripting.

Subscript Parsing
This discussion applies mainly to associative array key strings and to patterns used for
reverse subscripting (the `r', `R', `i', etc. flags), but it may also affect parameter
substitutions that appear as part of an arithmetic expression in an ordinary subscript.

To avoid subscript parsing limitations in assignments to associative array elements, use
the append syntax:

aa+=('key with "*strange*" characters' 'value string')

The basic rule to remember when writing a subscript expression is that all text between
the opening `[' and the closing `]' is interpreted as if it were in double quotes (see
zshmisc(1)). However, unlike double quotes which normally cannot nest, subscript expres-
sions may appear inside double-quoted strings or inside other subscript expressions (or
both!), so the rules have two important differences.

The first difference is that brackets (`[' and `]') must appear as balanced pairs in a
subscript expression unless they are preceded by a backslash (`\'). Therefore, within a
subscript expression (and unlike true double-quoting) the sequence `\[' becomes `[', and
similarly `\]' becomes `]'. This applies even in cases where a backslash is not normally
required; for example, the pattern `[^[]' (to match any character other than an open
bracket) should be written `[^\[]' in a reverse-subscript pattern. However, note that
`\[^\[\]' and even `\[^[]' mean the same thing, because backslashes are always stripped
when they appear before brackets!

The same rule applies to parentheses (`(' and `)') and braces (`{' and `}'): they must ap-
pear either in balanced pairs or preceded by a backslash, and backslashes that protect
parentheses or braces are removed during parsing. This is because parameter expansions
may be surrounded by balanced braces, and subscript flags are introduced by balanced
parentheses.

The second difference is that a double-quote (`"') may appear as part of a subscript ex-
pression without being preceded by a backslash, and therefore that the two characters `\"'
remain as two characters in the subscript (in true double-quoting, `\"' becomes `"').
However, because of the standard shell quoting rules, any double-quotes that appear must
occur in balanced pairs unless preceded by a backslash. This makes it more difficult to
write a subscript expression that contains an odd number of double-quote characters, but
the reason for this difference is so that when a subscript expression appears inside true
double-quotes, one can still write `\"' (rather than `\\\"') for `"'.

To use an odd number of double quotes as a key in an assignment, use the typeset builtin
and an enclosing pair of double quotes; to refer to the value of that key, again use dou-
ble quotes:

typeset -A aa
typeset "aa[one\"two\"three\"quotes]"=QQQ
print "$aa[one\"two\"three\"quotes]"

It is important to note that the quoting rules do not change when a parameter expansion
with a subscript is nested inside another subscript expression. That is, it is not neces-
sary to use additional backslashes within the inner subscript expression; they are removed
only once, from the innermost subscript outwards. Parameters are also expanded from the
innermost subscript first, as each expansion is encountered left to right in the outer ex-
pression.

A further complication arises from a way in which subscript parsing is not different from
double quote parsing. As in true double-quoting, the sequences `\*', and `\@' remain as
two characters when they appear in a subscript expression. To use a literal `*' or `@' as
an associative array key, the `e' flag must be used:

typeset -A aa
aa[(e)*]=star
print $aa[(e)*]

A last detail must be considered when reverse subscripting is performed. Parameters ap-
pearing in the subscript expression are first expanded and then the complete expression is
interpreted as a pattern. This has two effects: first, parameters behave as if GLOB_SUBST
were on (and it cannot be turned off); second, backslashes are interpreted twice, once
when parsing the array subscript and again when parsing the pattern. In a reverse sub-
script, it's necessary to use four backslashes to cause a single backslash to match liter-
ally in the pattern. For complex patterns, it is often easiest to assign the desired pat-
tern to a parameter and then refer to that parameter in the subscript, because then the
backslashes, brackets, parentheses, etc., are seen only when the complete expression is
converted to a pattern. To match the value of a parameter literally in a reverse sub-
script, rather than as a pattern, use `${(q)name}' (see zshexpn(1)) to quote the expanded
value.

Note that the `k' and `K' flags are reverse subscripting for an ordinary array, but are
not reverse subscripting for an associative array! (For an associative array, the keys in
the array itself are interpreted as patterns by those flags; the subscript is a plain
string in that case.)

One final note, not directly related to subscripting: the numeric names of positional pa-
rameters (described below) are parsed specially, so for example `$2foo' is equivalent to
`${2}foo'. Therefore, to use subscript syntax to extract a substring from a positional
parameter, the expansion must be surrounded by braces; for example, `${2[3,5]}' evaluates
to the third through fifth characters of the second positional parameter, but `$2[3,5]' is
the entire second parameter concatenated with the filename generation pattern `[3,5]'.

POSITIONAL PARAMETERS
The positional parameters provide access to the command-line arguments of a shell func-
tion, shell script, or the shell itself; see the section `Invocation', and also the sec-
tion `Functions'. The parameter n, where n is a number, is the nth positional parameter.
The parameter `$0' is a special case, see the section `Parameters Set By The Shell'.

The parameters *, @ and argv are arrays containing all the positional parameters; thus
`$argv[n]', etc., is equivalent to simply `$n'. Note that the options KSH_ARRAYS or
KSH_ZERO_SUBSCRIPT apply to these arrays as well, so with either of those options set,
`${argv[0]}' is equivalent to `$1' and so on.

Positional parameters may be changed after the shell or function starts by using the set
builtin, by assigning to the argv array, or by direct assignment of the form `n=value'
where n is the number of the positional parameter to be changed. This also creates (with
empty values) any of the positions from 1 to n that do not already have values. Note
that, because the positional parameters form an array, an array assignment of the form
`n=(value ...)' is allowed, and has the effect of shifting all the values at positions
greater than n by as many positions as necessary to accommodate the new values.

LOCAL PARAMETERS
Shell function executions delimit scopes for shell parameters. (Parameters are dynami-
cally scoped.) The typeset builtin, and its alternative forms declare, integer, local and
readonly (but not export), can be used to declare a parameter as being local to the inner-
most scope.

When a parameter is read or assigned to, the innermost existing parameter of that name is
used. (That is, the local parameter hides any less-local parameter.) However, assigning
to a non-existent parameter, or declaring a new parameter with export, causes it to be
created in the outermost scope.

Local parameters disappear when their scope ends. unset can be used to delete a parameter
while it is still in scope; any outer parameter of the same name remains hidden.

Special parameters may also be made local; they retain their special attributes unless ei-
ther the existing or the newly-created parameter has the -h (hide) attribute. This may
have unexpected effects: there is no default value, so if there is no assignment at the
point the variable is made local, it will be set to an empty value (or zero in the case of
integers). The following:

typeset PATH=/new/directory:$PATH

is valid for temporarily allowing the shell or programmes called from it to find the pro-
grams in /new/directory inside a function.

Note that the restriction in older versions of zsh that local parameters were never ex-
ported has been removed.

PARAMETERS SET BY THE SHELL
In the parameter lists that follow, the mark `<S>' indicates that the parameter is spe-
cial. `<Z>' indicates that the parameter does not exist when the shell initializes in sh
or ksh emulation mode.

The following parameters are automatically set by the shell:

! <S> The process ID of the last command started in the background with &, put into the
background with the bg builtin, or spawned with coproc.

# <S> The number of positional parameters in decimal. Note that some confusion may occur
with the syntax $#param which substitutes the length of param. Use ${#} to resolve
ambiguities. In particular, the sequence `$#-...' in an arithmetic expression is
interpreted as the length of the parameter -, q.v.

ARGC <S> <Z>
Same as #.

$ <S> The process ID of this shell. Note that this indicates the original shell started
by invoking zsh; all processes forked from the shells without executing a new pro-
gram, such as subshells started by (...), substitute the same value.

- <S> Flags supplied to the shell on invocation or by the set or setopt commands.

* <S> An array containing the positional parameters.

argv <S> <Z>
Same as *. Assigning to argv changes the local positional parameters, but argv is
not itself a local parameter. Deleting argv with unset in any function deletes it
everywhere, although only the innermost positional parameter array is deleted (so *
and @ in other scopes are not affected).

@ <S> Same as argv[@], even when argv is not set.

? <S> The exit status returned by the last command.

0 <S> The name used to invoke the current shell, or as set by the -c command line option
upon invocation. If the FUNCTION_ARGZERO option is set, $0 is set upon entry to a
shell function to the name of the function, and upon entry to a sourced script to
the name of the script, and reset to its previous value when the function or script
returns.

status <S> <Z>
Same as ?.

pipestatus <S> <Z>
An array containing the exit statuses returned by all commands in the last pipe-
line.

_ <S> The last argument of the previous command. Also, this parameter is set in the en-
vironment of every command executed to the full pathname of the command.

CPUTYPE
The machine type (microprocessor class or machine model), as determined at run
time.

EGID <S>
The effective group ID of the shell process. If you have sufficient privileges,
you may change the effective group ID of the shell process by assigning to this pa-
rameter. Also (assuming sufficient privileges), you may start a single command
with a different effective group ID by `(EGID=gid; command)'

If this is made local, it is not implicitly set to 0, but may be explicitly set lo-
cally.

EUID <S>
The effective user ID of the shell process. If you have sufficient privileges, you
may change the effective user ID of the shell process by assigning to this parame-
ter. Also (assuming sufficient privileges), you may start a single command with a
different effective user ID by `(EUID=uid; command)'

If this is made local, it is not implicitly set to 0, but may be explicitly set lo-
cally.

ERRNO <S>
The value of errno (see errno(3)) as set by the most recently failed system call.
This value is system dependent and is intended for debugging purposes. It is also
useful with the zsh/system module which allows the number to be turned into a name
or message.

FUNCNEST <S>
Integer. If greater than or equal to zero, the maximum nesting depth of shell
functions. When it is exceeded, an error is raised at the point where a function
is called. The default value is determined when the shell is configured, but is
typically 500. Increasing the value increases the danger of a runaway function re-
cursion causing the shell to crash. Setting a negative value turns off the check.

GID <S>
The real group ID of the shell process. If you have sufficient privileges, you may
change the group ID of the shell process by assigning to this parameter. Also (as-
suming sufficient privileges), you may start a single command under a different
group ID by `(GID=gid; command)'

If this is made local, it is not implicitly set to 0, but may be explicitly set lo-
cally.

HISTCMD
The current history event number in an interactive shell, in other words the event
number for the command that caused $HISTCMD to be read. If the current history
event modifies the history, HISTCMD changes to the new maximum history event num-
ber.

HOST The current hostname.

LINENO <S>
The line number of the current line within the current script, sourced file, or
shell function being executed, whichever was started most recently. Note that in
the case of shell functions the line number refers to the function as it appeared
in the original definition, not necessarily as displayed by the functions builtin.

LOGNAME
If the corresponding variable is not set in the environment of the shell, it is
initialized to the login name corresponding to the current login session. This pa-
rameter is exported by default but this can be disabled using the typeset builtin.
The value is set to the string returned by the getlogin(3) system call if that is
available.

MACHTYPE
The machine type (microprocessor class or machine model), as determined at compile
time.

OLDPWD The previous working directory. This is set when the shell initializes and when-
ever the directory changes.

OPTARG <S>
The value of the last option argument processed by the getopts command.

OPTIND <S>
The index of the last option argument processed by the getopts command.

OSTYPE The operating system, as determined at compile time.

PPID <S>
The process ID of the parent of the shell. As for $$, the value indicates the par-
ent of the original shell and does not change in subshells.

PWD The present working directory. This is set when the shell initializes and whenever
the directory changes.

RANDOM <S>
A pseudo-random integer from 0 to 32767, newly generated each time this parameter
is referenced. The random number generator can be seeded by assigning a numeric
value to RANDOM.

The values of RANDOM form an intentionally-repeatable pseudo-random sequence; sub-
shells that reference RANDOM will result in identical pseudo-random values unless
the value of RANDOM is referenced or seeded in the parent shell in between subshell
invocations.

SECONDS <S>
The number of seconds since shell invocation. If this parameter is assigned a
value, then the value returned upon reference will be the value that was assigned
plus the number of seconds since the assignment.

Unlike other special parameters, the type of the SECONDS parameter can be changed
using the typeset command. Only integer and one of the floating point types are
allowed. For example, `typeset -F SECONDS' causes the value to be reported as a
floating point number. The value is available to microsecond accuracy, although
the shell may show more or fewer digits depending on the use of typeset. See the
documentation for the builtin typeset in zshbuiltins(1) for more details.

SHLVL <S>
Incremented by one each time a new shell is started.

signals
An array containing the names of the signals. Note that with the standard zsh num-
bering of array indices, where the first element has index 1, the signals are off-
set by 1 from the signal number used by the operating system. For example, on typ-
ical Unix-like systems HUP is signal number 1, but is referred to as $signals[2].
This is because of EXIT at position 1 in the array, which is used internally by zsh
but is not known to the operating system.

TRY_BLOCK_ERROR <S>
In an always block, indicates whether the preceding list of code caused an error.
The value is 1 to indicate an error, 0 otherwise. It may be reset, clearing the
error condition. See Complex Commands in zshmisc(1)

TRY_BLOCK_INTERRUPT <S>
This variable works in a similar way to TRY_BLOCK_ERROR, but represents the status
of an interrupt from the signal SIGINT, which typically comes from the keyboard
when the user types ^C. If set to 0, any such interrupt will be reset; otherwise,
the interrupt is propagated after the always block.

Note that it is possible that an interrupt arrives during the execution of the al-
ways block; this interrupt is also propagated.

TTY The name of the tty associated with the shell, if any.

TTYIDLE <S>
The idle time of the tty associated with the shell in seconds or -1 if there is no
such tty.

UID <S>
The real user ID of the shell process. If you have sufficient privileges, you may
change the user ID of the shell by assigning to this parameter. Also (assuming
sufficient privileges), you may start a single command under a different user ID by
`(UID=uid; command)'

If this is made local, it is not implicitly set to 0, but may be explicitly set lo-
cally.

USERNAME <S>
The username corresponding to the real user ID of the shell process. If you have
sufficient privileges, you may change the username (and also the user ID and group
ID) of the shell by assigning to this parameter. Also (assuming sufficient privi-
leges), you may start a single command under a different username (and user ID and
group ID) by `(USERNAME=username; command)'

VENDOR The vendor, as determined at compile time.

zsh_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
An array (colon-separated list) indicating the context of shell code that is being
run. Each time a piece of shell code that is stored within the shell is executed a
string is temporarily appended to the array to indicate the type of operation that
is being performed. Read in order the array gives an indication of the stack of
operations being performed with the most immediate context last.

Note that the variable does not give information on syntactic context such as pipe-
lines or subshells. Use $ZSH_SUBSHELL to detect subshells.

The context is one of the following:
cmdarg Code specified by the -c option to the command line that invoked the shell.

cmdsubst
Command substitution using the `...` or $(...) construct.

equalsubst
File substitution using the =(...) construct.

eval Code executed by the eval builtin.

evalautofunc
Code executed with the KSH_AUTOLOAD mechanism in order to define an au-
toloaded function.

fc Code from the shell history executed by the -e option to the fc builtin.

file Lines of code being read directly from a file, for example by the source
builtin.

filecode
Lines of code being read from a .zwc file instead of directly from the
source file.

globqual
Code executed by the e or + glob qualifier.

globsort
Code executed to order files by the o glob qualifier.

insubst
File substitution using the <(...) construct.

loadautofunc
Code read directly from a file to define an autoloaded function.

outsubst
File substitution using the >(...) construct.

sched Code executed by the sched builtin.

shfunc A shell function.

stty Code passed to stty by the STTY environment variable. Normally this is
passed directly to the system's stty command, so this value is unlikely to
be seen in practice.

style Code executed as part of a style retrieved by the zstyle builtin from the
zsh/zutil module.

toplevel
The highest execution level of a script or interactive shell.

trap Code executed as a trap defined by the trap builtin. Traps defined as func-
tions have the context shfunc. As traps are asynchronous they may have a
different hierarchy from other code.

zpty Code executed by the zpty builtin from the zsh/zpty module.

zregexparse-guard
Code executed as a guard by the zregexparse command from the zsh/zutil mod-
ule.

zregexparse-action
Code executed as an action by the zregexparse command from the zsh/zutil
module.

ZSH_ARGZERO
If zsh was invoked to run a script, this is the name of the script. Otherwise, it
is the name used to invoke the current shell. This is the same as the value of $0
when the POSIX_ARGZERO option is set, but is always available.

ZSH_EXECUTION_STRING
If the shell was started with the option -c, this contains the argument passed to
the option. Otherwise it is not set.

ZSH_NAME
Expands to the basename of the command used to invoke this instance of zsh.

ZSH_PATCHLEVEL
The output of `git describe --tags --long' for the zsh repository used to build the
shell. This is most useful in order to keep track of versions of the shell during
development between releases; hence most users should not use it and should instead
rely on $ZSH_VERSION.

zsh_scheduled_events
See the section `The zsh/sched Module' in zshmodules(1).

ZSH_SCRIPT
If zsh was invoked to run a script, this is the name of the script, otherwise it is
unset.

ZSH_SUBSHELL
Readonly integer. Initially zero, incremented each time the shell forks to create
a subshell for executing code. Hence `(print $ZSH_SUBSHELL)' and `print $(print
$ZSH_SUBSHELL)' output 1, while `( (print $ZSH_SUBSHELL) )' outputs 2.

ZSH_VERSION
The version number of the release of zsh.

PARAMETERS USED BY THE SHELL
The following parameters are used by the shell. Again, `<S>' indicates that the parameter
is special and `<Z>' indicates that the parameter does not exist when the shell initial-
izes in sh or ksh emulation mode.

In cases where there are two parameters with an upper- and lowercase form of the same
name, such as path and PATH, the lowercase form is an array and the uppercase form is a
scalar with the elements of the array joined together by colons. These are similar to
tied parameters created via `typeset -T'. The normal use for the colon-separated form is
for exporting to the environment, while the array form is easier to manipulate within the
shell. Note that unsetting either of the pair will unset the other; they retain their
special properties when recreated, and recreating one of the pair will recreate the other.

ARGV0 If exported, its value is used as the argv[0] of external commands. Usually used
in constructs like `ARGV0=emacs nethack'.

BAUD The rate in bits per second at which data reaches the terminal. The line editor
will use this value in order to compensate for a slow terminal by delaying updates
to the display until necessary. If the parameter is unset or the value is zero the
compensation mechanism is turned off. The parameter is not set by default.

This parameter may be profitably set in some circumstances, e.g. for slow modems
dialing into a communications server, or on a slow wide area network. It should be
set to the baud rate of the slowest part of the link for best performance.

cdpath <S> <Z> (CDPATH <S>)
An array (colon-separated list) of directories specifying the search path for the
cd command.

COLUMNS <S>
The number of columns for this terminal session. Used for printing select lists
and for the line editor.

CORRECT_IGNORE
If set, is treated as a pattern during spelling correction. Any potential correc-
tion that matches the pattern is ignored. For example, if the value is `_*' then
completion functions (which, by convention, have names beginning with `_') will
never be offered as spelling corrections. The pattern does not apply to the cor-
rection of file names, as applied by the CORRECT_ALL option (so with the example
just given files beginning with `_' in the current directory would still be com-
pleted).

CORRECT_IGNORE_FILE
If set, is treated as a pattern during spelling correction of file names. Any file
name that matches the pattern is never offered as a correction. For example, if
the value is `.*' then dot file names will never be offered as spelling correc-
tions. This is useful with the CORRECT_ALL option.

DIRSTACKSIZE
The maximum size of the directory stack, by default there is no limit. If the
stack gets larger than this, it will be truncated automatically. This is useful
with the AUTO_PUSHD option.

ENV If the ENV environment variable is set when zsh is invoked as sh or ksh, $ENV is
sourced after the profile scripts. The value of ENV is subjected to parameter ex-
pansion, command substitution, and arithmetic expansion before being interpreted as
a pathname. Note that ENV is not used unless the shell is interactive and zsh is
emulating sh or ksh.

FCEDIT The default editor for the fc builtin. If FCEDIT is not set, the parameter EDITOR
is used; if that is not set either, a builtin default, usually vi, is used.

fignore <S> <Z> (FIGNORE <S>)
An array (colon separated list) containing the suffixes of files to be ignored dur-
ing filename completion. However, if completion only generates files with suffixes
in this list, then these files are completed anyway.

fpath <S> <Z> (FPATH <S>)
An array (colon separated list) of directories specifying the search path for func-
tion definitions. This path is searched when a function with the -u attribute is
referenced. If an executable file is found, then it is read and executed in the
current environment.

histchars <S>
Three characters used by the shell's history and lexical analysis mechanism. The
first character signals the start of a history expansion (default `!'). The second
character signals the start of a quick history substitution (default `^'). The
third character is the comment character (default `#').

The characters must be in the ASCII character set; any attempt to set histchars to
characters with a locale-dependent meaning will be rejected with an error message.

HISTCHARS <S> <Z>
Same as histchars. (Deprecated.)

HISTFILE
The file to save the history in when an interactive shell exits. If unset, the
history is not saved.

HISTORY_IGNORE
If set, is treated as a pattern at the time history files are written. Any poten-
tial history entry that matches the pattern is skipped. For example, if the value
is `fc *' then commands that invoke the interactive history editor are never writ-
ten to the history file.

Note that HISTORY_IGNORE defines a single pattern: to specify alternatives use the
`(first|second|...)' syntax.

Compare the HIST_NO_STORE option or the zshaddhistory hook, either of which would
prevent such commands from being added to the interactive history at all. If you
wish to use HISTORY_IGNORE to stop history being added in the first place, you can
define the following hook:

zshaddhistory() {
emulate -L zsh
## uncomment if HISTORY_IGNORE
## should use EXTENDED_GLOB syntax
# setopt extendedglob
[[ $1 != ${~HISTORY_IGNORE} ]]
}

HISTSIZE <S>
The maximum number of events stored in the internal history list. If you use the
HIST_EXPIRE_DUPS_FIRST option, setting this value larger than the SAVEHIST size
will give you the difference as a cushion for saving duplicated history events.

If this is made local, it is not implicitly set to 0, but may be explicitly set lo-
cally.

HOME <S>
The default argument for the cd command. This is not set automatically by the
shell in sh, ksh or csh emulation, but it is typically present in the environment
anyway, and if it becomes set it has its usual special behaviour.

IFS <S>
Internal field separators (by default space, tab, newline and NUL), that are used
to separate words which result from command or parameter expansion and words read
by the read builtin. Any characters from the set space, tab and newline that ap-
pear in the IFS are called IFS white space. One or more IFS white space characters
or one non-IFS white space character together with any adjacent IFS white space
character delimit a field. If an IFS white space character appears twice consecu-
tively in the IFS, this character is treated as if it were not an IFS white space
character.

If the parameter is unset, the default is used. Note this has a different effect
from setting the parameter to an empty string.

KEYBOARD_HACK
This variable defines a character to be removed from the end of the command line
before interpreting it (interactive shells only). It is intended to fix the problem
with keys placed annoyingly close to return and replaces the SUNKEYBOARDHACK option
which did this for backquotes only. Should the chosen character be one of single-
quote, doublequote or backquote, there must also be an odd number of them on the
command line for the last one to be removed.

For backward compatibility, if the SUNKEYBOARDHACK option is explicitly set, the
value of KEYBOARD_HACK reverts to backquote. If the option is explicitly unset,
this variable is set to empty.

KEYTIMEOUT
The time the shell waits, in hundredths of seconds, for another key to be pressed
when reading bound multi-character sequences.

LANG <S>
This variable determines the locale category for any category not specifically se-
lected via a variable starting with `LC_'.

LC_ALL <S>
This variable overrides the value of the `LANG' variable and the value of any of
the other variables starting with `LC_'.

LC_COLLATE <S>
This variable determines the locale category for character collation information
within ranges in glob brackets and for sorting.

LC_CTYPE <S>
This variable determines the locale category for character handling functions. If
the MULTIBYTE option is in effect this variable or LANG should contain a value that
reflects the character set in use, even if it is a single-byte character set, un-
less only the 7-bit subset (ASCII) is used. For example, if the character set is
ISO-8859-1, a suitable value might be en_US.iso88591 (certain Linux distributions)
or en_US.ISO8859-1 (MacOS).

LC_MESSAGES <S>
This variable determines the language in which messages should be written. Note
that zsh does not use message catalogs.

LC_NUMERIC <S>
This variable affects the decimal point character and thousands separator character
for the formatted input/output functions and string conversion functions. Note
that zsh ignores this setting when parsing floating point mathematical expressions.

LC_TIME <S>
This variable determines the locale category for date and time formatting in prompt
escape sequences.

LINES <S>
The number of lines for this terminal session. Used for printing select lists and
for the line editor.

LISTMAX
In the line editor, the number of matches to list without asking first. If the
value is negative, the list will be shown if it spans at most as many lines as
given by the absolute value. If set to zero, the shell asks only if the top of the
listing would scroll off the screen.

LOGCHECK
The interval in seconds between checks for login/logout activity using the watch
parameter.

MAIL If this parameter is set and mailpath is not set, the shell looks for mail in the
specified file.

MAILCHECK
The interval in seconds between checks for new mail.

mailpath <S> <Z> (MAILPATH <S>)
An array (colon-separated list) of filenames to check for new mail. Each filename
can be followed by a `?' and a message that will be printed. The message will un-
dergo parameter expansion, command substitution and arithmetic expansion with the
variable $_ defined as the name of the file that has changed. The default message
is `You have new mail'. If an element is a directory instead of a file the shell
will recursively check every file in every subdirectory of the element.

manpath <S> <Z> (MANPATH <S> <Z>)
An array (colon-separated list) whose value is not used by the shell. The manpath
array can be useful, however, since setting it also sets MANPATH, and vice versa.

match
mbegin
mend Arrays set by the shell when the b globbing flag is used in pattern matches. See
the subsection Globbing flags in the documentation for Filename Generation in zsh-
expn(1).

MATCH
MBEGIN
MEND Set by the shell when the m globbing flag is used in pattern matches. See the sub-
section Globbing flags in the documentation for Filename Generation in zshexpn(1).

module_path <S> <Z> (MODULE_PATH <S>)
An array (colon-separated list) of directories that zmodload searches for dynami-
cally loadable modules. This is initialized to a standard pathname, usually
`/usr/local/lib/zsh/$ZSH_VERSION'. (The `/usr/local/lib' part varies from instal-
lation to installation.) For security reasons, any value set in the environment
when the shell is started will be ignored.

These parameters only exist if the installation supports dynamic module loading.

NULLCMD <S>
The command name to assume if a redirection is specified with no command. Defaults
to cat. For sh/ksh behavior, change this to :. For csh-like behavior, unset this
parameter; the shell will print an error message if null commands are entered.

path <S> <Z> (PATH <S>)
An array (colon-separated list) of directories to search for commands. When this
parameter is set, each directory is scanned and all files found are put in a hash
table.

POSTEDIT <S>
This string is output whenever the line editor exits. It usually contains termcap
strings to reset the terminal.

PROMPT <S> <Z>
PROMPT2 <S> <Z>
PROMPT3 <S> <Z>
PROMPT4 <S> <Z>
Same as PS1, PS2, PS3 and PS4, respectively.

prompt <S> <Z>
Same as PS1.

PROMPT_EOL_MARK
When the PROMPT_CR and PROMPT_SP options are set, the PROMPT_EOL_MARK parameter can
be used to customize how the end of partial lines are shown. This parameter under-
goes prompt expansion, with the PROMPT_PERCENT option set. If not set, the default
behavior is equivalent to the value `%B%S%#%s%b'.

PS1 <S>
The primary prompt string, printed before a command is read. It undergoes a spe-
cial form of expansion before being displayed; see EXPANSION OF PROMPT SEQUENCES in
zshmisc(1). The default is `%m%# '.

PS2 <S>
The secondary prompt, printed when the shell needs more information to complete a
command. It is expanded in the same way as PS1. The default is `%_> ', which dis-
plays any shell constructs or quotation marks which are currently being processed.

PS3 <S>
Selection prompt used within a select loop. It is expanded in the same way as PS1.
The default is `?# '.

PS4 <S>
The execution trace prompt. Default is `+%N:%i> ', which displays the name of the
current shell structure and the line number within it. In sh or ksh emulation, the
default is `+ '.

psvar <S> <Z> (PSVAR <S>)
An array (colon-separated list) whose elements can be used in PROMPT strings. Set-
ting psvar also sets PSVAR, and vice versa.

READNULLCMD <S>
The command name to assume if a single input redirection is specified with no com-
mand. Defaults to more.

REPORTMEMORY
If nonnegative, commands whose maximum resident set size (roughly speaking, main
memory usage) in kilobytes is greater than this value have timing statistics re-
ported. The format used to output statistics is the value of the TIMEFMT parame-
ter, which is the same as for the REPORTTIME variable and the time builtin; note
that by default this does not output memory usage. Appending " max RSS %M" to the
value of TIMEFMT causes it to output the value that triggered the report. If RE-
PORTTIME is also in use, at most a single report is printed for both triggers.
This feature requires the getrusage() system call, commonly supported by modern
Unix-like systems.

REPORTTIME
If nonnegative, commands whose combined user and system execution times (measured
in seconds) are greater than this value have timing statistics printed for them.
Output is suppressed for commands executed within the line editor, including com-
pletion; commands explicitly marked with the time keyword still cause the summary
to be printed in this case.

REPLY This parameter is reserved by convention to pass string values between shell
scripts and shell builtins in situations where a function call or redirection are
impossible or undesirable. The read builtin and the select complex command may set
REPLY, and filename generation both sets and examines its value when evaluating
certain expressions. Some modules also employ REPLY for similar purposes.

reply As REPLY, but for array values rather than strings.

RPROMPT <S>
RPS1 <S>
This prompt is displayed on the right-hand side of the screen when the primary
prompt is being displayed on the left. This does not work if the SINGLE_LINE_ZLE
option is set. It is expanded in the same way as PS1.

RPROMPT2 <S>
RPS2 <S>
This prompt is displayed on the right-hand side of the screen when the secondary
prompt is being displayed on the left. This does not work if the SINGLE_LINE_ZLE
option is set. It is expanded in the same way as PS2.

SAVEHIST
The maximum number of history events to save in the history file.

If this is made local, it is not implicitly set to 0, but may be explicitly set lo-
cally.

SPROMPT <S>
The prompt used for spelling correction. The sequence `%R' expands to the string
which presumably needs spelling correction, and `%r' expands to the proposed cor-
rection. All other prompt escapes are also allowed.

The actions available at the prompt are [nyae]:
n (`no') (default)
Discard the correction and run the command.
y (`yes')
Make the correction and run the command.
a (`abort')
Discard the entire command line without running it.
e (`edit')
Resume editing the command line.

STTY If this parameter is set in a command's environment, the shell runs the stty com-
mand with the value of this parameter as arguments in order to set up the terminal
before executing the command. The modes apply only to the command, and are reset
when it finishes or is suspended. If the command is suspended and continued later
with the fg or wait builtins it will see the modes specified by STTY, as if it were
not suspended. This (intentionally) does not apply if the command is continued via
`kill -CONT'. STTY is ignored if the command is run in the background, or if it is
in the environment of the shell but not explicitly assigned to in the input line.
This avoids running stty at every external command by accidentally exporting it.
Also note that STTY should not be used for window size specifications; these will
not be local to the command.

TERM <S>
The type of terminal in use. This is used when looking up termcap sequences. An
assignment to TERM causes zsh to re-initialize the terminal, even if the value does
not change (e.g., `TERM=$TERM'). It is necessary to make such an assignment upon
any change to the terminal definition database or terminal type in order for the
new settings to take effect.

TERMINFO <S>
A reference to your terminfo database, used by the `terminfo' library when the sys-
tem has it; see terminfo(5). If set, this causes the shell to reinitialise the
terminal, making the workaround `TERM=$TERM' unnecessary.

TERMINFO_DIRS <S>
A colon-seprarated list of terminfo databases, used by the `terminfo' library when
the system has it; see terminfo(5). This variable is only used by certain terminal
libraries, in particular ncurses; see terminfo(5) to check support on your system.
If set, this causes the shell to reinitialise the terminal, making the workaround
`TERM=$TERM' unnecessary. Note that unlike other colon-separated arrays this is
not tied to a zsh array.

TIMEFMT
The format of process time reports with the time keyword. The default is `%J %U
user %S system %P cpu %*E total'. Recognizes the following escape sequences, al-
though not all may be available on all systems, and some that are available may not
be useful:

%% A `%'.
%U CPU seconds spent in user mode.
%S CPU seconds spent in kernel mode.
%E Elapsed time in seconds.
%P The CPU percentage, computed as 100*(%U+%S)/%E.
%W Number of times the process was swapped.
%X The average amount in (shared) text space used in kilobytes.
%D The average amount in (unshared) data/stack space used in kilobytes.
%K The total space used (%X+%D) in kilobytes.
%M The maximum memory the process had in use at any time in kilobytes.
%F The number of major page faults (page needed to be brought from disk).
%R The number of minor page faults.
%I The number of input operations.
%O The number of output operations.
%r The number of socket messages received.
%s The number of socket messages sent.
%k The number of signals received.
%w Number of voluntary context switches (waits).
%c Number of involuntary context switches.
%J The name of this job.

A star may be inserted between the percent sign and flags printing time (e.g.,
`%*E'); this causes the time to be printed in `hh:mm:ss.ttt' format (hours and min-
utes are only printed if they are not zero). Alternatively, `m' or `u' may be used
(e.g., `%mE') to produce time output in milliseconds or microseconds, respectively.

TMOUT If this parameter is nonzero, the shell will receive an ALRM signal if a command is
not entered within the specified number of seconds after issuing a prompt. If there
is a trap on SIGALRM, it will be executed and a new alarm is scheduled using the
value of the TMOUT parameter after executing the trap. If no trap is set, and the
idle time of the terminal is not less than the value of the TMOUT parameter, zsh
terminates. Otherwise a new alarm is scheduled to TMOUT seconds after the last
keypress.

TMPPREFIX
A pathname prefix which the shell will use for all temporary files. Note that this
should include an initial part for the file name as well as any directory names.
The default is `/tmp/zsh'.

TMPSUFFIX
A filename suffix which the shell will use for temporary files created by process
substitutions (e.g., `=(list)'). Note that the value should include a leading dot
`.' if intended to be interpreted as a file extension. The default is not to ap-
pend any suffix, thus this parameter should be assigned only when needed and then
unset again.

watch <S> <Z> (WATCH <S>)
An array (colon-separated list) of login/logout events to report.

If it contains the single word `all', then all login/logout events are reported.
If it contains the single word `notme', then all events are reported as with `all'
except $USERNAME.

An entry in this list may consist of a username, an `@' followed by a remote host-
name, and a `%' followed by a line (tty). Any of these may be a pattern (be sure
to quote this during the assignment to watch so that it does not immediately per-
form file generation); the setting of the EXTENDED_GLOB option is respected. Any
or all of these components may be present in an entry; if a login/logout event
matches all of them, it is reported.

For example, with the EXTENDED_GLOB option set, the following:

watch=('^(pws|barts)')

causes reports for activity associated with any user other than pws or barts.

WATCHFMT
The format of login/logout reports if the watch parameter is set. Default is `%n
has %a %l from %m'. Recognizes the following escape sequences:

%n The name of the user that logged in/out.

%a The observed action, i.e. "logged on" or "logged off".

%l The line (tty) the user is logged in on.

%M The full hostname of the remote host.

%m The hostname up to the first `.'. If only the IP address is available or
the utmp field contains the name of an X-windows display, the whole name is
printed.

NOTE: The `%m' and `%M' escapes will work only if there is a host name field
in the utmp on your machine. Otherwise they are treated as ordinary
strings.

%S (%s)
Start (stop) standout mode.

%U (%u)
Start (stop) underline mode.

%B (%b)
Start (stop) boldface mode.

%t
%@ The time, in 12-hour, am/pm format.

%T The time, in 24-hour format.

%w The date in `day-dd' format.

%W The date in `mm/dd/yy' format.

%D The date in `yy-mm-dd' format.

%D{string}
The date formatted as string using the strftime function, with zsh exten-
sions as described by EXPANSION OF PROMPT SEQUENCES in zshmisc(1).

%(x:true-text:false-text)
Specifies a ternary expression. The character following the x is arbitrary;
the same character is used to separate the text for the "true" result from
that for the "false" result. Both the separator and the right parenthesis
may be escaped with a backslash. Ternary expressions may be nested.

The test character x may be any one of `l', `n', `m' or `M', which indicate
a `true' result if the corresponding escape sequence would return a
non-empty value; or it may be `a', which indicates a `true' result if the
watched user has logged in, or `false' if he has logged out. Other charac-
ters evaluate to neither true nor false; the entire expression is omitted in
this case.

If the result is `true', then the true-text is formatted according to the
rules above and printed, and the false-text is skipped. If `false', the
true-text is skipped and the false-text is formatted and printed. Either or
both of the branches may be empty, but both separators must be present in
any case.

WORDCHARS <S>
A list of non-alphanumeric characters considered part of a word by the line editor.

ZBEEP If set, this gives a string of characters, which can use all the same codes as the
bindkey command as described in the zsh/zle module entry in zshmodules(1), that
will be output to the terminal instead of beeping. This may have a visible instead
of an audible effect; for example, the string `\e[?5h\e[?5l' on a vt100 or xterm
will have the effect of flashing reverse video on and off (if you usually use re-
verse video, you should use the string `\e[?5l\e[?5h' instead). This takes prece-
dence over the NOBEEP option.

ZDOTDIR
The directory to search for shell startup files (.zshrc, etc), if not $HOME.

zle_bracketed_paste
Many terminal emulators have a feature that allows applications to identify when
text is pasted into the terminal rather than being typed normally. For ZLE, this
means that special characters such as tabs and newlines can be inserted instead of
invoking editor commands. Furthermore, pasted text forms a single undo event and
if the region is active, pasted text will replace the region.

This two-element array contains the terminal escape sequences for enabling and dis-
abling the feature. These escape sequences are used to enable bracketed paste when
ZLE is active and disable it at other times. Unsetting the parameter has the ef-
fect of ensuring that bracketed paste remains disabled.

zle_highlight
An array describing contexts in which ZLE should highlight the input text. See
Character Highlighting in zshzle(1).

ZLE_LINE_ABORTED
This parameter is set by the line editor when an error occurs. It contains the
line that was being edited at the point of the error. `print -zr --
$ZLE_LINE_ABORTED' can be used to recover the line. Only the most recent line of
this kind is remembered.

ZLE_REMOVE_SUFFIX_CHARS
ZLE_SPACE_SUFFIX_CHARS
These parameters are used by the line editor. In certain circumstances suffixes
(typically space or slash) added by the completion system will be removed automati-
cally, either because the next editing command was not an insertable character, or
because the character was marked as requiring the suffix to be removed.

These variables can contain the sets of characters that will cause the suffix to be
removed. If ZLE_REMOVE_SUFFIX_CHARS is set, those characters will cause the suffix
to be removed; if ZLE_SPACE_SUFFIX_CHARS is set, those characters will cause the
suffix to be removed and replaced by a space.

If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is equivalent to:

ZLE_REMOVE_SUFFIX_CHARS=$' \t\n;&|'

If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no characters have this behaviour.
ZLE_SPACE_SUFFIX_CHARS takes precedence, so that the following:

ZLE_SPACE_SUFFIX_CHARS=$'&|'

causes the characters `&' and `|' to remove the suffix but to replace it with a
space.

To illustrate the difference, suppose that the option AUTO_REMOVE_SLASH is in ef-
fect and the directory DIR has just been completed, with an appended /, following
which the user types `&'. The default result is `DIR&'. With ZLE_REMOVE_SUF-
FIX_CHARS set but without including `&' the result is `DIR/&'. With ZLE_SPACE_SUF-
FIX_CHARS set to include `&' the result is `DIR &'.

Note that certain completions may provide their own suffix removal or replacement
behaviour which overrides the values described here. See the completion system
documentation in zshcompsys(1).

ZLE_RPROMPT_INDENT <S>
If set, used to give the indentation between the right hand side of the right
prompt in the line editor as given by RPS1 or RPROMPT and the right hand side of
the screen. If not set, the value 1 is used.

Typically this will be used to set the value to 0 so that the prompt appears flush
with the right hand side of the screen. This is not the default as many terminals
do not handle this correctly, in particular when the prompt appears at the extreme
bottom right of the screen. Recent virtual terminals are more likely to handle
this case correctly. Some experimentation is necessary.

ZSHOPTIONS(1) General Commands Manual ZSHOPTIONS(1)

NAME
zshoptions - zsh options

SPECIFYING OPTIONS
Options are primarily referred to by name. These names are case insensitive and under-
scores are ignored. For example, `allexport' is equivalent to `A__lleXP_ort'.

The sense of an option name may be inverted by preceding it with `no', so `setopt No_Beep'
is equivalent to `unsetopt beep'. This inversion can only be done once, so `nonobeep' is
not a synonym for `beep'. Similarly, `tify' is not a synonym for `nonotify' (the inver-
sion of `notify').

Some options also have one or more single letter names. There are two sets of single let-
ter options: one used by default, and another used to emulate sh/ksh (used when the SH_OP-
TION_LETTERS option is set). The single letter options can be used on the shell command
line, or with the set, setopt and unsetopt builtins, as normal Unix options preceded by
`-'.

The sense of the single letter options may be inverted by using `+' instead of `-'. Some
of the single letter option names refer to an option being off, in which case the inver-
sion of that name refers to the option being on. For example, `+n' is the short name of
`exec', and `-n' is the short name of its inversion, `noexec'.

In strings of single letter options supplied to the shell at startup, trailing whitespace
will be ignored; for example the string `-f ' will be treated just as `-f', but the
string `-f i' is an error. This is because many systems which implement the `#!' mecha-
nism for calling scripts do not strip trailing whitespace.

DESCRIPTION OF OPTIONS
In the following list, options set by default in all emulations are marked <D>; those set
by default only in csh, ksh, sh, or zsh emulations are marked <C>, <K>, <S>, <Z> as appro-
priate. When listing options (by `setopt', `unsetopt', `set -o' or `set +o'), those
turned on by default appear in the list prefixed with `no'. Hence (unless KSH_OP-
TION_PRINT is set), `setopt' shows all options whose settings are changed from the de-
fault.

Changing Directories
AUTO_CD (-J)
If a command is issued that can't be executed as a normal command, and the command
is the name of a directory, perform the cd command to that directory. This option
is only applicable if the option SHIN_STDIN is set, i.e. if commands are being read
from standard input. The option is designed for interactive use; it is recommended
that cd be used explicitly in scripts to avoid ambiguity.

AUTO_PUSHD (-N)
Make cd push the old directory onto the directory stack.

CDABLE_VARS (-T)
If the argument to a cd command (or an implied cd with the AUTO_CD option set) is
not a directory, and does not begin with a slash, try to expand the expression as
if it were preceded by a `~' (see the section `Filename Expansion').

CD_SILENT
Never print the working directory after a cd (whether explicit or implied with the
AUTO_CD option set). cd normally prints the working directory when the argument
given to it was -, a stack entry, or the name of a directory found under CDPATH.
Note that this is distinct from pushd's stack-printing behaviour, which is con-
trolled by PUSHD_SILENT. This option overrides the printing-related effects of
POSIX_CD.

CHASE_DOTS
When changing to a directory containing a path segment `..' which would otherwise
be treated as canceling the previous segment in the path (in other words, `foo/..'
would be removed from the path, or if `..' is the first part of the path, the last
part of the current working directory would be removed), instead resolve the path
to the physical directory. This option is overridden by CHASE_LINKS.

For example, suppose /foo/bar is a link to the directory /alt/rod. Without this
option set, `cd /foo/bar/..' changes to /foo; with it set, it changes to /alt. The
same applies if the current directory is /foo/bar and `cd ..' is used. Note that
all other symbolic links in the path will also be resolved.

CHASE_LINKS (-w)
Resolve symbolic links to their true values when changing directory. This also has
the effect of CHASE_DOTS, i.e. a `..' path segment will be treated as referring to
the physical parent, even if the preceding path segment is a symbolic link.

POSIX_CD <K> <S>
Modifies the behaviour of cd, chdir and pushd commands to make them more compatible
with the POSIX standard. The behaviour with the option unset is described in the
documentation for the cd builtin in zshbuiltins(1). If the option is set, the
shell does not test for directories beneath the local directory (`.') until after
all directories in cdpath have been tested, and the cd and chdir commands do not
recognise arguments of the form `{+|-}n' as directory stack entries.

Also, if the option is set, the conditions under which the shell prints the new di-
rectory after changing to it are modified. It is no longer restricted to interac-
tive shells (although printing of the directory stack with pushd is still limited
to interactive shells); and any use of a component of CDPATH, including a `.' but
excluding an empty component that is otherwise treated as `.', causes the directory
to be printed.

PUSHD_IGNORE_DUPS
Don't push multiple copies of the same directory onto the directory stack.

PUSHD_MINUS
Exchanges the meanings of `+' and `-' when used with a number to specify a direc-
tory in the stack.

PUSHD_SILENT (-E)
Do not print the directory stack after pushd or popd.

PUSHD_TO_HOME (-D)
Have pushd with no arguments act like `pushd $HOME'.

Completion
ALWAYS_LAST_PROMPT <D>
If unset, key functions that list completions try to return to the last prompt if
given a numeric argument. If set these functions try to return to the last prompt
if given no numeric argument.

ALWAYS_TO_END
If a completion is performed with the cursor within a word, and a full completion
is inserted, the cursor is moved to the end of the word. That is, the cursor is
moved to the end of the word if either a single match is inserted or menu comple-
tion is performed.

AUTO_LIST (-9) <D>
Automatically list choices on an ambiguous completion.

AUTO_MENU <D>
Automatically use menu completion after the second consecutive request for comple-
tion, for example by pressing the tab key repeatedly. This option is overridden by
MENU_COMPLETE.

AUTO_NAME_DIRS
Any parameter that is set to the absolute name of a directory immediately becomes a
name for that directory, that will be used by the `%~' and related prompt se-
quences, and will be available when completion is performed on a word starting with
`~'. (Otherwise, the parameter must be used in the form `~param' first.)

AUTO_PARAM_KEYS <D>
If a parameter name was completed and a following character (normally a space) au-
tomatically inserted, and the next character typed is one of those that have to
come directly after the name (like `}', `:', etc.), the automatically added charac-
ter is deleted, so that the character typed comes immediately after the parameter
name. Completion in a brace expansion is affected similarly: the added character
is a `,', which will be removed if `}' is typed next.

AUTO_PARAM_SLASH <D>
If a parameter is completed whose content is the name of a directory, then add a
trailing slash instead of a space.

AUTO_REMOVE_SLASH <D>
When the last character resulting from a completion is a slash and the next charac-
ter typed is a word delimiter, a slash, or a character that ends a command (such as
a semicolon or an ampersand), remove the slash.

BASH_AUTO_LIST
On an ambiguous completion, automatically list choices when the completion function
is called twice in succession. This takes precedence over AUTO_LIST. The setting
of LIST_AMBIGUOUS is respected. If AUTO_MENU is set, the menu behaviour will then
start with the third press. Note that this will not work with MENU_COMPLETE, since
repeated completion calls immediately cycle through the list in that case.

COMPLETE_ALIASES
Prevents aliases on the command line from being internally substituted before com-
pletion is attempted. The effect is to make the alias a distinct command for com-
pletion purposes.

COMPLETE_IN_WORD
If unset, the cursor is set to the end of the word if completion is started. Other-
wise it stays there and completion is done from both ends.

GLOB_COMPLETE
When the current word has a glob pattern, do not insert all the words resulting
from the expansion but generate matches as for completion and cycle through them
like MENU_COMPLETE. The matches are generated as if a `*' was added to the end of
the word, or inserted at the cursor when COMPLETE_IN_WORD is set. This actually
uses pattern matching, not globbing, so it works not only for files but for any
completion, such as options, user names, etc.

Note that when the pattern matcher is used, matching control (for example, case-in-
sensitive or anchored matching) cannot be used. This limitation only applies when
the current word contains a pattern; simply turning on the GLOB_COMPLETE option
does not have this effect.

HASH_LIST_ALL <D>
Whenever a command completion or spelling correction is attempted, make sure the
entire command path is hashed first. This makes the first completion slower but
avoids false reports of spelling errors.

LIST_AMBIGUOUS <D>
This option works when AUTO_LIST or BASH_AUTO_LIST is also set. If there is an un-
ambiguous prefix to insert on the command line, that is done without a completion
list being displayed; in other words, auto-listing behaviour only takes place when
nothing would be inserted. In the case of BASH_AUTO_LIST, this means that the list
will be delayed to the third call of the function.

LIST_BEEP <D>
Beep on an ambiguous completion. More accurately, this forces the completion wid-
gets to return status 1 on an ambiguous completion, which causes the shell to beep
if the option BEEP is also set; this may be modified if completion is called from a
user-defined widget.

LIST_PACKED
Try to make the completion list smaller (occupying less lines) by printing the
matches in columns with different widths.

LIST_ROWS_FIRST
Lay out the matches in completion lists sorted horizontally, that is, the second
match is to the right of the first one, not under it as usual.

LIST_TYPES (-X) <D>
When listing files that are possible completions, show the type of each file with a
trailing identifying mark.

MENU_COMPLETE (-Y)
On an ambiguous completion, instead of listing possibilities or beeping, insert the
first match immediately. Then when completion is requested again, remove the first
match and insert the second match, etc. When there are no more matches, go back to
the first one again. reverse-menu-complete may be used to loop through the list in
the other direction. This option overrides AUTO_MENU.

REC_EXACT (-S)
If the string on the command line exactly matches one of the possible completions,
it is accepted, even if there is another completion (i.e. that string with some-
thing else added) that also matches.

Expansion and Globbing
BAD_PATTERN (+2) <C> <Z>
If a pattern for filename generation is badly formed, print an error message. (If
this option is unset, the pattern will be left unchanged.)

BARE_GLOB_QUAL <Z>
In a glob pattern, treat a trailing set of parentheses as a qualifier list, if it
contains no `|', `(' or (if special) `~' characters. See the section `Filename
Generation'.

BRACE_CCL
Expand expressions in braces which would not otherwise undergo brace expansion to a
lexically ordered list of all the characters. See the section `Brace Expansion'.

CASE_GLOB <D>
Make globbing (filename generation) sensitive to case. Note that other uses of
patterns are always sensitive to case. If the option is unset, the presence of any
character which is special to filename generation will cause case-insensitive
matching. For example, cvs(/) can match the directory CVS owing to the presence of
the globbing flag (unless the option BARE_GLOB_QUAL is unset).

CASE_MATCH <D>
Make regular expressions using the zsh/regex module (including matches with =~)
sensitive to case.

CSH_NULL_GLOB <C>
If a pattern for filename generation has no matches, delete the pattern from the
argument list; do not report an error unless all the patterns in a command have no
matches. Overrides NOMATCH.

EQUALS <Z>
Perform = filename expansion. (See the section `Filename Expansion'.)

EXTENDED_GLOB
Treat the `#', `~' and `^' characters as part of patterns for filename generation,
etc. (An initial unquoted `~' always produces named directory expansion.)

FORCE_FLOAT
Constants in arithmetic evaluation will be treated as floating point even without
the use of a decimal point; the values of integer variables will be converted to
floating point when used in arithmetic expressions. Integers in any base will be
converted.

GLOB (+F, ksh: +f) <D>
Perform filename generation (globbing). (See the section `Filename Generation'.)

GLOB_ASSIGN <C>
If this option is set, filename generation (globbing) is performed on the right
hand side of scalar parameter assignments of the form `name=pattern (e.g. `foo=*').
If the result has more than one word the parameter will become an array with those
words as arguments. This option is provided for backwards compatibility only: glob-
bing is always performed on the right hand side of array assignments of the form
`name=(value)' (e.g. `foo=(*)') and this form is recommended for clarity; with this
option set, it is not possible to predict whether the result will be an array or a
scalar.

GLOB_DOTS (-4)
Do not require a leading `.' in a filename to be matched explicitly.

GLOB_STAR_SHORT
When this option is set and the default zsh-style globbing is in effect, the pat-
tern `**/*' can be abbreviated to `**' and the pattern `***/*' can be abbreviated
to ***. Hence `**.c' finds a file ending in .c in any subdirectory, and `***.c'
does the same while also following symbolic links. A / immediately after the `**'
or `***' forces the pattern to be treated as the unabbreviated form.

GLOB_SUBST <C> <K> <S>
Treat any characters resulting from parameter expansion as being eligible for file-
name expansion and filename generation, and any characters resulting from command
substitution as being eligible for filename generation. Braces (and commas in be-
tween) do not become eligible for expansion.

HIST_SUBST_PATTERN
Substitutions using the :s and :& history modifiers are performed with pattern
matching instead of string matching. This occurs wherever history modifiers are
valid, including glob qualifiers and parameters. See the section Modifiers in zsh-
expn(1).

IGNORE_BRACES (-I) <S>
Do not perform brace expansion. For historical reasons this also includes the ef-
fect of the IGNORE_CLOSE_BRACES option.

IGNORE_CLOSE_BRACES
When neither this option nor IGNORE_BRACES is set, a sole close brace character `}'
is syntactically significant at any point on a command line. This has the effect
that no semicolon or newline is necessary before the brace terminating a function
or current shell construct. When either option is set, a closing brace is syntac-
tically significant only in command position. Unlike IGNORE_BRACES, this option
does not disable brace expansion.

For example, with both options unset a function may be defined in the following
fashion:

args() { echo $# }

while if either option is set, this does not work and something equivalent to the
following is required:

args() { echo $#; }

KSH_GLOB <K>
In pattern matching, the interpretation of parentheses is affected by a preceding
`@', `*', `+', `?' or `!'. See the section `Filename Generation'.

MAGIC_EQUAL_SUBST
All unquoted arguments of the form `anything=expression' appearing after the com-
mand name have filename expansion (that is, where expression has a leading `~' or
`=') performed on expression as if it were a parameter assignment. The argument is
not otherwise treated specially; it is passed to the command as a single argument,
and not used as an actual parameter assignment. For example, in echo
foo=~/bar:~/rod, both occurrences of ~ would be replaced. Note that this happens
anyway with typeset and similar statements.

This option respects the setting of the KSH_TYPESET option. In other words, if
both options are in effect, arguments looking like assignments will not undergo
word splitting.

MARK_DIRS (-8, ksh: -X)
Append a trailing `/' to all directory names resulting from filename generation
(globbing).

MULTIBYTE <D>
Respect multibyte characters when found in strings. When this option is set,
strings are examined using the system library to determine how many bytes form a
character, depending on the current locale. This affects the way characters are
counted in pattern matching, parameter values and various delimiters.

The option is on by default if the shell was compiled with MULTIBYTE_SUPPORT; oth-
erwise it is off by default and has no effect if turned on.

If the option is off a single byte is always treated as a single character. This
setting is designed purely for examining strings known to contain raw bytes or
other values that may not be characters in the current locale. It is not necessary
to unset the option merely because the character set for the current locale does
not contain multibyte characters.

The option does not affect the shell's editor, which always uses the locale to de-
termine multibyte characters. This is because the character set displayed by the
terminal emulator is independent of shell settings.

NOMATCH (+3) <C> <Z>
If a pattern for filename generation has no matches, print an error, instead of
leaving it unchanged in the argument list. This also applies to file expansion of
an initial `~' or `='.

NULL_GLOB (-G)
If a pattern for filename generation has no matches, delete the pattern from the
argument list instead of reporting an error. Overrides NOMATCH.

NUMERIC_GLOB_SORT
If numeric filenames are matched by a filename generation pattern, sort the file-
names numerically rather than lexicographically.

RC_EXPAND_PARAM (-P)
Array expansions of the form `foo${xx}bar', where the parameter xx is set to (a b
c), are substituted with `fooabar foobbar foocbar' instead of the default `fooa b
cbar'. Note that an empty array will therefore cause all arguments to be removed.

REMATCH_PCRE
If set, regular expression matching with the =~ operator will use Perl-Compatible
Regular Expressions from the PCRE library. (The zsh/pcre module must be avail-
able.) If not set, regular expressions will use the extended regexp syntax pro-
vided by the system libraries.

SH_GLOB <K> <S>
Disables the special meaning of `(', `|', `)' and '<' for globbing the result of
parameter and command substitutions, and in some other places where the shell ac-
cepts patterns. If SH_GLOB is set but KSH_GLOB is not, the shell allows the inter-
pretation of subshell expressions enclosed in parentheses in some cases where there
is no space before the opening parenthesis, e.g. !(true) is interpreted as if there
were a space after the !. This option is set by default if zsh is invoked as sh or
ksh.

UNSET (+u, ksh: +u) <K> <S> <Z>
Treat unset parameters as if they were empty when substituting, and as if they were
zero when reading their values in arithmetic expansion and arithmetic commands.
Otherwise they are treated as an error.

WARN_CREATE_GLOBAL
Print a warning message when a global parameter is created in a function by an as-
signment or in math context. This often indicates that a parameter has not been
declared local when it should have been. Parameters explicitly declared global
from within a function using typeset -g do not cause a warning. Note that there is
no warning when a local parameter is assigned to in a nested function, which may
also indicate an error.

WARN_NESTED_VAR
Print a warning message when an existing parameter from an enclosing function
scope, or global, is set in a function by an assignment or in math context. As-
signment to shell special parameters does not cause a warning. This is the compan-
ion to WARN_CREATE_GLOBAL as in this case the warning is only printed when a param-
eter is not created. Where possible, use of typeset -g to set the parameter sup-
presses the error, but note that this needs to be used every time the parameter is
set. To restrict the effect of this option to a single function scope, use `func-
tions -W'.

For example, the following code produces a warning for the assignment inside the
function nested as that overrides the value within toplevel

toplevel() {
local foo="in fn"
nested
}
nested() {
foo="in nested"
}
setopt warn_nested_var
toplevel

History
APPEND_HISTORY <D>
If this is set, zsh sessions will append their history list to the history file,
rather than replace it. Thus, multiple parallel zsh sessions will all have the new
entries from their history lists added to the history file, in the order that they
exit. The file will still be periodically re-written to trim it when the number of
lines grows 20% beyond the value specified by $SAVEHIST (see also the
HIST_SAVE_BY_COPY option).

BANG_HIST (+K) <C> <Z>
Perform textual history expansion, csh-style, treating the character `!' specially.

EXTENDED_HISTORY <C>
Save each command's beginning timestamp (in seconds since the epoch) and the dura-
tion (in seconds) to the history file. The format of this prefixed data is:

`: <beginning time>:<elapsed seconds>;<command>'.

HIST_ALLOW_CLOBBER
Add `|' to output redirections in the history. This allows history references to
clobber files even when CLOBBER is unset.

HIST_BEEP <D>
Beep in ZLE when a widget attempts to access a history entry which isn't there.

HIST_EXPIRE_DUPS_FIRST
If the internal history needs to be trimmed to add the current command line, set-
ting this option will cause the oldest history event that has a duplicate to be
lost before losing a unique event from the list. You should be sure to set the
value of HISTSIZE to a larger number than SAVEHIST in order to give you some room
for the duplicated events, otherwise this option will behave just like HIST_IG-
NORE_ALL_DUPS once the history fills up with unique events.

HIST_FCNTL_LOCK
When writing out the history file, by default zsh uses ad-hoc file locking to avoid
known problems with locking on some operating systems. With this option locking is
done by means of the system's fcntl call, where this method is available. On re-
cent operating systems this may provide better performance, in particular avoiding
history corruption when files are stored on NFS.

HIST_FIND_NO_DUPS
When searching for history entries in the line editor, do not display duplicates of
a line previously found, even if the duplicates are not contiguous.

HIST_IGNORE_ALL_DUPS
If a new command line being added to the history list duplicates an older one, the
older command is removed from the list (even if it is not the previous event).

HIST_IGNORE_DUPS (-h)
Do not enter command lines into the history list if they are duplicates of the pre-
vious event.

HIST_IGNORE_SPACE (-g)
Remove command lines from the history list when the first character on the line is
a space, or when one of the expanded aliases contains a leading space. Only normal
aliases (not global or suffix aliases) have this behaviour. Note that the command
lingers in the internal history until the next command is entered before it van-
ishes, allowing you to briefly reuse or edit the line. If you want to make it van-
ish right away without entering another command, type a space and press return.

HIST_LEX_WORDS
By default, shell history that is read in from files is split into words on all
white space. This means that arguments with quoted whitespace are not correctly
handled, with the consequence that references to words in history lines that have
been read from a file may be inaccurate. When this option is set, words read in
from a history file are divided up in a similar fashion to normal shell command
line handling. Although this produces more accurately delimited words, if the size
of the history file is large this can be slow. Trial and error is necessary to de-
cide.

HIST_NO_FUNCTIONS
Remove function definitions from the history list. Note that the function lingers
in the internal history until the next command is entered before it vanishes, al-
lowing you to briefly reuse or edit the definition.

HIST_NO_STORE
Remove the history (fc -l) command from the history list when invoked. Note that
the command lingers in the internal history until the next command is entered be-
fore it vanishes, allowing you to briefly reuse or edit the line.

HIST_REDUCE_BLANKS
Remove superfluous blanks from each command line being added to the history list.

HIST_SAVE_BY_COPY <D>
When the history file is re-written, we normally write out a copy of the file named
$HISTFILE.new and then rename it over the old one. However, if this option is un-
set, we instead truncate the old history file and write out the new version
in-place. If one of the history-appending options is enabled, this option only has
an effect when the enlarged history file needs to be re-written to trim it down to
size. Disable this only if you have special needs, as doing so makes it possible
to lose history entries if zsh gets interrupted during the save.

When writing out a copy of the history file, zsh preserves the old file's permis-
sions and group information, but will refuse to write out a new file if it would
change the history file's owner.

HIST_SAVE_NO_DUPS
When writing out the history file, older commands that duplicate newer ones are
omitted.

HIST_VERIFY
Whenever the user enters a line with history expansion, don't execute the line di-
rectly; instead, perform history expansion and reload the line into the editing
buffer.

INC_APPEND_HISTORY
This option works like APPEND_HISTORY except that new history lines are added to
the $HISTFILE incrementally (as soon as they are entered), rather than waiting un-
til the shell exits. The file will still be periodically re-written to trim it
when the number of lines grows 20% beyond the value specified by $SAVEHIST (see
also the HIST_SAVE_BY_COPY option).

INC_APPEND_HISTORY_TIME
This option is a variant of INC_APPEND_HISTORY in which, where possible, the his-
tory entry is written out to the file after the command is finished, so that the
time taken by the command is recorded correctly in the history file in EX-
TENDED_HISTORY format. This means that the history entry will not be available im-
mediately from other instances of the shell that are using the same history file.

This option is only useful if INC_APPEND_HISTORY and SHARE_HISTORY are turned off.
The three options should be considered mutually exclusive.

SHARE_HISTORY <K>

This option both imports new commands from the history file, and also causes your
typed commands to be appended to the history file (the latter is like specifying
INC_APPEND_HISTORY, which should be turned off if this option is in effect). The
history lines are also output with timestamps ala EXTENDED_HISTORY (which makes it
easier to find the spot where we left off reading the file after it gets re-writ-
ten).

By default, history movement commands visit the imported lines as well as the local
lines, but you can toggle this on and off with the set-local-history zle binding.
It is also possible to create a zle widget that will make some commands ignore im-
ported commands, and some include them.

If you find that you want more control over when commands get imported, you may
wish to turn SHARE_HISTORY off, INC_APPEND_HISTORY or INC_APPEND_HISTORY_TIME (see
above) on, and then manually import commands whenever you need them using `fc -RI'.

Initialisation
ALL_EXPORT (-a, ksh: -a)
All parameters subsequently defined are automatically exported.

GLOBAL_EXPORT <Z>
If this option is set, passing the -x flag to the builtins declare, float, integer,
readonly and typeset (but not local) will also set the -g flag; hence parameters
exported to the environment will not be made local to the enclosing function, un-
less they were already or the flag +g is given explicitly. If the option is unset,
exported parameters will be made local in just the same way as any other parameter.

This option is set by default for backward compatibility; it is not recommended
that its behaviour be relied upon. Note that the builtin export always sets both
the -x and -g flags, and hence its effect extends beyond the scope of the enclosing
function; this is the most portable way to achieve this behaviour.

GLOBAL_RCS (-d) <D>
If this option is unset, the startup files /etc/zsh/zprofile, /etc/zsh/zshrc,
/etc/zsh/zlogin and /etc/zsh/zlogout will not be run. It can be disabled and
re-enabled at any time, including inside local startup files (.zshrc, etc.).

RCS (+f) <D>
After /etc/zsh/zshenv is sourced on startup, source the .zshenv, /etc/zsh/zprofile,
.zprofile, /etc/zsh/zshrc, .zshrc, /etc/zsh/zlogin, .zlogin, and .zlogout files, as
described in the section `Files'. If this option is unset, the /etc/zsh/zshenv
file is still sourced, but any of the others will not be; it can be set at any time
to prevent the remaining startup files after the currently executing one from being
sourced.

Input/Output
ALIASES <D>
Expand aliases.

CLOBBER (+C, ksh: +C) <D>
Allows `>' redirection to truncate existing files. Otherwise `>!' or `>|' must be
used to truncate a file.

If the option is not set, and the option APPEND_CREATE is also not set, `>>!' or
`>>|' must be used to create a file. If either option is set, `>>' may be used.

CORRECT (-0)
Try to correct the spelling of commands. Note that, when the HASH_LIST_ALL option
is not set or when some directories in the path are not readable, this may falsely
report spelling errors the first time some commands are used.

The shell variable CORRECT_IGNORE may be set to a pattern to match words that will
never be offered as corrections.

CORRECT_ALL (-O)
Try to correct the spelling of all arguments in a line.

The shell variable CORRECT_IGNORE_FILE may be set to a pattern to match file names
that will never be offered as corrections.

DVORAK Use the Dvorak keyboard instead of the standard qwerty keyboard as a basis for ex-
amining spelling mistakes for the CORRECT and CORRECT_ALL options and the
spell-word editor command.

FLOW_CONTROL <D>
If this option is unset, output flow control via start/stop characters (usually as-
signed to ^S/^Q) is disabled in the shell's editor.

IGNORE_EOF (-7)
Do not exit on end-of-file. Require the use of exit or logout instead. However,
ten consecutive EOFs will cause the shell to exit anyway, to avoid the shell hang-
ing if its tty goes away.

Also, if this option is set and the Zsh Line Editor is used, widgets implemented by
shell functions can be bound to EOF (normally Control-D) without printing the nor-
mal warning message. This works only for normal widgets, not for completion wid-
gets.

INTERACTIVE_COMMENTS (-k) <K> <S>
Allow comments even in interactive shells.

HASH_CMDS <D>
Note the location of each command the first time it is executed. Subsequent invo-
cations of the same command will use the saved location, avoiding a path search.
If this option is unset, no path hashing is done at all. However, when CORRECT is
set, commands whose names do not appear in the functions or aliases hash tables are
hashed in order to avoid reporting them as spelling errors.

HASH_DIRS <D>
Whenever a command name is hashed, hash the directory containing it, as well as all
directories that occur earlier in the path. Has no effect if neither HASH_CMDS nor
CORRECT is set.

HASH_EXECUTABLES_ONLY
When hashing commands because of HASH_CMDS, check that the file to be hashed is ac-
tually an executable. This option is unset by default as if the path contains a
large number of commands, or consists of many remote files, the additional tests
can take a long time. Trial and error is needed to show if this option is benefi-
cial.

MAIL_WARNING (-U)
Print a warning message if a mail file has been accessed since the shell last
checked.

PATH_DIRS (-Q)
Perform a path search even on command names with slashes in them. Thus if
`/usr/local/bin' is in the user's path, and he or she types `X11/xinit', the com-
mand `/usr/local/bin/X11/xinit' will be executed (assuming it exists). Commands
explicitly beginning with `/', `./' or `../' are not subject to the path search.
This also applies to the `.' and source builtins.

Note that subdirectories of the current directory are always searched for executa-
bles specified in this form. This takes place before any search indicated by this
option, and regardless of whether `.' or the current directory appear in the com-
mand search path.

PATH_SCRIPT <K> <S>
If this option is not set, a script passed as the first non-option argument to the
shell must contain the name of the file to open. If this option is set, and the
script does not specify a directory path, the script is looked for first in the
current directory, then in the command path. See the section INVOCATION in zsh(1).

PRINT_EIGHT_BIT
Print eight bit characters literally in completion lists, etc. This option is not
necessary if your system correctly returns the printability of eight bit characters
(see ctype(3)).

PRINT_EXIT_VALUE (-1)
Print the exit value of programs with non-zero exit status. This is only available
at the command line in interactive shells.

RC_QUOTES
Allow the character sequence `''' to signify a single quote within singly quoted
strings. Note this does not apply in quoted strings using the format $'...', where
a backslashed single quote can be used.

RM_STAR_SILENT (-H) <K> <S>
Do not query the user before executing `rm *' or `rm path/*'.

RM_STAR_WAIT
If querying the user before executing `rm *' or `rm path/*', first wait ten seconds
and ignore anything typed in that time. This avoids the problem of reflexively an-
swering `yes' to the query when one didn't really mean it. The wait and query can
always be avoided by expanding the `*' in ZLE (with tab).

SHORT_LOOPS <C> <Z>
Allow the short forms of for, repeat, select, if, and function constructs.

SUN_KEYBOARD_HACK (-L)
If a line ends with a backquote, and there are an odd number of backquotes on the
line, ignore the trailing backquote. This is useful on some keyboards where the
return key is too small, and the backquote key lies annoyingly close to it. As an
alternative the variable KEYBOARD_HACK lets you choose the character to be removed.

Job Control
AUTO_CONTINUE
With this option set, stopped jobs that are removed from the job table with the
disown builtin command are automatically sent a CONT signal to make them running.

AUTO_RESUME (-W)
Treat single word simple commands without redirection as candidates for resumption
of an existing job.

BG_NICE (-6) <C> <Z>
Run all background jobs at a lower priority. This option is set by default.

CHECK_JOBS <Z>
Report the status of background and suspended jobs before exiting a shell with job
control; a second attempt to exit the shell will succeed. NO_CHECK_JOBS is best
used only in combination with NO_HUP, else such jobs will be killed automatically.

The check is omitted if the commands run from the previous command line included a
`jobs' command, since it is assumed the user is aware that there are background or
suspended jobs. A `jobs' command run from one of the hook functions defined in the
section SPECIAL FUNCTIONS in zshmisc(1) is not counted for this purpose.

CHECK_RUNNING_JOBS <Z>
Check for both running and suspended jobs when CHECK_JOBS is enabled. When this
option is disabled, zsh checks only for suspended jobs, which matches the default
behavior of bash.

This option has no effect unless CHECK_JOBS is set.

HUP <Z>
Send the HUP signal to running jobs when the shell exits.

LONG_LIST_JOBS (-R)
Print job notifications in the long format by default.

MONITOR (-m, ksh: -m)
Allow job control. Set by default in interactive shells.

NOTIFY (-5, ksh: -b) <Z>
Report the status of background jobs immediately, rather than waiting until just
before printing a prompt.

POSIX_JOBS <K> <S>
This option makes job control more compliant with the POSIX standard.

When the option is not set, the MONITOR option is unset on entry to subshells, so
that job control is no longer active. When the option is set, the MONITOR option
and job control remain active in the subshell, but note that the subshell has no
access to jobs in the parent shell.

When the option is not set, jobs put in the background or foreground with bg or fg
are displayed with the same information that would be reported by jobs. When the
option is set, only the text is printed. The output from jobs itself is not af-
fected by the option.

When the option is not set, job information from the parent shell is saved for out-
put within a subshell (for example, within a pipeline). When the option is set,
the output of jobs is empty until a job is started within the subshell.

In previous versions of the shell, it was necessary to enable POSIX_JOBS in order
for the builtin command wait to return the status of background jobs that had al-
ready exited. This is no longer the case.

Prompting
PROMPT_BANG <K>
If set, `!' is treated specially in prompt expansion. See EXPANSION OF PROMPT SE-
QUENCES in zshmisc(1).

PROMPT_CR (+V) <D>
Print a carriage return just before printing a prompt in the line editor. This is
on by default as multi-line editing is only possible if the editor knows where the
start of the line appears.

PROMPT_SP <D>
Attempt to preserve a partial line (i.e. a line that did not end with a newline)
that would otherwise be covered up by the command prompt due to the PROMPT_CR op-
tion. This works by outputting some cursor-control characters, including a series
of spaces, that should make the terminal wrap to the next line when a partial line
is present (note that this is only successful if your terminal has automatic mar-
gins, which is typical).

When a partial line is preserved, by default you will see an inverse+bold character
at the end of the partial line: a `%' for a normal user or a `#' for root. If
set, the shell parameter PROMPT_EOL_MARK can be used to customize how the end of
partial lines are shown.

NOTE: if the PROMPT_CR option is not set, enabling this option will have no effect.
This option is on by default.

PROMPT_PERCENT <C> <Z>
If set, `%' is treated specially in prompt expansion. See EXPANSION OF PROMPT SE-
QUENCES in zshmisc(1).

PROMPT_SUBST <K> <S>
If set, parameter expansion, command substitution and arithmetic expansion are per-
formed in prompts. Substitutions within prompts do not affect the command status.

TRANSIENT_RPROMPT
Remove any right prompt from display when accepting a command line. This may be
useful with terminals with other cut/paste methods.

Scripts and Functions
ALIAS_FUNC_DEF <S>
By default, zsh does not allow the definition of functions using the `name ()' syn-
tax if name was expanded as an alias: this causes an error. This is usually the
desired behaviour, as otherwise the combination of an alias and a function based on
the same definition can easily cause problems.

When this option is set, aliases can be used for defining functions.

For example, consider the following definitions as they might occur in a startup
file.

alias foo=bar
foo() {
print This probably does not do what you expect.
}

Here, foo is expanded as an alias to bar before the () is encountered, so the func-
tion defined would be named bar. By default this is instead an error in native
mode. Note that quoting any part of the function name, or using the keyword func-
tion, avoids the problem, so is recommended when the function name can also be an
alias.

C_BASES
Output hexadecimal numbers in the standard C format, for example `0xFF' instead of
the usual `16#FF'. If the option OCTAL_ZEROES is also set (it is not by default),
octal numbers will be treated similarly and hence appear as `077' instead of
`8#77'. This option has no effect on the choice of the output base, nor on the
output of bases other than hexadecimal and octal. Note that these formats will be
understood on input irrespective of the setting of C_BASES.

C_PRECEDENCES
This alters the precedence of arithmetic operators to be more like C and other pro-
gramming languages; the section ARITHMETIC EVALUATION in zshmisc(1) has an explicit
list.

DEBUG_BEFORE_CMD <D>
Run the DEBUG trap before each command; otherwise it is run after each command.
Setting this option mimics the behaviour of ksh 93; with the option unset the be-
haviour is that of ksh 88.

ERR_EXIT (-e, ksh: -e)
If a command has a non-zero exit status, execute the ZERR trap, if set, and exit.
This is disabled while running initialization scripts.

The behaviour is also disabled inside DEBUG traps. In this case the option is han-
dled specially: it is unset on entry to the trap. If the option DEBUG_BEFORE_CMD
is set, as it is by default, and the option ERR_EXIT is found to have been set on
exit, then the command for which the DEBUG trap is being executed is skipped. The
option is restored after the trap exits.

Non-zero status in a command list containing && or || is ignored for commands not
at the end of the list. Hence

false && true

does not trigger exit.

Exiting due to ERR_EXIT has certain interactions with asynchronous jobs noted in
the section JOBS in zshmisc(1).

ERR_RETURN
If a command has a non-zero exit status, return immediately from the enclosing
function. The logic is similar to that for ERR_EXIT, except that an implicit re-
turn statement is executed instead of an exit. This will trigger an exit at the
outermost level of a non-interactive script.

Normally this option inherits the behaviour of ERR_EXIT that code followed by `&&'
`||' does not trigger a return. Hence in the following:

summit || true

no return is forced as the combined effect always has a zero return status.

Note. however, that if summit in the above example is itself a function, code in-
side it is considered separately: it may force a return from summit (assuming the
option remains set within summit), but not from the enclosing context. This behav-
iour is different from ERR_EXIT which is unaffected by function scope.

EVAL_LINENO <Z>
If set, line numbers of expressions evaluated using the builtin eval are tracked
separately of the enclosing environment. This applies both to the parameter LINENO
and the line number output by the prompt escape %i. If the option is set, the
prompt escape %N will output the string `(eval)' instead of the script or function
name as an indication. (The two prompt escapes are typically used in the parame-
ter PS4 to be output when the option XTRACE is set.) If EVAL_LINENO is unset, the
line number of the surrounding script or function is retained during the evalua-
tion.

EXEC (+n, ksh: +n) <D>
Do execute commands. Without this option, commands are read and checked for syntax
errors, but not executed. This option cannot be turned off in an interactive
shell, except when `-n' is supplied to the shell at startup.

FUNCTION_ARGZERO <C> <Z>
When executing a shell function or sourcing a script, set $0 temporarily to the
name of the function/script. Note that toggling FUNCTION_ARGZERO from on to off
(or off to on) does not change the current value of $0. Only the state upon entry
to the function or script has an effect. Compare POSIX_ARGZERO.

LOCAL_LOOPS
When this option is not set, the effect of break and continue commands may propa-
gate outside function scope, affecting loops in calling functions. When the option
is set in a calling function, a break or a continue that is not caught within a
called function (regardless of the setting of the option within that function) pro-
duces a warning and the effect is cancelled.

LOCAL_OPTIONS <K>
If this option is set at the point of return from a shell function, most options
(including this one) which were in force upon entry to the function are restored;
options that are not restored are PRIVILEGED and RESTRICTED. Otherwise, only this
option, and the LOCAL_LOOPS, XTRACE and PRINT_EXIT_VALUE options are restored.
Hence if this is explicitly unset by a shell function the other options in force at
the point of return will remain so. A shell function can also guarantee itself a
known shell configuration with a formulation like `emulate -L zsh'; the -L acti-
vates LOCAL_OPTIONS.

LOCAL_PATTERNS
If this option is set at the point of return from a shell function, the state of
pattern disables, as set with the builtin command `disable -p', is restored to what
it was when the function was entered. The behaviour of this option is similar to
the effect of LOCAL_OPTIONS on options; hence `emulate -L sh' (or indeed any other
emulation with the -L option) activates LOCAL_PATTERNS.

LOCAL_TRAPS <K>
If this option is set when a signal trap is set inside a function, then the previ-
ous status of the trap for that signal will be restored when the function exits.
Note that this option must be set prior to altering the trap behaviour in a func-
tion; unlike LOCAL_OPTIONS, the value on exit from the function is irrelevant.
However, it does not need to be set before any global trap for that to be correctly
restored by a function. For example,

unsetopt localtraps
trap - INT
fn() { setopt localtraps; trap '' INT; sleep 3; }

will restore normal handling of SIGINT after the function exits.

MULTI_FUNC_DEF <Z>
Allow definitions of multiple functions at once in the form `fn1 fn2...()'; if the
option is not set, this causes a parse error. Definition of multiple functions
with the function keyword is always allowed. Multiple function definitions are not
often used and can cause obscure errors.

MULTIOS <Z>
Perform implicit tees or cats when multiple redirections are attempted (see the
section `Redirection').

OCTAL_ZEROES <S>
Interpret any integer constant beginning with a 0 as octal, per IEEE Std
1003.2-1992 (ISO 9945-2:1993). This is not enabled by default as it causes prob-
lems with parsing of, for example, date and time strings with leading zeroes.

Sequences of digits indicating a numeric base such as the `08' component in `08#77'
are always interpreted as decimal, regardless of leading zeroes.

PIPE_FAIL
By default, when a pipeline exits the exit status recorded by the shell and re-
turned by the shell variable $? reflects that of the rightmost element of a pipe-
line. If this option is set, the exit status instead reflects the status of the
rightmost element of the pipeline that was non-zero, or zero if all elements exited
with zero status.

SOURCE_TRACE
If set, zsh will print an informational message announcing the name of each file it
loads. The format of the output is similar to that for the XTRACE option, with the
message <sourcetrace>. A file may be loaded by the shell itself when it starts up
and shuts down (Startup/Shutdown Files) or by the use of the `source' and `dot'
builtin commands.

TYPESET_SILENT
If this is unset, executing any of the `typeset' family of commands with no options
and a list of parameters that have no values to be assigned but already exist will
display the value of the parameter. If the option is set, they will only be shown
when parameters are selected with the `-m' option. The option `-p' is available
whether or not the option is set.

VERBOSE (-v, ksh: -v)
Print shell input lines as they are read.

XTRACE (-x, ksh: -x)
Print commands and their arguments as they are executed. The output is preceded by
the value of $PS4, formatted as described in the section EXPANSION OF PROMPT SE-
QUENCES in zshmisc(1).

Shell Emulation
APPEND_CREATE <K> <S>
This option only applies when NO_CLOBBER (-C) is in effect.

If this option is not set, the shell will report an error when a append redirection
(>>) is used on a file that does not already exists (the traditional zsh behaviour
of NO_CLOBBER). If the option is set, no error is reported (POSIX behaviour).

BASH_REMATCH
When set, matches performed with the =~ operator will set the BASH_REMATCH array
variable, instead of the default MATCH and match variables. The first element of
the BASH_REMATCH array will contain the entire matched text and subsequent elements
will contain extracted substrings. This option makes more sense when KSH_ARRAYS is
also set, so that the entire matched portion is stored at index 0 and the first
substring is at index 1. Without this option, the MATCH variable contains the en-
tire matched text and the match array variable contains substrings.

BSD_ECHO <S>
Make the echo builtin compatible with the BSD echo(1) command. This disables back-
slashed escape sequences in echo strings unless the -e option is specified.

CONTINUE_ON_ERROR
If a fatal error is encountered (see the section ERRORS in zshmisc(1)), and the
code is running in a script, the shell will resume execution at the next statement
in the script at the top level, in other words outside all functions or shell con-
structs such as loops and conditions. This mimics the behaviour of interactive
shells, where the shell returns to the line editor to read a new command; it was
the normal behaviour in versions of zsh before 5.0.1.

CSH_JUNKIE_HISTORY <C>
A history reference without an event specifier will always refer to the previous
command. Without this option, such a history reference refers to the same event as
the previous history reference on the current command line, defaulting to the pre-
vious command.

CSH_JUNKIE_LOOPS <C>
Allow loop bodies to take the form `list; end' instead of `do list; done'.

CSH_JUNKIE_QUOTES <C>
Changes the rules for single- and double-quoted text to match that of csh. These
require that embedded newlines be preceded by a backslash; unescaped newlines will
cause an error message. In double-quoted strings, it is made impossible to escape
`$', ``' or `"' (and `\' itself no longer needs escaping). Command substitutions
are only expanded once, and cannot be nested.

CSH_NULLCMD <C>
Do not use the values of NULLCMD and READNULLCMD when running redirections with no
command. This make such redirections fail (see the section `Redirection').

KSH_ARRAYS <K> <S>
Emulate ksh array handling as closely as possible. If this option is set, array
elements are numbered from zero, an array parameter without subscript refers to the
first element instead of the whole array, and braces are required to delimit a sub-
script (`${path[2]}' rather than just `$path[2]') or to apply modifiers to any pa-
rameter (`${PWD:h}' rather than `$PWD:h').

KSH_AUTOLOAD <K> <S>
Emulate ksh function autoloading. This means that when a function is autoloaded,
the corresponding file is merely executed, and must define the function itself.
(By default, the function is defined to the contents of the file. However, the
most common ksh-style case - of the file containing only a simple definition of the
function - is always handled in the ksh-compatible manner.)

KSH_OPTION_PRINT <K>
Alters the way options settings are printed: instead of separate lists of set and
unset options, all options are shown, marked `on' if they are in the non-default
state, `off' otherwise.

KSH_TYPESET
This option is now obsolete: a better appropximation to the behaviour of other
shells is obtained with the reserved word interface to declare, export, float, in-
teger, local, readonly and typeset. Note that the option is only applied when the
reserved word interface is not in use.

Alters the way arguments to the typeset family of commands, including declare, ex-
port, float, integer, local and readonly, are processed. Without this option, zsh
will perform normal word splitting after command and parameter expansion in argu-
ments of an assignment; with it, word splitting does not take place in those cases.

KSH_ZERO_SUBSCRIPT
Treat use of a subscript of value zero in array or string expressions as a refer-
ence to the first element, i.e. the element that usually has the subscript 1. Ig-
nored if KSH_ARRAYS is also set.

If neither this option nor KSH_ARRAYS is set, accesses to an element of an array or
string with subscript zero return an empty element or string, while attempts to set
element zero of an array or string are treated as an error. However, attempts to
set an otherwise valid subscript range that includes zero will succeed. For exam-
ple, if KSH_ZERO_SUBSCRIPT is not set,

array[0]=(element)

is an error, while

array[0,1]=(element)

is not and will replace the first element of the array.

This option is for compatibility with older versions of the shell and is not recom-
mended in new code.

POSIX_ALIASES <K> <S>
When this option is set, reserved words are not candidates for alias expansion: it
is still possible to declare any of them as an alias, but the alias will never be
expanded. Reserved words are described in the section RESERVED WORDS in zsh-
misc(1).

Alias expansion takes place while text is being read; hence when this option is set
it does not take effect until the end of any function or other piece of shell code
parsed as one unit. Note this may cause differences from other shells even when
the option is in effect. For example, when running a command with `zsh -c', or
even `zsh -o posixaliases -c', the entire command argument is parsed as one unit,
so aliases defined within the argument are not available even in later lines. If
in doubt, avoid use of aliases in non-interactive code.

POSIX_ARGZERO
This option may be used to temporarily disable FUNCTION_ARGZERO and thereby restore
the value of $0 to the name used to invoke the shell (or as set by the -c command
line option). For compatibility with previous versions of the shell, emulations
use NO_FUNCTION_ARGZERO instead of POSIX_ARGZERO, which may result in unexpected
scoping of $0 if the emulation mode is changed inside a function or script. To
avoid this, explicitly enable POSIX_ARGZERO in the emulate command:

emulate sh -o POSIX_ARGZERO

Note that NO_POSIX_ARGZERO has no effect unless FUNCTION_ARGZERO was already en-
abled upon entry to the function or script.

POSIX_BUILTINS <K> <S>
When this option is set the command builtin can be used to execute shell builtin
commands. Parameter assignments specified before shell functions and special
builtins are kept after the command completes unless the special builtin is pre-
fixed with the command builtin. Special builtins are ., :, break, continue, de-
clare, eval, exit, export, integer, local, readonly, return, set, shift, source,
times, trap and unset.

In addition, various error conditions associated with the above builtins or exec
cause a non-interactive shell to exit and an interactive shell to return to its
top-level processing.

Furthermore, functions and shell builtins are not executed after an exec prefix;
the command to be executed must be an external command found in the path.

Furthermore, the getopts builtin behaves in a POSIX-compatible fashion in that the
associated variable OPTIND is not made local to functions.

Moreover, the warning and special exit code from [[ -o non_existent_option ]] are
suppressed.

POSIX_IDENTIFIERS <K> <S>
When this option is set, only the ASCII characters a to z, A to Z, 0 to 9 and _ may
be used in identifiers (names of shell parameters and modules).

In addition, setting this option limits the effect of parameter substitution with
no braces, so that the expression $# is treated as the parameter $# even if fol-
lowed by a valid parameter name. When it is unset, zsh allows expressions of the
form $#name to refer to the length of $name, even for special variables, for exam-
ple in expressions such as $#- and $#*.

Another difference is that with the option set assignment to an unset variable in
arithmetic context causes the variable to be created as a scalar rather than a nu-
meric type. So after `unset t; (( t = 3 ))'. without POSIX_IDENTIFIERS set t has
integer type, while with it set it has scalar type.

When the option is unset and multibyte character support is enabled (i.e. it is
compiled in and the option MULTIBYTE is set), then additionally any alphanumeric
characters in the local character set may be used in identifiers. Note that
scripts and functions written with this feature are not portable, and also that
both options must be set before the script or function is parsed; setting them dur-
ing execution is not sufficient as the syntax variable=value has already been
parsed as a command rather than an assignment.

If multibyte character support is not compiled into the shell this option is ig-
nored; all octets with the top bit set may be used in identifiers. This is
non-standard but is the traditional zsh behaviour.

POSIX_STRINGS <K> <S>
This option affects processing of quoted strings. Currently it only affects the
behaviour of null characters, i.e. character 0 in the portable character set corre-
sponding to US ASCII.

When this option is not set, null characters embedded within strings of the form
$'...' are treated as ordinary characters. The entire string is maintained within
the shell and output to files where necessary, although owing to restrictions of
the library interface the string is truncated at the null character in file names,
environment variables, or in arguments to external programs.

When this option is set, the $'...' expression is truncated at the null character.
Note that remaining parts of the same string beyond the termination of the quotes
are not truncated.

For example, the command line argument a$'b\0c'd is treated with the option off as
the characters a, b, null, c, d, and with the option on as the characters a, b, d.

POSIX_TRAPS <K> <S>
When this option is set, the usual zsh behaviour of executing traps for EXIT on
exit from shell functions is suppressed. In that case, manipulating EXIT traps al-
ways alters the global trap for exiting the shell; the LOCAL_TRAPS option is ig-
nored for the EXIT trap. Furthermore, a return statement executed in a trap with
no argument passes back from the function the value from the surrounding context,
not from code executed within the trap.

SH_FILE_EXPANSION <K> <S>
Perform filename expansion (e.g., ~ expansion) before parameter expansion, command
substitution, arithmetic expansion and brace expansion. If this option is unset,
it is performed after brace expansion, so things like `~$USERNAME' and `~{pfal-
stad,rc}' will work.

SH_NULLCMD <K> <S>
Do not use the values of NULLCMD and READNULLCMD when doing redirections, use `:'
instead (see the section `Redirection').

SH_OPTION_LETTERS <K> <S>
If this option is set the shell tries to interpret single letter options (which are
used with set and setopt) like ksh does. This also affects the value of the - spe-
cial parameter.

SH_WORD_SPLIT (-y) <K> <S>
Causes field splitting to be performed on unquoted parameter expansions. Note that
this option has nothing to do with word splitting. (See zshexpn(1).)

TRAPS_ASYNC
While waiting for a program to exit, handle signals and run traps immediately.
Otherwise the trap is run after a child process has exited. Note this does not af-
fect the point at which traps are run for any case other than when the shell is
waiting for a child process.

Shell State
INTERACTIVE (-i, ksh: -i)
This is an interactive shell. This option is set upon initialisation if the stan-
dard input is a tty and commands are being read from standard input. (See the dis-
cussion of SHIN_STDIN.) This heuristic may be overridden by specifying a state for
this option on the command line. The value of this option can only be changed via
flags supplied at invocation of the shell. It cannot be changed once zsh is run-
ning.

LOGIN (-l, ksh: -l)
This is a login shell. If this option is not explicitly set, the shell becomes a
login shell if the first character of the argv[0] passed to the shell is a `-'.

PRIVILEGED (-p, ksh: -p)
Turn on privileged mode. Typically this is used when script is to be run with ele-
vated privileges. This should be done as follows directly with the -p option to zsh
so that it takes effect during startup.

#!/bin/zsh -p

The option is enabled automatically on startup if the effective user (group) ID is
not equal to the real user (group) ID. In this case, turning the option off causes
the effective user and group IDs to be set to the real user and group IDs. Be aware
that if that fails the shell may be running with different IDs than was intended so
a script should check for failure and act accordingly, for example:

unsetopt privileged || exit

The PRIVILEGED option disables sourcing user startup files. If zsh is invoked as
`sh' or `ksh' with this option set, /etc/suid_profile is sourced (after /etc/pro-
file on interactive shells). Sourcing ~/.profile is disabled and the contents of
the ENV variable is ignored. This option cannot be changed using the -m option of
setopt and unsetopt, and changing it inside a function always changes it globally
regardless of the LOCAL_OPTIONS option.

RESTRICTED (-r)
Enables restricted mode. This option cannot be changed using unsetopt, and setting
it inside a function always changes it globally regardless of the LOCAL_OPTIONS op-
tion. See the section `Restricted Shell'.

SHIN_STDIN (-s, ksh: -s)
Commands are being read from the standard input. Commands are read from standard
input if no command is specified with -c and no file of commands is specified. If
SHIN_STDIN is set explicitly on the command line, any argument that would otherwise
have been taken as a file to run will instead be treated as a normal positional pa-
rameter. Note that setting or unsetting this option on the command line does not
necessarily affect the state the option will have while the shell is running - that
is purely an indicator of whether or not commands are actually being read from
standard input. The value of this option can only be changed via flags supplied at
invocation of the shell. It cannot be changed once zsh is running.

SINGLE_COMMAND (-t, ksh: -t)
If the shell is reading from standard input, it exits after a single command has
been executed. This also makes the shell non-interactive, unless the INTERACTIVE
option is explicitly set on the command line. The value of this option can only be
changed via flags supplied at invocation of the shell. It cannot be changed once
zsh is running.

Zle
BEEP (+B) <D>
Beep on error in ZLE.

COMBINING_CHARS
Assume that the terminal displays combining characters correctly. Specifically, if
a base alphanumeric character is followed by one or more zero-width punctuation
characters, assume that the zero-width characters will be displayed as modifica-
tions to the base character within the same width. Not all terminals handle this.
If this option is not set, zero-width characters are displayed separately with spe-
cial mark-up.

If this option is set, the pattern test [[:WORD:]] matches a zero-width punctuation
character on the assumption that it will be used as part of a word in combination
with a word character. Otherwise the base shell does not handle combining charac-
ters specially.

EMACS If ZLE is loaded, turning on this option has the equivalent effect of `bindkey -e'.
In addition, the VI option is unset. Turning it off has no effect. The option
setting is not guaranteed to reflect the current keymap. This option is provided
for compatibility; bindkey is the recommended interface.

OVERSTRIKE
Start up the line editor in overstrike mode.

SINGLE_LINE_ZLE (-M) <K>
Use single-line command line editing instead of multi-line.

Note that although this is on by default in ksh emulation it only provides superfi-
cial compatibility with the ksh line editor and reduces the effectiveness of the
zsh line editor. As it has no effect on shell syntax, many users may wish to dis-
able this option when using ksh emulation interactively.

VI If ZLE is loaded, turning on this option has the equivalent effect of `bindkey -v'.
In addition, the EMACS option is unset. Turning it off has no effect. The option
setting is not guaranteed to reflect the current keymap. This option is provided
for compatibility; bindkey is the recommended interface.

ZLE (-Z)
Use the zsh line editor. Set by default in interactive shells connected to a ter-
minal.

OPTION ALIASES
Some options have alternative names. These aliases are never used for output, but can be
used just like normal option names when specifying options to the shell.

BRACE_EXPAND
NO_IGNORE_BRACES (ksh and bash compatibility)

DOT_GLOB
GLOB_DOTS (bash compatibility)

HASH_ALL
HASH_CMDS (bash compatibility)

HIST_APPEND
APPEND_HISTORY (bash compatibility)

HIST_EXPAND
BANG_HIST (bash compatibility)

LOG NO_HIST_NO_FUNCTIONS (ksh compatibility)

MAIL_WARN
MAIL_WARNING (bash compatibility)

ONE_CMD
SINGLE_COMMAND (bash compatibility)

PHYSICAL
CHASE_LINKS (ksh and bash compatibility)

PROMPT_VARS
PROMPT_SUBST (bash compatibility)

STDIN SHIN_STDIN (ksh compatibility)

TRACK_ALL
HASH_CMDS (ksh compatibility)

SINGLE LETTER OPTIONS
Default set
-0 CORRECT
-1 PRINT_EXIT_VALUE
-2 NO_BAD_PATTERN
-3 NO_NOMATCH
-4 GLOB_DOTS
-5 NOTIFY
-6 BG_NICE
-7 IGNORE_EOF
-8 MARK_DIRS
-9 AUTO_LIST
-B NO_BEEP
-C NO_CLOBBER
-D PUSHD_TO_HOME
-E PUSHD_SILENT
-F NO_GLOB
-G NULL_GLOB
-H RM_STAR_SILENT
-I IGNORE_BRACES
-J AUTO_CD
-K NO_BANG_HIST
-L SUN_KEYBOARD_HACK
-M SINGLE_LINE_ZLE
-N AUTO_PUSHD
-O CORRECT_ALL
-P RC_EXPAND_PARAM
-Q PATH_DIRS
-R LONG_LIST_JOBS
-S REC_EXACT
-T CDABLE_VARS
-U MAIL_WARNING
-V NO_PROMPT_CR
-W AUTO_RESUME
-X LIST_TYPES
-Y MENU_COMPLETE
-Z ZLE
-a ALL_EXPORT
-e ERR_EXIT
-f NO_RCS
-g HIST_IGNORE_SPACE
-h HIST_IGNORE_DUPS
-i INTERACTIVE
-k INTERACTIVE_COMMENTS
-l LOGIN
-m MONITOR
-n NO_EXEC
-p PRIVILEGED
-r RESTRICTED
-s SHIN_STDIN
-t SINGLE_COMMAND
-u NO_UNSET
-v VERBOSE
-w CHASE_LINKS
-x XTRACE
-y SH_WORD_SPLIT

sh/ksh emulation set
-C NO_CLOBBER
-T TRAPS_ASYNC
-X MARK_DIRS
-a ALL_EXPORT
-b NOTIFY
-e ERR_EXIT
-f NO_GLOB
-i INTERACTIVE
-l LOGIN
-m MONITOR
-n NO_EXEC
-p PRIVILEGED
-r RESTRICTED
-s SHIN_STDIN
-t SINGLE_COMMAND
-u NO_UNSET
-v VERBOSE
-x XTRACE

Also note
-A Used by set for setting arrays
-b Used on the command line to specify end of option processing
-c Used on the command line to specify a single command
-m Used by setopt for pattern-matching option setting
-o Used in all places to allow use of long option names
-s Used by set to sort positional parameters

ZSHBUILTINS(1) General Commands Manual ZSHBUILTINS(1)

NAME
zshbuiltins - zsh built-in commands

SHELL BUILTIN COMMANDS
Some shell builtin commands take options as described in individual entries; these are of-
ten referred to in the list below as `flags' to avoid confusion with shell options, which
may also have an effect on the behaviour of builtin commands. In this introductory sec-
tion, `option' always has the meaning of an option to a command that should be familiar to
most command line users.

Typically, options are single letters preceded by a hyphen (-). Options that take an ar-
gument accept it either immediately following the option letter or after white space, for
example `print -C3 {1..9}' or `print -C 3 {1..9}' are equivalent. Arguments to options
are not the same as arguments to the command; the documentation indicates which is which.
Options that do not take an argument may be combined in a single word, for example `print
-rca -- *' and `print -r -c -a -- *' are equivalent.

Some shell builtin commands also take options that begin with `+' instead of `-'. The
list below makes clear which commands these are.

Options (together with their individual arguments, if any) must appear in a group before
any non-option arguments; once the first non-option argument has been found, option pro-
cessing is terminated.

All builtin commands other than `echo' and precommand modifiers, even those that have no
options, can be given the argument `--' to terminate option processing. This indicates
that the following words are non-option arguments, but is otherwise ignored. This is use-
ful in cases where arguments to the command may begin with `-'. For historical reasons,
most builtin commands (including `echo') also recognize a single `-' in a separate word
for this purpose; note that this is less standard and use of `--' is recommended.

- simple command
See the section `Precommand Modifiers' in zshmisc(1).

. file [ arg ... ]
Read commands from file and execute them in the current shell environment.

If file does not contain a slash, or if PATH_DIRS is set, the shell looks in the
components of $path to find the directory containing file. Files in the current
directory are not read unless `.' appears somewhere in $path. If a file named
`file.zwc' is found, is newer than file, and is the compiled form (created with the
zcompile builtin) of file, then commands are read from that file instead of file.

If any arguments arg are given, they become the positional parameters; the old po-
sitional parameters are restored when the file is done executing. However, if no
arguments are given, the positional parameters remain those of the calling context,
and no restoring is done.

If file was not found the return status is 127; if file was found but contained a
syntax error the return status is 126; else the return status is the exit status of
the last command executed.

: [ arg ... ]
This command does nothing, although normal argument expansions is performed which
may have effects on shell parameters. A zero exit status is returned.

alias [ {+|-}gmrsL ] [ name[=value] ... ]
For each name with a corresponding value, define an alias with that value. A
trailing space in value causes the next word to be checked for alias expansion. If
the -g flag is present, define a global alias; global aliases are expanded even if
they do not occur in command position.

If the -s flag is present, define a suffix alias: if the command word on a command
line is in the form `text.name', where text is any non-empty string, it is replaced
by the text `value text.name'. Note that name is treated as a literal string, not
a pattern. A trailing space in value is not special in this case. For example,

alias -s ps='gv --'

will cause the command `*.ps' to be expanded to `gv -- *.ps'. As alias expansion
is carried out earlier than globbing, the `*.ps' will then be expanded. Suffix
aliases constitute a different name space from other aliases (so in the above exam-
ple it is still possible to create an alias for the command ps) and the two sets
are never listed together.

For each name with no value, print the value of name, if any. With no arguments,
print all currently defined aliases other than suffix aliases. If the -m flag is
given the arguments are taken as patterns (they should be quoted to preserve them
from being interpreted as glob patterns), and the aliases matching these patterns
are printed. When printing aliases and one of the -g, -r or -s flags is present,
restrict the printing to global, regular or suffix aliases, respectively; a regular
alias is one which is neither a global nor a suffix alias. Using `+' instead of
`-', or ending the option list with a single `+', prevents the values of the
aliases from being printed.

If the -L flag is present, then print each alias in a manner suitable for putting
in a startup script. The exit status is nonzero if a name (with no value) is given
for which no alias has been defined.

For more on aliases, include common problems, see the section ALIASING in zsh-
misc(1).

autoload [ {+|-}RTUXdkmrtWz ] [ -w ] [ name ... ]
See the section `Autoloading Functions' in zshmisc(1) for full details. The fpath
parameter will be searched to find the function definition when the function is
first referenced.

If name consists of an absolute path, the function is defined to load from the file
given (searching as usual for dump files in the given location). The name of the
function is the basename (non-directory part) of the file. It is normally an error
if the function is not found in the given location; however, if the option -d is
given, searching for the function defaults to $fpath. If a function is loaded by
absolute path, any functions loaded from it that are marked for autoload without an
absolute path have the load path of the parent function temporarily prepended to
$fpath.

If the option -r or -R is given, the function is searched for immediately and the
location is recorded internally for use when the function is executed; a relative
path is expanded using the value of $PWD. This protects against a change to $fpath
after the call to autoload. With -r, if the function is not found, it is silently
left unresolved until execution; with -R, an error message is printed and command
processing aborted immediately the search fails, i.e. at the autoload command
rather than at function execution..

The flag -X may be used only inside a shell function. It causes the calling func-
tion to be marked for autoloading and then immediately loaded and executed, with
the current array of positional parameters as arguments. This replaces the previ-
ous definition of the function. If no function definition is found, an error is
printed and the function remains undefined and marked for autoloading. If an argu-
ment is given, it is used as a directory (i.e. it does not include the name of the
function) in which the function is to be found; this may be combined with the -d
option to allow the function search to default to $fpath if it is not in the given
location.

The flag +X attempts to load each name as an autoloaded function, but does not exe-
cute it. The exit status is zero (success) if the function was not previously de-
fined and a definition for it was found. This does not replace any existing defi-
nition of the function. The exit status is nonzero (failure) if the function was
already defined or when no definition was found. In the latter case the function
remains undefined and marked for autoloading. If ksh-style autoloading is enabled,
the function created will contain the contents of the file plus a call to the func-
tion itself appended to it, thus giving normal ksh autoloading behaviour on the
first call to the function. If the -m flag is also given each name is treated as a
pattern and all functions already marked for autoload that match the pattern are
loaded.

With the -t flag, turn on execution tracing; with -T, turn on execution tracing
only for the current function, turning it off on entry to any called functions that
do not also have tracing enabled.

With the -U flag, alias expansion is suppressed when the function is loaded.

With the -w flag, the names are taken as names of files compiled with the zcompile
builtin, and all functions defined in them are marked for autoloading.

The flags -z and -k mark the function to be autoloaded using the zsh or ksh style,
as if the option KSH_AUTOLOAD were unset or were set, respectively. The flags
override the setting of the option at the time the function is loaded.

Note that the autoload command makes no attempt to ensure the shell options set
during the loading or execution of the file have any particular value. For this,
the emulate command can be used:

emulate zsh -c 'autoload -Uz func'

arranges that when func is loaded the shell is in native zsh emulation, and this
emulation is also applied when func is run.

Some of the functions of autoload are also provided by functions -u or functions
-U, but autoload is a more comprehensive interface.

bg [ job ... ]
job ... &
Put each specified job in the background, or the current job if none is specified.

bindkey
See the section `Zle Builtins' in zshzle(1).

break [ n ]
Exit from an enclosing for, while, until, select or repeat loop. If an arithmetic
expression n is specified, then break n levels instead of just one.

builtin name [ args ... ]
Executes the builtin name, with the given args.

bye Same as exit.

cap See the section `The zsh/cap Module' in zshmodules(1).

cd [ -qsLP ] [ arg ]
cd [ -qsLP ] old new
cd [ -qsLP ] {+|-}n
Change the current directory. In the first form, change the current directory to
arg, or to the value of $HOME if arg is not specified. If arg is `-', change to
the previous directory.

Otherwise, if arg begins with a slash, attempt to change to the directory given by
arg.

If arg does not begin with a slash, the behaviour depends on whether the current
directory `.' occurs in the list of directories contained in the shell parameter
cdpath. If it does not, first attempt to change to the directory arg under the
current directory, and if that fails but cdpath is set and contains at least one
element attempt to change to the directory arg under each component of cdpath in
turn until successful. If `.' occurs in cdpath, then cdpath is searched strictly
in order so that `.' is only tried at the appropriate point.

The order of testing cdpath is modified if the option POSIX_CD is set, as described
in the documentation for the option.

If no directory is found, the option CDABLE_VARS is set, and a parameter named arg
exists whose value begins with a slash, treat its value as the directory. In that
case, the parameter is added to the named directory hash table.

The second form of cd substitutes the string new for the string old in the name of
the current directory, and tries to change to this new directory.

The third form of cd extracts an entry from the directory stack, and changes to
that directory. An argument of the form `+n' identifies a stack entry by counting
from the left of the list shown by the dirs command, starting with zero. An argu-
ment of the form `-n' counts from the right. If the PUSHD_MINUS option is set, the
meanings of `+' and `-' in this context are swapped. If the POSIX_CD option is
set, this form of cd is not recognised and will be interpreted as the first form.

If the -q (quiet) option is specified, the hook function chpwd and the functions in
the array chpwd_functions are not called. This is useful for calls to cd that do
not change the environment seen by an interactive user.

If the -s option is specified, cd refuses to change the current directory if the
given pathname contains symlinks. If the -P option is given or the CHASE_LINKS op-
tion is set, symbolic links are resolved to their true values. If the -L option is
given symbolic links are retained in the directory (and not resolved) regardless of
the state of the CHASE_LINKS option.

chdir Same as cd.

clone See the section `The zsh/clone Module' in zshmodules(1).

command [ -pvV ] simple command
The simple command argument is taken as an external command instead of a function
or builtin and is executed. If the POSIX_BUILTINS option is set, builtins will also
be executed but certain special properties of them are suppressed. The -p flag
causes a default path to be searched instead of that in $path. With the -v flag,
command is similar to whence and with -V, it is equivalent to whence -v.

See also the section `Precommand Modifiers' in zshmisc(1).

comparguments
See the section `The zsh/computil Module' in zshmodules(1).

compcall
See the section `The zsh/compctl Module' in zshmodules(1).

compctl
See the section `The zsh/compctl Module' in zshmodules(1).

compdescribe
See the section `The zsh/computil Module' in zshmodules(1).

compfiles
See the section `The zsh/computil Module' in zshmodules(1).

compgroups
See the section `The zsh/computil Module' in zshmodules(1).

compquote
See the section `The zsh/computil Module' in zshmodules(1).

comptags
See the section `The zsh/computil Module' in zshmodules(1).

comptry
See the section `The zsh/computil Module' in zshmodules(1).

compvalues
See the section `The zsh/computil Module' in zshmodules(1).

continue [ n ]
Resume the next iteration of the enclosing for, while, until, select or repeat
loop. If an arithmetic expression n is specified, break out of n-1 loops and resume
at the nth enclosing loop.

declare
Same as typeset.

dirs [ -c ] [ arg ... ]
dirs [ -lpv ]
With no arguments, print the contents of the directory stack. Directories are
added to this stack with the pushd command, and removed with the cd or popd com-
mands. If arguments are specified, load them onto the directory stack, replacing
anything that was there, and push the current directory onto the stack.

-c clear the directory stack.

-l print directory names in full instead of using of using ~ expressions (see
Dynamic and Static named directories in zshexpn(1)).

-p print directory entries one per line.

-v number the directories in the stack when printing.

disable [ -afmprs ] name ...
Temporarily disable the named hash table elements or patterns. The default is to
disable builtin commands. This allows you to use an external command with the same
name as a builtin command. The -a option causes disable to act on regular or
global aliases. The -s option causes disable to act on suffix aliases. The -f op-
tion causes disable to act on shell functions. The -r options causes disable to
act on reserved words. Without arguments all disabled hash table elements from the
corresponding hash table are printed. With the -m flag the arguments are taken as
patterns (which should be quoted to prevent them from undergoing filename expan-
sion), and all hash table elements from the corresponding hash table matching these
patterns are disabled. Disabled objects can be enabled with the enable command.

With the option -p, name ... refer to elements of the shell's pattern syntax as de-
scribed in the section `Filename Generation'. Certain elements can be disabled
separately, as given below.

Note that patterns not allowed by the current settings for the options EX-
TENDED_GLOB, KSH_GLOB and SH_GLOB are never enabled, regardless of the setting
here. For example, if EXTENDED_GLOB is not active, the pattern ^ is ineffective
even if `disable -p "^"' has not been issued. The list below indicates any option
settings that restrict the use of the pattern. It should be noted that setting
SH_GLOB has a wider effect than merely disabling patterns as certain expressions,
in particular those involving parentheses, are parsed differently.

The following patterns may be disabled; all the strings need quoting on the command
line to prevent them from being interpreted immediately as patterns and the pat-
terns are shown below in single quotes as a reminder.

'?' The pattern character ? wherever it occurs, including when preceding a
parenthesis with KSH_GLOB.

'*' The pattern character * wherever it occurs, including recursive globbing and
when preceding a parenthesis with KSH_GLOB.

'[' Character classes.

'<' (NO_SH_GLOB)
Numeric ranges.

'|' (NO_SH_GLOB)
Alternation in grouped patterns, case statements, or KSH_GLOB parenthesised
expressions.

'(' (NO_SH_GLOB)
Grouping using single parentheses. Disabling this does not disable the use
of parentheses for KSH_GLOB where they are introduced by a special charac-
ter, nor for glob qualifiers (use `setopt NO_BARE_GLOB_QUAL' to disable glob
qualifiers that use parentheses only).

'~' (EXTENDED_GLOB)
Exclusion in the form A~B.

'^' (EXTENDED_GLOB)
Exclusion in the form A^B.

'#' (EXTENDED_GLOB)
The pattern character # wherever it occurs, both for repetition of a previ-
ous pattern and for indicating globbing flags.

'?(' (KSH_GLOB)
The grouping form ?(...). Note this is also disabled if '?' is disabled.

'*(' (KSH_GLOB)
The grouping form *(...). Note this is also disabled if '*' is disabled.

'+(' (KSH_GLOB)
The grouping form +(...).

'!(' (KSH_GLOB)
The grouping form !(...).

'@(' (KSH_GLOB)
The grouping form @(...).

disown [ job ... ]
job ... &|
job ... &!
Remove the specified jobs from the job table; the shell will no longer report their
status, and will not complain if you try to exit an interactive shell with them
running or stopped. If no job is specified, disown the current job.

If the jobs are currently stopped and the AUTO_CONTINUE option is not set, a warn-
ing is printed containing information about how to make them running after they
have been disowned. If one of the latter two forms is used, the jobs will automat-
ically be made running, independent of the setting of the AUTO_CONTINUE option.

echo [ -neE ] [ arg ... ]
Write each arg on the standard output, with a space separating each one. If the -n
flag is not present, print a newline at the end. echo recognizes the following es-
cape sequences:

\a bell character
\b backspace
\c suppress subsequent characters and final newline
\e escape
\f form feed
\n linefeed (newline)
\r carriage return
\t horizontal tab
\v vertical tab
\\ backslash
\0NNN character code in octal
\xNN character code in hexadecimal
\uNNNN unicode character code in hexadecimal
\UNNNNNNNN
unicode character code in hexadecimal

The -E flag, or the BSD_ECHO option, can be used to disable these escape sequences.
In the latter case, -e flag can be used to enable them.

Note that for standards compliance a double dash does not terminate option process-
ing; instead, it is printed directly. However, a single dash does terminate option
processing, so the first dash, possibly following options, is not printed, but ev-
erything following it is printed as an argument. The single dash behaviour is dif-
ferent from other shells. For a more portable way of printing text, see printf,
and for a more controllable way of printing text within zsh, see print.

echotc See the section `The zsh/termcap Module' in zshmodules(1).

echoti See the section `The zsh/terminfo Module' in zshmodules(1).

emulate [ -lLR ] [ {zsh|sh|ksh|csh} [ flags ... ] ]
Without any argument print current emulation mode.

With single argument set up zsh options to emulate the specified shell as much as
possible. csh will never be fully emulated. If the argument is not one of the
shells listed above, zsh will be used as a default; more precisely, the tests per-
formed on the argument are the same as those used to determine the emulation at
startup based on the shell name, see the section COMPATIBILITY in zsh(1) . In ad-
dition to setting shell options, the command also restores the pristine state of
pattern enables, as if all patterns had been enabled using enable -p.

If the emulate command occurs inside a function that has been marked for execution
tracing with functions -t then the xtrace option will be turned on regardless of
emulation mode or other options. Note that code executed inside the function by
the ., source, or eval commands is not considered to be running directly from the
function, hence does not provoke this behaviour.

If the -R switch is given, all settable options are reset to their default value
corresponding to the specified emulation mode, except for certain options describ-
ing the interactive environment; otherwise, only those options likely to cause
portability problems in scripts and functions are altered. If the -L switch is
given, the options LOCAL_OPTIONS, LOCAL_PATTERNS and LOCAL_TRAPS will be set as
well, causing the effects of the emulate command and any setopt, disable -p or en-
able -p, and trap commands to be local to the immediately surrounding shell func-
tion, if any; normally these options are turned off in all emulation modes except
ksh. The -L switch is mutually exclusive with the use of -c in flags.

If there is a single argument and the -l switch is given, the options that would be
set or unset (the latter indicated with the prefix `no') are listed. -l can be
combined with -L or -R and the list will be modified in the appropriate way. Note
the list does not depend on the current setting of options, i.e. it includes all
options that may in principle change, not just those that would actually change.

The flags may be any of the invocation-time flags described in the section INVOCA-
TION in zsh(1), except that `-o EMACS' and `-o VI' may not be used. Flags such as
`+r'/`+o RESTRICTED' may be prohibited in some circumstances.

If -c arg appears in flags, arg is evaluated while the requested emulation is tem-
porarily in effect. In this case the emulation mode and all options are restored
to their previous values before emulate returns. The -R switch may precede the
name of the shell to emulate; note this has a meaning distinct from including -R in
flags.

Use of -c enables `sticky' emulation mode for functions defined within the evalu-
ated expression: the emulation mode is associated thereafter with the function so
that whenever the function is executed the emulation (respecting the -R switch, if
present) and all options are set (and pattern disables cleared) before entry to the
function, and the state is restored after exit. If the function is called when the
sticky emulation is already in effect, either within an `emulate shell -c' expres-
sion or within another function with the same sticky emulation, entry and exit from
the function do not cause options to be altered (except due to standard processing
such as the LOCAL_OPTIONS option). This also applies to functions marked for au-
toload within the sticky emulation; the appropriate set of options will be applied
at the point the function is loaded as well as when it is run.

For example:

emulate sh -c 'fni() { setopt cshnullglob; }
fno() { fni; }'
fno

The two functions fni and fno are defined with sticky sh emulation. fno is then
executed, causing options associated with emulations to be set to their values in
sh. fno then calls fni; because fni is also marked for sticky sh emulation, no op-
tion changes take place on entry to or exit from it. Hence the option cshnullglob,
turned off by sh emulation, will be turned on within fni and remain on return to
fno. On exit from fno, the emulation mode and all options will be restored to the
state they were in before entry to the temporary emulation.

The documentation above is typically sufficient for the intended purpose of execut-
ing code designed for other shells in a suitable environment. More detailed rules
follow.
1. The sticky emulation environment provided by `emulate shell -c' is identical
to that provided by entry to a function marked for sticky emulation as a
consequence of being defined in such an environment. Hence, for example,
the sticky emulation is inherited by subfunctions defined within functions
with sticky emulation.
2. No change of options takes place on entry to or exit from functions that are
not marked for sticky emulation, other than those that would normally take
place, even if those functions are called within sticky emulation.
3. No special handling is provided for functions marked for autoload nor for
functions present in wordcode created by the zcompile command.
4. The presence or absence of the -R switch to emulate corresponds to different
sticky emulation modes, so for example `emulate sh -c', `emulate -R sh -c'
and `emulate csh -c' are treated as three distinct sticky emulations.
5. Difference in shell options supplied in addition to the basic emulation also
mean the sticky emulations are different, so for example `emulate zsh -c'
and `emulate zsh -o cbases -c' are treated as distinct sticky emulations.

enable [ -afmprs ] name ...
Enable the named hash table elements, presumably disabled earlier with disable.
The default is to enable builtin commands. The -a option causes enable to act on
regular or global aliases. The -s option causes enable to act on suffix aliases.
The -f option causes enable to act on shell functions. The -r option causes enable
to act on reserved words. Without arguments all enabled hash table elements from
the corresponding hash table are printed. With the -m flag the arguments are taken
as patterns (should be quoted) and all hash table elements from the corresponding
hash table matching these patterns are enabled. Enabled objects can be disabled
with the disable builtin command.

enable -p reenables patterns disabled with disable -p. Note that it does not over-
ride globbing options; for example, `enable -p "~"' does not cause the pattern
character ~ to be active unless the EXTENDED_GLOB option is also set. To enable
all possible patterns (so that they may be individually disabled with disable -p),
use `setopt EXTENDED_GLOB KSH_GLOB NO_SH_GLOB'.

eval [ arg ... ]
Read the arguments as input to the shell and execute the resulting command(s) in
the current shell process. The return status is the same as if the commands had
been executed directly by the shell; if there are no args or they contain no com-
mands (i.e. are an empty string or whitespace) the return status is zero.

exec [ -cl ] [ -a argv0 ] [ command [ arg ... ] ]
Replace the current shell with command rather than forking. If command is a shell
builtin command or a shell function, the shell executes it, and exits when the com-
mand is complete.

With -c clear the environment; with -l prepend - to the argv[0] string of the com-
mand executed (to simulate a login shell); with -a argv0 set the argv[0] string of
the command executed. See the section `Precommand Modifiers' in zshmisc(1).

If the option POSIX_BUILTINS is set, command is never interpreted as a shell
builtin command or shell function. This means further precommand modifiers such as
builtin and noglob are also not interpreted within the shell. Hence command is al-
ways found by searching the command path.

If command is omitted but any redirections are specified, then the redirections
will take effect in the current shell.

exit [ n ]
Exit the shell with the exit status specified by an arithmetic expression n; if
none is specified, use the exit status from the last command executed. An EOF con-
dition will also cause the shell to exit, unless the IGNORE_EOF option is set.

See notes at the end of the section JOBS in zshmisc(1) for some possibly unexpected
interactions of the exit command with jobs.

export [ name[=value] ... ]
The specified names are marked for automatic export to the environment of subse-
quently executed commands. Equivalent to typeset -gx. If a parameter specified
does not already exist, it is created in the global scope.

false [ arg ... ]
Do nothing and return an exit status of 1.

fc [ -e ename ] [ -LI ] [ -m match ] [ old=new ... ] [ first [ last ] ]
fc -l [ -LI ] [ -nrdfEiD ] [ -t timefmt ] [ -m match ]
[ old=new ... ] [ first [ last ] ]
fc -p [ -a ] [ filename [ histsize [ savehistsize ] ] ]
fc -P
fc -ARWI [ filename ]
The fc command controls the interactive history mechanism. Note that reading and
writing of history options is only performed if the shell is interactive. Usually
this is detected automatically, but it can be forced by setting the interactive op-
tion when starting the shell.

The first two forms of this command select a range of events from first to last
from the history list. The arguments first and last may be specified as a number
or as a string. A negative number is used as an offset to the current history
event number. A string specifies the most recent event beginning with the given
string. All substitutions old=new, if any, are then performed on the text of the
events.

In addition to the number range,
-I restricts to only internal events (not from $HISTFILE)
-L restricts to only local events (not from other shells, see SHARE_HISTORY in
zshoptions(1) -- note that $HISTFILE is considered local when read at
startup)
-m takes the first argument as a pattern (should be quoted) and only the his-
tory events matching this pattern are considered

If first is not specified, it will be set to -1 (the most recent event), or to -16
if the -l flag is given. If last is not specified, it will be set to first, or to
-1 if the -l flag is given. However, if the current event has added entries to the
history with `print -s' or `fc -R', then the default last for -l includes all new
history entries since the current event began.

When the -l flag is given, the resulting events are listed on standard output.
Otherwise the editor program specified by -e ename is invoked on a file containing
these history events. If -e is not given, the value of the parameter FCEDIT is
used; if that is not set the value of the parameter EDITOR is used; if that is not
set a builtin default, usually `vi' is used. If ename is `-', no editor is in-
voked. When editing is complete, the edited command is executed.

The flag -r reverses the order of the events and the flag -n suppresses event num-
bers when listing.

Also when listing,
-d prints timestamps for each event
-f prints full time-date stamps in the US `MM/DD/YY hh:mm' format
-E prints full time-date stamps in the European `dd.mm.yyyy hh:mm' format
-i prints full time-date stamps in ISO8601 `yyyy-mm-dd hh:mm' format
-t fmt prints time and date stamps in the given format; fmt is formatted with the
strftime function with the zsh extensions described for the %D{string}
prompt format in the section EXPANSION OF PROMPT SEQUENCES in zshmisc(1).
The resulting formatted string must be no more than 256 characters or will
not be printed
-D prints elapsed times; may be combined with one of the options above

`fc -p' pushes the current history list onto a stack and switches to a new history
list. If the -a option is also specified, this history list will be automatically
popped when the current function scope is exited, which is a much better solution
than creating a trap function to call `fc -P' manually. If no arguments are speci-
fied, the history list is left empty, $HISTFILE is unset, and $HISTSIZE & $SAVEHIST
are set to their default values. If one argument is given, $HISTFILE is set to
that filename, $HISTSIZE & $SAVEHIST are left unchanged, and the history file is
read in (if it exists) to initialize the new list. If a second argument is speci-
fied, $HISTSIZE & $SAVEHIST are instead set to the single specified numeric value.
Finally, if a third argument is specified, $SAVEHIST is set to a separate value
from $HISTSIZE. You are free to change these environment values for the new his-
tory list however you desire in order to manipulate the new history list.

`fc -P' pops the history list back to an older list saved by `fc -p'. The current
list is saved to its $HISTFILE before it is destroyed (assuming that $HISTFILE and
$SAVEHIST are set appropriately, of course). The values of $HISTFILE, $HISTSIZE,
and $SAVEHIST are restored to the values they had when `fc -p' was called. Note
that this restoration can conflict with making these variables "local", so your
best bet is to avoid local declarations for these variables in functions that use
`fc -p'. The one other guaranteed-safe combination is declaring these variables to
be local at the top of your function and using the automatic option (-a) with `fc
-p'. Finally, note that it is legal to manually pop a push marked for automatic
popping if you need to do so before the function exits.

`fc -R' reads the history from the given file, `fc -W' writes the history out to
the given file, and `fc -A' appends the history out to the given file. If no file-
name is specified, the $HISTFILE is assumed. If the -I option is added to -R, only
those events that are not already contained within the internal history list are
added. If the -I option is added to -A or -W, only those events that are new since
last incremental append/write to the history file are appended/written. In any
case, the created file will have no more than $SAVEHIST entries.

fg [ job ... ]
job ...
Bring each specified job in turn to the foreground. If no job is specified, resume
the current job.

float [ {+|-}Hghlprtux ] [ {+|-}EFLRZ [ n ] ] [ name[=value] ... ]
Equivalent to typeset -E, except that options irrelevant to floating point numbers
are not permitted.

functions [ {+|-}UkmtTuWz ] [ -x num ] [ name ... ]
functions -c oldfn newfn
functions -M [-s] mathfn [ min [ max [ shellfn ] ] ]
functions -M [ -m pattern ... ]
functions +M [ -m ] mathfn ...
Equivalent to typeset -f, with the exception of the -c, -x, -M and -W options. For
functions -u and functions -U, see autoload, which provides additional options.

The -x option indicates that any functions output will have each leading tab for
indentation, added by the shell to show syntactic structure, expanded to the given
number num of spaces. num can also be 0 to suppress all indentation.

The -W option turns on the option WARN_NESTED_VAR for the named function or func-
tions only. The option is turned off at the start of nested functions (apart from
anonoymous functions) unless the called function also has the -W attribute.

The -c option causes oldfn to be copied to newfn. The copy is efficiently handled
internally by reference counting. If oldfn was marked for autoload it is first
loaded and if this fails the copy fails. Either function may subsequently be rede-
fined without affecting the other. A typical idiom is that oldfn is the name of a
library shell function which is then redefined to call newfn, thereby installing a
modified version of the function.

Use of the -M option may not be combined with any of the options handled by typeset
-f.

functions -M mathfn defines mathfn as the name of a mathematical function recog-
nised in all forms of arithmetical expressions; see the section `Arithmetic Evalua-
tion' in zshmisc(1). By default mathfn may take any number of comma-separated ar-
guments. If min is given, it must have exactly min args; if min and max are both
given, it must have at least min and at most max args. max may be -1 to indicate
that there is no upper limit.

By default the function is implemented by a shell function of the same name; if
shellfn is specified it gives the name of the corresponding shell function while
mathfn remains the name used in arithmetical expressions. The name of the function
in $0 is mathfn (not shellfn as would usually be the case), provided the option
FUNCTION_ARGZERO is in effect. The positional parameters in the shell function
correspond to the arguments of the mathematical function call. The result of the
last arithmetical expression evaluated inside the shell function (even if it is a
form that normally only returns a status) gives the result of the mathematical
function.

If the additional option -s is given to functions -M, the argument to the function
is a single string: anything between the opening and matching closing parenthesis
is passed to the function as a single argument, even if it includes commas or white
space. The minimum and maximum argument specifiers must therefore be 1 if given.
An empty argument list is passed as a zero-length string.

functions -M with no arguments lists all such user-defined functions in the same
form as a definition. With the additional option -m and a list of arguments, all
functions whose mathfn matches one of the pattern arguments are listed.

function +M removes the list of mathematical functions; with the additional option
-m the arguments are treated as patterns and all functions whose mathfn matches the
pattern are removed. Note that the shell function implementing the behaviour is
not removed (regardless of whether its name coincides with mathfn).

For example, the following prints the cube of 3:

zmath_cube() { (( $1 * $1 * $1 )) }
functions -M cube 1 1 zmath_cube
print $(( cube(3) ))

The following string function takes a single argument, including the commas, so
prints 11:

stringfn() { (( $#1 )) }
functions -Ms stringfn
print $(( stringfn(foo,bar,rod) ))

getcap See the section `The zsh/cap Module' in zshmodules(1).

getln [ -AclneE ] name ...
Read the top value from the buffer stack and put it in the shell parameter name.
Equivalent to read -zr.

getopts optstring name [ arg ... ]
Checks the args for legal options. If the args are omitted, use the positional pa-
rameters. A valid option argument begins with a `+' or a `-'. An argument not be-
ginning with a `+' or a `-', or the argument `--', ends the options. Note that a
single `-' is not considered a valid option argument. optstring contains the let-
ters that getopts recognizes. If a letter is followed by a `:', that option re-
quires an argument. The options can be separated from the argument by blanks.

Each time it is invoked, getopts places the option letter it finds in the shell pa-
rameter name, prepended with a `+' when arg begins with a `+'. The index of the
next arg is stored in OPTIND. The option argument, if any, is stored in OPTARG.

The first option to be examined may be changed by explicitly assigning to OPTIND.
OPTIND has an initial value of 1, and is normally set to 1 upon entry to a shell
function and restored upon exit (this is disabled by the POSIX_BUILTINS option).
OPTARG is not reset and retains its value from the most recent call to getopts. If
either of OPTIND or OPTARG is explicitly unset, it remains unset, and the index or
option argument is not stored. The option itself is still stored in name in this
case.

A leading `:' in optstring causes getopts to store the letter of any invalid option
in OPTARG, and to set name to `?' for an unknown option and to `:' when a required
argument is missing. Otherwise, getopts sets name to `?' and prints an error mes-
sage when an option is invalid. The exit status is nonzero when there are no more
options.

hash [ -Ldfmrv ] [ name[=value] ] ...
hash can be used to directly modify the contents of the command hash table, and the
named directory hash table. Normally one would modify these tables by modifying
one's PATH (for the command hash table) or by creating appropriate shell parameters
(for the named directory hash table). The choice of hash table to work on is de-
termined by the -d option; without the option the command hash table is used, and
with the option the named directory hash table is used.

A command name starting with a / is never hashed, whether by explicit use of the
hash command or otherwise. Such a command is always found by direct look up in the
file system.

Given no arguments, and neither the -r or -f options, the selected hash table will
be listed in full.

The -r option causes the selected hash table to be emptied. It will be subse-
quently rebuilt in the normal fashion. The -f option causes the selected hash ta-
ble to be fully rebuilt immediately. For the command hash table this hashes all
the absolute directories in the PATH, and for the named directory hash table this
adds all users' home directories. These two options cannot be used with any argu-
ments.

The -m option causes the arguments to be taken as patterns (which should be quoted)
and the elements of the hash table matching those patterns are printed. This is
the only way to display a limited selection of hash table elements.

For each name with a corresponding value, put `name' in the selected hash table,
associating it with the pathname `value'. In the command hash table, this means
that whenever `name' is used as a command argument, the shell will try to execute
the file given by `value'. In the named directory hash table, this means that
`value' may be referred to as `~name'.

For each name with no corresponding value, attempt to add name to the hash table,
checking what the appropriate value is in the normal manner for that hash table.
If an appropriate value can't be found, then the hash table will be unchanged.

The -v option causes hash table entries to be listed as they are added by explicit
specification. If has no effect if used with -f.

If the -L flag is present, then each hash table entry is printed in the form of a
call to hash.

history
Same as fc -l.

integer [ {+|-}Hghlprtux ] [ {+|-}LRZi [ n ] ] [ name[=value] ... ]
Equivalent to typeset -i, except that options irrelevant to integers are not per-
mitted.

jobs [ -dlprs ] [ job ... ]
jobs -Z string
Lists information about each given job, or all jobs if job is omitted. The -l flag
lists process IDs, and the -p flag lists process groups. If the -r flag is speci-
fied only running jobs will be listed and if the -s flag is given only stopped jobs
are shown. If the -d flag is given, the directory from which the job was started
(which may not be the current directory of the job) will also be shown.

The -Z option replaces the shell's argument and environment space with the given
string, truncated if necessary to fit. This will normally be visible in ps (ps(1))
listings. This feature is typically used by daemons, to indicate their state.

kill [ -s signal_name | -n signal_number | -sig ] job ...
kill -l [ sig ... ]
Sends either SIGTERM or the specified signal to the given jobs or processes. Sig-
nals are given by number or by names, with or without the `SIG' prefix. If the
signal being sent is not `KILL' or `CONT', then the job will be sent a `CONT' sig-
nal if it is stopped. The argument job can be the process ID of a job not in the
job list. In the second form, kill -l, if sig is not specified the signal names
are listed. Otherwise, for each sig that is a name, the corresponding signal num-
ber is listed. For each sig that is a signal number or a number representing the
exit status of a process which was terminated or stopped by a signal the name of
the signal is printed.

On some systems, alternative signal names are allowed for a few signals. Typical
examples are SIGCHLD and SIGCLD or SIGPOLL and SIGIO, assuming they correspond to
the same signal number. kill -l will only list the preferred form, however kill -l
alt will show if the alternative form corresponds to a signal number. For example,
under Linux kill -l IO and kill -l POLL both output 29, hence kill -IO and kill
-POLL have the same effect.

Many systems will allow process IDs to be negative to kill a process group or zero
to kill the current process group.

let arg ...
Evaluate each arg as an arithmetic expression. See the section `Arithmetic Evalua-
tion' in zshmisc(1) for a description of arithmetic expressions. The exit status
is 0 if the value of the last expression is nonzero, 1 if it is zero, and 2 if an
error occurred.

limit [ -hs ] [ resource [ limit ] ] ...
Set or display resource limits. Unless the -s flag is given, the limit applies
only the children of the shell. If -s is given without other arguments, the re-
source limits of the current shell is set to the previously set resource limits of
the children.

If limit is not specified, print the current limit placed on resource, otherwise
set the limit to the specified value. If the -h flag is given, use hard limits in-
stead of soft limits. If no resource is given, print all limits.

When looping over multiple resources, the shell will abort immediately if it de-
tects a badly formed argument. However, if it fails to set a limit for some other
reason it will continue trying to set the remaining limits.

resource can be one of:

addressspace
Maximum amount of address space used.
aiomemorylocked
Maximum amount of memory locked in RAM for AIO operations.
aiooperations
Maximum number of AIO operations.
cachedthreads
Maximum number of cached threads.
coredumpsize
Maximum size of a core dump.
cputime
Maximum CPU seconds per process.
datasize
Maximum data size (including stack) for each process.
descriptors
Maximum value for a file descriptor.
filesize
Largest single file allowed.
kqueues
Maximum number of kqueues allocated.
maxproc
Maximum number of processes.
maxpthreads
Maximum number of threads per process.
memorylocked
Maximum amount of memory locked in RAM.
memoryuse
Maximum resident set size.
msgqueue
Maximum number of bytes in POSIX message queues.
posixlocks
Maximum number of POSIX locks per user.
pseudoterminals
Maximum number of pseudo-terminals.
resident
Maximum resident set size.
sigpending
Maximum number of pending signals.
sockbufsize
Maximum size of all socket buffers.
stacksize
Maximum stack size for each process.
swapsize
Maximum amount of swap used.
vmemorysize
Maximum amount of virtual memory.

Which of these resource limits are available depends on the system. resource can
be abbreviated to any unambiguous prefix. It can also be an integer, which corre-
sponds to the integer defined for the resource by the operating system.

If argument corresponds to a number which is out of the range of the resources con-
figured into the shell, the shell will try to read or write the limit anyway, and
will report an error if this fails. As the shell does not store such resources in-
ternally, an attempt to set the limit will fail unless the -s option is present.

limit is a number, with an optional scaling factor, as follows:

nh hours
nk kilobytes (default)
nm megabytes or minutes
ng gigabytes
[mm:]ss
minutes and seconds

The limit command is not made available by default when the shell starts in a mode
emulating another shell. It can be made available with the command `zmodload -F
zsh/rlimits b:limit'.

local [ {+|-}AHUahlprtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] ... ]
Same as typeset, except that the options -g, and -f are not permitted. In this
case the -x option does not force the use of -g, i.e. exported variables will be
local to functions.

log List all users currently logged in who are affected by the current setting of the
watch parameter.

logout [ n ]
Same as exit, except that it only works in a login shell.

noglob simple command
See the section `Precommand Modifiers' in zshmisc(1).

popd [ -q ] [ {+|-}n ]
Remove an entry from the directory stack, and perform a cd to the new top direc-
tory. With no argument, the current top entry is removed. An argument of the form
`+n' identifies a stack entry by counting from the left of the list shown by the
dirs command, starting with zero. An argument of the form -n counts from the
right. If the PUSHD_MINUS option is set, the meanings of `+' and `-' in this con-
text are swapped.

If the -q (quiet) option is specified, the hook function chpwd and the functions in
the array $chpwd_functions are not called, and the new directory stack is not
printed. This is useful for calls to popd that do not change the environment seen
by an interactive user.

print [ -abcDilmnNoOpPrsSz ] [ -u n ] [ -f format ] [ -C cols ]
[ -v name ] [ -xX tabstop ] [ -R [ -en ]] [ arg ... ]
With the `-f' option the arguments are printed as described by printf. With no
flags or with the flag `-', the arguments are printed on the standard output as de-
scribed by echo, with the following differences: the escape sequence `\M-x' (or
`\Mx') metafies the character x (sets the highest bit), `\C-x' (or `\Cx') produces
a control character (`\C-@' and `\C-?' give the characters NULL and delete), a
character code in octal is represented by `\NNN' (instead of `\0NNN'), and `\E' is
a synonym for `\e'. Finally, if not in an escape sequence, `\' escapes the follow-
ing character and is not printed.

-a Print arguments with the column incrementing first. Only useful with the -c
and -C options.

-b Recognize all the escape sequences defined for the bindkey command, see the
section `Zle Builtins' in zshzle(1).

-c Print the arguments in columns. Unless -a is also given, arguments are
printed with the row incrementing first.

-C cols
Print the arguments in cols columns. Unless -a is also given, arguments are
printed with the row incrementing first.

-D Treat the arguments as paths, replacing directory prefixes with ~ expres-
sions corresponding to directory names, as appropriate.

-i If given together with -o or -O, sorting is performed case-independently.

-l Print the arguments separated by newlines instead of spaces. Note: if the
list of arguments is empty, print -l will still output one empty line. To
print a possibly-empty list of arguments one per line, use print -C1, as in
`print -rC1 -- "$list[@]"'.

-m Take the first argument as a pattern (should be quoted), and remove it from
the argument list together with subsequent arguments that do not match this
pattern.

-n Do not add a newline to the output.

-N Print the arguments separated and terminated by nulls. Again, print -rNC1 --
"$list[@]" is a canonical way to print an arbitrary list as null-delimited
records.

-o Print the arguments sorted in ascending order.

-O Print the arguments sorted in descending order.

-p Print the arguments to the input of the coprocess.

-P Perform prompt expansion (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)).
In combination with `-f', prompt escape sequences are parsed only within in-
terpolated arguments, not within the format string.

-r Ignore the escape conventions of echo.

-R Emulate the BSD echo command, which does not process escape sequences unless
the -e flag is given. The -n flag suppresses the trailing newline. Only
the -e and -n flags are recognized after -R; all other arguments and options
are printed.

-s Place the results in the history list instead of on the standard output.
Each argument to the print command is treated as a single word in the his-
tory, regardless of its content.

-S Place the results in the history list instead of on the standard output. In
this case only a single argument is allowed; it will be split into words as
if it were a full shell command line. The effect is similar to reading the
line from a history file with the HIST_LEX_WORDS option active.

-u n Print the arguments to file descriptor n.

-v name
Store the printed arguments as the value of the parameter name.

-x tab-stop
Expand leading tabs on each line of output in the printed string assuming a
tab stop every tab-stop characters. This is appropriate for formatting code
that may be indented with tabs. Note that leading tabs of any argument to
print, not just the first, are expanded, even if print is using spaces to
separate arguments (the column count is maintained across arguments but may
be incorrect on output owing to previous unexpanded tabs).

The start of the output of each print command is assumed to be aligned with
a tab stop. Widths of multibyte characters are handled if the option MULTI-
BYTE is in effect. This option is ignored if other formatting options are
in effect, namely column alignment or printf style, or if output is to a
special location such as shell history or the command line editor.

-X tab-stop
This is similar to -x, except that all tabs in the printed string are ex-
panded. This is appropriate if tabs in the arguments are being used to pro-
duce a table format.

-z Push the arguments onto the editing buffer stack, separated by spaces.

If any of `-m', `-o' or `-O' are used in combination with `-f' and there are no ar-
guments (after the removal process in the case of `-m') then nothing is printed.

printf [ -v name ] format [ arg ... ]
Print the arguments according to the format specification. Formatting rules are the
same as used in C. The same escape sequences as for echo are recognised in the for-
mat. All C conversion specifications ending in one of csdiouxXeEfgGn are handled.
In addition to this, `%b' can be used instead of `%s' to cause escape sequences in
the argument to be recognised and `%q' can be used to quote the argument in such a
way that allows it to be reused as shell input. With the numeric format specifiers,
if the corresponding argument starts with a quote character, the numeric value of
the following character is used as the number to print; otherwise the argument is
evaluated as an arithmetic expression. See the section `Arithmetic Evaluation' in
zshmisc(1) for a description of arithmetic expressions. With `%n', the correspond-
ing argument is taken as an identifier which is created as an integer parameter.

Normally, conversion specifications are applied to each argument in order but they
can explicitly specify the nth argument is to be used by replacing `%' by `%n$' and
`*' by `*n$'. It is recommended that you do not mix references of this explicit
style with the normal style and the handling of such mixed styles may be subject to
future change.

If arguments remain unused after formatting, the format string is reused until all
arguments have been consumed. With the print builtin, this can be suppressed by us-
ing the -r option. If more arguments are required by the format than have been
specified, the behaviour is as if zero or an empty string had been specified as the
argument.

The -v option causes the output to be stored as the value of the parameter name,
instead of printed. If name is an array and the format string is reused when con-
suming arguments then one array element will be used for each use of the format
string.

pushd [ -qsLP ] [ arg ]
pushd [ -qsLP ] old new
pushd [ -qsLP ] {+|-}n
Change the current directory, and push the old current directory onto the directory
stack. In the first form, change the current directory to arg. If arg is not
specified, change to the second directory on the stack (that is, exchange the top
two entries), or change to $HOME if the PUSHD_TO_HOME option is set or if there is
only one entry on the stack. Otherwise, arg is interpreted as it would be by cd.
The meaning of old and new in the second form is also the same as for cd.

The third form of pushd changes directory by rotating the directory list. An argu-
ment of the form `+n' identifies a stack entry by counting from the left of the
list shown by the dirs command, starting with zero. An argument of the form `-n'
counts from the right. If the PUSHD_MINUS option is set, the meanings of `+' and
`-' in this context are swapped.

If the -q (quiet) option is specified, the hook function chpwd and the functions in
the array $chpwd_functions are not called, and the new directory stack is not
printed. This is useful for calls to pushd that do not change the environment seen
by an interactive user.

If the option -q is not specified and the shell option PUSHD_SILENT is not set, the
directory stack will be printed after a pushd is performed.

The options -s, -L and -P have the same meanings as for the cd builtin.

pushln [ arg ... ]
Equivalent to print -nz.

pwd [ -rLP ]
Print the absolute pathname of the current working directory. If the -r or the -P
flag is specified, or the CHASE_LINKS option is set and the -L flag is not given,
the printed path will not contain symbolic links.

r Same as fc -e -.

read [ -rszpqAclneE ] [ -t [ num ] ] [ -k [ num ] ] [ -d delim ]
[ -u n ] [ name[?prompt] ] [ name ... ]
Read one line and break it into fields using the characters in $IFS as separators,
except as noted below. The first field is assigned to the first name, the second
field to the second name, etc., with leftover fields assigned to the last name. If
name is omitted then REPLY is used for scalars and reply for arrays.

-r Raw mode: a `\' at the end of a line does not signify line continuation and
backslashes in the line don't quote the following character and are not re-
moved.

-s Don't echo back characters if reading from the terminal.

-q Read only one character from the terminal and set name to `y' if this char-
acter was `y' or `Y' and to `n' otherwise. With this flag set the return
status is zero only if the character was `y' or `Y'. This option may be
used with a timeout (see -t); if the read times out, or encounters end of
file, status 2 is returned. Input is read from the terminal unless one of
-u or -p is present. This option may also be used within zle widgets.

-k [ num ]
Read only one (or num) characters. All are assigned to the first name,
without word splitting. This flag is ignored when -q is present. Input is
read from the terminal unless one of -u or -p is present. This option may
also be used within zle widgets.

Note that despite the mnemonic `key' this option does read full characters,
which may consist of multiple bytes if the option MULTIBYTE is set.

-z Read one entry from the editor buffer stack and assign it to the first name,
without word splitting. Text is pushed onto the stack with `print -z' or
with push-line from the line editor (see zshzle(1)). This flag is ignored
when the -k or -q flags are present.

-e
-E The input read is printed (echoed) to the standard output. If the -e flag
is used, no input is assigned to the parameters.

-A The first name is taken as the name of an array and all words are assigned
to it.

-c
-l These flags are allowed only if called inside a function used for completion
(specified with the -K flag to compctl). If the -c flag is given, the words
of the current command are read. If the -l flag is given, the whole line is
assigned as a scalar. If both flags are present, -l is used and -c is ig-
nored.

-n Together with -c, the number of the word the cursor is on is read. With -l,
the index of the character the cursor is on is read. Note that the command
name is word number 1, not word 0, and that when the cursor is at the end of
the line, its character index is the length of the line plus one.

-u n Input is read from file descriptor n.

-p Input is read from the coprocess.

-d delim
Input is terminated by the first character of delim instead of by newline.

-t [ num ]
Test if input is available before attempting to read. If num is present, it
must begin with a digit and will be evaluated to give a number of seconds,
which may be a floating point number; in this case the read times out if in-
put is not available within this time. If num is not present, it is taken
to be zero, so that read returns immediately if no input is available. If
no input is available, return status 1 and do not set any variables.

This option is not available when reading from the editor buffer with -z,
when called from within completion with -c or -l, with -q which clears the
input queue before reading, or within zle where other mechanisms should be
used to test for input.

Note that read does not attempt to alter the input processing mode. The de-
fault mode is canonical input, in which an entire line is read at a time, so
usually `read -t' will not read anything until an entire line has been
typed. However, when reading from the terminal with -k input is processed
one key at a time; in this case, only availability of the first character is
tested, so that e.g. `read -t -k 2' can still block on the second character.
Use two instances of `read -t -k' if this is not what is wanted.

If the first argument contains a `?', the remainder of this word is used as a
prompt on standard error when the shell is interactive.

The value (exit status) of read is 1 when an end-of-file is encountered, or when -c
or -l is present and the command is not called from a compctl function, or as de-
scribed for -q. Otherwise the value is 0.

The behavior of some combinations of the -k, -p, -q, -u and -z flags is undefined.
Presently -q cancels all the others, -p cancels -u, -k cancels -z, and otherwise -z
cancels both -p and -u.

The -c or -l flags cancel any and all of -kpquz.

readonly
Same as typeset -r. With the POSIX_BUILTINS option set, same as typeset -gr.

rehash Same as hash -r.

return [ n ]
Causes a shell function or `.' script to return to the invoking script with the re-
turn status specified by an arithmetic expression n. If n is omitted, the return
status is that of the last command executed.

If return was executed from a trap in a TRAPNAL function, the effect is different
for zero and non-zero return status. With zero status (or after an implicit return
at the end of the trap), the shell will return to whatever it was previously pro-
cessing; with a non-zero status, the shell will behave as interrupted except that
the return status of the trap is retained. Note that the numeric value of the sig-
nal which caused the trap is passed as the first argument, so the statement `return
$((128+$1))' will return the same status as if the signal had not been trapped.

sched See the section `The zsh/sched Module' in zshmodules(1).

set [ {+|-}options | {+|-}o [ option_name ] ] ... [ {+|-}A [ name ] ]
[ arg ... ]
Set the options for the shell and/or set the positional parameters, or declare and
set an array. If the -s option is given, it causes the specified arguments to be
sorted before assigning them to the positional parameters (or to the array name if
-A is used). With +s sort arguments in descending order. For the meaning of the
other flags, see zshoptions(1). Flags may be specified by name using the -o op-
tion. If no option name is supplied with -o, the current option states are printed:
see the description of setopt below for more information on the format. With +o
they are printed in a form that can be used as input to the shell.

If the -A flag is specified, name is set to an array containing the given args; if
no name is specified, all arrays are printed together with their values.

If +A is used and name is an array, the given arguments will replace the initial
elements of that array; if no name is specified, all arrays are printed without
their values.

The behaviour of arguments after -A name or +A name depends on whether the option
KSH_ARRAYS is set. If it is not set, all arguments following name are treated as
values for the array, regardless of their form. If the option is set, normal op-
tion processing continues at that point; only regular arguments are treated as val-
ues for the array. This means that

set -A array -x -- foo

sets array to `-x -- foo' if KSH_ARRAYS is not set, but sets the array to foo and
turns on the option `-x' if it is set.

If the -A flag is not present, but there are arguments beyond the options, the po-
sitional parameters are set. If the option list (if any) is terminated by `--',
and there are no further arguments, the positional parameters will be unset.

If no arguments and no `--' are given, then the names and values of all parameters
are printed on the standard output. If the only argument is `+', the names of all
parameters are printed.

For historical reasons, `set -' is treated as `set +xv' and `set - args' as `set
+xv -- args' when in any other emulation mode than zsh's native mode.

setcap See the section `The zsh/cap Module' in zshmodules(1).

setopt [ {+|-}options | {+|-}o option_name ] [ -m ] [ name ... ]
Set the options for the shell. All options specified either with flags or by name
are set.

If no arguments are supplied, the names of all options currently set are printed.
The form is chosen so as to minimize the differences from the default options for
the current emulation (the default emulation being native zsh, shown as <Z> in
zshoptions(1)). Options that are on by default for the emulation are shown with
the prefix no only if they are off, while other options are shown without the pre-
fix no and only if they are on. In addition to options changed from the default
state by the user, any options activated automatically by the shell (for example,
SHIN_STDIN or INTERACTIVE) will be shown in the list. The format is further modi-
fied by the option KSH_OPTION_PRINT, however the rationale for choosing options
with or without the no prefix remains the same in this case.

If the -m flag is given the arguments are taken as patterns (which should be quoted
to protect them from filename expansion), and all options with names matching these
patterns are set.

Note that a bad option name does not cause execution of subsequent shell code to be
aborted; this is behaviour is different from that of `set -o'. This is because set
is regarded as a special builtin by the POSIX standard, but setopt is not.

shift [ -p ] [ n ] [ name ... ]
The positional parameters ${n+1} ... are renamed to $1 ..., where n is an arith-
metic expression that defaults to 1. If any names are given then the arrays with
these names are shifted instead of the positional parameters.

If the option -p is given arguments are instead removed (popped) from the end
rather than the start of the array.

source file [ arg ... ]
Same as `.', except that the current directory is always searched and is always
searched first, before directories in $path.

stat See the section `The zsh/stat Module' in zshmodules(1).

suspend [ -f ]
Suspend the execution of the shell (send it a SIGTSTP) until it receives a SIGCONT.
Unless the -f option is given, this will refuse to suspend a login shell.

test [ arg ... ]
[ [ arg ... ] ]
Like the system version of test. Added for compatibility; use conditional expres-
sions instead (see the section `Conditional Expressions'). The main differences
between the conditional expression syntax and the test and [ builtins are: these
commands are not handled syntactically, so for example an empty variable expansion
may cause an argument to be omitted; syntax errors cause status 2 to be returned
instead of a shell error; and arithmetic operators expect integer arguments rather
than arithmetic expressions.

The command attempts to implement POSIX and its extensions where these are speci-
fied. Unfortunately there are intrinsic ambiguities in the syntax; in particular
there is no distinction between test operators and strings that resemble them. The
standard attempts to resolve these for small numbers of arguments (up to four); for
five or more arguments compatibility cannot be relied on. Users are urged wherever
possible to use the `[[' test syntax which does not have these ambiguities.

times Print the accumulated user and system times for the shell and for processes run
from the shell.

trap [ arg ] [ sig ... ]
arg is a series of commands (usually quoted to protect it from immediate evaluation
by the shell) to be read and executed when the shell receives any of the signals
specified by one or more sig args. Each sig can be given as a number, or as the
name of a signal either with or without the string SIG in front (e.g. 1, HUP, and
SIGHUP are all the same signal).

If arg is `-', then the specified signals are reset to their defaults, or, if no
sig args are present, all traps are reset.

If arg is an empty string, then the specified signals are ignored by the shell (and
by the commands it invokes).

If arg is omitted but one or more sig args are provided (i.e. the first argument
is a valid signal number or name), the effect is the same as if arg had been speci-
fied as `-'.

The trap command with no arguments prints a list of commands associated with each
signal.

If sig is ZERR then arg will be executed after each command with a nonzero exit
status. ERR is an alias for ZERR on systems that have no SIGERR signal (this is
the usual case).

If sig is DEBUG then arg will be executed before each command if the option DE-
BUG_BEFORE_CMD is set (as it is by default), else after each command. Here, a
`command' is what is described as a `sublist' in the shell grammar, see the section
SIMPLE COMMANDS & PIPELINES in zshmisc(1). If DEBUG_BEFORE_CMD is set various ad-
ditional features are available. First, it is possible to skip the next command by
setting the option ERR_EXIT; see the description of the ERR_EXIT option in zshop-
tions(1). Also, the shell parameter ZSH_DEBUG_CMD is set to the string correspond-
ing to the command to be executed following the trap. Note that this string is re-
constructed from the internal format and may not be formatted the same way as the
original text. The parameter is unset after the trap is executed.

If sig is 0 or EXIT and the trap statement is executed inside the body of a func-
tion, then the command arg is executed after the function completes. The value of
$? at the start of execution is the exit status of the shell or the return status
of the function exiting. If sig is 0 or EXIT and the trap statement is not exe-
cuted inside the body of a function, then the command arg is executed when the
shell terminates; the trap runs before any zshexit hook functions.

ZERR, DEBUG, and EXIT traps are not executed inside other traps. ZERR and DEBUG
traps are kept within subshells, while other traps are reset.

Note that traps defined with the trap builtin are slightly different from those de-
fined as `TRAPNAL () { ... }', as the latter have their own function environment
(line numbers, local variables, etc.) while the former use the environment of the
command in which they were called. For example,

trap 'print $LINENO' DEBUG

will print the line number of a command executed after it has run, while

TRAPDEBUG() { print $LINENO; }

will always print the number zero.

Alternative signal names are allowed as described under kill above. Defining a
trap under either name causes any trap under an alternative name to be removed.
However, it is recommended that for consistency users stick exclusively to one name
or another.

true [ arg ... ]
Do nothing and return an exit status of 0.

ttyctl [ -fu ]
The -f option freezes the tty (i.e. terminal or terminal emulator), and -u un-
freezes it. When the tty is frozen, no changes made to the tty settings by exter-
nal programs will be honored by the shell, except for changes in the size of the
screen; the shell will simply reset the settings to their previous values as soon
as each command exits or is suspended. Thus, stty and similar programs have no ef-
fect when the tty is frozen. Freezing the tty does not cause the current state to
be remembered: instead, it causes future changes to the state to be blocked.

Without options it reports whether the terminal is frozen or not.

Note that, regardless of whether the tty is frozen or not, the shell needs to
change the settings when the line editor starts, so unfreezing the tty does not
guarantee settings made on the command line are preserved. Strings of commands run
between editing the command line will see a consistent tty state. See also the
shell variable STTY for a means of initialising the tty before running external
commands.

type [ -wfpamsS ] name ...
Equivalent to whence -v.

typeset [ {+|-}AHUaghlmrtux ] [ {+|-}EFLRZip [ n ] ]
[ + ] [ name[=value] ... ]
typeset -T [ {+|-}Uglrux ] [ {+|-}LRZp [ n ] ]
[ + | SCALAR[=value] array[=(value ...)] [ sep ] ]
typeset -f [ {+|-}TUkmtuz ] [ + ] [ name ... ]
Set or display attributes and values for shell parameters.

Except as noted below for control flags that change the behavior, a parameter is
created for each name that does not already refer to one. When inside a function,
a new parameter is created for every name (even those that already exist), and is
unset again when the function completes. See `Local Parameters' in zshparam(1).
The same rules apply to special shell parameters, which retain their special at-
tributes when made local.

For each name=value assignment, the parameter name is set to value.

If the shell option TYPESET_SILENT is not set, for each remaining name that refers
to a parameter that is already set, the name and value of the parameter are printed
in the form of an assignment. Nothing is printed for newly-created parameters, or
when any attribute flags listed below are given along with the name. Using `+' in-
stead of minus to introduce an attribute turns it off.

If no name is present, the names and values of all parameters are printed. In this
case the attribute flags restrict the display to only those parameters that have
the specified attributes, and using `+' rather than `-' to introduce the flag sup-
presses printing of the values of parameters when there is no parameter name.

All forms of the command handle scalar assignment. Array assignment is possible if
any of the reserved words declare, export, float, integer, local, readonly or type-
set is matched when the line is parsed (N.B. not when it is executed). In this
case the arguments are parsed as assignments, except that the `+=' syntax and the
GLOB_ASSIGN option are not supported, and scalar values after = are not split fur-
ther into words, even if expanded (regardless of the setting of the KSH_TYPESET op-
tion; this option is obsolete).

Examples of the differences between command and reserved word parsing:

# Reserved word parsing
typeset svar=$(echo one word) avar=(several words)

The above creates a scalar parameter svar and an array parameter avar as if the as-
signments had been

svar="one word"
avar=(several words)

On the other hand:

# Normal builtin interface
builtin typeset svar=$(echo two words)

The builtin keyword causes the above to use the standard builtin interface to type-
set in which argument parsing is performed in the same way as for other commands.
This example creates a scalar svar containing the value two and another scalar pa-
rameter words with no value. An array value in this case would either cause an er-
ror or be treated as an obscure set of glob qualifiers.

Arbitrary arguments are allowed if they take the form of assignments after command
line expansion; however, these only perform scalar assignment:

var='svar=val'
typeset $var

The above sets the scalar parameter svar to the value val. Parentheses around the
value within var would not cause array assignment as they will be treated as ordi-
nary characters when $var is substituted. Any non-trivial expansion in the name
part of the assignment causes the argument to be treated in this fashion:

typeset {var1,var2,var3}=name

The above syntax is valid, and has the expected effect of setting the three parame-
ters to the same value, but the command line is parsed as a set of three normal
command line arguments to typeset after expansion. Hence it is not possible to as-
sign to multiple arrays by this means.

Note that each interface to any of the commands my be disabled separately. For ex-
ample, `disable -r typeset' disables the reserved word interface to typeset, expos-
ing the builtin interface, while `disable typeset' disables the builtin. Note that
disabling the reserved word interface for typeset may cause problems with the out-
put of `typeset -p', which assumes the reserved word interface is available in or-
der to restore array and associative array values.

Unlike parameter assignment statements, typeset's exit status on an assignment that
involves a command substitution does not reflect the exit status of the command
substitution. Therefore, to test for an error in a command substitution, separate
the declaration of the parameter from its initialization:

# WRONG
typeset var1=$(exit 1) || echo "Trouble with var1"

# RIGHT
typeset var1 && var1=$(exit 1) || echo "Trouble with var1"

To initialize a parameter param to a command output and mark it readonly, use type-
set -r param or readonly param after the parameter assignment statement.

If no attribute flags are given, and either no name arguments are present or the
flag +m is used, then each parameter name printed is preceded by a list of the at-
tributes of that parameter (array, association, exported, float, integer, readonly,
or undefined for autoloaded parameters not yet loaded). If +m is used with attri-
bute flags, and all those flags are introduced with +, the matching parameter names
are printed but their values are not.

The following control flags change the behavior of typeset:

+ If `+' appears by itself in a separate word as the last option, then the
names of all parameters (functions with -f) are printed, but the values
(function bodies) are not. No name arguments may appear, and it is an error
for any other options to follow `+'. The effect of `+' is as if all attri-
bute flags which precede it were given with a `+' prefix. For example,
`typeset -U +' is equivalent to `typeset +U' and displays the names of all
arrays having the uniqueness attribute, whereas `typeset -f -U +' displays
the names of all autoloadable functions. If + is the only option, then type
information (array, readonly, etc.) is also printed for each parameter, in
the same manner as `typeset +m "*"'.

-g The -g (global) means that any resulting parameter will not be restricted to
local scope. Note that this does not necessarily mean that the parameter
will be global, as the flag will apply to any existing parameter (even if
unset) from an enclosing function. This flag does not affect the parameter
after creation, hence it has no effect when listing existing parameters, nor
does the flag +g have any effect except in combination with -m (see below).

-m If the -m flag is given the name arguments are taken as patterns (use quot-
ing to prevent these from being interpreted as file patterns). With no at-
tribute flags, all parameters (or functions with the -f flag) with matching
names are printed (the shell option TYPESET_SILENT is not used in this
case).

If the +g flag is combined with -m, a new local parameter is created for ev-
ery matching parameter that is not already local. Otherwise -m applies all
other flags or assignments to the existing parameters.

Except when assignments are made with name=value, using +m forces the match-
ing parameters and their attributes to be printed, even inside a function.
Note that -m is ignored if no patterns are given, so `typeset -m' displays
attributes but `typeset -a +m' does not.

-p [ n ]
If the -p option is given, parameters and values are printed in the form of
a typeset command with an assignment, regardless of other flags and options.
Note that the -H flag on parameters is respected; no value will be shown for
these parameters.

-p may be followed by an optional integer argument. Currently only the
value 1 is supported. In this case arrays and associative arrays are
printed with newlines between indented elements for readability.

-T [ scalar[=value] array[=(value ...)] [ sep ] ]
This flag has a different meaning when used with -f; see below. Otherwise
the -T option requires zero, two, or three arguments to be present. With no
arguments, the list of parameters created in this fashion is shown. With
two or three arguments, the first two are the name of a scalar and of an ar-
ray parameter (in that order) that will be tied together in the manner of
$PATH and $path. The optional third argument is a single-character separa-
tor which will be used to join the elements of the array to form the scalar;
if absent, a colon is used, as with $PATH. Only the first character of the
separator is significant; any remaining characters are ignored. Multibyte
characters are not yet supported.

Only one of the scalar and array parameters may be assigned an initial value
(the restrictions on assignment forms described above also apply).

Both the scalar and the array may be manipulated as normal. If one is un-
set, the other will automatically be unset too. There is no way of untying
the variables without unsetting them, nor of converting the type of one of
them with another typeset command; +T does not work, assigning an array to
scalar is an error, and assigning a scalar to array sets it to be a sin-
gle-element array.

Note that both `typeset -xT ...' and `export -T ...' work, but only the
scalar will be marked for export. Setting the value using the scalar ver-
sion causes a split on all separators (which cannot be quoted). It is pos-
sible to apply -T to two previously tied variables but with a different sep-
arator character, in which case the variables remain joined as before but
the separator is changed.

When an existing scalar is tied to a new array, the value of the scalar is
preserved but no attribute other than export will be preserved.

Attribute flags that transform the final value (-L, -R, -Z, -l, -u) are only ap-
plied to the expanded value at the point of a parameter expansion expression using
`$'. They are not applied when a parameter is retrieved internally by the shell
for any purpose.

The following attribute flags may be specified:

-A The names refer to associative array parameters; see `Array Parameters' in
zshparam(1).

-L [ n ]
Left justify and remove leading blanks from the value when the parameter is
expanded. If n is nonzero, it defines the width of the field. If n is
zero, the width is determined by the width of the value of the first assign-
ment. In the case of numeric parameters, the length of the complete value
assigned to the parameter is used to determine the width, not the value that
would be output.

The width is the count of characters, which may be multibyte characters if
the MULTIBYTE option is in effect. Note that the screen width of the char-
acter is not taken into account; if this is required, use padding with pa-
rameter expansion flags ${(ml...)...} as described in `Parameter Expansion
Flags' in zshexpn(1).

When the parameter is expanded, it is filled on the right with blanks or
truncated if necessary to fit the field. Note truncation can lead to unex-
pected results with numeric parameters. Leading zeros are removed if the -Z
flag is also set.

-R [ n ]
Similar to -L, except that right justification is used; when the parameter
is expanded, the field is left filled with blanks or truncated from the end.
May not be combined with the -Z flag.

-U For arrays (but not for associative arrays), keep only the first occurrence
of each duplicated value. This may also be set for tied parameters (see -T)
or colon-separated special parameters like PATH or FIGNORE, etc. Note the
flag takes effect on assignment, and the type of the variable being assigned
to is determinative; for variables with shared values it is therefore recom-
mended to set the flag for all interfaces, e.g. `typeset -U PATH path'.

This flag has a different meaning when used with -f; see below.

-Z [ n ]
Specially handled if set along with the -L flag. Otherwise, similar to -R,
except that leading zeros are used for padding instead of blanks if the
first non-blank character is a digit. Numeric parameters are specially han-
dled: they are always eligible for padding with zeroes, and the zeroes are
inserted at an appropriate place in the output.

-a The names refer to array parameters. An array parameter may be created this
way, but it may be assigned to in the typeset statement only if the reserved
word form of typeset is enabled (as it is by default). When displaying,
both normal and associative arrays are shown.

-f The names refer to functions rather than parameters. No assignments can be
made, and the only other valid flags are -t, -T, -k, -u, -U and -z. The
flag -t turns on execution tracing for this function; the flag -T does the
same, but turns off tracing for any named (not anonymous) function called
from the present one, unless that function also has the -t or -T flag. The
-u and -U flags cause the function to be marked for autoloading; -U also
causes alias expansion to be suppressed when the function is loaded. See
the description of the `autoload' builtin for details.

Note that the builtin functions provides the same basic capabilities as
typeset -f but gives access to a few extra options; autoload gives further
additional options for the case typeset -fu and typeset -fU.

-h Hide: only useful for special parameters (those marked `<S>' in the table in
zshparam(1)), and for local parameters with the same name as a special pa-
rameter, though harmless for others. A special parameter with this attri-
bute will not retain its special effect when made local. Thus after `type-
set -h PATH', a function containing `typeset PATH' will create an ordinary
local parameter without the usual behaviour of PATH. Alternatively, the lo-
cal parameter may itself be given this attribute; hence inside a function
`typeset -h PATH' creates an ordinary local parameter and the special PATH
parameter is not altered in any way. It is also possible to create a local
parameter using `typeset +h special', where the local copy of special will
retain its special properties regardless of having the -h attribute. Global
special parameters loaded from shell modules (currently those in zsh/mapfile
and zsh/parameter) are automatically given the -h attribute to avoid name
clashes.

-H Hide value: specifies that typeset will not display the value of the parame-
ter when listing parameters; the display for such parameters is always as if
the `+' flag had been given. Use of the parameter is in other respects nor-
mal, and the option does not apply if the parameter is specified by name, or
by pattern with the -m option. This is on by default for the parameters in
the zsh/parameter and zsh/mapfile modules. Note, however, that unlike the
-h flag this is also useful for non-special parameters.

-i [ n ]
Use an internal integer representation. If n is nonzero it defines the out-
put arithmetic base, otherwise it is determined by the first assignment.
Bases from 2 to 36 inclusive are allowed.

-E [ n ]
Use an internal double-precision floating point representation. On output
the variable will be converted to scientific notation. If n is nonzero it
defines the number of significant figures to display; the default is ten.

-F [ n ]
Use an internal double-precision floating point representation. On output
the variable will be converted to fixed-point decimal notation. If n is
nonzero it defines the number of digits to display after the decimal point;
the default is ten.

-l Convert the result to lower case whenever the parameter is expanded. The
value is not converted when assigned.

-r The given names are marked readonly. Note that if name is a special parame-
ter, the readonly attribute can be turned on, but cannot then be turned off.

If the POSIX_BUILTINS option is set, the readonly attribute is more restric-
tive: unset variables can be marked readonly and cannot then be set; fur-
thermore, the readonly attribute cannot be removed from any variable.

It is still possible to change other attributes of the variable though, some
of which like -U or -Z would affect the value. More generally, the readonly
attribute should not be relied on as a security mechanism.

Note that in zsh (like in pdksh but unlike most other shells) it is still
possible to create a local variable of the same name as this is considered a
different variable (though this variable, too, can be marked readonly). Spe-
cial variables that have been made readonly retain their value and readonly
attribute when made local.

-t Tags the named parameters. Tags have no special meaning to the shell. This
flag has a different meaning when used with -f; see above.

-u Convert the result to upper case whenever the parameter is expanded. The
value is not converted when assigned. This flag has a different meaning
when used with -f; see above.

-x Mark for automatic export to the environment of subsequently executed com-
mands. If the option GLOBAL_EXPORT is set, this implies the option -g, un-
less +g is also explicitly given; in other words the parameter is not made
local to the enclosing function. This is for compatibility with previous
versions of zsh.

ulimit [ -HSa ] [ { -bcdfiklmnpqrsTtvwx | -N resource } [ limit ] ... ]
Set or display resource limits of the shell and the processes started by the shell.
The value of limit can be a number in the unit specified below or one of the values
`unlimited', which removes the limit on the resource, or `hard', which uses the
current value of the hard limit on the resource.

By default, only soft limits are manipulated. If the -H flag is given use hard lim-
its instead of soft limits. If the -S flag is given together with the -H flag set
both hard and soft limits.

If no options are used, the file size limit (-f) is assumed.

If limit is omitted the current value of the specified resources are printed. When
more than one resource value is printed, the limit name and unit is printed before
each value.

Not all the following resources are supported on all systems. Running ulimit -a
will show which are supported.

-a Lists all of the current resource limits.
-b Socket buffer size in bytes (N.B. not kilobytes)
-c 512-byte blocks on the size of core dumps.
-d Kilobytes on the size of the data segment.
-f 512-byte blocks on the size of files written.
-i The number of pending signals.
-k The number of kqueues allocated.
-l Kilobytes on the size of locked-in memory.
-m Kilobytes on the size of physical memory.
-n open file descriptors.
-p The number of pseudo-terminals.
-q Bytes in POSIX message queues.
-r Maximum real time priority. On some systems where this is not available,
such as NetBSD, this has the same effect as -T for compatibility with sh.
-s Kilobytes on the size of the stack.
-T The number of simultaneous threads available to the user.
-t CPU seconds to be used.
-u The number of processes available to the user.
-v Kilobytes on the size of virtual memory. On some systems this refers to the
limit called `address space'.
-w Kilobytes on the size of swapped out memory.
-x The number of locks on files.

A resource may also be specified by integer in the form `-N resource', where re-
source corresponds to the integer defined for the resource by the operating system.
This may be used to set the limits for resources known to the shell which do not
correspond to option letters. Such limits will be shown by number in the output of
`ulimit -a'.

The number may alternatively be out of the range of limits compiled into the shell.
The shell will try to read or write the limit anyway, and will report an error if
this fails.

umask [ -S ] [ mask ]
The umask is set to mask. mask can be either an octal number or a symbolic value
as described in chmod(1). If mask is omitted, the current value is printed. The
-S option causes the mask to be printed as a symbolic value. Otherwise, the mask
is printed as an octal number. Note that in the symbolic form the permissions you
specify are those which are to be allowed (not denied) to the users specified.

unalias [ -ams ] name ...
Removes aliases. This command works the same as unhash -a, except that the -a op-
tion removes all regular or global aliases, or with -s all suffix aliases: in this
case no name arguments may appear. The options -m (remove by pattern) and -s with-
out -a (remove listed suffix aliases) behave as for unhash -a. Note that the mean-
ing of -a is different between unalias and unhash.

unfunction
Same as unhash -f.

unhash [ -adfms ] name ...
Remove the element named name from an internal hash table. The default is remove
elements from the command hash table. The -a option causes unhash to remove regu-
lar or global aliases; note when removing a global aliases that the argument must
be quoted to prevent it from being expanded before being passed to the command.
The -s option causes unhash to remove suffix aliases. The -f option causes unhash
to remove shell functions. The -d options causes unhash to remove named directo-
ries. If the -m flag is given the arguments are taken as patterns (should be
quoted) and all elements of the corresponding hash table with matching names will
be removed.

unlimit [ -hs ] resource ...
The resource limit for each resource is set to the hard limit. If the -h flag is
given and the shell has appropriate privileges, the hard resource limit for each
resource is removed. The resources of the shell process are only changed if the -s
flag is given.

The unlimit command is not made available by default when the shell starts in a
mode emulating another shell. It can be made available with the command `zmodload
-F zsh/rlimits b:unlimit'.

unset [ -fmv ] name ...
Each named parameter is unset. Local parameters remain local even if unset; they
appear unset within scope, but the previous value will still reappear when the
scope ends.

Individual elements of associative array parameters may be unset by using subscript
syntax on name, which should be quoted (or the entire command prefixed with noglob)
to protect the subscript from filename generation.

If the -m flag is specified the arguments are taken as patterns (should be quoted)
and all parameters with matching names are unset. Note that this cannot be used
when unsetting associative array elements, as the subscript will be treated as part
of the pattern.

The -v flag specifies that name refers to parameters. This is the default behav-
iour.

unset -f is equivalent to unfunction.

unsetopt [ {+|-}options | {+|-}o option_name ] [ name ... ]
Unset the options for the shell. All options specified either with flags or by
name are unset. If no arguments are supplied, the names of all options currently
unset are printed. If the -m flag is given the arguments are taken as patterns
(which should be quoted to preserve them from being interpreted as glob patterns),
and all options with names matching these patterns are unset.

vared See the section `Zle Builtins' in zshzle(1).

wait [ job ... ]
Wait for the specified jobs or processes. If job is not given then all currently
active child processes are waited for. Each job can be either a job specification
or the process ID of a job in the job table. The exit status from this command is
that of the job waited for. If job represents an unknown job or process ID, a
warning is printed (unless the POSIX_BUILTINS option is set) and the exit status is
127.

It is possible to wait for recent processes (specified by process ID, not by job)
that were running in the background even if the process has exited. Typically the
process ID will be recorded by capturing the value of the variable $! immediately
after the process has been started. There is a limit on the number of process IDs
remembered by the shell; this is given by the value of the system configuration pa-
rameter CHILD_MAX. When this limit is reached, older process IDs are discarded,
least recently started processes first.

Note there is no protection against the process ID wrapping, i.e. if the wait is
not executed soon enough there is a chance the process waited for is the wrong one.
A conflict implies both process IDs have been generated by the shell, as other pro-
cesses are not recorded, and that the user is potentially interested in both, so
this problem is intrinsic to process IDs.

whence [ -vcwfpamsS ] [ -x num ] name ...
For each name, indicate how it would be interpreted if used as a command name.

If name is not an alias, built-in command, external command, shell function, hashed
command, or a reserved word, the exit status shall be non-zero, and -- if -v, -c,
or -w was passed -- a message will be written to standard output. (This is differ-
ent from other shells that write that message to standard error.)

whence is most useful when name is only the last path component of a command, i.e.
does not include a `/'; in particular, pattern matching only succeeds if just the
non-directory component of the command is passed.

-v Produce a more verbose report.

-c Print the results in a csh-like format. This takes precedence over -v.

-w For each name, print `name: word' where word is one of alias, builtin, com-
mand, function, hashed, reserved or none, according as name corresponds to
an alias, a built-in command, an external command, a shell function, a com-
mand defined with the hash builtin, a reserved word, or is not recognised.
This takes precedence over -v and -c.

-f Causes the contents of a shell function to be displayed, which would other-
wise not happen unless the -c flag were used.

-p Do a path search for name even if it is an alias, reserved word, shell func-
tion or builtin.

-a Do a search for all occurrences of name throughout the command path. Nor-
mally only the first occurrence is printed.

-m The arguments are taken as patterns (pattern characters should be quoted),
and the information is displayed for each command matching one of these pat-
terns.

-s If a pathname contains symlinks, print the symlink-free pathname as well.

-S As -s, but if the pathname had to be resolved by following multiple sym-
links, the intermediate steps are printed, too. The symlink resolved at
each step might be anywhere in the path.

-x num Expand tabs when outputting shell functions using the -c option. This has
the same effect as the -x option to the functions builtin.

where [ -wpmsS ] [ -x num ] name ...
Equivalent to whence -ca.

which [ -wpamsS ] [ -x num ] name ...
Equivalent to whence -c.

zcompile [ -U ] [ -z | -k ] [ -R | -M ] file [ name ... ]
zcompile -ca [ -m ] [ -R | -M ] file [ name ... ]
zcompile -t file [ name ... ]
This builtin command can be used to compile functions or scripts, storing the com-
piled form in a file, and to examine files containing the compiled form. This al-
lows faster autoloading of functions and sourcing of scripts by avoiding parsing of
the text when the files are read.

The first form (without the -c, -a or -t options) creates a compiled file. If only
the file argument is given, the output file has the name `file.zwc' and will be
placed in the same directory as the file. The shell will load the compiled file
instead of the normal function file when the function is autoloaded; see the sec-
tion `Autoloading Functions' in zshmisc(1) for a description of how autoloaded
functions are searched. The extension .zwc stands for `zsh word code'.

If there is at least one name argument, all the named files are compiled into the
output file given as the first argument. If file does not end in .zwc, this exten-
sion is automatically appended. Files containing multiple compiled functions are
called `digest' files, and are intended to be used as elements of the FPATH/fpath
special array.

The second form, with the -c or -a options, writes the compiled definitions for all
the named functions into file. For -c, the names must be functions currently de-
fined in the shell, not those marked for autoloading. Undefined functions that are
marked for autoloading may be written by using the -a option, in which case the
fpath is searched and the contents of the definition files for those functions, if
found, are compiled into file. If both -c and -a are given, names of both defined
functions and functions marked for autoloading may be given. In either case, the
functions in files written with the -c or -a option will be autoloaded as if the
KSH_AUTOLOAD option were unset.

The reason for handling loaded and not-yet-loaded functions with different options
is that some definition files for autoloading define multiple functions, including
the function with the same name as the file, and, at the end, call that function.
In such cases the output of `zcompile -c' does not include the additional functions
defined in the file, and any other initialization code in the file is lost. Using
`zcompile -a' captures all this extra information.

If the -m option is combined with -c or -a, the names are used as patterns and all
functions whose names match one of these patterns will be written. If no name is
given, the definitions of all functions currently defined or marked as autoloaded
will be written.

Note the second form cannot be used for compiling functions that include redirec-
tions as part of the definition rather than within the body of the function; for
example

fn1() { { ... } >~/logfile }

can be compiled but

fn1() { ... } >~/logfile

cannot. It is possible to use the first form of zcompile to compile autoloadable
functions that include the full function definition instead of just the body of the
function.

The third form, with the -t option, examines an existing compiled file. Without
further arguments, the names of the original files compiled into it are listed.
The first line of output shows the version of the shell which compiled the file and
how the file will be used (i.e. by reading it directly or by mapping it into mem-
ory). With arguments, nothing is output and the return status is set to zero if
definitions for all names were found in the compiled file, and non-zero if the def-
inition for at least one name was not found.

Other options:

-U Aliases are not expanded when compiling the named files.

-R When the compiled file is read, its contents are copied into the shell's
memory, rather than memory-mapped (see -M). This happens automatically on
systems that do not support memory mapping.

When compiling scripts instead of autoloadable functions, it is often desir-
able to use this option; otherwise the whole file, including the code to de-
fine functions which have already been defined, will remain mapped, conse-
quently wasting memory.

-M The compiled file is mapped into the shell's memory when read. This is done
in such a way that multiple instances of the shell running on the same host
will share this mapped file. If neither -R nor -M is given, the zcompile
builtin decides what to do based on the size of the compiled file.

-k
-z These options are used when the compiled file contains functions which are
to be autoloaded. If -z is given, the function will be autoloaded as if the
KSH_AUTOLOAD option is not set, even if it is set at the time the compiled
file is read, while if the -k is given, the function will be loaded as if
KSH_AUTOLOAD is set. These options also take precedence over any -k or -z
options specified to the autoload builtin. If neither of these options is
given, the function will be loaded as determined by the setting of the
KSH_AUTOLOAD option at the time the compiled file is read.

These options may also appear as many times as necessary between the listed
names to specify the loading style of all following functions, up to the
next -k or -z.

The created file always contains two versions of the compiled format, one
for big-endian machines and one for small-endian machines. The upshot of
this is that the compiled file is machine independent and if it is read or
mapped, only one half of the file is actually used (and mapped).

zformat
See the section `The zsh/zutil Module' in zshmodules(1).

zftp See the section `The zsh/zftp Module' in zshmodules(1).

zle See the section `Zle Builtins' in zshzle(1).

zmodload [ -dL ] [ -s ] [ ... ]
zmodload -F [ -alLme -P param ] module [ [+-]feature ... ]
zmodload -e [ -A ] [ ... ]
zmodload [ -a [ -bcpf [ -I ] ] ] [ -iL ] ...
zmodload -u [ -abcdpf [ -I ] ] [ -iL ] ...
zmodload -A [ -L ] [ modalias[=module] ... ]
zmodload -R modalias ...
Performs operations relating to zsh's loadable modules. Loading of modules while
the shell is running (`dynamical loading') is not available on all operating sys-
tems, or on all installations on a particular operating system, although the zmod-
load command itself is always available and can be used to manipulate modules built
into versions of the shell executable without dynamical loading.

Without arguments the names of all currently loaded binary modules are printed.
The -L option causes this list to be in the form of a series of zmodload commands.
Forms with arguments are:

zmodload [ -is ] name ...
zmodload -u [ -i ] name ...
In the simplest case, zmodload loads a binary module. The module must be in
a file with a name consisting of the specified name followed by a standard
suffix, usually `.so' (`.sl' on HPUX). If the module to be loaded is al-
ready loaded the duplicate module is ignored. If zmodload detects an incon-
sistency, such as an invalid module name or circular dependency list, the
current code block is aborted. If it is available, the module is loaded if
necessary, while if it is not available, non-zero status is silently re-
turned. The option -i is accepted for compatibility but has no effect.

The named module is searched for in the same way a command is, using $mod-
ule_path instead of $path. However, the path search is performed even when
the module name contains a `/', which it usually does. There is no way to
prevent the path search.

If the module supports features (see below), zmodload tries to enable all
features when loading a module. If the module was successfully loaded but
not all features could be enabled, zmodload returns status 2.

If the option -s is given, no error is printed if the module was not avail-
able (though other errors indicating a problem with the module are printed).
The return status indicates if the module was loaded. This is appropriate
if the caller considers the module optional.

With -u, zmodload unloads modules. The same name must be given that was
given when the module was loaded, but it is not necessary for the module to
exist in the file system. The -i option suppresses the error if the module
is already unloaded (or was never loaded).

Each module has a boot and a cleanup function. The module will not be
loaded if its boot function fails. Similarly a module can only be unloaded
if its cleanup function runs successfully.

zmodload -F [ -almLe -P param ] module [ [+-]feature ... ]
zmodload -F allows more selective control over the features provided by mod-
ules. With no options apart from -F, the module named module is loaded, if
it was not already loaded, and the list of features is set to the required
state. If no features are specified, the module is loaded, if it was not
already loaded, but the state of features is unchanged. Each feature may be
preceded by a + to turn the feature on, or - to turn it off; the + is as-
sumed if neither character is present. Any feature not explicitly mentioned
is left in its current state; if the module was not previously loaded this
means any such features will remain disabled. The return status is zero if
all features were set, 1 if the module failed to load, and 2 if some fea-
tures could not be set (for example, a parameter couldn't be added because
there was a different parameter of the same name) but the module was loaded.

The standard features are builtins, conditions, parameters and math func-
tions; these are indicated by the prefix `b:', `c:' (`C:' for an infix con-
dition), `p:' and `f:', respectively, followed by the name that the corre-
sponding feature would have in the shell. For example, `b:strftime' indi-
cates a builtin named strftime and p:EPOCHSECONDS indicates a parameter
named EPOCHSECONDS. The module may provide other (`abstract') features of
its own as indicated by its documentation; these have no prefix.

With -l or -L, features provided by the module are listed. With -l alone, a
list of features together with their states is shown, one feature per line.
With -L alone, a zmodload -F command that would cause enabled features of
the module to be turned on is shown. With -lL, a zmodload -F command that
would cause all the features to be set to their current state is shown. If
one of these combinations is given with the option -P param then the parame-
ter param is set to an array of features, either features together with
their state or (if -L alone is given) enabled features.

With the option -L the module name may be omitted; then a list of all en-
abled features for all modules providing features is printed in the form of
zmodload -F commands. If -l is also given, the state of both enabled and
disabled features is output in that form.

A set of features may be provided together with -l or -L and a module name;
in that case only the state of those features is considered. Each feature
may be preceded by + or - but the character has no effect. If no set of
features is provided, all features are considered.

With -e, the command first tests that the module is loaded; if it is not,
status 1 is returned. If the module is loaded, the list of features given
as an argument is examined. Any feature given with no prefix is simply
tested to see if the module provides it; any feature given with a prefix +
or - is tested to see if is provided and in the given state. If the tests
on all features in the list succeed, status 0 is returned, else status 1.

With -m, each entry in the given list of features is taken as a pattern to
be matched against the list of features provided by the module. An initial
+ or - must be given explicitly. This may not be combined with the -a op-
tion as autoloads must be specified explicitly.

With -a, the given list of features is marked for autoload from the speci-
fied module, which may not yet be loaded. An optional + may appear before
the feature name. If the feature is prefixed with -, any existing autoload
is removed. The options -l and -L may be used to list autoloads. Autoload-
ing is specific to individual features; when the module is loaded only the
requested feature is enabled. Autoload requests are preserved if the module
is subsequently unloaded until an explicit `zmodload -Fa module -feature' is
issued. It is not an error to request an autoload for a feature of a module
that is already loaded.

When the module is loaded each autoload is checked against the features ac-
tually provided by the module; if the feature is not provided the autoload
request is deleted. A warning message is output; if the module is being
loaded to provide a different feature, and that autoload is successful,
there is no effect on the status of the current command. If the module is
already loaded at the time when zmodload -Fa is run, an error message is
printed and status 1 returned.

zmodload -Fa can be used with the -l, -L, -e and -P options for listing and
testing the existence of autoloadable features. In this case -l is ignored
if -L is specified. zmodload -FaL with no module name lists autoloads for
all modules.

Note that only standard features as described above can be autoloaded; other
features require the module to be loaded before enabling.

zmodload -d [ -L ] [ name ]
zmodload -d name dep ...
zmodload -ud name [ dep ... ]
The -d option can be used to specify module dependencies. The modules named
in the second and subsequent arguments will be loaded before the module
named in the first argument.

With -d and one argument, all dependencies for that module are listed. With
-d and no arguments, all module dependencies are listed. This listing is by
default in a Makefile-like format. The -L option changes this format to a
list of zmodload -d commands.

If -d and -u are both used, dependencies are removed. If only one argument
is given, all dependencies for that module are removed.

zmodload -ab [ -L ]
zmodload -ab [ -i ] name [ builtin ... ]
zmodload -ub [ -i ] builtin ...
The -ab option defines autoloaded builtins. It defines the specified
builtins. When any of those builtins is called, the module specified in the
first argument is loaded and all its features are enabled (for selective
control of features use `zmodload -F -a' as described above). If only the
name is given, one builtin is defined, with the same name as the module. -i
suppresses the error if the builtin is already defined or autoloaded, but
not if another builtin of the same name is already defined.

With -ab and no arguments, all autoloaded builtins are listed, with the mod-
ule name (if different) shown in parentheses after the builtin name. The -L
option changes this format to a list of zmodload -a commands.

If -b is used together with the -u option, it removes builtins previously
defined with -ab. This is only possible if the builtin is not yet loaded.
-i suppresses the error if the builtin is already removed (or never ex-
isted).

Autoload requests are retained if the module is subsequently unloaded until
an explicit `zmodload -ub builtin' is issued.

zmodload -ac [ -IL ]
zmodload -ac [ -iI ] name [ cond ... ]
zmodload -uc [ -iI ] cond ...
The -ac option is used to define autoloaded condition codes. The cond
strings give the names of the conditions defined by the module. The optional
-I option is used to define infix condition names. Without this option pre-
fix condition names are defined.

If given no condition names, all defined names are listed (as a series of
zmodload commands if the -L option is given).

The -uc option removes definitions for autoloaded conditions.

zmodload -ap [ -L ]
zmodload -ap [ -i ] name [ parameter ... ]
zmodload -up [ -i ] parameter ...
The -p option is like the -b and -c options, but makes zmodload work on au-
toloaded parameters instead.

zmodload -af [ -L ]
zmodload -af [ -i ] name [ function ... ]
zmodload -uf [ -i ] function ...
The -f option is like the -b, -p, and -c options, but makes zmodload work on
autoloaded math functions instead.

zmodload -a [ -L ]
zmodload -a [ -i ] name [ builtin ... ]
zmodload -ua [ -i ] builtin ...
Equivalent to -ab and -ub.

zmodload -e [ -A ] [ string ... ]
The -e option without arguments lists all loaded modules; if the -A option
is also given, module aliases corresponding to loaded modules are also
shown. If arguments are provided, nothing is printed; the return status is
set to zero if all strings given as arguments are names of loaded modules
and to one if at least on string is not the name of a loaded module. This
can be used to test for the availability of things implemented by modules.
In this case, any aliases are automatically resolved and the -A flag is not
used.

zmodload -A [ -L ] [ modalias[=module] ... ]
For each argument, if both modalias and module are given, define modalias to
be an alias for the module module. If the module modalias is ever subse-
quently requested, either via a call to zmodload or implicitly, the shell
will attempt to load module instead. If module is not given, show the defi-
nition of modalias. If no arguments are given, list all defined module
aliases. When listing, if the -L flag was also given, list the definition
as a zmodload command to recreate the alias.

The existence of aliases for modules is completely independent of whether
the name resolved is actually loaded as a module: while the alias exists,
loading and unloading the module under any alias has exactly the same effect
as using the resolved name, and does not affect the connection between the
alias and the resolved name which can be removed either by zmodload -R or by
redefining the alias. Chains of aliases (i.e. where the first resolved name
is itself an alias) are valid so long as these are not circular. As the
aliases take the same format as module names, they may include path separa-
tors: in this case, there is no requirement for any part of the path named
to exist as the alias will be resolved first. For example, `any/old/alias'
is always a valid alias.

Dependencies added to aliased modules are actually added to the resolved
module; these remain if the alias is removed. It is valid to create an
alias whose name is one of the standard shell modules and which resolves to
a different module. However, if a module has dependencies, it will not be
possible to use the module name as an alias as the module will already be
marked as a loadable module in its own right.

Apart from the above, aliases can be used in the zmodload command anywhere
module names are required. However, aliases will not be shown in lists of
loaded modules with a bare `zmodload'.

zmodload -R modalias ...
For each modalias argument that was previously defined as a module alias via
zmodload -A, delete the alias. If any was not defined, an error is caused
and the remainder of the line is ignored.

Note that zsh makes no distinction between modules that were linked into the shell
and modules that are loaded dynamically. In both cases this builtin command has to
be used to make available the builtins and other things defined by modules (unless
the module is autoloaded on these definitions). This is true even for systems that
don't support dynamic loading of modules.

zparseopts
See the section `The zsh/zutil Module' in zshmodules(1).

zprof See the section `The zsh/zprof Module' in zshmodules(1).

zpty See the section `The zsh/zpty Module' in zshmodules(1).

zregexparse
See the section `The zsh/zutil Module' in zshmodules(1).

zsocket
See the section `The zsh/net/socket Module' in zshmodules(1).

zstyle See the section `The zsh/zutil Module' in zshmodules(1).

ztcp See the section `The zsh/net/tcp Module' in zshmodules(1).

ZSHZLE(1) General Commands Manual ZSHZLE(1)

NAME
zshzle - zsh command line editor

DESCRIPTION
If the ZLE option is set (which it is by default in interactive shells) and the shell in-
put is attached to the terminal, the user is able to edit command lines.

There are two display modes. The first, multiline mode, is the default. It only works if
the TERM parameter is set to a valid terminal type that can move the cursor up. The sec-
ond, single line mode, is used if TERM is invalid or incapable of moving the cursor up, or
if the SINGLE_LINE_ZLE option is set. This mode is similar to ksh, and uses no termcap
sequences. If TERM is "emacs", the ZLE option will be unset by default.

The parameters BAUD, COLUMNS, and LINES are also used by the line editor. See Parameters
Used By The Shell in zshparam(1).

The parameter zle_highlight is also used by the line editor; see Character Highlighting
below. Highlighting of special characters and the region between the cursor and the mark
(as set with set-mark-command in Emacs mode, or by visual-mode in Vi mode) is enabled by
default; consult this reference for more information. Irascible conservatives will wish
to know that all highlighting may be disabled by the following setting:

zle_highlight=(none)

In many places, references are made to the numeric argument. This can by default be en-
tered in emacs mode by holding the alt key and typing a number, or pressing escape before
each digit, and in vi command mode by typing the number before entering a command. Gener-
ally the numeric argument causes the next command entered to be repeated the specified
number of times, unless otherwise noted below; this is implemented by the digit-argument
widget. See also the Arguments subsection of the Widgets section for some other ways the
numeric argument can be modified.

KEYMAPS
A keymap in ZLE contains a set of bindings between key sequences and ZLE commands. The
empty key sequence cannot be bound.

There can be any number of keymaps at any time, and each keymap has one or more names. If
all of a keymap's names are deleted, it disappears. bindkey can be used to manipulate
keymap names.

Initially, there are eight keymaps:

emacs EMACS emulation
viins vi emulation - insert mode
vicmd vi emulation - command mode
viopp vi emulation - operator pending
visual vi emulation - selection active
isearch
incremental search mode
command
read a command name
.safe fallback keymap

The `.safe' keymap is special. It can never be altered, and the name can never be re-
moved. However, it can be linked to other names, which can be removed. In the future
other special keymaps may be added; users should avoid using names beginning with `.' for
their own keymaps.

In addition to these names, either `emacs' or `viins' is also linked to the name `main'.
If one of the VISUAL or EDITOR environment variables contain the string `vi' when the
shell starts up then it will be `viins', otherwise it will be `emacs'. bindkey's -e and
-v options provide a convenient way to override this default choice.

When the editor starts up, it will select the `main' keymap. If that keymap doesn't ex-
ist, it will use `.safe' instead.

In the `.safe' keymap, each single key is bound to self-insert, except for ^J (line feed)
and ^M (return) which are bound to accept-line. This is deliberately not pleasant to use;
if you are using it, it means you deleted the main keymap, and you should put it back.

Reading Commands
When ZLE is reading a command from the terminal, it may read a sequence that is bound to
some command and is also a prefix of a longer bound string. In this case ZLE will wait a
certain time to see if more characters are typed, and if not (or they don't match any
longer string) it will execute the binding. This timeout is defined by the KEYTIMEOUT pa-
rameter; its default is 0.4 sec. There is no timeout if the prefix string is not itself
bound to a command.

The key timeout is also applied when ZLE is reading the bytes from a multibyte character
string when it is in the appropriate mode. (This requires that the shell was compiled
with multibyte mode enabled; typically also the locale has characters with the UTF-8 en-
coding, although any multibyte encoding known to the operating system is supported.) If
the second or a subsequent byte is not read within the timeout period, the shell acts as
if ? were typed and resets the input state.

As well as ZLE commands, key sequences can be bound to other strings, by using `bindkey
-s'. When such a sequence is read, the replacement string is pushed back as input, and
the command reading process starts again using these fake keystrokes. This input can it-
self invoke further replacement strings, but in order to detect loops the process will be
stopped if there are twenty such replacements without a real command being read.

A key sequence typed by the user can be turned into a command name for use in user-defined
widgets with the read-command widget, described in the subsection `Miscellaneous' of the
section `Standard Widgets' below.

Local Keymaps
While for normal editing a single keymap is used exclusively, in many modes a local keymap
allows for some keys to be customised. For example, in an incremental search mode, a bind-
ing in the isearch keymap will override a binding in the main keymap but all keys that are
not overridden can still be used.

If a key sequence is defined in a local keymap, it will hide a key sequence in the global
keymap that is a prefix of that sequence. An example of this occurs with the binding of iw
in viopp as this hides the binding of i in vicmd. However, a longer sequence in the global
keymap that shares the same prefix can still apply so for example the binding of ^Xa in
the global keymap will be unaffected by the binding of ^Xb in the local keymap.

ZLE BUILTINS
The ZLE module contains three related builtin commands. The bindkey command manipulates
keymaps and key bindings; the vared command invokes ZLE on the value of a shell parameter;
and the zle command manipulates editing widgets and allows command line access to ZLE com-
mands from within shell functions.

bindkey [ options ] -l [ -L ] [ keymap ... ]
bindkey [ options ] -d
bindkey [ options ] -D keymap ...
bindkey [ options ] -A old-keymap new-keymap
bindkey [ options ] -N new-keymap [ old-keymap ]
bindkey [ options ] -m
bindkey [ options ] -r in-string ...
bindkey [ options ] -s in-string out-string ...
bindkey [ options ] in-string command ...
bindkey [ options ] [ in-string ]
bindkey's options can be divided into three categories: keymap selection for the
current command, operation selection, and others. The keymap selection options
are:

-e Selects keymap `emacs' for any operations by the current command, and also
links `emacs' to `main' so that it is selected by default the next time the
editor starts.

-v Selects keymap `viins' for any operations by the current command, and also
links `viins' to `main' so that it is selected by default the next time the
editor starts.

-a Selects keymap `vicmd' for any operations by the current command.

-M keymap
The keymap specifies a keymap name that is selected for any operations by
the current command.

If a keymap selection is required and none of the options above are used, the
`main' keymap is used. Some operations do not permit a keymap to be selected,
namely:

-l List all existing keymap names; if any arguments are given, list just those
keymaps.

If the -L option is also used, list in the form of bindkey commands to cre-
ate or link the keymaps. `bindkey -lL main' shows which keymap is linked to
`main', if any, and hence if the standard emacs or vi emulation is in ef-
fect. This option does not show the .safe keymap because it cannot be cre-
ated in that fashion; however, neither is `bindkey -lL .safe' reported as an
error, it simply outputs nothing.

-d Delete all existing keymaps and reset to the default state.

-D keymap ...
Delete the named keymaps.

-A old-keymap new-keymap
Make the new-keymap name an alias for old-keymap, so that both names refer
to the same keymap. The names have equal standing; if either is deleted,
the other remains. If there is already a keymap with the new-keymap name,
it is deleted.

-N new-keymap [ old-keymap ]
Create a new keymap, named new-keymap. If a keymap already has that name,
it is deleted. If an old-keymap name is given, the new keymap is initial-
ized to be a duplicate of it, otherwise the new keymap will be empty.

To use a newly created keymap, it should be linked to main. Hence the sequence of
commands to create and use a new keymap `mymap' initialized from the emacs keymap
(which remains unchanged) is:

bindkey -N mymap emacs
bindkey -A mymap main

Note that while `bindkey -A newmap main' will work when newmap is emacs or viins,
it will not work for vicmd, as switching from vi insert to command mode becomes im-
possible.

The following operations act on the `main' keymap if no keymap selection option was
given:

-m Add the built-in set of meta-key bindings to the selected keymap. Only keys
that are unbound or bound to self-insert are affected.

-r in-string ...
Unbind the specified in-strings in the selected keymap. This is exactly
equivalent to binding the strings to undefined-key.

When -R is also used, interpret the in-strings as ranges.

When -p is also used, the in-strings specify prefixes. Any binding that has
the given in-string as a prefix, not including the binding for the in-string
itself, if any, will be removed. For example,

bindkey -rpM viins '^['

will remove all bindings in the vi-insert keymap beginning with an escape
character (probably cursor keys), but leave the binding for the escape char-
acter itself (probably vi-cmd-mode). This is incompatible with the option
-R.

-s in-string out-string ...
Bind each in-string to each out-string. When in-string is typed, out-string
will be pushed back and treated as input to the line editor. When -R is
also used, interpret the in-strings as ranges.

Note that both in-string and out-string are subject to the same form of in-
terpretation, as described below.

in-string command ...
Bind each in-string to each command. When -R is used, interpret the
in-strings as ranges.

[ in-string ]
List key bindings. If an in-string is specified, the binding of that string
in the selected keymap is displayed. Otherwise, all key bindings in the se-
lected keymap are displayed. (As a special case, if the -e or -v option is
used alone, the keymap is not displayed - the implicit linking of keymaps is
the only thing that happens.)

When the option -p is used, the in-string must be present. The listing
shows all bindings which have the given key sequence as a prefix, not in-
cluding any bindings for the key sequence itself.

When the -L option is used, the list is in the form of bindkey commands to
create the key bindings.

When the -R option is used as noted above, a valid range consists of two charac-
ters, with an optional `-' between them. All characters between the two specified,
inclusive, are bound as specified.

For either in-string or out-string, the following escape sequences are recognised:

\a bell character
\b backspace
\e, \E escape
\f form feed
\n linefeed (newline)
\r carriage return
\t horizontal tab
\v vertical tab
\NNN character code in octal
\xNN character code in hexadecimal
\uNNNN unicode character code in hexadecimal
\UNNNNNNNN
unicode character code in hexadecimal
\M[-]X character with meta bit set
\C[-]X control character
^X control character

In all other cases, `\' escapes the following character. Delete is written as
`^?'. Note that `\M^?' and `^\M?' are not the same, and that (unlike emacs), the
bindings `\M-X' and `\eX' are entirely distinct, although they are initialized to
the same bindings by `bindkey -m'.

vared [ -Aacghe ] [ -p prompt ] [ -r rprompt ]
[ -M main-keymap ] [ -m vicmd-keymap ]
[ -i init-widget ] [ -f finish-widget ]
[ -t tty ] name
The value of the parameter name is loaded into the edit buffer, and the line editor
is invoked. When the editor exits, name is set to the string value returned by the
editor. When the -c flag is given, the parameter is created if it doesn't already
exist. The -a flag may be given with -c to create an array parameter, or the -A
flag to create an associative array. If the type of an existing parameter does not
match the type to be created, the parameter is unset and recreated. The -g flag
may be given to suppress warnings from the WARN_CREATE_GLOBAL and WARN_NESTED_VAR
options.

If an array or array slice is being edited, separator characters as defined in $IFS
will be shown quoted with a backslash, as will backslashes themselves. Conversely,
when the edited text is split into an array, a backslash quotes an immediately fol-
lowing separator character or backslash; no other special handling of backslashes,
or any handling of quotes, is performed.

Individual elements of existing array or associative array parameters may be edited
by using subscript syntax on name. New elements are created automatically, even
without -c.

If the -p flag is given, the following string will be taken as the prompt to dis-
play at the left. If the -r flag is given, the following string gives the prompt
to display at the right. If the -h flag is specified, the history can be accessed
from ZLE. If the -e flag is given, typing ^D (Control-D) on an empty line causes
vared to exit immediately with a non-zero return value.

The -M option gives a keymap to link to the main keymap during editing, and the -m
option gives a keymap to link to the vicmd keymap during editing. For vi-style
editing, this allows a pair of keymaps to override viins and vicmd. For
emacs-style editing, only -M is normally needed but the -m option may still be
used. On exit, the previous keymaps will be restored.

Vared calls the usual `zle-line-init' and `zle-line-finish' hooks before and after
it takes control. Using the -i and -f options, it is possible to replace these with
other custom widgets.

If `-t tty' is given, tty is the name of a terminal device to be used instead of
the default /dev/tty. If tty does not refer to a terminal an error is reported.

zle
zle -l [ -L | -a ] [ string ... ]
zle -D widget ...
zle -A old-widget new-widget
zle -N widget [ function ]
zle -f flag [ flag... ]
zle -C widget completion-widget function
zle -R [ -c ] [ display-string ] [ string ... ]
zle -M string
zle -U string
zle -K keymap
zle -F [ -L | -w ] [ fd [ handler ] ]
zle -I
zle -T [ tc function | -r tc | -L ]
zle widget [ -n num ] [ -Nw ] [ -K keymap ] args ...
The zle builtin performs a number of different actions concerning ZLE.

With no options and no arguments, only the return status will be set. It is zero
if ZLE is currently active and widgets could be invoked using this builtin command
and non-zero otherwise. Note that even if non-zero status is returned, zle may
still be active as part of the completion system; this does not allow direct calls
to ZLE widgets.

Otherwise, which operation it performs depends on its options:

-l [ -L | -a ] [ string ]
List all existing user-defined widgets. If the -L option is used, list in
the form of zle commands to create the widgets.

When combined with the -a option, all widget names are listed, including the
builtin ones. In this case the -L option is ignored.

If at least one string is given, and -a is present or -L is not used, noth-
ing will be printed. The return status will be zero if all strings are
names of existing widgets and non-zero if at least one string is not a name
of a defined widget. If -a is also present, all widget names are used for
the comparison including builtin widgets, else only user-defined widgets are
used.

If at least one string is present and the -L option is used, user-defined
widgets matching any string are listed in the form of zle commands to create
the widgets.

-D widget ...
Delete the named widgets.

-A old-widget new-widget
Make the new-widget name an alias for old-widget, so that both names refer
to the same widget. The names have equal standing; if either is deleted,
the other remains. If there is already a widget with the new-widget name,
it is deleted.

-N widget [ function ]
Create a user-defined widget. If there is already a widget with the speci-
fied name, it is overwritten. When the new widget is invoked from within
the editor, the specified shell function is called. If no function name is
specified, it defaults to the same name as the widget. For further informa-
tion, see the section `Widgets' below.

-f flag [ flag... ]
Set various flags on the running widget. Possible values for flag are:

yank for indicating that the widget has yanked text into the buffer. If the
widget is wrapping an existing internal widget, no further action is neces-
sary, but if it has inserted the text manually, then it should also take
care to set YANK_START and YANK_END correctly. yankbefore does the same but
is used when the yanked text appears after the cursor.

kill for indicating that text has been killed into the cutbuffer. When re-
peatedly invoking a kill widget, text is appended to the cutbuffer instead
of replacing it, but when wrapping such widgets, it is necessary to call
`zle -f kill' to retain this effect.

vichange for indicating that the widget represents a vi change that can be
repeated as a whole with `vi-repeat-change'. The flag should be set early in
the function before inspecting the value of NUMERIC or invoking other wid-
gets. This has no effect for a widget invoked from insert mode. If insert
mode is active when the widget finishes, the change extends until next re-
turning to command mode.

-C widget completion-widget function
Create a user-defined completion widget named widget. The completion widget
will behave like the built-in completion-widget whose name is given as com-
pletion-widget. To generate the completions, the shell function function
will be called. For further information, see zshcompwid(1).

-R [ -c ] [ display-string ] [ string ... ]
Redisplay the command line; this is to be called from within a user-defined
widget to allow changes to become visible. If a display-string is given and
not empty, this is shown in the status line (immediately below the line be-
ing edited).

If the optional strings are given they are listed below the prompt in the
same way as completion lists are printed. If no strings are given but the -c
option is used such a list is cleared.

Note that this option is only useful for widgets that do not exit immedi-
ately after using it because the strings displayed will be erased immedi-
ately after return from the widget.

This command can safely be called outside user defined widgets; if zle is
active, the display will be refreshed, while if zle is not active, the com-
mand has no effect. In this case there will usually be no other arguments.

The status is zero if zle was active, else one.

-M string
As with the -R option, the string will be displayed below the command line;
unlike the -R option, the string will not be put into the status line but
will instead be printed normally below the prompt. This means that the
string will still be displayed after the widget returns (until it is over-
written by subsequent commands).

-U string
This pushes the characters in the string onto the input stack of ZLE. After
the widget currently executed finishes ZLE will behave as if the characters
in the string were typed by the user.

As ZLE uses a stack, if this option is used repeatedly the last string
pushed onto the stack will be processed first. However, the characters in
each string will be processed in the order in which they appear in the
string.

-K keymap
Selects the keymap named keymap. An error message will be displayed if
there is no such keymap.

This keymap selection affects the interpretation of following keystrokes
within this invocation of ZLE. Any following invocation (e.g., the next
command line) will start as usual with the `main' keymap selected.

-F [ -L | -w ] [ fd [ handler ] ]
Only available if your system supports one of the `poll' or `select' system
calls; most modern systems do.

Installs handler (the name of a shell function) to handle input from file
descriptor fd. Installing a handler for an fd which is already handled
causes the existing handler to be replaced. Any number of handlers for any
number of readable file descriptors may be installed. Note that zle makes
no attempt to check whether this fd is actually readable when installing the
handler. The user must make their own arrangements for handling the file
descriptor when zle is not active.

When zle is attempting to read data, it will examine both the terminal and
the list of handled fd's. If data becomes available on a handled fd, zle
calls handler with the fd which is ready for reading as the first argument.
Under normal circumstances this is the only argument, but if an error was
detected, a second argument provides details: `hup' for a disconnect, `nval'
for a closed or otherwise invalid descriptor, or `err' for any other condi-
tion. Systems that support only the `select' system call always use `err'.

If the option -w is also given, the handler is instead a line editor widget,
typically a shell function made into a widget using `zle -N'. In that case
handler can use all the facilities of zle to update the current editing
line. Note, however, that as handling fd takes place at a low level changes
to the display will not automatically appear; the widget should call `zle
-R' to force redisplay. As of this writing, widget handlers only support a
single argument and thus are never passed a string for error state, so wid-
gets must be prepared to test the descriptor themselves.

If either type of handler produces output to the terminal, it should call
`zle -I' before doing so (see below). Handlers should not attempt to read
from the terminal.

If no handler is given, but an fd is present, any handler for that fd is re-
moved. If there is none, an error message is printed and status 1 is re-
turned.

If no arguments are given, or the -L option is supplied, a list of handlers
is printed in a form which can be stored for later execution.

An fd (but not a handler) may optionally be given with the -L option; in
this case, the function will list the handler if any, else silently return
status 1.

Note that this feature should be used with care. Activity on one of the
fd's which is not properly handled can cause the terminal to become unus-
able. Removing an fd handler from within a signal trap may cause unpre-
dictable behavior.

Here is a simple example of using this feature. A connection to a remote
TCP port is created using the ztcp command; see the description of the
zsh/net/tcp module in zshmodules(1). Then a handler is installed which sim-
ply prints out any data which arrives on this connection. Note that `se-
lect' will indicate that the file descriptor needs handling if the remote
side has closed the connection; we handle that by testing for a failed read.

if ztcp pwspc 2811; then
tcpfd=$REPLY
handler() {
zle -I
local line
if ! read -r line <&$1; then
# select marks this fd if we reach EOF,
# so handle this specially.
print "[Read on fd $1 failed, removing.]" >&2
zle -F $1
return 1
fi
print -r - $line
}
zle -F $tcpfd handler
fi

-I Unusually, this option is most useful outside ordinary widget functions,
though it may be used within if normal output to the terminal is required.
It invalidates the current zle display in preparation for output; typically
this will be from a trap function. It has no effect if zle is not active.
When a trap exits, the shell checks to see if the display needs restoring,
hence the following will print output in such a way as not to disturb the
line being edited:

TRAPUSR1() {
# Invalidate zle display
[[ -o zle ]] && zle -I
# Show output
print Hello
}

In general, the trap function may need to test whether zle is active before
using this method (as shown in the example), since the zsh/zle module may
not even be loaded; if it is not, the command can be skipped.

It is possible to call `zle -I' several times before control is returned to
the editor; the display will only be invalidated the first time to minimise
disruption.

Note that there are normally better ways of manipulating the display from
within zle widgets; see, for example, `zle -R' above.

The returned status is zero if zle was invalidated, even though this may
have been by a previous call to `zle -I' or by a system notification. To
test if a zle widget may be called at this point, execute zle with no argu-
ments and examine the return status.

-T This is used to add, list or remove internal transformations on the process-
ing performed by the line editor. It is typically used only for debugging
or testing and is therefore of little interest to the general user.

`zle -T transformation func' specifies that the given transformation (see
below) is effected by shell function func.

`zle -Tr transformation' removes the given transformation if it was present
(it is not an error if none was).

`zle -TL' can be used to list all transformations currently in operation.

Currently the only transformation is tc. This is used instead of outputting
termcap codes to the terminal. When the transformation is in operation the
shell function is passed the termcap code that would be output as its first
argument; if the operation required a numeric argument, that is passed as a
second argument. The function should set the shell variable REPLY to the
transformed termcap code. Typically this is used to produce some simply
formatted version of the code and optional argument for debugging or test-
ing. Note that this transformation is not applied to other non-printing
characters such as carriage returns and newlines.

widget [ -n num ] [ -Nw ] [ -K keymap ] args ...
Invoke the specified widget. This can only be done when ZLE is active; nor-
mally this will be within a user-defined widget.

With the options -n and -N, the current numeric argument will be saved and
then restored after the call to widget; `-n num' sets the numeric argument
temporarily to num, while `-N' sets it to the default, i.e. as if there were
none.

With the option -K, keymap will be used as the current keymap during the ex-
ecution of the widget. The previous keymap will be restored when the widget
exits.

Normally, calling a widget in this way does not set the special parameter
WIDGET and related parameters, so that the environment appears as if the
top-level widget called by the user were still active. With the option -w,
WIDGET and related parameters are set to reflect the widget being executed
by the zle call.

Any further arguments will be passed to the widget; note that as standard
argument handling is performed, any general argument list should be preceded
by --. If it is a shell function, these are passed down as positional pa-
rameters; for builtin widgets it is up to the widget in question what it
does with them. Currently arguments are only handled by the incremen-
tal-search commands, the history-search-forward and -backward and the corre-
sponding functions prefixed by vi-, and by universal-argument. No error is
flagged if the command does not use the arguments, or only uses some of
them.

The return status reflects the success or failure of the operation carried
out by the widget, or if it is a user-defined widget the return status of
the shell function.

A non-zero return status causes the shell to beep when the widget exits, un-
less the BEEP options was unset or the widget was called via the zle com-
mand. Thus if a user defined widget requires an immediate beep, it should
call the beep widget directly.

WIDGETS
All actions in the editor are performed by `widgets'. A widget's job is simply to perform
some small action. The ZLE commands that key sequences in keymaps are bound to are in
fact widgets. Widgets can be user-defined or built in.

The standard widgets built into ZLE are listed in Standard Widgets below. Other built-in
widgets can be defined by other modules (see zshmodules(1)). Each built-in widget has two
names: its normal canonical name, and the same name preceded by a `.'. The `.' name is
special: it can't be rebound to a different widget. This makes the widget available even
when its usual name has been redefined.

User-defined widgets are defined using `zle -N', and implemented as shell functions. When
the widget is executed, the corresponding shell function is executed, and can perform
editing (or other) actions. It is recommended that user-defined widgets should not have
names starting with `.'.

USER-DEFINED WIDGETS
User-defined widgets, being implemented as shell functions, can execute any normal shell
command. They can also run other widgets (whether built-in or user-defined) using the zle
builtin command. The standard input of the function is redirected from /dev/null to pre-
vent external commands from unintentionally blocking ZLE by reading from the terminal, but
read -k or read -q can be used to read characters. Finally, they can examine and edit the
ZLE buffer being edited by reading and setting the special parameters described below.

These special parameters are always available in widget functions, but are not in any way
special outside ZLE. If they have some normal value outside ZLE, that value is temporar-
ily inaccessible, but will return when the widget function exits. These special parame-
ters in fact have local scope, like parameters created in a function using local.

Inside completion widgets and traps called while ZLE is active, these parameters are
available read-only.

Note that the parameters appear as local to any ZLE widget in which they appear. Hence if
it is desired to override them this needs to be done within a nested function:

widget-function() {
# $WIDGET here refers to the special variable
# that is local inside widget-function
() {
# This anonymous nested function allows WIDGET
# to be used as a local variable. The -h
# removes the special status of the variable.
local -h WIDGET
}
}

BUFFER (scalar)
The entire contents of the edit buffer. If it is written to, the cursor remains at
the same offset, unless that would put it outside the buffer.

BUFFERLINES (integer)
The number of screen lines needed for the edit buffer currently displayed on screen
(i.e. without any changes to the preceding parameters done after the last redis-
play); read-only.

CONTEXT (scalar)
The context in which zle was called to read a line; read-only. One of the values:

start The start of a command line (at prompt PS1).

cont A continuation to a command line (at prompt PS2).

select In a select loop (at prompt PS3).

vared Editing a variable in vared.

CURSOR (integer)
The offset of the cursor, within the edit buffer. This is in the range 0 to $#BUF-
FER, and is by definition equal to $#LBUFFER. Attempts to move the cursor outside
the buffer will result in the cursor being moved to the appropriate end of the buf-
fer.

CUTBUFFER (scalar)
The last item cut using one of the `kill-' commands; the string which the next yank
would insert in the line. Later entries in the kill ring are in the array kill-
ring. Note that the command `zle copy-region-as-kill string' can be used to set
the text of the cut buffer from a shell function and cycle the kill ring in the
same way as interactively killing text.

HISTNO (integer)
The current history number. Setting this has the same effect as moving up or down
in the history to the corresponding history line. An attempt to set it is ignored
if the line is not stored in the history. Note this is not the same as the parame-
ter HISTCMD, which always gives the number of the history line being added to the
main shell's history. HISTNO refers to the line being retrieved within zle.

ISEARCHMATCH_ACTIVE (integer)
ISEARCHMATCH_START (integer)
ISEARCHMATCH_END (integer)
ISEARCHMATCH_ACTIVE indicates whether a part of the BUFFER is currently matched by
an incremental search pattern. ISEARCHMATCH_START and ISEARCHMATCH_END give the lo-
cation of the matched part and are in the same units as CURSOR. They are only valid
for reading when ISEARCHMATCH_ACTIVE is non-zero.

All parameters are read-only.

KEYMAP (scalar)
The name of the currently selected keymap; read-only.

KEYS (scalar)
The keys typed to invoke this widget, as a literal string; read-only.

KEYS_QUEUED_COUNT (integer)
The number of bytes pushed back to the input queue and therefore available for
reading immediately before any I/O is done; read-only. See also PENDING; the two
values are distinct.

killring (array)
The array of previously killed items, with the most recently killed first. This
gives the items that would be retrieved by a yank-pop in the same order. Note,
however, that the most recently killed item is in $CUTBUFFER; $killring shows the
array of previous entries.

The default size for the kill ring is eight, however the length may be changed by
normal array operations. Any empty string in the kill ring is ignored by the
yank-pop command, hence the size of the array effectively sets the maximum length
of the kill ring, while the number of non-zero strings gives the current length,
both as seen by the user at the command line.

LASTABORTEDSEARCH (scalar)
The last search string used by an interactive search that was aborted by the user
(status 3 returned by the search widget).

LASTSEARCH (scalar)
The last search string used by an interactive search; read-only. This is set even
if the search failed (status 0, 1 or 2 returned by the search widget), but not if
it was aborted by the user.

LASTWIDGET (scalar)
The name of the last widget that was executed; read-only.

LBUFFER (scalar)
The part of the buffer that lies to the left of the cursor position. If it is as-
signed to, only that part of the buffer is replaced, and the cursor remains between
the new $LBUFFER and the old $RBUFFER.

MARK (integer)
Like CURSOR, but for the mark. With vi-mode operators that wait for a movement com-
mand to select a region of text, setting MARK allows the selection to extend in
both directions from the initial cursor position.

NUMERIC (integer)
The numeric argument. If no numeric argument was given, this parameter is unset.
When this is set inside a widget function, builtin widgets called with the zle
builtin command will use the value assigned. If it is unset inside a widget func-
tion, builtin widgets called behave as if no numeric argument was given.

PENDING (integer)
The number of bytes pending for input, i.e. the number of bytes which have already
been typed and can immediately be read. On systems where the shell is not able to
get this information, this parameter will always have a value of zero. Read-only.
See also KEYS_QUEUED_COUNT; the two values are distinct.

PREBUFFER (scalar)
In a multi-line input at the secondary prompt, this read-only parameter contains
the contents of the lines before the one the cursor is currently in.

PREDISPLAY (scalar)
Text to be displayed before the start of the editable text buffer. This does not
have to be a complete line; to display a complete line, a newline must be appended
explicitly. The text is reset on each new invocation (but not recursive invoca-
tion) of zle.

POSTDISPLAY (scalar)
Text to be displayed after the end of the editable text buffer. This does not have
to be a complete line; to display a complete line, a newline must be prepended ex-
plicitly. The text is reset on each new invocation (but not recursive invocation)
of zle.

RBUFFER (scalar)
The part of the buffer that lies to the right of the cursor position. If it is as-
signed to, only that part of the buffer is replaced, and the cursor remains between
the old $LBUFFER and the new $RBUFFER.

REGION_ACTIVE (integer)
Indicates if the region is currently active. It can be assigned 0 or 1 to deacti-
vate and activate the region respectively. A value of 2 activates the region in
line-wise mode with the highlighted text extending for whole lines only; see Char-
acter Highlighting below.

region_highlight (array)
Each element of this array may be set to a string that describes highlighting for
an arbitrary region of the command line that will take effect the next time the
command line is redisplayed. Highlighting of the non-editable parts of the command
line in PREDISPLAY and POSTDISPLAY are possible, but note that the P flag is needed
for character indexing to include PREDISPLAY.

Each string consists of the following parts:

o Optionally, a `P' to signify that the start and end offset that follow in-
clude any string set by the PREDISPLAY special parameter; this is needed if
the predisplay string itself is to be highlighted. Whitespace may follow
the `P'.

o A start offset in the same units as CURSOR, terminated by whitespace.

o An end offset in the same units as CURSOR, terminated by whitespace.

o A highlight specification in the same format as used for contexts in the pa-
rameter zle_highlight, see the section `Character Highlighting' below; for
example, standout or fg=red,bold

For example,

region_highlight=("P0 20 bold")

specifies that the first twenty characters of the text including any predisplay
string should be highlighted in bold.

Note that the effect of region_highlight is not saved and disappears as soon as the
line is accepted.

The final highlighting on the command line depends on both region_highlight and
zle_highlight; see the section CHARACTER HIGHLIGHTING below for details.

registers (associative array)
The contents of each of the vi register buffers. These are typically set using
vi-set-buffer followed by a delete, change or yank command.

SUFFIX_ACTIVE (integer)
SUFFIX_START (integer)
SUFFIX_END (integer)
SUFFIX_ACTIVE indicates whether an auto-removable completion suffix is currently
active. SUFFIX_START and SUFFIX_END give the location of the suffix and are in the
same units as CURSOR. They are only valid for reading when SUFFIX_ACTIVE is
non-zero.

All parameters are read-only.

UNDO_CHANGE_NO (integer)
A number representing the state of the undo history. The only use of this is pass-
ing as an argument to the undo widget in order to undo back to the recorded point.
Read-only.

UNDO_LIMIT_NO (integer)
A number corresponding to an existing change in the undo history; compare
UNDO_CHANGE_NO. If this is set to a value greater than zero, the undo command will
not allow the line to be undone beyond the given change number. It is still possi-
ble to use `zle undo change' in a widget to undo beyond that point; in that case,
it will not be possible to undo at all until UNDO_LIMIT_NO is reduced. Set to 0 to
disable the limit.

A typical use of this variable in a widget function is as follows (note the addi-
tional function scope is required):

() {
local UNDO_LIMIT_NO=$UNDO_CHANGE_NO
# Perform some form of recursive edit.
}

WIDGET (scalar)
The name of the widget currently being executed; read-only.

WIDGETFUNC (scalar)
The name of the shell function that implements a widget defined with either zle -N
or zle -C. In the former case, this is the second argument to the zle -N command
that defined the widget, or the first argument if there was no second argument. In
the latter case this is the third argument to the zle -C command that defined the
widget. Read-only.

WIDGETSTYLE (scalar)
Describes the implementation behind the completion widget currently being executed;
the second argument that followed zle -C when the widget was defined. This is the
name of a builtin completion widget. For widgets defined with zle -N this is set
to the empty string. Read-only.

YANK_ACTIVE (integer)
YANK_START (integer)
YANK_END (integer)
YANK_ACTIVE indicates whether text has just been yanked (pasted) into the buffer.
YANK_START and YANK_END give the location of the pasted text and are in the same
units as CURSOR. They are only valid for reading when YANK_ACTIVE is non-zero.
They can also be assigned by widgets that insert text in a yank-like fashion, for
example wrappers of bracketed-paste. See also zle -f.

YANK_ACTIVE is read-only.

ZLE_RECURSIVE (integer)
Usually zero, but incremented inside any instance of recursive-edit. Hence indi-
cates the current recursion level.

ZLE_RECURSIVE is read-only.

ZLE_STATE (scalar)
Contains a set of space-separated words that describe the current zle state.

Currently, the states shown are the insert mode as set by the overwrite-mode or
vi-replace widgets and whether history commands will visit imported entries as con-
trolled by the set-local-history widget. The string contains `insert' if charac-
ters to be inserted on the command line move existing characters to the right or
`overwrite' if characters to be inserted overwrite existing characters. It contains
`localhistory' if only local history commands will be visited or `globalhistory' if
imported history commands will also be visited.

The substrings are sorted in alphabetical order so that if you want to test for two
specific substrings in a future-proof way, you can do match by doing:

if [[ $ZLE_STATE == *globalhistory*insert* ]]; then ...; fi

Special Widgets
There are a few user-defined widgets which are special to the shell. If they do not ex-
ist, no special action is taken. The environment provided is identical to that for any
other editing widget.

zle-isearch-exit
Executed at the end of incremental search at the point where the isearch prompt is
removed from the display. See zle-isearch-update for an example.

zle-isearch-update
Executed within incremental search when the display is about to be redrawn. Addi-
tional output below the incremental search prompt can be generated by using `zle
-M' within the widget. For example,

zle-isearch-update() { zle -M "Line $HISTNO"; }
zle -N zle-isearch-update

Note the line output by `zle -M' is not deleted on exit from incremental search.
This can be done from a zle-isearch-exit widget:

zle-isearch-exit() { zle -M ""; }
zle -N zle-isearch-exit

zle-line-pre-redraw
Executed whenever the input line is about to be redrawn, providing an opportunity
to update the region_highlight array.

zle-line-init
Executed every time the line editor is started to read a new line of input. The
following example puts the line editor into vi command mode when it starts up.

zle-line-init() { zle -K vicmd; }
zle -N zle-line-init

(The command inside the function sets the keymap directly; it is equivalent to zle
vi-cmd-mode.)

zle-line-finish
This is similar to zle-line-init but is executed every time the line editor has
finished reading a line of input.

zle-history-line-set
Executed when the history line changes.

zle-keymap-select
Executed every time the keymap changes, i.e. the special parameter KEYMAP is set to
a different value, while the line editor is active. Initialising the keymap when
the line editor starts does not cause the widget to be called.

The value $KEYMAP within the function reflects the new keymap. The old keymap is
passed as the sole argument.

This can be used for detecting switches between the vi command (vicmd) and insert
(usually main) keymaps.

STANDARD WIDGETS
The following is a list of all the standard widgets, and their default bindings in emacs
mode, vi command mode and vi insert mode (the `emacs', `vicmd' and `viins' keymaps, re-
spectively).

Note that cursor keys are bound to movement keys in all three keymaps; the shell assumes
that the cursor keys send the key sequences reported by the terminal-handling library
(termcap or terminfo). The key sequences shown in the list are those based on the VT100,
common on many modern terminals, but in fact these are not necessarily bound. In the case
of the viins keymap, the initial escape character of the sequences serves also to return
to the vicmd keymap: whether this happens is determined by the KEYTIMEOUT parameter, see
zshparam(1).

Movement
vi-backward-blank-word (unbound) (B) (unbound)
Move backward one word, where a word is defined as a series of non-blank charac-
ters.

vi-backward-blank-word-end (unbound) (gE) (unbound)
Move to the end of the previous word, where a word is defined as a series of
non-blank characters.

backward-char (^B ESC-[D) (unbound) (unbound)
Move backward one character.

vi-backward-char (unbound) (^H h ^?) (ESC-[D)
Move backward one character, without changing lines.

backward-word (ESC-B ESC-b) (unbound) (unbound)
Move to the beginning of the previous word.

emacs-backward-word
Move to the beginning of the previous word.

vi-backward-word (unbound) (b) (unbound)
Move to the beginning of the previous word, vi-style.

vi-backward-word-end (unbound) (ge) (unbound)
Move to the end of the previous word, vi-style.

beginning-of-line (^A) (unbound) (unbound)
Move to the beginning of the line. If already at the beginning of the line, move
to the beginning of the previous line, if any.

vi-beginning-of-line
Move to the beginning of the line, without changing lines.

down-line (unbound) (unbound) (unbound)
Move down a line in the buffer.

end-of-line (^E) (unbound) (unbound)
Move to the end of the line. If already at the end of the line, move to the end of
the next line, if any.

vi-end-of-line (unbound) ($) (unbound)
Move to the end of the line. If an argument is given to this command, the cursor
will be moved to the end of the line (argument - 1) lines down.

vi-forward-blank-word (unbound) (W) (unbound)
Move forward one word, where a word is defined as a series of non-blank characters.

vi-forward-blank-word-end (unbound) (E) (unbound)
Move to the end of the current word, or, if at the end of the current word, to the
end of the next word, where a word is defined as a series of non-blank characters.

forward-char (^F ESC-[C) (unbound) (unbound)
Move forward one character.

vi-forward-char (unbound) (space l) (ESC-[C)
Move forward one character.

vi-find-next-char (^X^F) (f) (unbound)
Read a character from the keyboard, and move to the next occurrence of it in the
line.

vi-find-next-char-skip (unbound) (t) (unbound)
Read a character from the keyboard, and move to the position just before the next
occurrence of it in the line.

vi-find-prev-char (unbound) (F) (unbound)
Read a character from the keyboard, and move to the previous occurrence of it in
the line.

vi-find-prev-char-skip (unbound) (T) (unbound)
Read a character from the keyboard, and move to the position just after the previ-
ous occurrence of it in the line.

vi-first-non-blank (unbound) (^) (unbound)
Move to the first non-blank character in the line.

vi-forward-word (unbound) (w) (unbound)
Move forward one word, vi-style.

forward-word (ESC-F ESC-f) (unbound) (unbound)
Move to the beginning of the next word. The editor's idea of a word is specified
with the WORDCHARS parameter.

emacs-forward-word
Move to the end of the next word.

vi-forward-word-end (unbound) (e) (unbound)
Move to the end of the next word.

vi-goto-column (ESC-|) (|) (unbound)
Move to the column specified by the numeric argument.

vi-goto-mark (unbound) (`) (unbound)
Move to the specified mark.

vi-goto-mark-line (unbound) (') (unbound)
Move to beginning of the line containing the specified mark.

vi-repeat-find (unbound) (;) (unbound)
Repeat the last vi-find command.

vi-rev-repeat-find (unbound) (,) (unbound)
Repeat the last vi-find command in the opposite direction.

up-line (unbound) (unbound) (unbound)
Move up a line in the buffer.

History Control
beginning-of-buffer-or-history (ESC-<) (gg) (unbound)
Move to the beginning of the buffer, or if already there, move to the first event
in the history list.

beginning-of-line-hist
Move to the beginning of the line. If already at the beginning of the buffer, move
to the previous history line.

beginning-of-history
Move to the first event in the history list.

down-line-or-history (^N ESC-[B) (j) (ESC-[B)
Move down a line in the buffer, or if already at the bottom line, move to the next
event in the history list.

vi-down-line-or-history (unbound) (+) (unbound)
Move down a line in the buffer, or if already at the bottom line, move to the next
event in the history list. Then move to the first non-blank character on the line.

down-line-or-search
Move down a line in the buffer, or if already at the bottom line, search forward in
the history for a line beginning with the first word in the buffer.

If called from a function by the zle command with arguments, the first argument is
taken as the string for which to search, rather than the first word in the buffer.

down-history (unbound) (^N) (unbound)
Move to the next event in the history list.

history-beginning-search-backward
Search backward in the history for a line beginning with the current line up to the
cursor. This leaves the cursor in its original position.

end-of-buffer-or-history (ESC->) (unbound) (unbound)
Move to the end of the buffer, or if already there, move to the last event in the
history list.

end-of-line-hist
Move to the end of the line. If already at the end of the buffer, move to the next
history line.

end-of-history
Move to the last event in the history list.

vi-fetch-history (unbound) (G) (unbound)
Fetch the history line specified by the numeric argument. This defaults to the
current history line (i.e. the one that isn't history yet).

history-incremental-search-backward (^R ^Xr) (unbound) (unbound)
Search backward incrementally for a specified string. The search is case-insensi-
tive if the search string does not have uppercase letters and no numeric argument
was given. The string may begin with `^' to anchor the search to the beginning of
the line. When called from a user-defined function returns the following statuses:
0, if the search succeeded; 1, if the search failed; 2, if the search term was a
bad pattern; 3, if the search was aborted by the send-break command.

A restricted set of editing functions is available in the mini-buffer. Keys are
looked up in the special isearch keymap, and if not found there in the main keymap
(note that by default the isearch keymap is empty). An interrupt signal, as de-
fined by the stty setting, will stop the search and go back to the original line.
An undefined key will have the same effect. Note that the following always perform
the same task within incremental searches and cannot be replaced by user defined
widgets, nor can the set of functions be extended. The supported functions are:

accept-and-hold
accept-and-infer-next-history
accept-line
accept-line-and-down-history
Perform the usual function after exiting incremental search. The command
line displayed is executed.

backward-delete-char
vi-backward-delete-char
Back up one place in the search history. If the search has been repeated
this does not immediately erase a character in the minibuffer.

accept-search
Exit incremental search, retaining the command line but performing no fur-
ther action. Note that this function is not bound by default and has no ef-
fect outside incremental search.

backward-delete-word
backward-kill-word
vi-backward-kill-word
Back up one character in the minibuffer; if multiple searches have been per-
formed since the character was inserted the search history is rewound to the
point just before the character was entered. Hence this has the effect of
repeating backward-delete-char.

clear-screen
Clear the screen, remaining in incremental search mode.

history-incremental-search-backward
Find the next occurrence of the contents of the mini-buffer. If the
mini-buffer is empty, the most recent previously used search string is rein-
stated.

history-incremental-search-forward
Invert the sense of the search.

magic-space
Inserts a non-magical space.

quoted-insert
vi-quoted-insert
Quote the character to insert into the minibuffer.

redisplay
Redisplay the command line, remaining in incremental search mode.

vi-cmd-mode
Select the `vicmd' keymap; the `main' keymap (insert mode) will be selected
initially.

In addition, the modifications that were made while in vi insert mode are
merged to form a single undo event.

vi-repeat-search
vi-rev-repeat-search
Repeat the search. The direction of the search is indicated in the
mini-buffer.

Any character that is not bound to one of the above functions, or self-insert or
self-insert-unmeta, will cause the mode to be exited. The character is then looked
up and executed in the keymap in effect at that point.

When called from a widget function by the zle command, the incremental search com-
mands can take a string argument. This will be treated as a string of keys, as for
arguments to the bindkey command, and used as initial input for the command. Any
characters in the string which are unused by the incremental search will be
silently ignored. For example,

zle history-incremental-search-backward forceps

will search backwards for forceps, leaving the minibuffer containing the string
`forceps'.

history-incremental-search-forward (^S ^Xs) (unbound) (unbound)
Search forward incrementally for a specified string. The search is case-insensi-
tive if the search string does not have uppercase letters and no numeric argument
was given. The string may begin with `^' to anchor the search to the beginning of
the line. The functions available in the mini-buffer are the same as for his-
tory-incremental-search-backward.

history-incremental-pattern-search-backward
history-incremental-pattern-search-forward
These widgets behave similarly to the corresponding widgets with no -pattern, but
the search string typed by the user is treated as a pattern, respecting the current
settings of the various options affecting pattern matching. See FILENAME GENERA-
TION in zshexpn(1) for a description of patterns. If no numeric argument was given
lowercase letters in the search string may match uppercase letters in the history.
The string may begin with `^' to anchor the search to the beginning of the line.

The prompt changes to indicate an invalid pattern; this may simply indicate the
pattern is not yet complete.

Note that only non-overlapping matches are reported, so an expression with wild-
cards may return fewer matches on a line than are visible by inspection.

history-search-backward (ESC-P ESC-p) (unbound) (unbound)
Search backward in the history for a line beginning with the first word in the buf-
fer.

If called from a function by the zle command with arguments, the first argument is
taken as the string for which to search, rather than the first word in the buffer.

vi-history-search-backward (unbound) (/) (unbound)
Search backward in the history for a specified string. The string may begin with
`^' to anchor the search to the beginning of the line.

A restricted set of editing functions is available in the mini-buffer. An inter-
rupt signal, as defined by the stty setting, will stop the search. The functions
available in the mini-buffer are: accept-line, backward-delete-char, vi-back-
ward-delete-char, backward-kill-word, vi-backward-kill-word, clear-screen, redis-
play, quoted-insert and vi-quoted-insert.

vi-cmd-mode is treated the same as accept-line, and magic-space is treated as a
space. Any other character that is not bound to self-insert or self-insert-unmeta
will beep and be ignored. If the function is called from vi command mode, the bind-
ings of the current insert mode will be used.

If called from a function by the zle command with arguments, the first argument is
taken as the string for which to search, rather than the first word in the buffer.

history-search-forward (ESC-N ESC-n) (unbound) (unbound)
Search forward in the history for a line beginning with the first word in the buf-
fer.

If called from a function by the zle command with arguments, the first argument is
taken as the string for which to search, rather than the first word in the buffer.

vi-history-search-forward (unbound) (?) (unbound)
Search forward in the history for a specified string. The string may begin with
`^' to anchor the search to the beginning of the line. The functions available in
the mini-buffer are the same as for vi-history-search-backward. Argument handling
is also the same as for that command.

infer-next-history (^X^N) (unbound) (unbound)
Search in the history list for a line matching the current one and fetch the event
following it.

insert-last-word (ESC-_ ESC-.) (unbound) (unbound)
Insert the last word from the previous history event at the cursor position. If a
positive numeric argument is given, insert that word from the end of the previous
history event. If the argument is zero or negative insert that word from the left
(zero inserts the previous command word). Repeating this command replaces the word
just inserted with the last word from the history event prior to the one just used;
numeric arguments can be used in the same way to pick a word from that event.

When called from a shell function invoked from a user-defined widget, the command
can take one to three arguments. The first argument specifies a history offset
which applies to successive calls to this widget: if it is -1, the default behav-
iour is used, while if it is 1, successive calls will move forwards through the
history. The value 0 can be used to indicate that the history line examined by the
previous execution of the command will be reexamined. Note that negative numbers
should be preceded by a `--' argument to avoid confusing them with options.

If two arguments are given, the second specifies the word on the command line in
normal array index notation (as a more natural alternative to the numeric argu-
ment). Hence 1 is the first word, and -1 (the default) is the last word.

If a third argument is given, its value is ignored, but it is used to signify that
the history offset is relative to the current history line, rather than the one re-
membered after the previous invocations of insert-last-word.

For example, the default behaviour of the command corresponds to

zle insert-last-word -- -1 -1

while the command

zle insert-last-word -- -1 1 -

always copies the first word of the line in the history immediately before the line
being edited. This has the side effect that later invocations of the widget will
be relative to that line.

vi-repeat-search (unbound) (n) (unbound)
Repeat the last vi history search.

vi-rev-repeat-search (unbound) (N) (unbound)
Repeat the last vi history search, but in reverse.

up-line-or-history (^P ESC-[A) (k) (ESC-[A)
Move up a line in the buffer, or if already at the top line, move to the previous
event in the history list.

vi-up-line-or-history (unbound) (-) (unbound)
Move up a line in the buffer, or if already at the top line, move to the previous
event in the history list. Then move to the first non-blank character on the line.

up-line-or-search
Move up a line in the buffer, or if already at the top line, search backward in the
history for a line beginning with the first word in the buffer.

If called from a function by the zle command with arguments, the first argument is
taken as the string for which to search, rather than the first word in the buffer.

up-history (unbound) (^P) (unbound)
Move to the previous event in the history list.

history-beginning-search-forward
Search forward in the history for a line beginning with the current line up to the
cursor. This leaves the cursor in its original position.

set-local-history
By default, history movement commands visit the imported lines as well as the local
lines. This widget lets you toggle this on and off, or set it with the numeric ar-
gument. Zero for both local and imported lines and nonzero for only local lines.

Modifying Text
vi-add-eol (unbound) (A) (unbound)
Move to the end of the line and enter insert mode.

vi-add-next (unbound) (a) (unbound)
Enter insert mode after the current cursor position, without changing lines.

backward-delete-char (^H ^?) (unbound) (unbound)
Delete the character behind the cursor.

vi-backward-delete-char (unbound) (X) (^H)
Delete the character behind the cursor, without changing lines. If in insert mode,
this won't delete past the point where insert mode was last entered.

backward-delete-word
Delete the word behind the cursor.

backward-kill-line
Kill from the beginning of the line to the cursor position.

backward-kill-word (^W ESC-^H ESC-^?) (unbound) (unbound)
Kill the word behind the cursor.

vi-backward-kill-word (unbound) (unbound) (^W)
Kill the word behind the cursor, without going past the point where insert mode was
last entered.

capitalize-word (ESC-C ESC-c) (unbound) (unbound)
Capitalize the current word and move past it.

vi-change (unbound) (c) (unbound)
Read a movement command from the keyboard, and kill from the cursor position to the
endpoint of the movement. Then enter insert mode. If the command is vi-change,
change the current line.

For compatibility with vi, if the command is vi-forward-word or vi-for-
ward-blank-word, the whitespace after the word is not included. If you prefer the
more consistent behaviour with the whitespace included use the following key bind-
ing:

bindkey -a -s cw dwi

vi-change-eol (unbound) (C) (unbound)
Kill to the end of the line and enter insert mode.

vi-change-whole-line (unbound) (S) (unbound)
Kill the current line and enter insert mode.

copy-region-as-kill (ESC-W ESC-w) (unbound) (unbound)
Copy the area from the cursor to the mark to the kill buffer.

If called from a ZLE widget function in the form `zle copy-region-as-kill string'
then string will be taken as the text to copy to the kill buffer. The cursor, the
mark and the text on the command line are not used in this case.

copy-prev-word (ESC-^_) (unbound) (unbound)
Duplicate the word to the left of the cursor.

copy-prev-shell-word
Like copy-prev-word, but the word is found by using shell parsing, whereas
copy-prev-word looks for blanks. This makes a difference when the word is quoted
and contains spaces.

vi-delete (unbound) (d) (unbound)
Read a movement command from the keyboard, and kill from the cursor position to the
endpoint of the movement. If the command is vi-delete, kill the current line.

delete-char
Delete the character under the cursor.

vi-delete-char (unbound) (x) (unbound)
Delete the character under the cursor, without going past the end of the line.

delete-word
Delete the current word.

down-case-word (ESC-L ESC-l) (unbound) (unbound)
Convert the current word to all lowercase and move past it.

vi-down-case (unbound) (gu) (unbound)
Read a movement command from the keyboard, and convert all characters from the cur-
sor position to the endpoint of the movement to lowercase. If the movement command
is vi-down-case, swap the case of all characters on the current line.

kill-word (ESC-D ESC-d) (unbound) (unbound)
Kill the current word.

gosmacs-transpose-chars
Exchange the two characters behind the cursor.

vi-indent (unbound) (>) (unbound)
Indent a number of lines.

vi-insert (unbound) (i) (unbound)
Enter insert mode.

vi-insert-bol (unbound) (I) (unbound)
Move to the first non-blank character on the line and enter insert mode.

vi-join (^X^J) (J) (unbound)
Join the current line with the next one.

kill-line (^K) (unbound) (unbound)
Kill from the cursor to the end of the line. If already on the end of the line,
kill the newline character.

vi-kill-line (unbound) (unbound) (^U)
Kill from the cursor back to wherever insert mode was last entered.

vi-kill-eol (unbound) (D) (unbound)
Kill from the cursor to the end of the line.

kill-region
Kill from the cursor to the mark.

kill-buffer (^X^K) (unbound) (unbound)
Kill the entire buffer.

kill-whole-line (^U) (unbound) (unbound)
Kill the current line.

vi-match-bracket (^X^B) (%) (unbound)
Move to the bracket character (one of {}, () or []) that matches the one under the
cursor. If the cursor is not on a bracket character, move forward without going
past the end of the line to find one, and then go to the matching bracket.

vi-open-line-above (unbound) (O) (unbound)
Open a line above the cursor and enter insert mode.

vi-open-line-below (unbound) (o) (unbound)
Open a line below the cursor and enter insert mode.

vi-oper-swap-case (unbound) (g~) (unbound)
Read a movement command from the keyboard, and swap the case of all characters from
the cursor position to the endpoint of the movement. If the movement command is
vi-oper-swap-case, swap the case of all characters on the current line.

overwrite-mode (^X^O) (unbound) (unbound)
Toggle between overwrite mode and insert mode.

vi-put-before (unbound) (P) (unbound)
Insert the contents of the kill buffer before the cursor. If the kill buffer con-
tains a sequence of lines (as opposed to characters), paste it above the current
line.

vi-put-after (unbound) (p) (unbound)
Insert the contents of the kill buffer after the cursor. If the kill buffer con-
tains a sequence of lines (as opposed to characters), paste it below the current
line.

put-replace-selection (unbound) (unbound) (unbound)
Replace the contents of the current region or selection with the contents of the
kill buffer. If the kill buffer contains a sequence of lines (as opposed to charac-
ters), the current line will be split by the pasted lines.

quoted-insert (^V) (unbound) (unbound)
Insert the next character typed into the buffer literally. An interrupt character
will not be inserted.

vi-quoted-insert (unbound) (unbound) (^Q ^V)
Display a `^' at the cursor position, and insert the next character typed into the
buffer literally. An interrupt character will not be inserted.

quote-line (ESC-') (unbound) (unbound)
Quote the current line; that is, put a `'' character at the beginning and the end,
and convert all `'' characters to `'\'''.

quote-region (ESC-") (unbound) (unbound)
Quote the region from the cursor to the mark.

vi-replace (unbound) (R) (unbound)
Enter overwrite mode.

vi-repeat-change (unbound) (.) (unbound)
Repeat the last vi mode text modification. If a count was used with the modifica-
tion, it is remembered. If a count is given to this command, it overrides the re-
membered count, and is remembered for future uses of this command. The cut buffer
specification is similarly remembered.

vi-replace-chars (unbound) (r) (unbound)
Replace the character under the cursor with a character read from the keyboard.

self-insert (printable characters) (unbound) (printable characters and some control char-
acters)
Insert a character into the buffer at the cursor position.

self-insert-unmeta (ESC-^I ESC-^J ESC-^M) (unbound) (unbound)
Insert a character into the buffer after stripping the meta bit and converting ^M
to ^J.

vi-substitute (unbound) (s) (unbound)
Substitute the next character(s).

vi-swap-case (unbound) (~) (unbound)
Swap the case of the character under the cursor and move past it.

transpose-chars (^T) (unbound) (unbound)
Exchange the two characters to the left of the cursor if at end of line, else ex-
change the character under the cursor with the character to the left.

transpose-words (ESC-T ESC-t) (unbound) (unbound)
Exchange the current word with the one before it.

With a positive numeric argument N, the word around the cursor, or following it if
the cursor is between words, is transposed with the preceding N words. The cursor
is put at the end of the resulting group of words.

With a negative numeric argument -N, the effect is the same as using a positive ar-
gument N except that the original cursor position is retained, regardless of how
the words are rearranged.

vi-unindent (unbound) (<) (unbound)
Unindent a number of lines.

vi-up-case (unbound) (gU) (unbound)
Read a movement command from the keyboard, and convert all characters from the cur-
sor position to the endpoint of the movement to lowercase. If the movement command
is vi-up-case, swap the case of all characters on the current line.

up-case-word (ESC-U ESC-u) (unbound) (unbound)
Convert the current word to all caps and move past it.

yank (^Y) (unbound) (unbound)
Insert the contents of the kill buffer at the cursor position.

yank-pop (ESC-y) (unbound) (unbound)
Remove the text just yanked, rotate the kill-ring (the history of previously killed
text) and yank the new top. Only works following yank, vi-put-before, vi-put-after
or yank-pop.

vi-yank (unbound) (y) (unbound)
Read a movement command from the keyboard, and copy the region from the cursor po-
sition to the endpoint of the movement into the kill buffer. If the command is
vi-yank, copy the current line.

vi-yank-whole-line (unbound) (Y) (unbound)
Copy the current line into the kill buffer.

vi-yank-eol
Copy the region from the cursor position to the end of the line into the kill buf-
fer. Arguably, this is what Y should do in vi, but it isn't what it actually does.

Arguments
digit-argument (ESC-0..ESC-9) (1-9) (unbound)
Start a new numeric argument, or add to the current one. See also vi-digit-or-be-
ginning-of-line. This only works if bound to a key sequence ending in a decimal
digit.

Inside a widget function, a call to this function treats the last key of the key
sequence which called the widget as the digit.

neg-argument (ESC--) (unbound) (unbound)
Changes the sign of the following argument.

universal-argument
Multiply the argument of the next command by 4. Alternatively, if this command is
followed by an integer (positive or negative), use that as the argument for the
next command. Thus digits cannot be repeated using this command. For example, if
this command occurs twice, followed immediately by forward-char, move forward six-
teen spaces; if instead it is followed by -2, then forward-char, move backward two
spaces.

Inside a widget function, if passed an argument, i.e. `zle universal-argument num',
the numeric argument will be set to num; this is equivalent to `NUMERIC=num'.

argument-base
Use the existing numeric argument as a numeric base, which must be in the range 2
to 36 inclusive. Subsequent use of digit-argument and universal-argument will in-
put a new numeric argument in the given base. The usual hexadecimal convention is
used: the letter a or A corresponds to 10, and so on. Arguments in bases requiring
digits from 10 upwards are more conveniently input with universal-argument, since
ESC-a etc. are not usually bound to digit-argument.

The function can be used with a command argument inside a user-defined widget. The
following code sets the base to 16 and lets the user input a hexadecimal argument
until a key out of the digit range is typed:

zle argument-base 16
zle universal-argument

Completion
accept-and-menu-complete
In a menu completion, insert the current completion into the buffer, and advance to
the next possible completion.

complete-word
Attempt completion on the current word.

delete-char-or-list (^D) (unbound) (unbound)
Delete the character under the cursor. If the cursor is at the end of the line,
list possible completions for the current word.

expand-cmd-path
Expand the current command to its full pathname.

expand-or-complete (TAB) (unbound) (TAB)
Attempt shell expansion on the current word. If that fails, attempt completion.

expand-or-complete-prefix
Attempt shell expansion on the current word up to cursor.

expand-history (ESC-space ESC-!) (unbound) (unbound)
Perform history expansion on the edit buffer.

expand-word (^X*) (unbound) (unbound)
Attempt shell expansion on the current word.

list-choices (ESC-^D) (^D =) (^D)
List possible completions for the current word.

list-expand (^Xg ^XG) (^G) (^G)
List the expansion of the current word.

magic-space
Perform history expansion and insert a space into the buffer. This is intended to
be bound to space.

menu-complete
Like complete-word, except that menu completion is used. See the MENU_COMPLETE op-
tion.

menu-expand-or-complete
Like expand-or-complete, except that menu completion is used.

reverse-menu-complete
Perform menu completion, like menu-complete, except that if a menu completion is
already in progress, move to the previous completion rather than the next.

end-of-list
When a previous completion displayed a list below the prompt, this widget can be
used to move the prompt below the list.

Miscellaneous
accept-and-hold (ESC-A ESC-a) (unbound) (unbound)
Push the contents of the buffer on the buffer stack and execute it.

accept-and-infer-next-history
Execute the contents of the buffer. Then search the history list for a line match-
ing the current one and push the event following onto the buffer stack.

accept-line (^J ^M) (^J ^M) (^J ^M)
Finish editing the buffer. Normally this causes the buffer to be executed as a
shell command.

accept-line-and-down-history (^O) (unbound) (unbound)
Execute the current line, and push the next history event on the buffer stack.

auto-suffix-remove
If the previous action added a suffix (space, slash, etc.) to the word on the com-
mand line, remove it. Otherwise do nothing. Removing the suffix ends any active
menu completion or menu selection.

This widget is intended to be called from user-defined widgets to enforce a desired
suffix-removal behavior.

auto-suffix-retain
If the previous action added a suffix (space, slash, etc.) to the word on the com-
mand line, force it to be preserved. Otherwise do nothing. Retaining the suffix
ends any active menu completion or menu selection.

This widget is intended to be called from user-defined widgets to enforce a desired
suffix-preservation behavior.

beep Beep, unless the BEEP option is unset.

bracketed-paste
This widget is invoked when text is pasted to the terminal emulator. It is not in-
tended to be bound to actual keys but instead to the special sequence generated by
the terminal emulator when text is pasted.

When invoked interactively, the pasted text is inserted to the buffer and placed in
the cutbuffer. If a numeric argument is given, shell quoting will be applied to
the pasted text before it is inserted.

When a named buffer is specified with vi-set-buffer ("x), the pasted text is stored
in that named buffer but not inserted.

When called from a widget function as `bracketed-paste name`, the pasted text is
assigned to the variable name and no other processing is done.

See also the zle_bracketed_paste parameter.

vi-cmd-mode (^X^V) (unbound) (^[)
Enter command mode; that is, select the `vicmd' keymap. Yes, this is bound by de-
fault in emacs mode.

vi-caps-lock-panic
Hang until any lowercase key is pressed. This is for vi users without the mental
capacity to keep track of their caps lock key (like the author).

clear-screen (^L ESC-^L) (^L) (^L)
Clear the screen and redraw the prompt.

deactivate-region
Make the current region inactive. This disables vim-style visual selection mode if
it is active.

describe-key-briefly
Reads a key sequence, then prints the function bound to that sequence.

exchange-point-and-mark (^X^X) (unbound) (unbound)
Exchange the cursor position (point) with the position of the mark. Unless a nega-
tive numeric argument is given, the region between point and mark is activated so
that it can be highlighted. If a zero numeric argument is given, the region is ac-
tivated but point and mark are not swapped.

execute-named-cmd (ESC-x) (:) (unbound)
Read the name of an editor command and execute it. Aliasing this widget with `zle
-A' or replacing it with `zle -N' has no effect when interpreting key bindings, but
`zle execute-named-cmd' will invoke such an alias or replacement.

A restricted set of editing functions is available in the mini-buffer. Keys are
looked up in the special command keymap, and if not found there in the main keymap.
An interrupt signal, as defined by the stty setting, will abort the function. Note
that the following always perform the same task within the executed-named-cmd envi-
ronment and cannot be replaced by user defined widgets, nor can the set of func-
tions be extended. The allowed functions are: backward-delete-char, vi-back-
ward-delete-char, clear-screen, redisplay, quoted-insert, vi-quoted-insert, back-
ward-kill-word, vi-backward-kill-word, kill-whole-line, vi-kill-line, back-
ward-kill-line, list-choices, delete-char-or-list, complete-word, accept-line, ex-
pand-or-complete and expand-or-complete-prefix.

kill-region kills the last word, and vi-cmd-mode is treated the same as ac-
cept-line. The space and tab characters, if not bound to one of these functions,
will complete the name and then list the possibilities if the AUTO_LIST option is
set. Any other character that is not bound to self-insert or self-insert-unmeta
will beep and be ignored. The bindings of the current insert mode will be used.

Currently this command may not be redefined or called by name.

execute-last-named-cmd (ESC-z) (unbound) (unbound)
Redo the last function executed with execute-named-cmd.

Like execute-named-cmd, this command may not be redefined, but it may be called by
name.

get-line (ESC-G ESC-g) (unbound) (unbound)
Pop the top line off the buffer stack and insert it at the cursor position.

pound-insert (unbound) (#) (unbound)
If there is no # character at the beginning of the buffer, add one to the beginning
of each line. If there is one, remove a # from each line that has one. In either
case, accept the current line. The INTERACTIVE_COMMENTS option must be set for
this to have any usefulness.

vi-pound-insert
If there is no # character at the beginning of the current line, add one. If there
is one, remove it. The INTERACTIVE_COMMENTS option must be set for this to have
any usefulness.

push-input
Push the entire current multiline construct onto the buffer stack and return to the
top-level (PS1) prompt. If the current parser construct is only a single line,
this is exactly like push-line. Next time the editor starts up or is popped with
get-line, the construct will be popped off the top of the buffer stack and loaded
into the editing buffer.

push-line (^Q ESC-Q ESC-q) (unbound) (unbound)
Push the current buffer onto the buffer stack and clear the buffer. Next time the
editor starts up, the buffer will be popped off the top of the buffer stack and
loaded into the editing buffer.

push-line-or-edit
At the top-level (PS1) prompt, equivalent to push-line. At a secondary (PS2)
prompt, move the entire current multiline construct into the editor buffer. The
latter is equivalent to push-input followed by get-line.

read-command
Only useful from a user-defined widget. A keystroke is read just as in normal op-
eration, but instead of the command being executed the name of the command that
would be executed is stored in the shell parameter REPLY. This can be used as the
argument of a future zle command. If the key sequence is not bound, status 1 is
returned; typically, however, REPLY is set to undefined-key to indicate a useless
key sequence.

recursive-edit
Only useful from a user-defined widget. At this point in the function, the editor
regains control until one of the standard widgets which would normally cause zle to
exit (typically an accept-line caused by hitting the return key) is executed. In-
stead, control returns to the user-defined widget. The status returned is non-zero
if the return was caused by an error, but the function still continues executing
and hence may tidy up. This makes it safe for the user-defined widget to alter the
command line or key bindings temporarily.

The following widget, caps-lock, serves as an example.

self-insert-ucase() {
LBUFFER+=${(U)KEYS[-1]}
}

integer stat

zle -N self-insert self-insert-ucase
zle -A caps-lock save-caps-lock
zle -A accept-line caps-lock

zle recursive-edit
stat=$?

zle -A .self-insert self-insert
zle -A save-caps-lock caps-lock
zle -D save-caps-lock

(( stat )) && zle send-break

return $stat

This causes typed letters to be inserted capitalised until either accept-line (i.e.
typically the return key) is typed or the caps-lock widget is invoked again; the
later is handled by saving the old definition of caps-lock as save-caps-lock and
then rebinding it to invoke accept-line. Note that an error from the recursive
edit is detected as a non-zero return status and propagated by using the send-break
widget.

redisplay (unbound) (^R) (^R)
Redisplays the edit buffer.

reset-prompt (unbound) (unbound) (unbound)
Force the prompts on both the left and right of the screen to be re-expanded, then
redisplay the edit buffer. This reflects changes both to the prompt variables
themselves and changes in the expansion of the values (for example, changes in time
or directory, or changes to the value of variables referred to by the prompt).

Otherwise, the prompt is only expanded each time zle starts, and when the display
has been interrupted by output from another part of the shell (such as a job noti-
fication) which causes the command line to be reprinted.

reset-prompt doesn't alter the special parameter LASTWIDGET.

send-break (^G ESC-^G) (unbound) (unbound)
Abort the current editor function, e.g. execute-named-command, or the editor it-
self, e.g. if you are in vared. Otherwise abort the parsing of the current line; in
this case the aborted line is available in the shell variable ZLE_LINE_ABORTED. If
the editor is aborted from within vared, the variable ZLE_VARED_ABORTED is set.

run-help (ESC-H ESC-h) (unbound) (unbound)
Push the buffer onto the buffer stack, and execute the command `run-help cmd',
where cmd is the current command. run-help is normally aliased to man.

vi-set-buffer (unbound) (") (unbound)
Specify a buffer to be used in the following command. There are 37 buffers that
can be specified: the 26 `named' buffers "a to "z, the `yank' buffer "0, the nine
`queued' buffers "1 to "9 and the `black hole' buffer "_. The named buffers can
also be specified as "A to "Z.

When a buffer is specified for a cut, change or yank command, the text concerned
replaces the previous contents of the specified buffer. If a named buffer is speci-
fied using a capital, the newly cut text is appended to the buffer instead of over-
writing it. When using the "_ buffer, nothing happens. This can be useful for
deleting text without affecting any buffers.

If no buffer is specified for a cut or change command, "1 is used, and the contents
of "1 to "8 are each shifted along one buffer; the contents of "9 is lost. If no
buffer is specified for a yank command, "0 is used. Finally, a paste command with-
out a specified buffer will paste the text from the most recent command regardless
of any buffer that might have been used with that command.

When called from a widget function by the zle command, the buffer can optionally be
specified with an argument. For example,

zle vi-set-buffer A

vi-set-mark (unbound) (m) (unbound)
Set the specified mark at the cursor position.

set-mark-command (^@) (unbound) (unbound)
Set the mark at the cursor position. If called with a negative numeric argument,
do not set the mark but deactivate the region so that it is no longer highlighted
(it is still usable for other purposes). Otherwise the region is marked as active.

spell-word (ESC-$ ESC-S ESC-s) (unbound) (unbound)
Attempt spelling correction on the current word.

split-undo
Breaks the undo sequence at the current change. This is useful in vi mode as
changes made in insert mode are coalesced on entering command mode. Similarly,
undo will normally revert as one all the changes made by a user-defined widget.

undefined-key
This command is executed when a key sequence that is not bound to any command is
typed. By default it beeps.

undo (^_ ^Xu ^X^U) (u) (unbound)
Incrementally undo the last text modification. When called from a user-defined
widget, takes an optional argument indicating a previous state of the undo history
as returned by the UNDO_CHANGE_NO variable; modifications are undone until that
state is reached, subject to any limit imposed by the UNDO_LIMIT_NO variable.

Note that when invoked from vi command mode, the full prior change made in insert
mode is reverted, the changes having been merged when command mode was selected.

redo (unbound) (^R) (unbound)
Incrementally redo undone text modifications.

vi-undo-change (unbound) (unbound) (unbound)
Undo the last text modification. If repeated, redo the modification.

visual-mode (unbound) (v) (unbound)
Toggle vim-style visual selection mode. If line-wise visual mode is currently en-
abled then it is changed to being character-wise. If used following an operator, it
forces the subsequent movement command to be treated as a character-wise movement.

visual-line-mode (unbound) (V) (unbound)
Toggle vim-style line-wise visual selection mode. If character-wise visual mode is
currently enabled then it is changed to being line-wise. If used following an oper-
ator, it forces the subsequent movement command to be treated as a line-wise move-
ment.

what-cursor-position (^X=) (ga) (unbound)
Print the character under the cursor, its code as an octal, decimal and hexadecimal
number, the current cursor position within the buffer and the column of the cursor
in the current line.

where-is
Read the name of an editor command and print the listing of key sequences that in-
voke the specified command. A restricted set of editing functions is available in
the mini-buffer. Keys are looked up in the special command keymap, and if not
found there in the main keymap.

which-command (ESC-?) (unbound) (unbound)
Push the buffer onto the buffer stack, and execute the command `which-command cmd'.
where cmd is the current command. which-command is normally aliased to whence.

vi-digit-or-beginning-of-line (unbound) (0) (unbound)
If the last command executed was a digit as part of an argument, continue the argu-
ment. Otherwise, execute vi-beginning-of-line.

Text Objects
Text objects are commands that can be used to select a block of text according to some
criteria. They are a feature of the vim text editor and so are primarily intended for use
with vi operators or from visual selection mode. However, they can also be used from
vi-insert or emacs mode. Key bindings listed below apply to the viopp and visual keymaps.

select-a-blank-word (aW)
Select a word including adjacent blanks, where a word is defined as a series of
non-blank characters. With a numeric argument, multiple words will be selected.

select-a-shell-word (aa)
Select the current command argument applying the normal rules for quoting.

select-a-word (aw)
Select a word including adjacent blanks, using the normal vi-style word definition.
With a numeric argument, multiple words will be selected.

select-in-blank-word (iW)
Select a word, where a word is defined as a series of non-blank characters. With a
numeric argument, multiple words will be selected.

select-in-shell-word (ia)
Select the current command argument applying the normal rules for quoting. If the
argument begins and ends with matching quote characters, these are not included in
the selection.

select-in-word (iw)
Select a word, using the normal vi-style word definition. With a numeric argument,
multiple words will be selected.

CHARACTER HIGHLIGHTING
The line editor has the ability to highlight characters or regions of the line that have a
particular significance. This is controlled by the array parameter zle_highlight, if it
has been set by the user.

If the parameter contains the single entry none all highlighting is turned off. Note the
parameter is still expected to be an array.

Otherwise each entry of the array should consist of a word indicating a context for high-
lighting, then a colon, then a comma-separated list of the types of highlighting to apply
in that context.

The contexts available for highlighting are the following:

default
Any text within the command line not affected by any other highlighting. Text out-
side the editable area of the command line is not affected.

isearch
When one of the incremental history search widgets is active, the area of the com-
mand line matched by the search string or pattern.

region The currently selected text. In emacs terminology, this is referred to as the re-
gion and is bounded by the cursor (point) and the mark. The region is only high-
lighted if it is active, which is the case after the mark is modified with
set-mark-command or exchange-point-and-mark. Note that whether or not the region
is active has no effect on its use within emacs style widgets, it simply determines
whether it is highlighted. In vi mode, the region corresponds to selected text in
visual mode.

special
Individual characters that have no direct printable representation but are shown in
a special manner by the line editor. These characters are described below.

suffix This context is used in completion for characters that are marked as suffixes that
will be removed if the completion ends at that point, the most obvious example be-
ing a slash (/) after a directory name. Note that suffix removal is configurable;
the circumstances under which the suffix will be removed may differ for different
completions.

paste Following a command to paste text, the characters that were inserted.

When region_highlight is set, the contexts that describe a region -- isearch, region, suf-
fix, and paste -- are applied first, then region_highlight is applied, then the remaining
zle_highlight contexts are applied. If a particular character is affected by multiple
specifications, the last specification wins.

zle_highlight may contain additional fields for controlling how terminal sequences to
change colours are output. Each of the following is followed by a colon and a string in
the same form as for key bindings. This will not be necessary for the vast majority of
terminals as the defaults shown in parentheses are widely used.

fg_start_code (\e[3)
The start of the escape sequence for the foreground colour. This is followed by
one to three ASCII digits representing the colour. Only used for palette colors,
i.e. not 24-bit colors specified via a color triplet.

fg_default_code (9)
The number to use instead of the colour to reset the default foreground colour.

fg_end_code (m)
The end of the escape sequence for the foreground colour.

bg_start_code (\e[4)
The start of the escape sequence for the background colour. See fg_start_code
above.

bg_default_code (9)
The number to use instead of the colour to reset the default background colour.

bg_end_code (m)
The end of the escape sequence for the background colour.

The available types of highlighting are the following. Note that not all types of high-
lighting are available on all terminals:

none No highlighting is applied to the given context. It is not useful for this to ap-
pear with other types of highlighting; it is used to override a default.

fg=colour
The foreground colour should be set to colour, a decimal integer, the name of one
of the eight most widely-supported colours or as a `#' followed by an RGB triplet
in hexadecimal format.

Not all terminals support this and, of those that do, not all provide facilities to
test the support, hence the user should decide based on the terminal type. Most
terminals support the colours black, red, green, yellow, blue, magenta, cyan and
white, which can be set by name. In addition. default may be used to set the ter-
minal's default foreground colour. Abbreviations are allowed; b or bl selects
black. Some terminals may generate additional colours if the bold attribute is
also present.

On recent terminals and on systems with an up-to-date terminal database the number
of colours supported may be tested by the command `echotc Co'; if this succeeds, it
indicates a limit on the number of colours which will be enforced by the line edi-
tor. The number of colours is in any case limited to 256 (i.e. the range 0 to
255).

Some modern terminal emulators have support for 24-bit true colour (16 million
colours). In this case, the hex triplet format can be used. This consists of a `#'
followed by either a three or six digit hexadecimal number describing the red,
green and blue components of the colour. Hex triplets can also be used with 88 and
256 colour terminals via the zsh/nearcolor module (see zshmodules(1)).

Colour is also known as color.

bg=colour
The background colour should be set to colour. This works similarly to the fore-
ground colour, except the background is not usually affected by the bold attribute.

bold The characters in the given context are shown in a bold font. Not all terminals
distinguish bold fonts.

standout
The characters in the given context are shown in the terminal's standout mode. The
actual effect is specific to the terminal; on many terminals it is inverse video.
On some such terminals, where the cursor does not blink it appears with standout
mode negated, making it less than clear where the cursor actually is. On such ter-
minals one of the other effects may be preferable for highlighting the region and
matched search string.

underline
The characters in the given context are shown underlined. Some terminals show the
foreground in a different colour instead; in this case whitespace will not be high-
lighted.

The characters described above as `special' are as follows. The formatting described here
is used irrespective of whether the characters are highlighted:

ASCII control characters
Control characters in the ASCII range are shown as `^' followed by the base charac-
ter.

Unprintable multibyte characters
This item applies to control characters not in the ASCII range, plus other charac-
ters as follows. If the MULTIBYTE option is in effect, multibyte characters not in
the ASCII character set that are reported as having zero width are treated as com-
bining characters when the option COMBINING_CHARS is on. If the option is off, or
if a character appears where a combining character is not valid, the character is
treated as unprintable.

Unprintable multibyte characters are shown as a hexadecimal number between angle
brackets. The number is the code point of the character in the wide character set;
this may or may not be Unicode, depending on the operating system.

Invalid multibyte characters
If the MULTIBYTE option is in effect, any sequence of one or more bytes that does
not form a valid character in the current character set is treated as a series of
bytes each shown as a special character. This case can be distinguished from other
unprintable characters as the bytes are represented as two hexadecimal digits be-
tween angle brackets, as distinct from the four or eight digits that are used for
unprintable characters that are nonetheless valid in the current character set.

Not all systems support this: for it to work, the system's representation of wide
characters must be code values from the Universal Character Set, as defined by IS0
10646 (also known as Unicode).

Wrapped double-width characters
When a double-width character appears in the final column of a line, it is instead
shown on the next line. The empty space left in the original position is high-
lighted as a special character.

If zle_highlight is not set or no value applies to a particular context, the defaults ap-
plied are equivalent to

zle_highlight=(region:standout special:standout
suffix:bold isearch:underline paste:standout)

i.e. both the region and special characters are shown in standout mode.

Within widgets, arbitrary regions may be highlighted by setting the special array parame-
ter region_highlight; see above.

ZSHCOMPWID(1) General Commands Manual ZSHCOMPWID(1)

NAME
zshcompwid - zsh completion widgets

DESCRIPTION
The shell's programmable completion mechanism can be manipulated in two ways; here the
low-level features supporting the newer, function-based mechanism are defined. A complete
set of shell functions based on these features is described in zshcompsys(1), and users
with no interest in adding to that system (or, potentially, writing their own -- see dic-
tionary entry for `hubris') should skip the current section. The older system based on
the compctl builtin command is described in zshcompctl(1).

Completion widgets are defined by the -C option to the zle builtin command provided by the
zsh/zle module (see zshzle(1)). For example,

zle -C complete expand-or-complete completer

defines a widget named `complete'. The second argument is the name of any of the builtin
widgets that handle completions: complete-word, expand-or-complete, expand-or-com-
plete-prefix, menu-complete, menu-expand-or-complete, reverse-menu-complete, list-choices,
or delete-char-or-list. Note that this will still work even if the widget in question has
been re-bound.

When this newly defined widget is bound to a key using the bindkey builtin command defined
in the zsh/zle module (see zshzle(1)), typing that key will call the shell function `com-
pleter'. This function is responsible for generating the possible matches using the
builtins described below. As with other ZLE widgets, the function is called with its
standard input closed.

Once the function returns, the completion code takes over control again and treats the
matches in the same manner as the specified builtin widget, in this case expand-or-com-
plete.

COMPLETION SPECIAL PARAMETERS
The parameters ZLE_REMOVE_SUFFIX_CHARS and ZLE_SPACE_SUFFIX_CHARS are used by the comple-
tion mechanism, but are not special. See Parameters Used By The Shell in zshparam(1).

Inside completion widgets, and any functions called from them, some parameters have spe-
cial meaning; outside these functions they are not special to the shell in any way. These
parameters are used to pass information between the completion code and the completion
widget. Some of the builtin commands and the condition codes use or change the current
values of these parameters. Any existing values will be hidden during execution of com-
pletion widgets; except for compstate, the parameters are reset on each function exit (in-
cluding nested function calls from within the completion widget) to the values they had
when the function was entered.

CURRENT
This is the number of the current word, i.e. the word the cursor is currently on in
the words array. Note that this value is only correct if the ksharrays option is
not set.

IPREFIX
Initially this will be set to the empty string. This parameter functions like PRE-
FIX; it contains a string which precedes the one in PREFIX and is not considered
part of the list of matches. Typically, a string is transferred from the beginning
of PREFIX to the end of IPREFIX, for example:

IPREFIX=${PREFIX%%\=*}=
PREFIX=${PREFIX#*=}

causes the part of the prefix up to and including the first equal sign not to be
treated as part of a matched string. This can be done automatically by the compset
builtin, see below.

ISUFFIX
As IPREFIX, but for a suffix that should not be considered part of the matches;
note that the ISUFFIX string follows the SUFFIX string.

PREFIX Initially this will be set to the part of the current word from the beginning of
the word up to the position of the cursor; it may be altered to give a common pre-
fix for all matches.

QIPREFIX
This parameter is read-only and contains the quoted string up to the word being
completed. E.g. when completing `"foo', this parameter contains the double quote.
If the -q option of compset is used (see below), and the original string was `"foo
bar' with the cursor on the `bar', this parameter contains `"foo '.

QISUFFIX
Like QIPREFIX, but containing the suffix.

SUFFIX Initially this will be set to the part of the current word from the cursor position
to the end; it may be altered to give a common suffix for all matches. It is most
useful when the option COMPLETE_IN_WORD is set, as otherwise the whole word on the
command line is treated as a prefix.

compstate
This is an associative array with various keys and values that the completion code
uses to exchange information with the completion widget. The keys are:

all_quotes
The -q option of the compset builtin command (see below) allows a quoted
string to be broken into separate words; if the cursor is on one of those
words, that word will be completed, possibly invoking `compset -q' recur-
sively. With this key it is possible to test the types of quoted strings
which are currently broken into parts in this fashion. Its value contains
one character for each quoting level. The characters are a single quote or
a double quote for strings quoted with these characters, a dollars sign for
strings quoted with $'...' and a backslash for strings not starting with a
quote character. The first character in the value always corresponds to the
innermost quoting level.

context
This will be set by the completion code to the overall context in which com-
pletion is attempted. Possible values are:

array_value
when completing inside the value of an array parameter assignment; in
this case the words array contains the words inside the parentheses.

brace_parameter
when completing the name of a parameter in a parameter expansion be-
ginning with ${. This context will also be set when completing pa-
rameter flags following ${(; the full command line argument is pre-
sented and the handler must test the value to be completed to ascer-
tain that this is the case.

assign_parameter
when completing the name of a parameter in a parameter assignment.

command
when completing for a normal command (either in command position or
for an argument of the command).

condition
when completing inside a `[[...]]' conditional expression; in this
case the words array contains only the words inside the conditional
expression.

math when completing in a mathematical environment such as a `((...))'
construct.

parameter
when completing the name of a parameter in a parameter expansion be-
ginning with $ but not ${.

redirect
when completing after a redirection operator.

subscript
when completing inside a parameter subscript.

value when completing the value of a parameter assignment.

exact Controls the behaviour when the REC_EXACT option is set. It will be set to
accept if an exact match would be accepted, and will be unset otherwise.

If it was set when at least one match equal to the string on the line was
generated, the match is accepted.

exact_string
The string of an exact match if one was found, otherwise unset.

ignored
The number of words that were ignored because they matched one of the pat-
terns given with the -F option to the compadd builtin command.

insert This controls the manner in which a match is inserted into the command line.
On entry to the widget function, if it is unset the command line is not to
be changed; if set to unambiguous, any prefix common to all matches is to be
inserted; if set to automenu-unambiguous, the common prefix is to be in-
serted and the next invocation of the completion code may start menu comple-
tion (due to the AUTO_MENU option being set); if set to menu or automenu
menu completion will be started for the matches currently generated (in the
latter case this will happen because the AUTO_MENU is set). The value may
also contain the string `tab' when the completion code would normally not
really do completion, but only insert the TAB character.

On exit it may be set to any of the values above (where setting it to the
empty string is the same as unsetting it), or to a number, in which case the
match whose number is given will be inserted into the command line. Nega-
tive numbers count backward from the last match (with `-1' selecting the
last match) and out-of-range values are wrapped around, so that a value of
zero selects the last match and a value one more than the maximum selects
the first. Unless the value of this key ends in a space, the match is in-
serted as in a menu completion, i.e. without automatically appending a
space.

Both menu and automenu may also specify the number of the match to insert,
given after a colon. For example, `menu:2' says to start menu completion,
beginning with the second match.

Note that a value containing the substring `tab' makes the matches generated
be ignored and only the TAB be inserted.

Finally, it may also be set to all, which makes all matches generated be in-
serted into the line.

insert_positions
When the completion system inserts an unambiguous string into the line,
there may be multiple places where characters are missing or where the char-
acter inserted differs from at least one match. The value of this key con-
tains a colon separated list of all these positions, as indexes into the
command line.

last_prompt
If this is set to a non-empty string for every match added, the completion
code will move the cursor back to the previous prompt after the list of com-
pletions has been displayed. Initially this is set or unset according to
the ALWAYS_LAST_PROMPT option.

list This controls whether or how the list of matches will be displayed. If it
is unset or empty they will never be listed; if its value begins with list,
they will always be listed; if it begins with autolist or ambiguous, they
will be listed when the AUTO_LIST or LIST_AMBIGUOUS options respectively
would normally cause them to be.

If the substring force appears in the value, this makes the list be shown
even if there is only one match. Normally, the list would be shown only if
there are at least two matches.

The value contains the substring packed if the LIST_PACKED option is set. If
this substring is given for all matches added to a group, this group will
show the LIST_PACKED behavior. The same is done for the LIST_ROWS_FIRST op-
tion with the substring rows.

Finally, if the value contains the string explanations, only the explanation
strings, if any, will be listed and if it contains messages, only the mes-
sages (added with the -x option of compadd) will be listed. If it contains
both explanations and messages both kinds of explanation strings will be
listed. It will be set appropriately on entry to a completion widget and
may be changed there.

list_lines
This gives the number of lines that are needed to display the full list of
completions. Note that to calculate the total number of lines to display
you need to add the number of lines needed for the command line to this
value, this is available as the value of the BUFFERLINES special parameter.

list_max
Initially this is set to the value of the LISTMAX parameter. It may be set
to any other value; when the widget exits this value will be used in the
same way as the value of LISTMAX.

nmatches
The number of matches generated and accepted by the completion code so far.

old_insert
On entry to the widget this will be set to the number of the match of an old
list of completions that is currently inserted into the command line. If no
match has been inserted, this is unset.

As with old_list, the value of this key will only be used if it is the
string keep. If it was set to this value by the widget and there was an old
match inserted into the command line, this match will be kept and if the
value of the insert key specifies that another match should be inserted,
this will be inserted after the old one.

old_list
This is set to yes if there is still a valid list of completions from a pre-
vious completion at the time the widget is invoked. This will usually be
the case if and only if the previous editing operation was a completion wid-
get or one of the builtin completion functions. If there is a valid list
and it is also currently shown on the screen, the value of this key is
shown.

After the widget has exited the value of this key is only used if it was set
to keep. In this case the completion code will continue to use this old
list. If the widget generated new matches, they will not be used.

parameter
The name of the parameter when completing in a subscript or in the value of
a parameter assignment.

pattern_insert
Normally this is set to menu, which specifies that menu completion will be
used whenever a set of matches was generated using pattern matching. If it
is set to any other non-empty string by the user and menu completion is not
selected by other option settings, the code will instead insert any common
prefix for the generated matches as with normal completion.

pattern_match
Locally controls the behaviour given by the GLOB_COMPLETE option. Initially
it is set to `*' if and only if the option is set. The completion widget
may set it to this value, to an empty string (which has the same effect as
unsetting it), or to any other non-empty string. If it is non-empty, un-
quoted metacharacters on the command line will be treated as patterns; if it
is `*', then additionally a wildcard `*' is assumed at the cursor position;
if it is empty or unset, metacharacters will be treated literally.

Note that the matcher specifications given to the compadd builtin command
are not used if this is set to a non-empty string.

quote When completing inside quotes, this contains the quotation character (i.e.
either a single quote, a double quote, or a backtick). Otherwise it is un-
set.

quoting
When completing inside single quotes, this is set to the string single; in-
side double quotes, the string double; inside backticks, the string back-
tick. Otherwise it is unset.

redirect
The redirection operator when completing in a redirection position, i.e. one
of <, >, etc.

restore
This is set to auto before a function is entered, which forces the special
parameters mentioned above (words, CURRENT, PREFIX, IPREFIX, SUFFIX, and
ISUFFIX) to be restored to their previous values when the function exits.
If a function unsets it or sets it to any other string, they will not be re-
stored.

to_end Specifies the occasions on which the cursor is moved to the end of a string
when a match is inserted. On entry to a widget function, it may be single
if this will happen when a single unambiguous match was inserted or match if
it will happen any time a match is inserted (for example, by menu comple-
tion; this is likely to be the effect of the ALWAYS_TO_END option).

On exit, it may be set to single as above. It may also be set to always, or
to the empty string or unset; in those cases the cursor will be moved to the
end of the string always or never respectively. Any other string is treated
as match.

unambiguous
This key is read-only and will always be set to the common (unambiguous)
prefix the completion code has generated for all matches added so far.

unambiguous_cursor
This gives the position the cursor would be placed at if the common prefix
in the unambiguous key were inserted, relative to the value of that key. The
cursor would be placed before the character whose index is given by this
key.

unambiguous_positions
This contains all positions where characters in the unambiguous string are
missing or where the character inserted differs from at least one of the
matches. The positions are given as indexes into the string given by the
value of the unambiguous key.

vared If completion is called while editing a line using the vared builtin, the
value of this key is set to the name of the parameter given as an argument
to vared. This key is only set while a vared command is active.

words This array contains the words present on the command line currently being edited.

COMPLETION BUILTIN COMMANDS
compadd [ -akqQfenUl12C ] [ -F array ]
[-P prefix ] [ -S suffix ]
[-p hidden-prefix ] [ -s hidden-suffix ]
[-i ignored-prefix ] [ -I ignored-suffix ]
[-W file-prefix ] [ -d array ]
[-J group-name ] [ -X explanation ] [ -x message ]
[-V group-name ] [ -o [ order ] ]
[-r remove-chars ] [ -R remove-func ]
[-D array ] [ -O array ] [ -A array ]
[-E number ]
[-M match-spec ] [ -- ] [ words ... ]

This builtin command can be used to add matches directly and control all the infor-
mation the completion code stores with each possible match. The return status is
zero if at least one match was added and non-zero if no matches were added.

The completion code breaks the string to complete into seven fields in the order:

The first field is an ignored prefix taken from the command line, the contents of
the IPREFIX parameter plus the string given with the -i option. With the -U option,
only the string from the -i option is used. The field <apre> is an optional prefix
string given with the -P option. The <hpre> field is a string that is considered
part of the match but that should not be shown when listing completions, given with
the -p option; for example, functions that do filename generation might specify a
common path prefix this way. <word> is the part of the match that should appear in
the list of completions, i.e. one of the words given at the end of the compadd com-
mand line. The suffixes <hsuf>, <asuf> and <isuf> correspond to the prefixes
<hpre>, <apre> and <ipre> and are given by the options -s, -S and -I, respectively.

The supported flags are:

-P prefix
This gives a string to be inserted before the given words. The string given
is not considered as part of the match and any shell metacharacters in it
will not be quoted when the string is inserted.

-S suffix
Like -P, but gives a string to be inserted after the match.

-p hidden-prefix
This gives a string that should be inserted into the command line before the
match but that should not appear in the list of matches. Unless the -U op-
tion is given, this string must be matched as part of the string on the com-
mand line.

-s hidden-suffix
Like `-p', but gives a string to insert after the match.

-i ignored-prefix
This gives a string to insert into the command line just before any string
given with the `-P' option. Without `-P' the string is inserted before the
string given with `-p' or directly before the match.

-I ignored-suffix
Like -i, but gives an ignored suffix.

-a With this flag the words are taken as names of arrays and the possible
matches are their values. If only some elements of the arrays are needed,
the words may also contain subscripts, as in `foo[2,-1]'.

-k With this flag the words are taken as names of associative arrays and the
possible matches are their keys. As for -a, the words may also contain sub-
scripts, as in `foo[(R)*bar*]'.

-d array
This adds per-match display strings. The array should contain one element
per word given. The completion code will then display the first element in-
stead of the first word, and so on. The array may be given as the name of an
array parameter or directly as a space-separated list of words in parenthe-
ses.

If there are fewer display strings than words, the leftover words will be
displayed unchanged and if there are more display strings than words, the
leftover display strings will be silently ignored.

-l This option only has an effect if used together with the -d option. If it is
given, the display strings are listed one per line, not arrayed in columns.

-o [ order ]
This controls the order in which matches are sorted. order is a comma-sepa-
rated list comprising the following possible values. These values can be
abbreviated to their initial two or three characters. Note that the order
forms part of the group name space so matches with different orderings will
not be in the same group.

match If given, the order of the output is determined by the match strings;
otherwise it is determined by the display strings (i.e. the strings
given by the -d option). This is the default if `-o' is specified but
the order argument is omitted.

nosort This specifies that the matches are pre-sorted and their order should
be preserved. This value only makes sense alone and cannot be com-
bined with any others.

numeric
If the matches include numbers, sort them numerically rather than
lexicographically.

reverse
Arrange the matches backwards by reversing the sort ordering.

-J group-name
Gives the name of the group of matches the words should be stored in.

-V group-name
Like -J but naming an unsorted group. This option is identical to the combi-
nation of -J and -o nosort.

-1 If given together with the -V option, makes only consecutive duplicates in
the group be removed. If combined with the -J option, this has no visible
effect. Note that groups with and without this flag are in different name
spaces.

-2 If given together with the -J or -V option, makes all duplicates be kept.
Again, groups with and without this flag are in different name spaces.

-X explanation
The explanation string will be printed with the list of matches, above the
group currently selected.

Within the explanation, the following sequences may be used to specify out-
put attributes as described in the section EXPANSION OF PROMPT SEQUENCES in
zshmisc(1): `%B', `%S', `%U', `%F', `%K' and their lower case counterparts,
as well as `%{...%}'. `%F', `%K' and `%{...%}' take arguments in the same
form as prompt expansion. (Note that the sequence `%G' is not available; an
argument to `%{' should be used instead.) The sequence `%%' produces a lit-
eral `%'.

These sequences are most often employed by users when customising the format
style (see zshcompsys(1)), but they must also be taken into account when
writing completion functions, as passing descriptions with unescaped `%'
characters to utility functions such as _arguments and _message may produce
unexpected results. If arbitrary text is to be passed in a description, it
can be escaped using e.g. ${my_str//\%/%%}.

-x message
Like -X, but the message will be printed even if there are no matches in the
group.

-q The suffix given with -S will be automatically removed if the next character
typed is a blank or does not insert anything, or if the suffix consists of
only one character and the next character typed is the same character.

-r remove-chars
This is a more versatile form of the -q option. The suffix given with -S or
the slash automatically added after completing directories will be automati-
cally removed if the next character typed inserts one of the characters
given in the remove-chars. This string is parsed as a characters class and
understands the backslash sequences used by the print command. For example,
`-r "a-z\t"' removes the suffix if the next character typed inserts a lower
case character or a TAB, and `-r "^0-9"' removes the suffix if the next
character typed inserts anything but a digit. One extra backslash sequence
is understood in this string: `\-' stands for all characters that insert
nothing. Thus `-S "=" -q' is the same as `-S "=" -r "= \t\n\-"'.

This option may also be used without the -S option; then any automatically
added space will be removed when one of the characters in the list is typed.

-R remove-func
This is another form of the -r option. When a suffix has been inserted and
the completion accepted, the function remove-func will be called after the
next character typed. It is passed the length of the suffix as an argument
and can use the special parameters available in ordinary (non-completion)
zle widgets (see zshzle(1)) to analyse and modify the command line.

-f If this flag is given, all of the matches built from words are marked as be-
ing the names of files. They are not required to be actual filenames, but
if they are, and the option LIST_TYPES is set, the characters describing the
types of the files in the completion lists will be shown. This also forces a
slash to be added when the name of a directory is completed.

-e This flag can be used to tell the completion code that the matches added are
parameter names for a parameter expansion. This will make the
AUTO_PARAM_SLASH and AUTO_PARAM_KEYS options be used for the matches.

-W file-prefix
This string is a pathname that will be prepended to each of the matches
formed by the given words together with any prefix specified by the -p op-
tion to form a complete filename for testing. Hence it is only useful if
combined with the -f flag, as the tests will not otherwise be performed.

-F array
Specifies an array containing patterns. Words matching one of these patterns
are ignored, i.e. not considered to be possible matches.

The array may be the name of an array parameter or a list of literal pat-
terns enclosed in parentheses and quoted, as in `-F "(*?.o *?.h)"'. If the
name of an array is given, the elements of the array are taken as the pat-
terns.

-Q This flag instructs the completion code not to quote any metacharacters in
the words when inserting them into the command line.

-M match-spec
This gives local match specifications as described below in the section
`Completion Matching Control'. This option may be given more than once. In
this case all match-specs given are concatenated with spaces between them to
form the specification string to use. Note that they will only be used if
the -U option is not given.

-n Specifies that the words added are to be used as possible matches, but are
not to appear in the completion listing.

-U If this flag is given, all words given will be accepted and no matching will
be done by the completion code. Normally this is used in functions that do
the matching themselves.

-O array
If this option is given, the words are not added to the set of possible com-
pletions. Instead, matching is done as usual and all of the words given as
arguments that match the string on the command line will be stored in the
array parameter whose name is given as array.

-A array
As the -O option, except that instead of those of the words which match be-
ing stored in array, the strings generated internally by the completion code
are stored. For example, with a matching specification of `-M "L:|no="', the
string `nof' on the command line and the string `foo' as one of the words,
this option stores the string `nofoo' in the array, whereas the -O option
stores the `foo' originally given.

-D array
As with -O, the words are not added to the set of possible completions. In-
stead, the completion code tests whether each word in turn matches what is
on the line. If the nth word does not match, the nth element of the array
is removed. Elements for which the corresponding word is matched are re-
tained.

-C This option adds a special match which expands to all other matches when in-
serted into the line, even those that are added after this option is used.
Together with the -d option it is possible to specify a string that should
be displayed in the list for this special match. If no string is given, it
will be shown as a string containing the strings that would be inserted for
the other matches, truncated to the width of the screen.

-E number
This option adds number empty matches after the words have been added. An
empty match takes up space in completion listings but will never be inserted
in the line and can't be selected with menu completion or menu selection.
This makes empty matches only useful to format completion lists and to make
explanatory string be shown in completion lists (since empty matches can be
given display strings with the -d option). And because all but one empty
string would otherwise be removed, this option implies the -V and -2 options
(even if an explicit -J option is given). This can be important to note as
it affects the name space into which matches are added.

-
-- This flag ends the list of flags and options. All arguments after it will be
taken as the words to use as matches even if they begin with hyphens.

Except for the -M flag, if any of these flags is given more than once, the first
one (and its argument) will be used.

compset -p number
compset -P [ number ] pattern
compset -s number
compset -S [ number ] pattern
compset -n begin [ end ]
compset -N beg-pat [ end-pat ]
compset -q
This command simplifies modification of the special parameters, while its return
status allows tests on them to be carried out.

The options are:

-p number
If the value of the PREFIX parameter is at least number characters long, the
first number characters are removed from it and appended to the contents of
the IPREFIX parameter.

-P [ number ] pattern
If the value of the PREFIX parameter begins with anything that matches the
pattern, the matched portion is removed from PREFIX and appended to IPREFIX.

Without the optional number, the longest match is taken, but if number is
given, anything up to the numberth match is moved. If the number is nega-
tive, the numberth longest match is moved. For example, if PREFIX contains
the string `a=b=c', then compset -P '*\=' will move the string `a=b=' into
the IPREFIX parameter, but compset -P 1 '*\=' will move only the string
`a='.

-s number
As -p, but transfer the last number characters from the value of SUFFIX to
the front of the value of ISUFFIX.

-S [ number ] pattern
As -P, but match the last portion of SUFFIX and transfer the matched portion
to the front of the value of ISUFFIX.

-n begin [ end ]
If the current word position as specified by the parameter CURRENT is
greater than or equal to begin, anything up to the beginth word is removed
from the words array and the value of the parameter CURRENT is decremented
by begin.

If the optional end is given, the modification is done only if the current
word position is also less than or equal to end. In this case, the words
from position end onwards are also removed from the words array.

Both begin and end may be negative to count backwards from the last element
of the words array.

-N beg-pat [ end-pat ]
If one of the elements of the words array before the one at the index given
by the value of the parameter CURRENT matches the pattern beg-pat, all ele-
ments up to and including the matching one are removed from the words array
and the value of CURRENT is changed to point to the same word in the changed
array.

If the optional pattern end-pat is also given, and there is an element in
the words array matching this pattern, the parameters are modified only if
the index of this word is higher than the one given by the CURRENT parameter
(so that the matching word has to be after the cursor). In this case, the
words starting with the one matching end-pat are also removed from the words
array. If words contains no word matching end-pat, the testing and modifica-
tion is performed as if it were not given.

-q The word currently being completed is split on spaces into separate words,
respecting the usual shell quoting conventions. The resulting words are
stored in the words array, and CURRENT, PREFIX, SUFFIX, QIPREFIX, and QISUF-
FIX are modified to reflect the word part that is completed.

In all the above cases the return status is zero if the test succeeded and the pa-
rameters were modified and non-zero otherwise. This allows one to use this builtin
in tests such as:

if compset -P '*\='; then ...

This forces anything up to and including the last equal sign to be ignored by the
completion code.

compcall [ -TD ]
This allows the use of completions defined with the compctl builtin from within
completion widgets. The list of matches will be generated as if one of the
non-widget completion functions (complete-word, etc.) had been called, except that
only compctls given for specific commands are used. To force the code to try com-
pletions defined with the -T option of compctl and/or the default completion
(whether defined by compctl -D or the builtin default) in the appropriate places,
the -T and/or -D flags can be passed to compcall.

The return status can be used to test if a matching compctl definition was found.
It is non-zero if a compctl was found and zero otherwise.

Note that this builtin is defined by the zsh/compctl module.

COMPLETION CONDITION CODES
The following additional condition codes for use within the [[ ... ]] construct are avail-
able in completion widgets. These work on the special parameters. All of these tests can
also be performed by the compset builtin, but in the case of the condition codes the con-
tents of the special parameters are not modified.

-prefix [ number ] pattern
true if the test for the -P option of compset would succeed.

-suffix [ number ] pattern
true if the test for the -S option of compset would succeed.

-after beg-pat
true if the test of the -N option with only the beg-pat given would succeed.

-between beg-pat end-pat
true if the test for the -N option with both patterns would succeed.

COMPLETION MATCHING CONTROL
It is possible by use of the -M option of the compadd builtin command to specify how the
characters in the string to be completed (referred to here as the command line) map onto
the characters in the list of matches produced by the completion code (referred to here as
the trial completions). Note that this is not used if the command line contains a glob
pattern and the GLOB_COMPLETE option is set or the pattern_match of the compstate special
association is set to a non-empty string.

The match-spec given as the argument to the -M option (see `Completion Builtin Commands'
above) consists of one or more matching descriptions separated by whitespace. Each de-
scription consists of a letter followed by a colon and then the patterns describing which
character sequences on the line match which character sequences in the trial completion.
Any sequence of characters not handled in this fashion must match exactly, as usual.

The forms of match-spec understood are as follows. In each case, the form with an upper
case initial character retains the string already typed on the command line as the final
result of completion, while with a lower case initial character the string on the command
line is changed into the corresponding part of the trial completion.

m:lpat=tpat
M:lpat=tpat
Here, lpat is a pattern that matches on the command line, corresponding to tpat
which matches in the trial completion.

l:lanchor|lpat=tpat
L:lanchor|lpat=tpat
l:lanchor||ranchor=tpat
L:lanchor||ranchor=tpat
b:lpat=tpat
B:lpat=tpat
These letters are for patterns that are anchored by another pattern on the left
side. Matching for lpat and tpat is as for m and M, but the pattern lpat matched on
the command line must be preceded by the pattern lanchor. The lanchor can be blank
to anchor the match to the start of the command line string; otherwise the anchor
can occur anywhere, but must match in both the command line and trial completion
strings.

If no lpat is given but a ranchor is, this matches the gap between substrings
matched by lanchor and ranchor. Unlike lanchor, the ranchor only needs to match the
trial completion string.

The b and B forms are similar to l and L with an empty anchor, but need to match
only the beginning of the word on the command line or trial completion, respec-
tively.

r:lpat|ranchor=tpat
R:lpat|ranchor=tpat
r:lanchor||ranchor=tpat
R:lanchor||ranchor=tpat
e:lpat=tpat
E:lpat=tpat
As l, L, b and B, with the difference that the command line and trial completion
patterns are anchored on the right side. Here an empty ranchor and the e and E
forms force the match to the end of the command line or trial completion string.

x: This form is used to mark the end of matching specifications: subsequent specifica-
tions are ignored. In a single standalone list of specifications this has no use
but where matching specifications are accumulated, such as from nested function
calls, it can allow one function to override another.

Each lpat, tpat or anchor is either an empty string or consists of a sequence of literal
characters (which may be quoted with a backslash), question marks, character classes, and
correspondence classes; ordinary shell patterns are not used. Literal characters match
only themselves, question marks match any character, and character classes are formed as
for globbing and match any character in the given set.

Correspondence classes are defined like character classes, but with two differences: they
are delimited by a pair of braces, and negated classes are not allowed, so the characters
! and ^ have no special meaning directly after the opening brace. They indicate that a
range of characters on the line match a range of characters in the trial completion, but
(unlike ordinary character classes) paired according to the corresponding position in the
sequence. For example, to make any ASCII lower case letter on the line match the corre-
sponding upper case letter in the trial completion, you can use `m:{a-z}={A-Z}' (however,
see below for the recommended form for this). More than one pair of classes can occur, in
which case the first class before the = corresponds to the first after it, and so on. If
one side has more such classes than the other side, the superfluous classes behave like
normal character classes. In anchor patterns correspondence classes also behave like nor-
mal character classes.

The standard `[:name:]' forms described for standard shell patterns (see the section FILE-
NAME GENERATION in zshexpn(1)) may appear in correspondence classes as well as normal
character classes. The only special behaviour in correspondence classes is if the form on
the left and the form on the right are each one of [:upper:], [:lower:]. In these cases
the character in the word and the character on the line must be the same up to a differ-
ence in case. Hence to make any lower case character on the line match the corresponding
upper case character in the trial completion you can use `m:{[:lower:]}={[:upper:]}'. Al-
though the matching system does not yet handle multibyte characters, this is likely to be
a future extension, at which point this syntax will handle arbitrary alphabets; hence this
form, rather than the use of explicit ranges, is the recommended form. In other cases
`[:name:]' forms are allowed. If the two forms on the left and right are the same, the
characters must match exactly. In remaining cases, the corresponding tests are applied to
both characters, but they are not otherwise constrained; any matching character in one set
goes with any matching character in the other set: this is equivalent to the behaviour of
ordinary character classes.

The pattern tpat may also be one or two stars, `*' or `**'. This means that the pattern on
the command line can match any number of characters in the trial completion. In this case
the pattern must be anchored (on either side); in the case of a single star, the anchor
then determines how much of the trial completion is to be included -- only the characters
up to the next appearance of the anchor will be matched. With two stars, substrings
matched by the anchor can be matched, too.

Examples:

The keys of the options association defined by the parameter module are the option names
in all-lower-case form, without underscores, and without the optional no at the beginning
even though the builtins setopt and unsetopt understand option names with upper case let-
ters, underscores, and the optional no. The following alters the matching rules so that
the prefix no and any underscore are ignored when trying to match the trial completions
generated and upper case letters on the line match the corresponding lower case letters in
the words:

compadd -M 'L:|[nN][oO]= M:_= M:{[:upper:]}={[:lower:]}' - \
${(k)options}

The first part says that the pattern `[nN][oO]' at the beginning (the empty anchor before
the pipe symbol) of the string on the line matches the empty string in the list of words
generated by completion, so it will be ignored if present. The second part does the same
for an underscore anywhere in the command line string, and the third part uses correspon-
dence classes so that any upper case letter on the line matches the corresponding lower
case letter in the word. The use of the upper case forms of the specification characters
(L and M) guarantees that what has already been typed on the command line (in particular
the prefix no) will not be deleted.

Note that the use of L in the first part means that it matches only when at the beginning
of both the command line string and the trial completion. I.e., the string `_NO_f' would
not be completed to `_NO_foo', nor would `NONO_f' be completed to `NONO_foo' because of
the leading underscore or the second `NO' on the line which makes the pattern fail even
though they are otherwise ignored. To fix this, one would use `B:[nN][oO]=' instead of the
first part. As described above, this matches at the beginning of the trial completion, in-
dependent of other characters or substrings at the beginning of the command line word
which are ignored by the same or other match-specs.

The second example makes completion case insensitive. This is just the same as in the op-
tion example, except here we wish to retain the characters in the list of completions:

compadd -M 'm:{[:lower:]}={[:upper:]}' ...

This makes lower case letters match their upper case counterparts. To make upper case
letters match the lower case forms as well:

compadd -M 'm:{[:lower:][:upper:]}={[:upper:][:lower:]}' ...

A nice example for the use of * patterns is partial word completion. Sometimes you would
like to make strings like `c.s.u' complete to strings like `comp.source.unix', i.e. the
word on the command line consists of multiple parts, separated by a dot in this example,
where each part should be completed separately -- note, however, that the case where each
part of the word, i.e. `comp', `source' and `unix' in this example, is to be completed
from separate sets of matches is a different problem to be solved by the implementation of
the completion widget. The example can be handled by:

compadd -M 'r:|.=* r:|=*' \
- comp.sources.unix comp.sources.misc ...

The first specification says that lpat is the empty string, while anchor is a dot; tpat is
*, so this can match anything except for the `.' from the anchor in the trial completion
word. So in `c.s.u', the matcher sees `c', followed by the empty string, followed by the
anchor `.', and likewise for the second dot, and replaces the empty strings before the an-
chors, giving `c[omp].s[ources].u[nix]', where the last part of the completion is just as
normal.

With the pattern shown above, the string `c.u' could not be completed to
`comp.sources.unix' because the single star means that no dot (matched by the anchor) can
be skipped. By using two stars as in `r:|.=**', however, `c.u' could be completed to
`comp.sources.unix'. This also shows that in some cases, especially if the anchor is a
real pattern, like a character class, the form with two stars may result in more matches
than one would like.

The second specification is needed to make this work when the cursor is in the middle of
the string on the command line and the option COMPLETE_IN_WORD is set. In this case the
completion code would normally try to match trial completions that end with the string as
typed so far, i.e. it will only insert new characters at the cursor position rather than
at the end. However in our example we would like the code to recognise matches which con-
tain extra characters after the string on the line (the `nix' in the example). Hence we
say that the empty string at the end of the string on the line matches any characters at
the end of the trial completion.

More generally, the specification

compadd -M 'r:|[.,_-]=* r:|=*' ...

allows one to complete words with abbreviations before any of the characters in the square
brackets. For example, to complete veryverylongfile.c rather than veryverylongheader.h
with the above in effect, you can just type very.c before attempting completion.

The specifications with both a left and a right anchor are useful to complete partial
words whose parts are not separated by some special character. For example, in some places
strings have to be completed that are formed `LikeThis' (i.e. the separate parts are de-
termined by a leading upper case letter) or maybe one has to complete strings with trail-
ing numbers. Here one could use the simple form with only one anchor as in:

compadd -M 'r:|[[:upper:]0-9]=* r:|=*' LikeTHIS FooHoo 5foo123 5bar234

But with this, the string `H' would neither complete to `FooHoo' nor to `LikeTHIS' because
in each case there is an upper case letter before the `H' and that is matched by the an-
chor. Likewise, a `2' would not be completed. In both cases this could be changed by using
`r:|[[:upper:]0-9]=**', but then `H' completes to both `LikeTHIS' and `FooHoo' and a `2'
matches the other strings because characters can be inserted before every upper case let-
ter and digit. To avoid this one would use:

compadd -M 'r:[^[:upper:]0-9]||[[:upper:]0-9]=** r:|=*' \
LikeTHIS FooHoo foo123 bar234

By using these two anchors, a `H' matches only upper case `H's that are immediately pre-
ceded by something matching the left anchor `[^[:upper:]0-9]'. The effect is, of course,
that `H' matches only the string `FooHoo', a `2' matches only `bar234' and so on.

When using the completion system (see zshcompsys(1)), users can define match specifica-
tions that are to be used for specific contexts by using the matcher and matcher-list
styles. The values for the latter will be used everywhere.

COMPLETION WIDGET EXAMPLE
The first step is to define the widget:

zle -C complete complete-word complete-files

Then the widget can be bound to a key using the bindkey builtin command:

bindkey '^X\t' complete

After that the shell function complete-files will be invoked after typing control-X and
TAB. The function should then generate the matches, e.g.:

complete-files () { compadd - * }

This function will complete files in the current directory matching the current word.

ZSHCOMPSYS(1) General Commands Manual ZSHCOMPSYS(1)

NAME
zshcompsys - zsh completion system

DESCRIPTION
This describes the shell code for the `new' completion system, referred to as compsys. It
is written in shell functions based on the features described in zshcompwid(1).

The features are contextual, sensitive to the point at which completion is started. Many
completions are already provided. For this reason, a user can perform a great many tasks
without knowing any details beyond how to initialize the system, which is described below
in INITIALIZATION.

The context that decides what completion is to be performed may be
o an argument or option position: these describe the position on the command line at
which completion is requested. For example `first argument to rmdir, the word be-
ing completed names a directory';

o a special context, denoting an element in the shell's syntax. For example `a word
in command position' or `an array subscript'.

A full context specification contains other elements, as we shall describe.

Besides commands names and contexts, the system employs two more concepts, styles and
tags. These provide ways for the user to configure the system's behaviour.

Tags play a dual role. They serve as a classification system for the matches, typically
indicating a class of object that the user may need to distinguish. For example, when
completing arguments of the ls command the user may prefer to try files before directo-
ries, so both of these are tags. They also appear as the rightmost element in a context
specification.

Styles modify various operations of the completion system, such as output formatting, but
also what kinds of completers are used (and in what order), or which tags are examined.
Styles may accept arguments and are manipulated using the zstyle command described in see
zshmodules(1).

In summary, tags describe what the completion objects are, and style how they are to be
completed. At various points of execution, the completion system checks what styles
and/or tags are defined for the current context, and uses that to modify its behavior.
The full description of context handling, which determines how tags and other elements of
the context influence the behaviour of styles, is described below in COMPLETION SYSTEM
CONFIGURATION.

When a completion is requested, a dispatcher function is called; see the description of
_main_complete in the list of control functions below. This dispatcher decides which func-
tion should be called to produce the completions, and calls it. The result is passed to
one or more completers, functions that implement individual completion strategies: simple
completion, error correction, completion with error correction, menu selection, etc.

More generally, the shell functions contained in the completion system are of two types:
o those beginning `comp' are to be called directly; there are only a few of these;

o those beginning `_' are called by the completion code. The shell functions of this
set, which implement completion behaviour and may be bound to keystrokes, are re-
ferred to as `widgets'. These proliferate as new completions are required.

INITIALIZATION
If the system was installed completely, it should be enough to call the shell function
compinit from your initialization file; see the next section. However, the function
compinstall can be run by a user to configure various aspects of the completion system.

Usually, compinstall will insert code into .zshrc, although if that is not writable it
will save it in another file and tell you that file's location. Note that it is up to you
to make sure that the lines added to .zshrc are actually run; you may, for example, need
to move them to an earlier place in the file if .zshrc usually returns early. So long as
you keep them all together (including the comment lines at the start and finish), you can
rerun compinstall and it will correctly locate and modify these lines. Note, however,
that any code you add to this section by hand is likely to be lost if you rerun compin-
stall, although lines using the command `zstyle' should be gracefully handled.

The new code will take effect next time you start the shell, or run .zshrc by hand; there
is also an option to make them take effect immediately. However, if compinstall has re-
moved definitions, you will need to restart the shell to see the changes.

To run compinstall you will need to make sure it is in a directory mentioned in your fpath
parameter, which should already be the case if zsh was properly configured as long as your
startup files do not remove the appropriate directories from fpath. Then it must be au-
toloaded (`autoload -U compinstall' is recommended). You can abort the installation any
time you are being prompted for information, and your .zshrc will not be altered at all;
changes only take place right at the end, where you are specifically asked for confirma-
tion.

Use of compinit
This section describes the use of compinit to initialize completion for the current ses-
sion when called directly; if you have run compinstall it will be called automatically
from your .zshrc.

To initialize the system, the function compinit should be in a directory mentioned in the
fpath parameter, and should be autoloaded (`autoload -U compinit' is recommended), and
then run simply as `compinit'. This will define a few utility functions, arrange for all
the necessary shell functions to be autoloaded, and will then re-define all widgets that
do completion to use the new system. If you use the menu-select widget, which is part of
the zsh/complist module, you should make sure that that module is loaded before the call
to compinit so that that widget is also re-defined. If completion styles (see below) are
set up to perform expansion as well as completion by default, and the TAB key is bound to
expand-or-complete, compinit will rebind it to complete-word; this is necessary to use the
correct form of expansion.

Should you need to use the original completion commands, you can still bind keys to the
old widgets by putting a `.' in front of the widget name, e.g. `.expand-or-complete'.

To speed up the running of compinit, it can be made to produce a dumped configuration that
will be read in on future invocations; this is the default, but can be turned off by call-
ing compinit with the option -D. The dumped file is .zcompdump in the same directory as
the startup files (i.e. $ZDOTDIR or $HOME); alternatively, an explicit file name can be
given by `compinit -d dumpfile'. The next invocation of compinit will read the dumped
file instead of performing a full initialization.

If the number of completion files changes, compinit will recognise this and produce a new
dump file. However, if the name of a function or the arguments in the first line of a
#compdef function (as described below) change, it is easiest to delete the dump file by
hand so that compinit will re-create it the next time it is run. The check performed to
see if there are new functions can be omitted by giving the option -C. In this case the
dump file will only be created if there isn't one already.

The dumping is actually done by another function, compdump, but you will only need to run
this yourself if you change the configuration (e.g. using compdef) and then want to dump
the new one. The name of the old dumped file will be remembered for this purpose.

If the parameter _compdir is set, compinit uses it as a directory where completion func-
tions can be found; this is only necessary if they are not already in the function search
path.

For security reasons compinit also checks if the completion system would use files not
owned by root or by the current user, or files in directories that are world- or
group-writable or that are not owned by root or by the current user. If such files or di-
rectories are found, compinit will ask if the completion system should really be used. To
avoid these tests and make all files found be used without asking, use the option -u, and
to make compinit silently ignore all insecure files and directories use the option -i.
This security check is skipped entirely when the -C option is given.

The security check can be retried at any time by running the function compaudit. This is
the same check used by compinit, but when it is executed directly any changes to fpath are
made local to the function so they do not persist. The directories to be checked may be
passed as arguments; if none are given, compaudit uses fpath and _compdir to find comple-
tion system directories, adding missing ones to fpath as necessary. To force a check of
exactly the directories currently named in fpath, set _compdir to an empty string before
calling compaudit or compinit.

The function bashcompinit provides compatibility with bash's programmable completion sys-
tem. When run it will define the functions, compgen and complete which correspond to the
bash builtins with the same names. It will then be possible to use completion specifica-
tions and functions written for bash.

Autoloaded files
The convention for autoloaded functions used in completion is that they start with an un-
derscore; as already mentioned, the fpath/FPATH parameter must contain the directory in
which they are stored. If zsh was properly installed on your system, then fpath/FPATH au-
tomatically contains the required directories for the standard functions.

For incomplete installations, if compinit does not find enough files beginning with an un-
derscore (fewer than twenty) in the search path, it will try to find more by adding the
directory _compdir to the search path. If that directory has a subdirectory named Base,
all subdirectories will be added to the path. Furthermore, if the subdirectory Base has a
subdirectory named Core, compinit will add all subdirectories of the subdirectories to the
path: this allows the functions to be in the same format as in the zsh source distribu-
tion.

When compinit is run, it searches all such files accessible via fpath/FPATH and reads the
first line of each of them. This line should contain one of the tags described below.
Files whose first line does not start with one of these tags are not considered to be part
of the completion system and will not be treated specially.

The tags are:

#compdef name ... [ -{p|P} pattern ... [ -N name ... ] ]
The file will be made autoloadable and the function defined in it will be called
when completing names, each of which is either the name of a command whose argu-
ments are to be completed or one of a number of special contexts in the form -con-
text- described below.

Each name may also be of the form `cmd=service'. When completing the command cmd,
the function typically behaves as if the command (or special context) service was
being completed instead. This provides a way of altering the behaviour of func-
tions that can perform many different completions. It is implemented by setting
the parameter $service when calling the function; the function may choose to inter-
pret this how it wishes, and simpler functions will probably ignore it.

If the #compdef line contains one of the options -p or -P, the words following are
taken to be patterns. The function will be called when completion is attempted for
a command or context that matches one of the patterns. The options -p and -P are
used to specify patterns to be tried before or after other completions respec-
tively. Hence -P may be used to specify default actions.

The option -N is used after a list following -p or -P; it specifies that remaining
words no longer define patterns. It is possible to toggle between the three op-
tions as many times as necessary.

#compdef -k style key-sequence ...
This option creates a widget behaving like the builtin widget style and binds it to
the given key-sequences, if any. The style must be one of the builtin widgets that
perform completion, namely complete-word, delete-char-or-list, expand-or-complete,
expand-or-complete-prefix, list-choices, menu-complete, menu-expand-or-complete, or
reverse-menu-complete. If the zsh/complist module is loaded (see zshmodules(1))
the widget menu-select is also available.

When one of the key-sequences is typed, the function in the file will be invoked to
generate the matches. Note that a key will not be re-bound if it already was (that
is, was bound to something other than undefined-key). The widget created has the
same name as the file and can be bound to any other keys using bindkey as usual.

#compdef -K widget-name style key-sequence [ name style seq ... ]
This is similar to -k except that only one key-sequence argument may be given for
each widget-name style pair. However, the entire set of three arguments may be re-
peated with a different set of arguments. Note in particular that the widget-name
must be distinct in each set. If it does not begin with `_' this will be added.
The widget-name should not clash with the name of any existing widget: names based
on the name of the function are most useful. For example,

#compdef -K _foo_complete complete-word "^X^C" \
_foo_list list-choices "^X^D"

(all on one line) defines a widget _foo_complete for completion, bound to `^X^C',
and a widget _foo_list for listing, bound to `^X^D'.

#autoload [ options ]
Functions with the #autoload tag are marked for autoloading but are not otherwise
treated specially. Typically they are to be called from within one of the comple-
tion functions. Any options supplied will be passed to the autoload builtin; a
typical use is +X to force the function to be loaded immediately. Note that the -U
and -z flags are always added implicitly.

The # is part of the tag name and no white space is allowed after it. The #compdef tags
use the compdef function described below; the main difference is that the name of the
function is supplied implicitly.

The special contexts for which completion functions can be defined are:

-array-value-
The right hand side of an array-assignment (`name=(...)')

-brace-parameter-
The name of a parameter expansion within braces (`${...}')

-assign-parameter-
The name of a parameter in an assignment, i.e. on the left hand side of an `='

-command-
A word in command position

-condition-
A word inside a condition (`[[...]]')

-default-
Any word for which no other completion is defined

-equal-
A word beginning with an equals sign

-first-
This is tried before any other completion function. The function called may set
the _compskip parameter to one of various values: all: no further completion is at-
tempted; a string containing the substring patterns: no pattern completion func-
tions will be called; a string containing default: the function for the `-default-'
context will not be called, but functions defined for commands will be.

-math- Inside mathematical contexts, such as `((...))'

-parameter-
The name of a parameter expansion (`$...')

-redirect-
The word after a redirection operator.

-subscript-
The contents of a parameter subscript.

-tilde-
After an initial tilde (`~'), but before the first slash in the word.

-value-
On the right hand side of an assignment.

Default implementations are supplied for each of these contexts. In most cases the con-
text -context- is implemented by a corresponding function _context, for example the con-
text `-tilde-' and the function `_tilde').

The contexts -redirect- and -value- allow extra context-specific information. (Inter-
nally, this is handled by the functions for each context calling the function _dispatch.)
The extra information is added separated by commas.

For the -redirect- context, the extra information is in the form `-redirect-,op,command',
where op is the redirection operator and command is the name of the command on the line.
If there is no command on the line yet, the command field will be empty.

For the -value- context, the form is `-value-,name,command', where name is the name of the
parameter on the left hand side of the assignment. In the case of elements of an associa-
tive array, for example `assoc=(key <TAB>', name is expanded to `name-key'. In certain
special contexts, such as completing after `make CFLAGS=', the command part gives the name
of the command, here make; otherwise it is empty.

It is not necessary to define fully specific completions as the functions provided will
try to generate completions by progressively replacing the elements with `-default-'. For
example, when completing after `foo=<TAB>', _value will try the names `-value-,foo,' (note
the empty command part), `-value-,foo,-default-' and`-value-,-default-,-default-', in that
order, until it finds a function to handle the context.

As an example:

compdef '_files -g "*.log"' '-redirect-,2>,-default-'

completes files matching `*.log' after `2> <TAB>' for any command with no more specific
handler defined.

Also:

compdef _foo -value-,-default-,-default-

specifies that _foo provides completions for the values of parameters for which no special
function has been defined. This is usually handled by the function _value itself.

The same lookup rules are used when looking up styles (as described below); for example

zstyle ':completion:*:*:-redirect-,2>,*:*' file-patterns '*.log'

is another way to make completion after `2> <TAB>' complete files matching `*.log'.

Functions
The following function is defined by compinit and may be called directly.

compdef [ -ane ] function name ... [ -{p|P} pattern ... [ -N name ...]]
compdef -d name ...
compdef -k [ -an ] function style key-sequence [ key-sequence ... ]
compdef -K [ -an ] function name style key-seq [ name style seq ... ]
The first form defines the function to call for completion in the given contexts as
described for the #compdef tag above.

Alternatively, all the arguments may have the form `cmd=service'. Here service
should already have been defined by `cmd1=service' lines in #compdef files, as de-
scribed above. The argument for cmd will be completed in the same way as service.

The function argument may alternatively be a string containing almost any shell
code. If the string contains an equal sign, the above will take precedence. The
option -e may be used to specify the first argument is to be evaluated as shell
code even if it contains an equal sign. The string will be executed using the eval
builtin command to generate completions. This provides a way of avoiding having to
define a new completion function. For example, to complete files ending in `.h' as
arguments to the command foo:

compdef '_files -g "*.h"' foo

The option -n prevents any completions already defined for the command or context
from being overwritten.

The option -d deletes any completion defined for the command or contexts listed.

The names may also contain -p, -P and -N options as described for the #compdef tag.
The effect on the argument list is identical, switching between definitions of pat-
terns tried initially, patterns tried finally, and normal commands and contexts.

The parameter $_compskip may be set by any function defined for a pattern context.
If it is set to a value containing the substring `patterns' none of the pat-
tern-functions will be called; if it is set to a value containing the substring
`all', no other function will be called. Setting $_compskip in this manner is of
particular utility when using the -p option, as otherwise the dispatcher will move
on to additional functions (likely the default one) after calling the pattern-con-
text one, which can mangle the display of completion possibilities if not handled
properly.

The form with -k defines a widget with the same name as the function that will be
called for each of the key-sequences; this is like the #compdef -k tag. The func-
tion should generate the completions needed and will otherwise behave like the
builtin widget whose name is given as the style argument. The widgets usable for
this are: complete-word, delete-char-or-list, expand-or-complete, expand-or-com-
plete-prefix, list-choices, menu-complete, menu-expand-or-complete, and re-
verse-menu-complete, as well as menu-select if the zsh/complist module is loaded.
The option -n prevents the key being bound if it is already to bound to something
other than undefined-key.

The form with -K is similar and defines multiple widgets based on the same func-
tion, each of which requires the set of three arguments name, style and key-se-
quence, where the latter two are as for -k and the first must be a unique widget
name beginning with an underscore.

Wherever applicable, the -a option makes the function autoloadable, equivalent to
autoload -U function.

The function compdef can be used to associate existing completion functions with new com-
mands. For example,

compdef _pids foo

uses the function _pids to complete process IDs for the command foo.

Note also the _gnu_generic function described below, which can be used to complete options
for commands that understand the `--help' option.

COMPLETION SYSTEM CONFIGURATION
This section gives a short overview of how the completion system works, and then more de-
tail on how users can configure how and when matches are generated.

Overview
When completion is attempted somewhere on the command line the completion system begins
building the context. The context represents everything that the shell knows about the
meaning of the command line and the significance of the cursor position. This takes ac-
count of a number of things including the command word (such as `grep' or `zsh') and op-
tions to which the current word may be an argument (such as the `-o' option to zsh which
takes a shell option as an argument).

The context starts out very generic ("we are beginning a completion") and becomes more
specific as more is learned ("the current word is in a position that is usually a command
name" or "the current word might be a variable name" and so on). Therefore the context
will vary during the same call to the completion system.

This context information is condensed into a string consisting of multiple fields sepa-
rated by colons, referred to simply as `the context' in the remainder of the documenta-
tion. Note that a user of the completion system rarely needs to compose a context string,
unless for example a new function is being written to perform completion for a new com-
mand. What a user may need to do is compose a style pattern, which is matched against a
context when needed to look up context-sensitive options that configure the completion
system.

The next few paragraphs explain how a context is composed within the completion function
suite. Following that is discussion of how styles are defined. Styles determine such
things as how the matches are generated, similarly to shell options but with much more
control. They are defined with the zstyle builtin command (see zshmodules(1)).

The context string always consists of a fixed set of fields, separated by colons and with
a leading colon before the first. Fields which are not yet known are left empty, but the
surrounding colons appear anyway. The fields are always in the order :completion:func-
tion:completer:command:argument:tag. These have the following meaning:

o The literal string completion, saying that this style is used by the completion
system. This distinguishes the context from those used by, for example, zle wid-
gets and ZFTP functions.

o The function, if completion is called from a named widget rather than through the
normal completion system. Typically this is blank, but it is set by special wid-
gets such as predict-on and the various functions in the Widget directory of the
distribution to the name of that function, often in an abbreviated form.

o The completer currently active, the name of the function without the leading under-
score and with other underscores converted to hyphens. A `completer' is in overall
control of how completion is to be performed; `complete' is the simplest, but other
completers exist to perform related tasks such as correction, or to modify the be-
haviour of a later completer. See the section `Control Functions' below for more
information.

o The command or a special -context-, just at it appears following the #compdef tag
or the compdef function. Completion functions for commands that have sub-commands
usually modify this field to contain the name of the command followed by a minus
sign and the sub-command. For example, the completion function for the cvs command
sets this field to cvs-add when completing arguments to the add subcommand.

o The argument; this indicates which command line or option argument we are complet-
ing. For command arguments this generally takes the form argument-n, where n is
the number of the argument, and for arguments to options the form option-opt-n
where n is the number of the argument to option opt. However, this is only the
case if the command line is parsed with standard UNIX-style options and arguments,
so many completions do not set this.

o The tag. As described previously, tags are used to discriminate between the types
of matches a completion function can generate in a certain context. Any completion
function may use any tag name it likes, but a list of the more common ones is given
below.

The context is gradually put together as the functions are executed, starting with the
main entry point, which adds :completion: and the function element if necessary. The com-
pleter then adds the completer element. The contextual completion adds the command and
argument options. Finally, the tag is added when the types of completion are known. For
example, the context name

:completion::complete:dvips:option-o-1:files

says that normal completion was attempted as the first argument to the option -o of the
command dvips:

dvips -o ...

and the completion function will generate filenames.

Usually completion will be tried for all possible tags in an order given by the completion
function. However, this can be altered by using the tag-order style. Completion is then
restricted to the list of given tags in the given order.

The _complete_help bindable command shows all the contexts and tags available for comple-
tion at a particular point. This provides an easy way of finding information for tag-or-
der and other styles. It is described in the section `Bindable Commands' below.

When looking up styles the completion system uses full context names, including the tag.
Looking up the value of a style therefore consists of two things: the context, which is
matched to the most specific (best fitting) style pattern, and the name of the style it-
self, which must be matched exactly. The following examples demonstrate that style pat-
terns may be loosely defined for styles that apply broadly, or as tightly defined as de-
sired for styles that apply in narrower circumstances.

For example, many completion functions can generate matches in a simple and a verbose form
and use the verbose style to decide which form should be used. To make all such functions
use the verbose form, put

zstyle ':completion:*' verbose yes

in a startup file (probably .zshrc). This gives the verbose style the value yes in every
context inside the completion system, unless that context has a more specific definition.
It is best to avoid giving the context as `*' in case the style has some meaning outside
the completion system.

Many such general purpose styles can be configured simply by using the compinstall func-
tion.

A more specific example of the use of the verbose style is by the completion for the kill
builtin. If the style is set, the builtin lists full job texts and process command lines;
otherwise it shows the bare job numbers and PIDs. To turn the style off for this use
only:

zstyle ':completion:*:*:kill:*:*' verbose no

For even more control, the style can use one of the tags `jobs' or `processes'. To turn
off verbose display only for jobs:

zstyle ':completion:*:*:kill:*:jobs' verbose no

The -e option to zstyle even allows completion function code to appear as the argument to
a style; this requires some understanding of the internals of completion functions (see
see zshcompwid(1))). For example,

zstyle -e ':completion:*' hosts 'reply=($myhosts)'

This forces the value of the hosts style to be read from the variable myhosts each time a
host name is needed; this is useful if the value of myhosts can change dynamically. For
another useful example, see the example in the description of the file-list style below.
This form can be slow and should be avoided for commonly examined styles such as menu and
list-rows-first.

Note that the order in which styles are defined does not matter; the style mechanism uses
the most specific possible match for a particular style to determine the set of values.
More precisely, strings are preferred over patterns (for example, `:completion::com-
plete:::foo' is more specific than `:completion::complete:::*'), and longer patterns are
preferred over shorter patterns.

A good rule of thumb is that any completion style pattern that needs to include more than
one wildcard (*) and that does not end in a tag name, should include all six colons (:),
possibly surrounding additional wildcards.

Style names like those of tags are arbitrary and depend on the completion function. How-
ever, the following two sections list some of the most common tags and styles.

Standard Tags
Some of the following are only used when looking up particular styles and do not refer to
a type of match.

accounts
used to look up the users-hosts style

all-expansions
used by the _expand completer when adding the single string containing all possible
expansions

all-files
for the names of all files (as distinct from a particular subset, see the
globbed-files tag).

arguments
for arguments to a command

arrays for names of array parameters

association-keys
for keys of associative arrays; used when completing inside a subscript to a param-
eter of this type

bookmarks
when completing bookmarks (e.g. for URLs and the zftp function suite)

builtins
for names of builtin commands

characters
for single characters in arguments of commands such as stty. Also used when com-
pleting character classes after an opening bracket

colormapids
for X colormap ids

colors for color names

commands
for names of external commands. Also used by complex commands such as cvs when
completing names subcommands.

contexts
for contexts in arguments to the zstyle builtin command

corrections
used by the _approximate and _correct completers for possible corrections

cursors
for cursor names used by X programs

default
used in some contexts to provide a way of supplying a default when more specific
tags are also valid. Note that this tag is used when only the function field of
the context name is set

descriptions
used when looking up the value of the format style to generate descriptions for
types of matches

devices
for names of device special files

directories
for names of directories -- local-directories is used instead when completing argu-
ments of cd and related builtin commands when the cdpath array is set

directory-stack
for entries in the directory stack

displays
for X display names

domains
for network domains

email-plugin
for email addresses from the `_email-plugin' backend of _email_addresses

expansions
used by the _expand completer for individual words (as opposed to the complete set
of expansions) resulting from the expansion of a word on the command line

extensions
for X server extensions

file-descriptors
for numbers of open file descriptors

files the generic file-matching tag used by functions completing filenames

fonts for X font names

fstypes
for file system types (e.g. for the mount command)

functions
names of functions -- normally shell functions, although certain commands may un-
derstand other kinds of function

globbed-files
for filenames when the name has been generated by pattern matching

groups for names of user groups

history-words
for words from the history

hosts for hostnames

indexes
for array indexes

jobs for jobs (as listed by the `jobs' builtin)

interfaces
for network interfaces

keymaps
for names of zsh keymaps

keysyms
for names of X keysyms

libraries
for names of system libraries

limits for system limits

local-directories
for names of directories that are subdirectories of the current working directory
when completing arguments of cd and related builtin commands (compare path-directo-
ries) -- when the cdpath array is unset, directories is used instead

manuals
for names of manual pages

mailboxes
for e-mail folders

maps for map names (e.g. NIS maps)

messages
used to look up the format style for messages

modifiers
for names of X modifiers

modules
for modules (e.g. zsh modules)

my-accounts
used to look up the users-hosts style

named-directories
for named directories (you wouldn't have guessed that, would you?)

names for all kinds of names

newsgroups
for USENET groups

nicknames
for nicknames of NIS maps

options
for command options

original
used by the _approximate, _correct and _expand completers when offering the origi-
nal string as a match

other-accounts
used to look up the users-hosts style

other-files
for the names of any non-directory files. This is used instead of all-files when
the list-dirs-first style is in effect.

packages
for packages (e.g. rpm or installed Debian packages)

parameters
for names of parameters

path-directories
for names of directories found by searching the cdpath array when completing argu-
ments of cd and related builtin commands (compare local-directories)

paths used to look up the values of the expand, ambiguous and special-dirs styles

pods for perl pods (documentation files)

ports for communication ports

prefixes
for prefixes (like those of a URL)

printers
for print queue names

processes
for process identifiers

processes-names
used to look up the command style when generating the names of processes for kil-
lall

sequences
for sequences (e.g. mh sequences)

sessions
for sessions in the zftp function suite

signals
for signal names

strings
for strings (e.g. the replacement strings for the cd builtin command)

styles for styles used by the zstyle builtin command

suffixes
for filename extensions

tags for tags (e.g. rpm tags)

targets
for makefile targets

time-zones
for time zones (e.g. when setting the TZ parameter)

types for types of whatever (e.g. address types for the xhost command)

urls used to look up the urls and local styles when completing URLs

users for usernames

values for one of a set of values in certain lists

variant
used by _pick_variant to look up the command to run when determining what program
is installed for a particular command name.

visuals
for X visuals

warnings
used to look up the format style for warnings

widgets
for zsh widget names

windows
for IDs of X windows

zsh-options
for shell options

Standard Styles
Note that the values of several of these styles represent boolean values. Any of the
strings `true', `on', `yes', and `1' can be used for the value `true' and any of the
strings `false', `off', `no', and `0' for the value `false'. The behavior for any other
value is undefined except where explicitly mentioned. The default value may be either
`true' or `false' if the style is not set.

Some of these styles are tested first for every possible tag corresponding to a type of
match, and if no style was found, for the default tag. The most notable styles of this
type are menu, list-colors and styles controlling completion listing such as list-packed
and last-prompt. When tested for the default tag, only the function field of the context
will be set so that a style using the default tag will normally be defined along the lines
of:

zstyle ':completion:*:default' menu ...

accept-exact
This is tested for the default tag in addition to the tags valid for the current
context. If it is set to `true' and any of the trial matches is the same as the
string on the command line, this match will immediately be accepted (even if it
would otherwise be considered ambiguous).

When completing pathnames (where the tag used is `paths') this style accepts any
number of patterns as the value in addition to the boolean values. Pathnames
matching one of these patterns will be accepted immediately even if the command
line contains some more partially typed pathname components and these match no file
under the directory accepted.

This style is also used by the _expand completer to decide if words beginning with
a tilde or parameter expansion should be expanded. For example, if there are pa-
rameters foo and foobar, the string `$foo' will only be expanded if accept-exact is
set to `true'; otherwise the completion system will be allowed to complete $foo to
$foobar. If the style is set to `continue', _expand will add the expansion as a
match and the completion system will also be allowed to continue.

accept-exact-dirs
This is used by filename completion. Unlike accept-exact it is a boolean. By de-
fault, filename completion examines all components of a path to see if there are
completions of that component, even if the component matches an existing directory.
For example, when completion after /usr/bin/, the function examines possible com-
pletions to /usr.

When this style is `true', any prefix of a path that matches an existing directory
is accepted without any attempt to complete it further. Hence, in the given exam-
ple, the path /usr/bin/ is accepted immediately and completion tried in that direc-
tory.

This style is also useful when completing after directories that magically appear
when referenced, such as ZFS .zfs directories or NetApp .snapshot directories.
When the style is set the shell does not check for the existence of the directory
within the parent directory.

If you wish to inhibit this behaviour entirely, set the path-completion style (see
below) to `false'.

add-space
This style is used by the _expand completer. If it is `true' (the default), a
space will be inserted after all words resulting from the expansion, or a slash in
the case of directory names. If the value is `file', the completer will only add a
space to names of existing files. Either a boolean `true' or the value `file' may
be combined with `subst', in which case the completer will not add a space to words
generated from the expansion of a substitution of the form `$(...)' or `${...}'.

The _prefix completer uses this style as a simple boolean value to decide if a
space should be inserted before the suffix.

ambiguous
This applies when completing non-final components of filename paths, in other words
those with a trailing slash. If it is set, the cursor is left after the first am-
biguous component, even if menu completion is in use. The style is always tested
with the paths tag.

assign-list
When completing after an equals sign that is being treated as an assignment, the
completion system normally completes only one filename. In some cases the value
may be a list of filenames separated by colons, as with PATH and similar parame-
ters. This style can be set to a list of patterns matching the names of such pa-
rameters.

The default is to complete lists when the word on the line already contains a
colon.

auto-description
If set, this style's value will be used as the description for options that are not
described by the completion functions, but that have exactly one argument. The se-
quence `%d' in the value will be replaced by the description for this argument.
Depending on personal preferences, it may be useful to set this style to something
like `specify: %d'. Note that this may not work for some commands.

avoid-completer
This is used by the _all_matches completer to decide if the string consisting of
all matches should be added to the list currently being generated. Its value is a
list of names of completers. If any of these is the name of the completer that
generated the matches in this completion, the string will not be added.

The default value for this style is `_expand _old_list _correct _approximate', i.e.
it contains the completers for which a string with all matches will almost never be
wanted.

cache-path
This style defines the path where any cache files containing dumped completion data
are stored. It defaults to `$ZDOTDIR/.zcompcache', or `$HOME/.zcompcache' if
$ZDOTDIR is not defined. The completion cache will not be used unless the
use-cache style is set.

cache-policy
This style defines the function that will be used to determine whether a cache
needs rebuilding. See the section on the _cache_invalid function below.

call-command
This style is used in the function for commands such as make and ant where calling
the command directly to generate matches suffers problems such as being slow or, as
in the case of make can potentially cause actions in the makefile to be executed.
If it is set to `true' the command is called to generate matches. The default value
of this style is `false'.

command
In many places, completion functions need to call external commands to generate the
list of completions. This style can be used to override the command that is called
in some such cases. The elements of the value are joined with spaces to form a
command line to execute. The value can also start with a hyphen, in which case the
usual command will be added to the end; this is most useful for putting `builtin'
or `command' in front to make sure the appropriate version of a command is called,
for example to avoid calling a shell function with the same name as an external
command.

As an example, the completion function for process IDs uses this style with the
processes tag to generate the IDs to complete and the list of processes to display
(if the verbose style is `true'). The list produced by the command should look
like the output of the ps command. The first line is not displayed, but is
searched for the string `PID' (or `pid') to find the position of the process IDs in
the following lines. If the line does not contain `PID', the first numbers in each
of the other lines are taken as the process IDs to complete.

Note that the completion function generally has to call the specified command for
each attempt to generate the completion list. Hence care should be taken to spec-
ify only commands that take a short time to run, and in particular to avoid any
that may never terminate.

command-path
This is a list of directories to search for commands to complete. The default for
this style is the value of the special parameter path.

commands
This is used by the function completing sub-commands for the system initialisation
scripts (residing in /etc/init.d or somewhere not too far away from that). Its
values give the default commands to complete for those commands for which the com-
pletion function isn't able to find them out automatically. The default for this
style are the two strings `start' and `stop'.

complete
This is used by the _expand_alias function when invoked as a bindable command. If
set to `true' and the word on the command line is not the name of an alias, match-
ing alias names will be completed.

complete-options
This is used by the completer for cd, chdir and pushd. For these commands a - is
used to introduce a directory stack entry and completion of these is far more com-
mon than completing options. Hence unless the value of this style is `true' op-
tions will not be completed, even after an initial -. If it is `true', options
will be completed after an initial - unless there is a preceding -- on the command
line.

completer
The strings given as the value of this style provide the names of the completer
functions to use. The available completer functions are described in the section
`Control Functions' below.

Each string may be either the name of a completer function or a string of the form
`function:name'. In the first case the completer field of the context will contain
the name of the completer without the leading underscore and with all other under-
scores replaced by hyphens. In the second case the function is the name of the
completer to call, but the context will contain the user-defined name in the com-
pleter field of the context. If the name starts with a hyphen, the string for the
context will be build from the name of the completer function as in the first case
with the name appended to it. For example:

zstyle ':completion:*' completer _complete _complete:-foo

Here, completion will call the _complete completer twice, once using `complete' and
once using `complete-foo' in the completer field of the context. Normally, using
the same completer more than once only makes sense when used with the `func-
tions:name' form, because otherwise the context name will be the same in all calls
to the completer; possible exceptions to this rule are the _ignored and _prefix
completers.

The default value for this style is `_complete _ignored': only completion will be
done, first using the ignored-patterns style and the $fignore array and then with-
out ignoring matches.

condition
This style is used by the _list completer function to decide if insertion of
matches should be delayed unconditionally. The default is `true'.

delimiters
This style is used when adding a delimiter for use with history modifiers or glob
qualifiers that have delimited arguments. It is an array of preferred delimiters
to add. Non-special characters are preferred as the completion system may other-
wise become confused. The default list is :, +, /, -, %. The list may be empty to
force a delimiter to be typed.

disabled
If this is set to `true', the _expand_alias completer and bindable command will try
to expand disabled aliases, too. The default is `false'.

domains
A list of names of network domains for completion. If this is not set, domain
names will be taken from the file /etc/resolv.conf.

environ
The environ style is used when completing for `sudo'. It is set to an array of
`VAR=value' assignments to be exported into the local environment before the com-
pletion for the target command is invoked.
zstyle ':completion:*:sudo::' environ \
PATH="/sbin:/usr/sbin:$PATH" HOME="/root"

expand This style is used when completing strings consisting of multiple parts, such as
path names.

If one of its values is the string `prefix', the partially typed word from the line
will be expanded as far as possible even if trailing parts cannot be completed.

If one of its values is the string `suffix', matching names for components after
the first ambiguous one will also be added. This means that the resulting string
is the longest unambiguous string possible. However, menu completion can be used
to cycle through all matches.

fake This style may be set for any completion context. It specifies additional strings
that will always be completed in that context. The form of each string is
`value:description'; the colon and description may be omitted, but any literal
colons in value must be quoted with a backslash. Any description provided is shown
alongside the value in completion listings.

It is important to use a sufficiently restrictive context when specifying fake
strings. Note that the styles fake-files and fake-parameters provide additional
features when completing files or parameters.

fake-always
This works identically to the fake style except that the ignored-patterns style is
not applied to it. This makes it possible to override a set of matches completely
by setting the ignored patterns to `*'.

The following shows a way of supplementing any tag with arbitrary data, but having
it behave for display purposes like a separate tag. In this example we use the
features of the tag-order style to divide the named-directories tag into two when
performing completion with the standard completer complete for arguments of cd.
The tag named-directories-normal behaves as normal, but the tag named-directo-
ries-mine contains a fixed set of directories. This has the effect of adding the
match group `extra directories' with the given completions.

zstyle ':completion::complete:cd:*' tag-order \
'named-directories:-mine:extra\ directories
named-directories:-normal:named\ directories *'
zstyle ':completion::complete:cd:*:named-directories-mine' \
fake-always mydir1 mydir2
zstyle ':completion::complete:cd:*:named-directories-mine' \
ignored-patterns '*'

fake-files
This style is used when completing files and looked up without a tag. Its values
are of the form `dir:names...'. This will add the names (strings separated by spa-
ces) as possible matches when completing in the directory dir, even if no such
files really exist. The dir may be a pattern; pattern characters or colons in dir
should be quoted with a backslash to be treated literally.

This can be useful on systems that support special file systems whose top-level
pathnames can not be listed or generated with glob patterns (but see accept-ex-
act-dirs for a more general way of dealing with this problem). It can also be used
for directories for which one does not have read permission.

The pattern form can be used to add a certain `magic' entry to all directories on a
particular file system.

fake-parameters
This is used by the completion function for parameter names. Its values are names
of parameters that might not yet be set but should be completed nonetheless. Each
name may also be followed by a colon and a string specifying the type of the param-
eter (like `scalar', `array' or `integer'). If the type is given, the name will
only be completed if parameters of that type are required in the particular con-
text. Names for which no type is specified will always be completed.

file-list
This style controls whether files completed using the standard builtin mechanism
are to be listed with a long list similar to ls -l. Note that this feature uses
the shell module zsh/stat for file information; this loads the builtin stat which
will replace any external stat executable. To avoid this the following code can be
included in an initialization file:

zmodload -i zsh/stat
disable stat

The style may either be set to a `true' value (or `all'), or one of the values `in-
sert' or `list', indicating that files are to be listed in long format in all cir-
cumstances, or when attempting to insert a file name, or when listing file names
without attempting to insert one.

More generally, the value may be an array of any of the above values, optionally
followed by =num. If num is present it gives the maximum number of matches for
which long listing style will be used. For example,

zstyle ':completion:*' file-list list=20 insert=10

specifies that long format will be used when listing up to 20 files or inserting a
file with up to 10 matches (assuming a listing is to be shown at all, for example
on an ambiguous completion), else short format will be used.

zstyle -e ':completion:*' file-list \
'(( ${+NUMERIC} )) && reply=(true)'

specifies that long format will be used any time a numeric argument is supplied,
else short format.

file-patterns
This is used by the standard function for completing filenames, _files. If the
style is unset up to three tags are offered, `globbed-files',`directories' and
`all-files', depending on the types of files expected by the caller of _files.
The first two (`globbed-files' and `directories') are normally offered together to
make it easier to complete files in sub-directories.

The file-patterns style provides alternatives to the default tags, which are not
used. Its value consists of elements of the form `pattern:tag'; each string may
contain any number of such specifications separated by spaces.

The pattern is a pattern that is to be used to generate filenames. Any occurrence
of the sequence `%p' is replaced by any pattern(s) passed by the function calling
_files. Colons in the pattern must be preceded by a backslash to make them distin-
guishable from the colon before the tag. If more than one pattern is needed, the
patterns can be given inside braces, separated by commas.

The tags of all strings in the value will be offered by _files and used when look-
ing up other styles. Any tags in the same word will be offered at the same time
and before later words. If no `:tag' is given the `files' tag will be used.

The tag may also be followed by an optional second colon and a description, which
will be used for the `%d' in the value of the format style (if that is set) instead
of the default description supplied by the completion function. If the description
given here contains itself a `%d', that is replaced with the description supplied
by the completion function.

For example, to make the rm command first complete only names of object files and
then the names of all files if there is no matching object file:

zstyle ':completion:*:*:rm:*:*' file-patterns \
'*.o:object-files' '%p:all-files'

To alter the default behaviour of file completion -- offer files matching a pattern
and directories on the first attempt, then all files -- to offer only matching
files on the first attempt, then directories, and finally all files:

zstyle ':completion:*' file-patterns \
'%p:globbed-files' '*(-/):directories' '*:all-files'

This works even where there is no special pattern: _files matches all files using
the pattern `*' at the first step and stops when it sees this pattern. Note also
it will never try a pattern more than once for a single completion attempt.

During the execution of completion functions, the EXTENDED_GLOB option is in ef-
fect, so the characters `#', `~' and `^' have special meanings in the patterns.

file-sort
The standard filename completion function uses this style without a tag to deter-
mine in which order the names should be listed; menu completion will cycle through
them in the same order. The possible values are: `size' to sort by the size of the
file; `links' to sort by the number of links to the file; `modification' (or `time'
or `date') to sort by the last modification time; `access' to sort by the last ac-
cess time; and `inode' (or `change') to sort by the last inode change time. If the
style is set to any other value, or is unset, files will be sorted alphabetically
by name. If the value contains the string `reverse', sorting is done in the oppo-
site order. If the value contains the string `follow', timestamps are associated
with the targets of symbolic links; the default is to use the timestamps of the
links themselves.

file-split-chars
A set of characters that will cause all file completions for the given context to
be split at the point where any of the characters occurs. A typical use is to set
the style to :; then everything up to and including the last : in the string so far
is ignored when completing files. As this is quite heavy-handed, it is usually
preferable to update completion functions for contexts where this behaviour is use-
ful.

filter The ldap plugin of email address completion (see _email_addresses) uses this style
to specify the attributes to match against when filtering entries. So for example,
if the style is set to `sn', matching is done against surnames. Standard LDAP fil-
tering is used so normal completion matching is bypassed. If this style is not
set, the LDAP plugin is skipped. You may also need to set the command style to
specify how to connect to your LDAP server.

force-list
This forces a list of completions to be shown at any point where listing is done,
even in cases where the list would usually be suppressed. For example, normally
the list is only shown if there are at least two different matches. By setting
this style to `always', the list will always be shown, even if there is only a sin-
gle match that will immediately be accepted. The style may also be set to a num-
ber. In this case the list will be shown if there are at least that many matches,
even if they would all insert the same string.

This style is tested for the default tag as well as for each tag valid for the cur-
rent completion. Hence the listing can be forced only for certain types of match.

format If this is set for the descriptions tag, its value is used as a string to display
above matches in completion lists. The sequence `%d' in this string will be re-
placed with a short description of what these matches are. This string may also
contain the output attribute sequences understood by compadd -X (see zshcomp-
wid(1)).

The style is tested with each tag valid for the current completion before it is
tested for the descriptions tag. Hence different format strings can be defined for
different types of match.

Note also that some completer functions define additional `%'-sequences. These are
described for the completer functions that make use of them.

Some completion functions display messages that may be customised by setting this
style for the messages tag. Here, the `%d' is replaced with a message given by the
completion function.

Finally, the format string is looked up with the warnings tag, for use when no
matches could be generated at all. In this case the `%d' is replaced with the de-
scriptions for the matches that were expected separated by spaces. The sequence
`%D' is replaced with the same descriptions separated by newlines.

It is possible to use printf-style field width specifiers with `%d' and similar es-
cape sequences. This is handled by the zformat builtin command from the zsh/zutil
module, see zshmodules(1).

glob This is used by the _expand completer. If it is set to `true' (the default), glob-
bing will be attempted on the words resulting from a previous substitution (see the
substitute style) or else the original string from the line.

global If this is set to `true' (the default), the _expand_alias completer and bindable
command will try to expand global aliases.

group-name
The completion system can group different types of matches, which appear in sepa-
rate lists. This style can be used to give the names of groups for particular
tags. For example, in command position the completion system generates names of
builtin and external commands, names of aliases, shell functions and parameters and
reserved words as possible completions. To have the external commands and shell
functions listed separately:

zstyle ':completion:*:*:-command-:*:commands' \
group-name commands
zstyle ':completion:*:*:-command-:*:functions' \
group-name functions

As a consequence, any match with the same tag will be displayed in the same group.

If the name given is the empty string the name of the tag for the matches will be
used as the name of the group. So, to have all different types of matches dis-
played separately, one can just set:

zstyle ':completion:*' group-name ''

All matches for which no group name is defined will be put in a group named -de-
fault-.

group-order
This style is additional to the group-name style to specify the order for display
of the groups defined by that style (compare tag-order, which determines which com-
pletions appear at all). The groups named are shown in the given order; any other
groups are shown in the order defined by the completion function.

For example, to have names of builtin commands, shell functions and external com-
mands appear in that order when completing in command position:

zstyle ':completion:*:*:-command-:*:*' group-order \
builtins functions commands

groups A list of names of UNIX groups. If this is not set, group names are taken from the
YP database or the file `/etc/group'.

hidden If this is set to `true', matches for the given context will not be listed, al-
though any description for the matches set with the format style will be shown. If
it is set to `all', not even the description will be displayed.

Note that the matches will still be completed; they are just not shown in the list.
To avoid having matches considered as possible completions at all, the tag-order
style can be modified as described below.

hosts A list of names of hosts that should be completed. If this is not set, hostnames
are taken from the file `/etc/hosts'.

hosts-ports
This style is used by commands that need or accept hostnames and network ports.
The strings in the value should be of the form `host:port'. Valid ports are deter-
mined by the presence of hostnames; multiple ports for the same host may appear.

ignore-line
This is tested for each tag valid for the current completion. If it is set to
`true', none of the words that are already on the line will be considered as possi-
ble completions. If it is set to `current', the word the cursor is on will not be
considered as a possible completion. The value `current-shown' is similar but only
applies if the list of completions is currently shown on the screen. Finally, if
the style is set to `other', all words on the line except for the current one will
be excluded from the possible completions.

The values `current' and `current-shown' are a bit like the opposite of the ac-
cept-exact style: only strings with missing characters will be completed.

Note that you almost certainly don't want to set this to `true' or `other' for a
general context such as `:completion:*'. This is because it would disallow comple-
tion of, for example, options multiple times even if the command in question ac-
cepts the option more than once.

ignore-parents
The style is tested without a tag by the function completing pathnames in order to
determine whether to ignore the names of directories already mentioned in the cur-
rent word, or the name of the current working directory. The value must include
one or both of the following strings:

parent The name of any directory whose path is already contained in the word on the
line is ignored. For example, when completing after foo/../, the directory
foo will not be considered a valid completion.

pwd The name of the current working directory will not be completed; hence, for
example, completion after ../ will not use the name of the current direc-
tory.

In addition, the value may include one or both of:

.. Ignore the specified directories only when the word on the line contains the
substring `../'.

directory
Ignore the specified directories only when names of directories are com-
pleted, not when completing names of files.

Excluded values act in a similar fashion to values of the ignored-patterns style,
so they can be restored to consideration by the _ignored completer.

extra-verbose
If set, the completion listing is more verbose at the cost of a probable decrease
in completion speed. Completion performance will suffer if this style is set to
`true'.

ignored-patterns
A list of patterns; any trial completion matching one of the patterns will be ex-
cluded from consideration. The _ignored completer can appear in the list of com-
pleters to restore the ignored matches. This is a more configurable version of the
shell parameter $fignore.

Note that the EXTENDED_GLOB option is set during the execution of completion func-
tions, so the characters `#', `~' and `^' have special meanings in the patterns.

insert This style is used by the _all_matches completer to decide whether to insert the
list of all matches unconditionally instead of adding the list as another match.

insert-ids
When completing process IDs, for example as arguments to the kill and wait builtins
the name of a command may be converted to the appropriate process ID. A problem
arises when the process name typed is not unique. By default (or if this style is
set explicitly to `menu') the name will be converted immediately to a set of possi-
ble IDs, and menu completion will be started to cycle through them.

If the value of the style is `single', the shell will wait until the user has typed
enough to make the command unique before converting the name to an ID; attempts at
completion will be unsuccessful until that point. If the value is any other
string, menu completion will be started when the string typed by the user is longer
than the common prefix to the corresponding IDs.

insert-tab
If this is set to `true', the completion system will insert a TAB character (assum-
ing that was used to start completion) instead of performing completion when there
is no non-blank character to the left of the cursor. If it is set to `false', com-
pletion will be done even there.

The value may also contain the substrings `pending' or `pending=val'. In this
case, the typed character will be inserted instead of starting completion when
there is unprocessed input pending. If a val is given, completion will not be done
if there are at least that many characters of unprocessed input. This is often
useful when pasting characters into a terminal. Note however, that it relies on
the $PENDING special parameter from the zsh/zle module being set properly which is
not guaranteed on all platforms.

The default value of this style is `true' except for completion within vared
builtin command where it is `false'.

insert-unambiguous
This is used by the _match and _approximate completers. These completers are often
used with menu completion since the word typed may bear little resemblance to the
final completion. However, if this style is `true', the completer will start menu
completion only if it could find no unambiguous initial string at least as long as
the original string typed by the user.

In the case of the _approximate completer, the completer field in the context will
already have been set to one of correct-num or approximate-num, where num is the
number of errors that were accepted.

In the case of the _match completer, the style may also be set to the string `pat-
tern'. Then the pattern on the line is left unchanged if it does not match unam-
biguously.

gain-privileges
If set to true, this style enables the use of commands like sudo or doas to gain
extra privileges when retrieving information for completion. This is only done when
a command such as sudo appears on the command-line. To force the use of, e.g. sudo
or to override any prefix that might be added due to gain-privileges, the command
style can be used with a value that begins with a hyphen.

keep-prefix
This style is used by the _expand completer. If it is `true', the completer will
try to keep a prefix containing a tilde or parameter expansion. Hence, for exam-
ple, the string `~/f*' would be expanded to `~/foo' instead of `/home/user/foo'.
If the style is set to `changed' (the default), the prefix will only be left un-
changed if there were other changes between the expanded words and the original
word from the command line. Any other value forces the prefix to be expanded un-
conditionally.

The behaviour of _expand when this style is `true' is to cause _expand to give up
when a single expansion with the restored prefix is the same as the original; hence
any remaining completers may be called.

last-prompt
This is a more flexible form of the ALWAYS_LAST_PROMPT option. If it is `true',
the completion system will try to return the cursor to the previous command line
after displaying a completion list. It is tested for all tags valid for the cur-
rent completion, then the default tag. The cursor will be moved back to the previ-
ous line if this style is `true' for all types of match. Note that unlike the AL-
WAYS_LAST_PROMPT option this is independent of the numeric argument.

known-hosts-files
This style should contain a list of files to search for host names and (if the
use-ip style is set) IP addresses in a format compatible with ssh known_hosts
files. If it is not set, the files /etc/ssh/ssh_known_hosts and ~/.ssh/known_hosts
are used.

list This style is used by the _history_complete_word bindable command. If it is set to
`true' it has no effect. If it is set to `false' matches will not be listed. This
overrides the setting of the options controlling listing behaviour, in particular
AUTO_LIST. The context always starts with `:completion:history-words'.

list-colors
If the zsh/complist module is loaded, this style can be used to set color specifi-
cations. This mechanism replaces the use of the ZLS_COLORS and ZLS_COLOURS parame-
ters described in the section `The zsh/complist Module' in zshmodules(1), but the
syntax is the same.

If this style is set for the default tag, the strings in the value are taken as
specifications that are to be used everywhere. If it is set for other tags, the
specifications are used only for matches of the type described by the tag. For
this to work best, the group-name style must be set to an empty string.

In addition to setting styles for specific tags, it is also possible to use group
names specified explicitly by the group-name tag together with the `(group)' syntax
allowed by the ZLS_COLORS and ZLS_COLOURS parameters and simply using the default
tag.

It is possible to use any color specifications already set up for the GNU version
of the ls command:

zstyle ':completion:*:default' list-colors \
${(s.:.)LS_COLORS}

The default colors are the same as for the GNU ls command and can be obtained by
setting the style to an empty string (i.e. '').

list-dirs-first
This is used by file completion. If set, directories to be completed are listed
separately from and before completion for other files, regardless of tag ordering.
In addition, the tag other-files is used in place of all-files for the remaining
files, to indicate that no directories are presented with that tag.

list-grouped
If this style is `true' (the default), the completion system will try to make cer-
tain completion listings more compact by grouping matches. For example, options
for commands that have the same description (shown when the verbose style is set to
`true') will appear as a single entry. However, menu selection can be used to cy-
cle through all the matches.

list-packed
This is tested for each tag valid in the current context as well as the default
tag. If it is set to `true', the corresponding matches appear in listings as if
the LIST_PACKED option were set. If it is set to `false', they are listed nor-
mally.

list-prompt
If this style is set for the default tag, completion lists that don't fit on the
screen can be scrolled (see the description of the zsh/complist module in zshmod-
ules(1)). The value, if not the empty string, will be displayed after every
screenful and the shell will prompt for a key press; if the style is set to the
empty string, a default prompt will be used.

The value may contain the escape sequences: `%l' or `%L', which will be replaced by
the number of the last line displayed and the total number of lines; `%m' or `%M',
the number of the last match shown and the total number of matches; and `%p' and
`%P', `Top' when at the beginning of the list, `Bottom' when at the end and the po-
sition shown as a percentage of the total length otherwise. In each case the form
with the uppercase letter will be replaced by a string of fixed width, padded to
the right with spaces, while the lowercase form will be replaced by a variable
width string. As in other prompt strings, the escape sequences `%S', `%s', `%B',
`%b', `%U', `%u' for entering and leaving the display modes standout, bold and un-
derline, and `%F', `%f', `%K', `%k' for changing the foreground background colour,
are also available, as is the form `%{...%}' for enclosing escape sequences which
display with zero (or, with a numeric argument, some other) width.

After deleting this prompt the variable LISTPROMPT should be unset for the removal
to take effect.

list-rows-first
This style is tested in the same way as the list-packed style and determines
whether matches are to be listed in a rows-first fashion as if the LIST_ROWS_FIRST
option were set.

list-suffixes
This style is used by the function that completes filenames. If it is `true', and
completion is attempted on a string containing multiple partially typed pathname
components, all ambiguous components will be shown. Otherwise, completion stops at
the first ambiguous component.

list-separator
The value of this style is used in completion listing to separate the string to
complete from a description when possible (e.g. when completing options). It de-
faults to `--' (two hyphens).

local This is for use with functions that complete URLs for which the corresponding files
are available directly from the file system. Its value should consist of three
strings: a hostname, the path to the default web pages for the server, and the di-
rectory name used by a user placing web pages within their home area.

For example:

zstyle ':completion:*' local toast \
/var/http/public/toast public_html

Completion after `http://toast/stuff/' will look for files in the directory
/var/http/public/toast/stuff, while completion after `http://toast/~yousir/' will
look for files in the directory ~yousir/public_html.

mail-directory
If set, zsh will assume that mailbox files can be found in the directory specified.
It defaults to `~/Mail'.

match-original
This is used by the _match completer. If it is set to only, _match will try to
generate matches without inserting a `*' at the cursor position. If set to any
other non-empty value, it will first try to generate matches without inserting the
`*' and if that yields no matches, it will try again with the `*' inserted. If it
is unset or set to the empty string, matching will only be performed with the `*'
inserted.

matcher
This style is tested separately for each tag valid in the current context. Its
value is placed before any match specifications given by the matcher-list style so
can override them via the use of an x: specification. The value should be in the
form described in the section `Completion Matching Control' in zshcompwid(1). For
examples of this, see the description of the tag-order style.

For notes comparing the use of this and the matcher-list style, see under the de-
scription of the tag-order style.

matcher-list
This style can be set to a list of match specifications that are to be applied ev-
erywhere. Match specifications are described in the section `Completion Matching
Control' in zshcompwid(1). The completion system will try them one after another
for each completer selected. For example, to try first simple completion and, if
that generates no matches, case-insensitive completion:

zstyle ':completion:*' matcher-list '' 'm:{a-zA-Z}={A-Za-z}'

By default each specification replaces the previous one; however, if a specifica-
tion is prefixed with +, it is added to the existing list. Hence it is possible to
create increasingly general specifications without repetition:

zstyle ':completion:*' matcher-list \
'' '+m:{a-z}={A-Z}' '+m:{A-Z}={a-z}'

It is possible to create match specifications valid for particular completers by
using the third field of the context. This applies only to completers that over-
ride the global matcher-list, which as of this writing includes only _prefix and
_ignored. For example, to use the completers _complete and _prefix but allow
case-insensitive completion only with _complete:

zstyle ':completion:*' completer _complete _prefix
zstyle ':completion:*:complete:*:*:*' matcher-list \
'' 'm:{a-zA-Z}={A-Za-z}'

User-defined names, as explained for the completer style, are available. This
makes it possible to try the same completer more than once with different match
specifications each time. For example, to try normal completion without a match
specification, then normal completion with case-insensitive matching, then correc-
tion, and finally partial-word completion:

zstyle ':completion:*' completer \
_complete _correct _complete:foo
zstyle ':completion:*:complete:*:*:*' matcher-list \
'' 'm:{a-zA-Z}={A-Za-z}'
zstyle ':completion:*:foo:*:*:*' matcher-list \
'm:{a-zA-Z}={A-Za-z} r:|[-_./]=* r:|=*'

If the style is unset in any context no match specification is applied. Note also
that some completers such as _correct and _approximate do not use the match speci-
fications at all, though these completers will only ever be called once even if the
matcher-list contains more than one element.

Where multiple specifications are useful, note that the entire completion is done
for each element of matcher-list, which can quickly reduce the shell's performance.
As a rough rule of thumb, one to three strings will give acceptable performance.
On the other hand, putting multiple space-separated values into the same string
does not have an appreciable impact on performance.

If there is no current matcher or it is empty, and the option NO_CASE_GLOB is in
effect, the matching for files is performed case-insensitively in any case. How-
ever, any matcher must explicitly specify case-insensitive matching if that is re-
quired.

For notes comparing the use of this and the matcher style, see under the descrip-
tion of the tag-order style.

max-errors
This is used by the _approximate and _correct completer functions to determine the
maximum number of errors to allow. The completer will try to generate completions
by first allowing one error, then two errors, and so on, until either a match or
matches were found or the maximum number of errors given by this style has been
reached.

If the value for this style contains the string `numeric', the completer function
will take any numeric argument as the maximum number of errors allowed. For exam-
ple, with

zstyle ':completion:*:approximate:::' max-errors 2 numeric

two errors are allowed if no numeric argument is given, but with a numeric argument
of six (as in `ESC-6 TAB'), up to six errors are accepted. Hence with a value of
`0 numeric', no correcting completion will be attempted unless a numeric argument
is given.

If the value contains the string `not-numeric', the completer will not try to gen-
erate corrected completions when given a numeric argument, so in this case the num-
ber given should be greater than zero. For example, `2 not-numeric' specifies that
correcting completion with two errors will usually be performed, but if a numeric
argument is given, correcting completion will not be performed.

The default value for this style is `2 numeric'.

max-matches-width
This style is used to determine the trade off between the width of the display used
for matches and the width used for their descriptions when the verbose style is in
effect. The value gives the number of display columns to reserve for the matches.
The default is half the width of the screen.

This has the most impact when several matches have the same description and so will
be grouped together. Increasing the style will allow more matches to be grouped
together; decreasing it will allow more of the description to be visible.

menu If this is `true' in the context of any of the tags defined for the current comple-
tion menu completion will be used. The value for a specific tag will take prece-
dence over that for the `default' tag.

If none of the values found in this way is `true' but at least one is set to
`auto', the shell behaves as if the AUTO_MENU option is set.

If one of the values is explicitly set to `false', menu completion will be explic-
itly turned off, overriding the MENU_COMPLETE option and other settings.

In the form `yes=num', where `yes' may be any of the `true' values (`yes', `true',
`on' and `1'), menu completion will be turned on if there are at least num matches.
In the form `yes=long', menu completion will be turned on if the list does not fit
on the screen. This does not activate menu completion if the widget normally only
lists completions, but menu completion can be activated in that case with the value
`yes=long-list' (Typically, the value `select=long-list' described later is more
useful as it provides control over scrolling.)

Similarly, with any of the `false' values (as in `no=10'), menu completion will not
be used if there are num or more matches.

The value of this widget also controls menu selection, as implemented by the
zsh/complist module. The following values may appear either alongside or instead
of the values above.

If the value contains the string `select', menu selection will be started uncondi-
tionally.

In the form `select=num', menu selection will only be started if there are at least
num matches. If the values for more than one tag provide a number, the smallest
number is taken.

Menu selection can be turned off explicitly by defining a value containing the
string`no-select'.

It is also possible to start menu selection only if the list of matches does not
fit on the screen by using the value `select=long'. To start menu selection even
if the current widget only performs listing, use the value `select=long-list'.

To turn on menu completion or menu selection when there are a certain number of
matches or the list of matches does not fit on the screen, both of `yes=' and `se-
lect=' may be given twice, once with a number and once with `long' or `long-list'.

Finally, it is possible to activate two special modes of menu selection. The word
`interactive' in the value causes interactive mode to be entered immediately when
menu selection is started; see the description of the zsh/complist module in zsh-
modules(1) for a description of interactive mode. Including the string `search'
does the same for incremental search mode. To select backward incremental search,
include the string `search-backward'.

muttrc If set, gives the location of the mutt configuration file. It defaults to `~/.mut-
trc'.

numbers
This is used with the jobs tag. If it is `true', the shell will complete job num-
bers instead of the shortest unambiguous prefix of the job command text. If the
value is a number, job numbers will only be used if that many words from the job
descriptions are required to resolve ambiguities. For example, if the value is
`1', strings will only be used if all jobs differ in the first word on their com-
mand lines.

old-list
This is used by the _oldlist completer. If it is set to `always', then standard
widgets which perform listing will retain the current list of matches, however they
were generated; this can be turned off explicitly with the value `never', giving
the behaviour without the _oldlist completer. If the style is unset, or any other
value, then the existing list of completions is displayed if it is not already;
otherwise, the standard completion list is generated; this is the default behaviour
of _oldlist. However, if there is an old list and this style contains the name of
the completer function that generated the list, then the old list will be used even
if it was generated by a widget which does not do listing.

For example, suppose you type ^Xc to use the _correct_word widget, which generates
a list of corrections for the word under the cursor. Usually, typing ^D would gen-
erate a standard list of completions for the word on the command line, and show
that. With _oldlist, it will instead show the list of corrections already gener-
ated.

As another example consider the _match completer: with the insert-unambiguous style
set to `true' it inserts only a common prefix string, if there is any. However,
this may remove parts of the original pattern, so that further completion could
produce more matches than on the first attempt. By using the _oldlist completer
and setting this style to _match, the list of matches generated on the first at-
tempt will be used again.

old-matches
This is used by the _all_matches completer to decide if an old list of matches
should be used if one exists. This is selected by one of the `true' values or by
the string `only'. If the value is `only', _all_matches will only use an old list
and won't have any effect on the list of matches currently being generated.

If this style is set it is generally unwise to call the _all_matches completer un-
conditionally. One possible use is for either this style or the completer style to
be defined with the -e option to zstyle to make the style conditional.

old-menu
This is used by the _oldlist completer. It controls how menu completion behaves
when a completion has already been inserted and the user types a standard comple-
tion key such as TAB. The default behaviour of _oldlist is that menu completion
always continues with the existing list of completions. If this style is set to
`false', however, a new completion is started if the old list was generated by a
different completion command; this is the behaviour without the _oldlist completer.

For example, suppose you type ^Xc to generate a list of corrections, and menu com-
pletion is started in one of the usual ways. Usually, or with this style set to
`false', typing TAB at this point would start trying to complete the line as it now
appears. With _oldlist, it instead continues to cycle through the list of correc-
tions.

original
This is used by the _approximate and _correct completers to decide if the original
string should be added as a possible completion. Normally, this is done only if
there are at least two possible corrections, but if this style is set to `true', it
is always added. Note that the style will be examined with the completer field in
the context name set to correct-num or approximate-num, where num is the number of
errors that were accepted.

packageset
This style is used when completing arguments of the Debian `dpkg' program. It con-
tains an override for the default package set for a given context. For example,

zstyle ':completion:*:complete:dpkg:option--status-1:*' \
packageset avail

causes available packages, rather than only installed packages, to be completed for
`dpkg --status'.

path The function that completes color names uses this style with the colors tag. The
value should be the pathname of a file containing color names in the format of an
X11 rgb.txt file. If the style is not set but this file is found in one of various
standard locations it will be used as the default.

path-completion
This is used by filename completion. By default, filename completion examines all
components of a path to see if there are completions of that component. For exam-
ple, /u/b/z can be completed to /usr/bin/zsh. Explicitly setting this style to
`false' inhibits this behaviour for path components up to the / before the cursor;
this overrides the setting of accept-exact-dirs.

Even with the style set to `false', it is still possible to complete multiple paths
by setting the option COMPLETE_IN_WORD and moving the cursor back to the first com-
ponent in the path to be completed. For example, /u/b/z can be completed to
/usr/bin/zsh if the cursor is after the /u.

pine-directory
If set, specifies the directory containing PINE mailbox files. There is no de-
fault, since recursively searching this directory is inconvenient for anyone who
doesn't use PINE.

ports A list of Internet service names (network ports) to complete. If this is not set,
service names are taken from the file `/etc/services'.

prefix-hidden
This is used for certain completions which share a common prefix, for example com-
mand options beginning with dashes. If it is `true', the prefix will not be shown
in the list of matches.

The default value for this style is `false'.

prefix-needed
This style is also relevant for matches with a common prefix. If it is set to
`true' this common prefix must be typed by the user to generate the matches.

The style is applicable to the options, signals, jobs, functions, and parameters
completion tags.

For command options, this means that the initial `-', `+', or `--' must be typed
explicitly before option names will be completed.

For signals, an initial `-' is required before signal names will be completed.

For jobs, an initial `%' is required before job names will be completed.

For function and parameter names, an initial `_' or `.' is required before function
or parameter names starting with those characters will be completed.

The default value for this style is `false' for function and parameter completions,
and `true' otherwise.

preserve-prefix
This style is used when completing path names. Its value should be a pattern
matching an initial prefix of the word to complete that should be left unchanged
under all circumstances. For example, on some Unices an initial `//' (double
slash) has a special meaning; setting this style to the string `//' will preserve
it. As another example, setting this style to `?:/' under Cygwin would allow com-
pletion after `a:/...' and so on.

range This is used by the _history completer and the _history_complete_word bindable com-
mand to decide which words should be completed.

If it is a single number, only the last N words from the history will be completed.

If it is a range of the form `max:slice', the last slice words will be completed;
then if that yields no matches, the slice words before those will be tried and so
on. This process stops either when at least one match has been found, or max words
have been tried.

The default is to complete all words from the history at once.

recursive-files
If this style is set, its value is an array of patterns to be tested against
`$PWD/': note the trailing slash, which allows directories in the pattern to be de-
limited unambiguously by including slashes on both sides. If an ordinary file com-
pletion fails and the word on the command line does not yet have a directory part
to its name, the style is retrieved using the same tag as for the completion just
attempted, then the elements tested against $PWD/ in turn. If one matches, then
the shell reattempts completion by prepending the word on the command line with
each directory in the expansion of **/*(/) in turn. Typically the elements of the
style will be set to restrict the number of directories beneath the current one to
a manageable number, for example `*/.git/*'.

For example,

zstyle ':completion:*' recursive-files '*/zsh/*'

If the current directory is /home/pws/zsh/Src, then zle_trTAB can be completed to
Zle/zle_tricky.c.

regular
This style is used by the _expand_alias completer and bindable command. If set to
`true' (the default), regular aliases will be expanded but only in command posi-
tion. If it is set to `false', regular aliases will never be expanded. If it is
set to `always', regular aliases will be expanded even if not in command position.

rehash If this is set when completing external commands, the internal list (hash) of com-
mands will be updated for each search by issuing the rehash command. There is a
speed penalty for this which is only likely to be noticeable when directories in
the path have slow file access.

remote-access
If set to `false', certain commands will be prevented from making Internet connec-
tions to retrieve remote information. This includes the completion for the CVS
command.

It is not always possible to know if connections are in fact to a remote site, so
some may be prevented unnecessarily.

remove-all-dups
The _history_complete_word bindable command and the _history completer use this to
decide if all duplicate matches should be removed, rather than just consecutive du-
plicates.

select-prompt
If this is set for the default tag, its value will be displayed during menu selec-
tion (see the menu style above) when the completion list does not fit on the screen
as a whole. The same escapes as for the list-prompt style are understood, except
that the numbers refer to the match or line the mark is on. A default prompt is
used when the value is the empty string.

select-scroll
This style is tested for the default tag and determines how a completion list is
scrolled during a menu selection (see the menu style above) when the completion
list does not fit on the screen as a whole. If the value is `0' (zero), the list
is scrolled by half-screenfuls; if it is a positive integer, the list is scrolled
by the given number of lines; if it is a negative number, the list is scrolled by a
screenful minus the absolute value of the given number of lines. The default is to
scroll by single lines.

separate-sections
This style is used with the manuals tag when completing names of manual pages. If
it is `true', entries for different sections are added separately using tag names
of the form `manual.X', where X is the section number. When the group-name style
is also in effect, pages from different sections will appear separately. This
style is also used similarly with the words style when completing words for the
dict command. It allows words from different dictionary databases to be added sepa-
rately. The default for this style is `false'.

show-ambiguity
If the zsh/complist module is loaded, this style can be used to highlight the first
ambiguous character in completion lists. The value is either a color indication
such as those supported by the list-colors style or, with a value of `true', a de-
fault of underlining is selected. The highlighting is only applied if the comple-
tion display strings correspond to the actual matches.

show-completer
Tested whenever a new completer is tried. If it is `true', the completion system
outputs a progress message in the listing area showing what completer is being
tried. The message will be overwritten by any output when completions are found
and is removed after completion is finished.

single-ignored
This is used by the _ignored completer when there is only one match. If its value
is `show', the single match will be displayed but not inserted. If the value is
`menu', then the single match and the original string are both added as matches and
menu completion is started, making it easy to select either of them.

sort This allows the standard ordering of matches to be overridden.

If its value is `true' or `false', sorting is enabled or disabled. Additionally
the values associated with the `-o' option to compadd can also be listed: match,
nosort, numeric, reverse. If it is not set for the context, the standard behaviour
of the calling widget is used.

The style is tested first against the full context including the tag, and if that
fails to produce a value against the context without the tag.

In many cases where a calling widget explicitly selects a particular ordering in
lieu of the default, a value of `true' is not honoured. An example of where this
is not the case is for command history where the default of sorting matches chrono-
logically may be overridden by setting the style to `true'.

In the _expand completer, if it is set to `true', the expansions generated will al-
ways be sorted. If it is set to `menu', then the expansions are only sorted when
they are offered as single strings but not in the string containing all possible
expansions.

special-dirs
Normally, the completion code will not produce the directory names `.' and `..' as
possible completions. If this style is set to `true', it will add both `.' and
`..' as possible completions; if it is set to `..', only `..' will be added.

The following example sets special-dirs to `..' when the current prefix is empty,
is a single `.', or consists only of a path beginning with `../'. Otherwise the
value is `false'.

zstyle -e ':completion:*' special-dirs \
'[[ $PREFIX = (../)#(|.|..) ]] && reply=(..)'

squeeze-slashes
If set to `true', sequences of slashes in filename paths (for example in
`foo//bar') will be treated as a single slash. This is the usual behaviour of UNIX
paths. However, by default the file completion function behaves as if there were a
`*' between the slashes.

stop If set to `true', the _history_complete_word bindable command will stop once when
reaching the beginning or end of the history. Invoking _history_complete_word will
then wrap around to the opposite end of the history. If this style is set to
`false' (the default), _history_complete_word will loop immediately as in a menu
completion.

strip-comments
If set to `true', this style causes non-essential comment text to be removed from
completion matches. Currently it is only used when completing e-mail addresses
where it removes any display name from the addresses, cutting them down to plain
user@host form.

subst-globs-only
This is used by the _expand completer. If it is set to `true', the expansion will
only be used if it resulted from globbing; hence, if expansions resulted from the
use of the substitute style described below, but these were not further changed by
globbing, the expansions will be rejected.

The default for this style is `false'.

substitute
This boolean style controls whether the _expand completer will first try to expand
all substitutions in the string (such as `$(...)' and `${...}').

The default is `true'.

suffix This is used by the _expand completer if the word starts with a tilde or contains a
parameter expansion. If it is set to `true', the word will only be expanded if it
doesn't have a suffix, i.e. if it is something like `~foo' or `$foo' rather than
`~foo/' or `$foo/bar', unless that suffix itself contains characters eligible for
expansion. The default for this style is `true'.

tag-order
This provides a mechanism for sorting how the tags available in a particular con-
text will be used.

The values for the style are sets of space-separated lists of tags. The tags in
each value will be tried at the same time; if no match is found, the next value is
used. (See the file-patterns style for an exception to this behavior.)

For example:

zstyle ':completion:*:complete:-command-:*:*' tag-order \
'commands functions'

specifies that completion in command position first offers external commands and
shell functions. Remaining tags will be tried if no completions are found.

In addition to tag names, each string in the value may take one of the following
forms:

- If any value consists of only a hyphen, then only the tags specified in the
other values are generated. Normally all tags not explicitly selected are
tried last if the specified tags fail to generate any matches. This means
that a single value consisting only of a single hyphen turns off completion.

! tags...
A string starting with an exclamation mark specifies names of tags that are
not to be used. The effect is the same as if all other possible tags for
the context had been listed.

tag:label ...
Here, tag is one of the standard tags and label is an arbitrary name.
Matches are generated as normal but the name label is used in contexts in-
stead of tag. This is not useful in words starting with !.

If the label starts with a hyphen, the tag is prepended to the label to form
the name used for lookup. This can be used to make the completion system
try a certain tag more than once, supplying different style settings for
each attempt; see below for an example.

tag:label:description
As before, but description will replace the `%d' in the value of the format
style instead of the default description supplied by the completion func-
tion. Spaces in the description must be quoted with a backslash. A `%d'
appearing in description is replaced with the description given by the com-
pletion function.

In any of the forms above the tag may be a pattern or several patterns in the form
`{pat1,pat2...}'. In this case all matching tags will be used except for any given
explicitly in the same string.

One use of these features is to try one tag more than once, setting other styles
differently on each attempt, but still to use all the other tags without having to
repeat them all. For example, to make completion of function names in command po-
sition ignore all the completion functions starting with an underscore the first
time completion is tried:

zstyle ':completion:*:*:-command-:*:*' tag-order \
'functions:-non-comp *' functions
zstyle ':completion:*:functions-non-comp' \
ignored-patterns '_*'

On the first attempt, all tags will be offered but the functions tag will be re-
placed by functions-non-comp. The ignored-patterns style is set for this tag to
exclude functions starting with an underscore. If there are no matches, the second
value of the tag-order style is used which completes functions using the default
tag, this time presumably including all function names.

The matches for one tag can be split into different groups. For example:

zstyle ':completion:*' tag-order \
'options:-long:long\ options
options:-short:short\ options
options:-single-letter:single\ letter\ options'
zstyle ':completion:*:options-long' \
ignored-patterns '[-+](|-|[^-]*)'
zstyle ':completion:*:options-short' \
ignored-patterns '--*' '[-+]?'
zstyle ':completion:*:options-single-letter' \
ignored-patterns '???*'

With the group-names style set, options beginning with `--', options beginning with
a single `-' or `+' but containing multiple characters, and single-letter options
will be displayed in separate groups with different descriptions.

Another use of patterns is to try multiple match specifications one after another.
The matcher-list style offers something similar, but it is tested very early in the
completion system and hence can't be set for single commands nor for more specific
contexts. Here is how to try normal completion without any match specification
and, if that generates no matches, try again with case-insensitive matching, re-
stricting the effect to arguments of the command foo:

zstyle ':completion:*:*:foo:*:*' tag-order '*' '*:-case'
zstyle ':completion:*-case' matcher 'm:{a-z}={A-Z}'

First, all the tags offered when completing after foo are tried using the normal
tag name. If that generates no matches, the second value of tag-order is used,
which tries all tags again except that this time each has -case appended to its
name for lookup of styles. Hence this time the value for the matcher style from
the second call to zstyle in the example is used to make completion case-insensi-
tive.

It is possible to use the -e option of the zstyle builtin command to specify condi-
tions for the use of particular tags. For example:

zstyle -e '*:-command-:*' tag-order '
if [[ -n $PREFIX$SUFFIX ]]; then
reply=( )
else
reply=( - )
fi'

Completion in command position will be attempted only if the string typed so far is
not empty. This is tested using the PREFIX special parameter; see zshcompwid for a
description of parameters which are special inside completion widgets. Setting re-
ply to an empty array provides the default behaviour of trying all tags at once;
setting it to an array containing only a hyphen disables the use of all tags and
hence of all completions.

If no tag-order style has been defined for a context, the strings `(|*-)argument-*
(|*-)option-* values' and `options' plus all tags offered by the completion func-
tion will be used to provide a sensible default behavior that causes arguments
(whether normal command arguments or arguments of options) to be completed before
option names for most commands.

urls This is used together with the urls tag by functions completing URLs.

If the value consists of more than one string, or if the only string does not name
a file or directory, the strings are used as the URLs to complete.

If the value contains only one string which is the name of a normal file the URLs
are taken from that file (where the URLs may be separated by white space or new-
lines).

Finally, if the only string in the value names a directory, the directory hierarchy
rooted at this directory gives the completions. The top level directory should be
the file access method, such as `http', `ftp', `bookmark' and so on. In many cases
the next level of directories will be a filename. The directory hierarchy can de-
scend as deep as necessary.

For example,

zstyle ':completion:*' urls ~/.urls
mkdir -p ~/.urls/ftp/ftp.zsh.org/pub

allows completion of all the components of the URL ftp://ftp.zsh.org/pub after
suitable commands such as `netscape' or `lynx'. Note, however, that access methods
and files are completed separately, so if the hosts style is set hosts can be com-
pleted without reference to the urls style.

See the description in the function _urls itself for more information (e.g. `more
$^fpath/_urls(N)').

use-cache
If this is set, the completion caching layer is activated for any completions which
use it (via the _store_cache, _retrieve_cache, and _cache_invalid functions). The
directory containing the cache files can be changed with the cache-path style.

use-compctl
If this style is set to a string not equal to false, 0, no, and off, the completion
system may use any completion specifications defined with the compctl builtin com-
mand. If the style is unset, this is done only if the zsh/compctl module is
loaded. The string may also contain the substring `first' to use completions de-
fined with `compctl -T', and the substring `default' to use the completion defined
with `compctl -D'.

Note that this is only intended to smooth the transition from compctl to the new
completion system and may disappear in the future.

Note also that the definitions from compctl will only be used if there is no spe-
cific completion function for the command in question. For example, if there is a
function _foo to complete arguments to the command foo, compctl will never be in-
voked for foo. However, the compctl version will be tried if foo only uses default
completion.

use-ip By default, the function _hosts that completes host names strips IP addresses from
entries read from host databases such as NIS and ssh files. If this style is
`true', the corresponding IP addresses can be completed as well. This style is not
use in any context where the hosts style is set; note also it must be set before
the cache of host names is generated (typically the first completion attempt).

users This may be set to a list of usernames to be completed. If it is not set all user-
names will be completed. Note that if it is set only that list of users will be
completed; this is because on some systems querying all users can take a prohibi-
tive amount of time.

users-hosts
The values of this style should be of the form `user@host' or `user:host'. It is
used for commands that need pairs of user- and hostnames. These commands will com-
plete usernames from this style (only), and will restrict subsequent hostname com-
pletion to hosts paired with that user in one of the values of the style.

It is possible to group values for sets of commands which allow a remote login,
such as rlogin and ssh, by using the my-accounts tag. Similarly, values for sets
of commands which usually refer to the accounts of other people, such as talk and
finger, can be grouped by using the other-accounts tag. More ambivalent commands
may use the accounts tag.

users-hosts-ports
Like users-hosts but used for commands like telnet and containing strings of the
form `user@host:port'.

verbose
If set, as it is by default, the completion listing is more verbose. In particular
many commands show descriptions for options if this style is `true'.

word This is used by the _list completer, which prevents the insertion of completions
until a second completion attempt when the line has not changed. The normal way of
finding out if the line has changed is to compare its entire contents between the
two occasions. If this style is `true', the comparison is instead performed only
on the current word. Hence if completion is performed on another word with the
same contents, completion will not be delayed.

CONTROL FUNCTIONS
The initialization script compinit redefines all the widgets which perform completion to
call the supplied widget function _main_complete. This function acts as a wrapper calling
the so-called `completer' functions that generate matches. If _main_complete is called
with arguments, these are taken as the names of completer functions to be called in the
order given. If no arguments are given, the set of functions to try is taken from the
completer style. For example, to use normal completion and correction if that doesn't
generate any matches:

zstyle ':completion:*' completer _complete _correct

after calling compinit. The default value for this style is `_complete _ignored', i.e.
normally only ordinary completion is tried, first with the effect of the ignored-patterns
style and then without it. The _main_complete function uses the return status of the com-
pleter functions to decide if other completers should be called. If the return status is
zero, no other completers are tried and the _main_complete function returns.

If the first argument to _main_complete is a single hyphen, the arguments will not be
taken as names of completers. Instead, the second argument gives a name to use in the
completer field of the context and the other arguments give a command name and arguments
to call to generate the matches.

The following completer functions are contained in the distribution, although users may
write their own. Note that in contexts the leading underscore is stripped, for example
basic completion is performed in the context `:completion::complete:...'.

_all_matches
This completer can be used to add a string consisting of all other matches. As it
influences later completers it must appear as the first completer in the list. The
list of all matches is affected by the avoid-completer and old-matches styles de-
scribed above.

It may be useful to use the _generic function described below to bind _all_matches
to its own keystroke, for example:

zle -C all-matches complete-word _generic
bindkey '^Xa' all-matches
zstyle ':completion:all-matches:*' old-matches only
zstyle ':completion:all-matches::::' completer _all_matches

Note that this does not generate completions by itself: first use any of the stan-
dard ways of generating a list of completions, then use ^Xa to show all matches.
It is possible instead to add a standard completer to the list and request that the
list of all matches should be directly inserted:

zstyle ':completion:all-matches::::' completer \
_all_matches _complete
zstyle ':completion:all-matches:*' insert true

In this case the old-matches style should not be set.

_approximate
This is similar to the basic _complete completer but allows the completions to un-
dergo corrections. The maximum number of errors can be specified by the max-errors
style; see the description of approximate matching in zshexpn(1) for how errors are
counted. Normally this completer will only be tried after the normal _complete
completer:

zstyle ':completion:*' completer _complete _approximate

This will give correcting completion if and only if normal completion yields no
possible completions. When corrected completions are found, the completer will
normally start menu completion allowing you to cycle through these strings.

This completer uses the tags corrections and original when generating the possible
corrections and the original string. The format style for the former may contain
the additional sequences `%e' and `%o' which will be replaced by the number of er-
rors accepted to generate the corrections and the original string, respectively.

The completer progressively increases the number of errors allowed up to the limit
by the max-errors style, hence if a completion is found with one error, no comple-
tions with two errors will be shown, and so on. It modifies the completer name in
the context to indicate the number of errors being tried: on the first try the com-
pleter field contains `approximate-1', on the second try `approximate-2', and so
on.

When _approximate is called from another function, the number of errors to accept
may be passed with the -a option. The argument is in the same format as the
max-errors style, all in one string.

Note that this completer (and the _correct completer mentioned below) can be quite
expensive to call, especially when a large number of errors are allowed. One way
to avoid this is to set up the completer style using the -e option to zstyle so
that some completers are only used when completion is attempted a second time on
the same string, e.g.:

zstyle -e ':completion:*' completer '
if [[ $_last_try != "$HISTNO$BUFFER$CURSOR" ]]; then
_last_try="$HISTNO$BUFFER$CURSOR"
reply=(_complete _match _prefix)
else
reply=(_ignored _correct _approximate)
fi'

This uses the HISTNO parameter and the BUFFER and CURSOR special parameters that
are available inside zle and completion widgets to find out if the command line
hasn't changed since the last time completion was tried. Only then are the _ig-
nored, _correct and _approximate completers called.

_canonical_paths [ -A var ] [ -N ] [ -MJV12nfX ] tag descr [ paths ... ]
This completion function completes all paths given to it, and also tries to offer
completions which point to the same file as one of the paths given (relative path
when an absolute path is given, and vice versa; when ..'s are present in the word
to be completed; and some paths got from symlinks).

-A, if specified, takes the paths from the array variable specified. Paths can also
be specified on the command line as shown above. -N, if specified, prevents canon-
icalizing the paths given before using them for completion, in case they are al-
ready so. The options -M, -J, -V, -1, -2, -n, -F, -X are passed to compadd.

See _description for a description of tag and descr.

_cmdambivalent
Completes the remaining positional arguments as an external command. The external
command and its arguments are completed as separate arguments (in a manner appro-
priate for completing /usr/bin/env) if there are two or more remaining positional
arguments on the command line, and as a quoted command string (in the manner of
system(...)) otherwise. See also _cmdstring and _precommand.

This function takes no arguments.

_cmdstring
Completes an external command as a single argument, as for system(...).

_complete
This completer generates all possible completions in a context-sensitive manner,
i.e. using the settings defined with the compdef function explained above and the
current settings of all special parameters. This gives the normal completion be-
haviour.

To complete arguments of commands, _complete uses the utility function _normal,
which is in turn responsible for finding the particular function; it is described
below. Various contexts of the form -context- are handled specifically. These are
all mentioned above as possible arguments to the #compdef tag.

Before trying to find a function for a specific context, _complete checks if the
parameter `compcontext' is set. Setting `compcontext' allows the usual completion
dispatching to be overridden which is useful in places such as a function that uses
vared for input. If it is set to an array, the elements are taken to be the possi-
ble matches which will be completed using the tag `values' and the description
`value'. If it is set to an associative array, the keys are used as the possible
completions and the values (if non-empty) are used as descriptions for the matches.
If `compcontext' is set to a string containing colons, it should be of the form
`tag:descr:action'. In this case the tag and descr give the tag and description to
use and the action indicates what should be completed in one of the forms accepted
by the _arguments utility function described below.

Finally, if `compcontext' is set to a string without colons, the value is taken as
the name of the context to use and the function defined for that context will be
called. For this purpose, there is a special context named -command-line- that
completes whole command lines (commands and their arguments). This is not used by
the completion system itself but is nonetheless handled when explicitly called.

_correct
Generate corrections, but not completions, for the current word; this is similar to
_approximate but will not allow any number of extra characters at the cursor as
that completer does. The effect is similar to spell-checking. It is based on _ap-
proximate, but the completer field in the context name is correct.

For example, with:

zstyle ':completion:::::' completer \
_complete _correct _approximate
zstyle ':completion:*:correct:::' max-errors 2 not-numeric
zstyle ':completion:*:approximate:::' max-errors 3 numeric

correction will accept up to two errors. If a numeric argument is given, correc-
tion will not be performed, but correcting completion will be, and will accept as
many errors as given by the numeric argument. Without a numeric argument, first
correction and then correcting completion will be tried, with the first one accept-
ing two errors and the second one accepting three errors.

When _correct is called as a function, the number of errors to accept may be given
following the -a option. The argument is in the same form a values to the accept
style, all in one string.

This completer function is intended to be used without the _approximate completer
or, as in the example, just before it. Using it after the _approximate completer
is useless since _approximate will at least generate the corrected strings gener-
ated by the _correct completer -- and probably more.

_expand
This completer function does not really perform completion, but instead checks if
the word on the command line is eligible for expansion and, if it is, gives de-
tailed control over how this expansion is done. For this to happen, the completion
system needs to be invoked with complete-word, not expand-or-complete (the default
binding for TAB), as otherwise the string will be expanded by the shell's internal
mechanism before the completion system is started. Note also this completer should
be called before the _complete completer function.

The tags used when generating expansions are all-expansions for the string contain-
ing all possible expansions, expansions when adding the possible expansions as sin-
gle matches and original when adding the original string from the line. The order
in which these strings are generated, if at all, can be controlled by the group-or-
der and tag-order styles, as usual.

The format string for all-expansions and for expansions may contain the sequence
`%o' which will be replaced by the original string from the line.

The kind of expansion to be tried is controlled by the substitute, glob and
subst-globs-only styles.

It is also possible to call _expand as a function, in which case the different
modes may be selected with options: -s for substitute, -g for glob and -o for
subst-globs-only.

_expand_alias
If the word the cursor is on is an alias, it is expanded and no other completers
are called. The types of aliases which are to be expanded can be controlled with
the styles regular, global and disabled.

This function is also a bindable command, see the section `Bindable Commands' be-
low.

_extensions
If the cursor follows the string `*.', filename extensions are completed. The ex-
tensions are taken from files in current directory or a directory specified at the
beginning of the current word. For exact matches, completion continues to allow
other completers such as _expand to expand the pattern. The standard add-space and
prefix-hidden styles are observed.

_external_pwds
Completes current directories of other zsh processes belonging to the current user.

This is intended to be used via _generic, bound to a custom key combination. Note
that pattern matching is enabled so matching is performed similar to how it works
with the _match completer.

_history
Complete words from the shell's command history. This completer can be controlled
by the remove-all-dups, and sort styles as for the _history_complete_word bindable
command, see the section `Bindable Commands' below and the section `Completion Sys-
tem Configuration' above.

_ignored
The ignored-patterns style can be set to a list of patterns which are compared
against possible completions; matching ones are removed. With this completer those
matches can be reinstated, as if no ignored-patterns style were set. The completer
actually generates its own list of matches; which completers are invoked is deter-
mined in the same way as for the _prefix completer. The single-ignored style is
also available as described above.

_list This completer allows the insertion of matches to be delayed until completion is
attempted a second time without the word on the line being changed. On the first
attempt, only the list of matches will be shown. It is affected by the styles con-
dition and word, see the section `Completion System Configuration' above.

_match This completer is intended to be used after the _complete completer. It behaves
similarly but the string on the command line may be a pattern to match against
trial completions. This gives the effect of the GLOB_COMPLETE option.

Normally completion will be performed by taking the pattern from the line, insert-
ing a `*' at the cursor position and comparing the resulting pattern with the pos-
sible completions generated. This can be modified with the match-original style
described above.

The generated matches will be offered in a menu completion unless the insert-unam-
biguous style is set to `true'; see the description above for other options for
this style.

Note that matcher specifications defined globally or used by the completion func-
tions (the styles matcher-list and matcher) will not be used.

_menu This completer was written as simple example function to show how menu completion
can be enabled in shell code. However, it has the notable effect of disabling menu
selection which can be useful with _generic based widgets. It should be used as the
first completer in the list. Note that this is independent of the setting of the
MENU_COMPLETE option and does not work with the other menu completion widgets such
as reverse-menu-complete, or accept-and-menu-complete.

_oldlist
This completer controls how the standard completion widgets behave when there is an
existing list of completions which may have been generated by a special completion
(i.e. a separately-bound completion command). It allows the ordinary completion
keys to continue to use the list of completions thus generated, instead of produc-
ing a new list of ordinary contextual completions. It should appear in the list of
completers before any of the widgets which generate matches. It uses two styles:
old-list and old-menu, see the section `Completion System Configuration' above.

_precommand
Complete an external command in word-separated arguments, as for exec and
/usr/bin/env.

_prefix
This completer can be used to try completion with the suffix (everything after the
cursor) ignored. In other words, the suffix will not be considered to be part of
the word to complete. The effect is similar to the expand-or-complete-prefix com-
mand.

The completer style is used to decide which other completers are to be called to
generate matches. If this style is unset, the list of completers set for the cur-
rent context is used -- except, of course, the _prefix completer itself. Further-
more, if this completer appears more than once in the list of completers only those
completers not already tried by the last invocation of _prefix will be called.

For example, consider this global completer style:

zstyle ':completion:*' completer \
_complete _prefix _correct _prefix:foo

Here, the _prefix completer tries normal completion but ignoring the suffix. If
that doesn't generate any matches, and neither does the call to the _correct com-
pleter after it, _prefix will be called a second time and, now only trying correc-
tion with the suffix ignored. On the second invocation the completer part of the
context appears as `foo'.

To use _prefix as the last resort and try only normal completion when it is in-
voked:

zstyle ':completion:*' completer _complete ... _prefix
zstyle ':completion::prefix:*' completer _complete

The add-space style is also respected. If it is set to `true' then _prefix will
insert a space between the matches generated (if any) and the suffix.

Note that this completer is only useful if the COMPLETE_IN_WORD option is set; oth-
erwise, the cursor will be moved to the end of the current word before the comple-
tion code is called and hence there will be no suffix.

_user_expand
This completer behaves similarly to the _expand completer but instead performs ex-
pansions defined by users. The styles add-space and sort styles specific to the
_expand completer are usable with _user_expand in addition to other styles handled
more generally by the completion system. The tag all-expansions is also available.

The expansion depends on the array style user-expand being defined for the current
context; remember that the context for completers is less specific than that for
contextual completion as the full context has not yet been determined. Elements of
the array may have one of the following forms:

$hash

hash is the name of an associative array. Note this is not a full parameter
expression, merely a $, suitably quoted to prevent immediate expansion, fol-
lowed by the name of an associative array. If the trial expansion word
matches a key in hash, the resulting expansion is the corresponding value.
_func

_func is the name of a shell function whose name must begin with _ but is
not otherwise special to the completion system. The function is called with
the trial word as an argument. If the word is to be expanded, the function
should set the array reply to a list of expansions. Optionally, it can set
REPLY to a word that will be used as a description for the set of expan-
sions. The return status of the function is irrelevant.
BINDABLE COMMANDS
In addition to the context-dependent completions provided, which are expected to work in
an intuitively obvious way, there are a few widgets implementing special behaviour which
can be bound separately to keys. The following is a list of these and their default bind-
ings.

_bash_completions
This function is used by two widgets, _bash_complete-word and _bash_list-choices.
It exists to provide compatibility with completion bindings in bash. The last
character of the binding determines what is completed: `!', command names; `$', en-
vironment variables; `@', host names; `/', file names; `~' user names. In bash,
the binding preceded by `\e' gives completion, and preceded by `^X' lists options.
As some of these bindings clash with standard zsh bindings, only `\e~' and `^X~'
are bound by default. To add the rest, the following should be added to .zshrc af-
ter compinit has been run:

for key in '!' '$' '@' '/' '~'; do
bindkey "\e$key" _bash_complete-word
bindkey "^X$key" _bash_list-choices
done

This includes the bindings for `~' in case they were already bound to something
else; the completion code does not override user bindings.

_correct_filename (^XC)
Correct the filename path at the cursor position. Allows up to six errors in the
name. Can also be called with an argument to correct a filename path, indepen-
dently of zle; the correction is printed on standard output.

_correct_word (^Xc)
Performs correction of the current argument using the usual contextual completions
as possible choices. This stores the string `correct-word' in the function field of
the context name and then calls the _correct completer.

_expand_alias (^Xa)
This function can be used as a completer and as a bindable command. It expands the
word the cursor is on if it is an alias. The types of alias expanded can be con-
trolled with the styles regular, global and disabled.

When used as a bindable command there is one additional feature that can be se-
lected by setting the complete style to `true'. In this case, if the word is not
the name of an alias, _expand_alias tries to complete the word to a full alias name
without expanding it. It leaves the cursor directly after the completed word so
that invoking _expand_alias once more will expand the now-complete alias name.

_expand_word (^Xe)
Performs expansion on the current word: equivalent to the standard expand-word
command, but using the _expand completer. Before calling it, the function field of
the context is set to `expand-word'.

_generic
This function is not defined as a widget and not bound by default. However, it can
be used to define a widget and will then store the name of the widget in the func-
tion field of the context and call the completion system. This allows custom com-
pletion widgets with their own set of style settings to be defined easily. For ex-
ample, to define a widget that performs normal completion and starts menu selec-
tion:

zle -C foo complete-word _generic
bindkey '...' foo
zstyle ':completion:foo:*' menu yes select=1

Note in particular that the completer style may be set for the context in order to
change the set of functions used to generate possible matches. If _generic is
called with arguments, those are passed through to _main_complete as the list of
completers in place of those defined by the completer style.

_history_complete_word (\e/)
Complete words from the shell's command history. This uses the list, re-
move-all-dups, sort, and stop styles.

_most_recent_file (^Xm)
Complete the name of the most recently modified file matching the pattern on the
command line (which may be blank). If given a numeric argument N, complete the Nth
most recently modified file. Note the completion, if any, is always unique.

_next_tags (^Xn)
This command alters the set of matches used to that for the next tag, or set of
tags, either as given by the tag-order style or as set by default; these matches
would otherwise not be available. Successive invocations of the command cycle
through all possible sets of tags.

_read_comp (^X^R)
Prompt the user for a string, and use that to perform completion on the current
word. There are two possibilities for the string. First, it can be a set of words
beginning `_', for example `_files -/', in which case the function with any argu-
ments will be called to generate the completions. Unambiguous parts of the func-
tion name will be completed automatically (normal completion is not available at
this point) until a space is typed.

Second, any other string will be passed as a set of arguments to compadd and should
hence be an expression specifying what should be completed.

A very restricted set of editing commands is available when reading the string:
`DEL' and `^H' delete the last character; `^U' deletes the line, and `^C' and `^G'
abort the function, while `RET' accepts the completion. Note the string is used
verbatim as a command line, so arguments must be quoted in accordance with standard
shell rules.

Once a string has been read, the next call to _read_comp will use the existing
string instead of reading a new one. To force a new string to be read, call
_read_comp with a numeric argument.

_complete_debug (^X?)
This widget performs ordinary completion, but captures in a temporary file a trace
of the shell commands executed by the completion system. Each completion attempt
gets its own file. A command to view each of these files is pushed onto the editor
buffer stack.

_complete_help (^Xh)
This widget displays information about the context names, the tags, and the comple-
tion functions used when completing at the current cursor position. If given a nu-
meric argument other than 1 (as in `ESC-2 ^Xh'), then the styles used and the con-
texts for which they are used will be shown, too.

Note that the information about styles may be incomplete; it depends on the infor-
mation available from the completion functions called, which in turn is determined
by the user's own styles and other settings.

_complete_help_generic
Unlike other commands listed here, this must be created as a normal ZLE widget
rather than a completion widget (i.e. with zle -N). It is used for generating help
with a widget bound to the _generic widget that is described above.

If this widget is created using the name of the function, as it is by default, then
when executed it will read a key sequence. This is expected to be bound to a call
to a completion function that uses the _generic widget. That widget will be exe-
cuted, and information provided in the same format that the _complete_help widget
displays for contextual completion.

If the widget's name contains debug, for example if it is created as `zle -N _com-
plete_debug_generic _complete_help_generic', it will read and execute the keystring
for a generic widget as before, but then generate debugging information as done by
_complete_debug for contextual completion.

If the widget's name contains noread, it will not read a keystring but instead ar-
range that the next use of a generic widget run in the same shell will have the ef-
fect as described above.

The widget works by setting the shell parameter ZSH_TRACE_GENERIC_WIDGET which is
read by _generic. Unsetting the parameter cancels any pending effect of the noread
form.

For example, after executing the following:

zle -N _complete_debug_generic _complete_help_generic
bindkey '^x:' _complete_debug_generic

typing `C-x :' followed by the key sequence for a generic widget will cause trace
output for that widget to be saved to a file.

_complete_tag (^Xt)
This widget completes symbol tags created by the etags or ctags programmes (note
there is no connection with the completion system's tags) stored in a file TAGS, in
the format used by etags, or tags, in the format created by ctags. It will look
back up the path hierarchy for the first occurrence of either file; if both exist,
the file TAGS is preferred. You can specify the full path to a TAGS or tags file
by setting the parameter $TAGSFILE or $tagsfile respectively. The corresponding
completion tags used are etags and vtags, after emacs and vi respectively.

UTILITY FUNCTIONS
Descriptions follow for utility functions that may be useful when writing completion func-
tions. If functions are installed in subdirectories, most of these reside in the Base
subdirectory. Like the example functions for commands in the distribution, the utility
functions generating matches all follow the convention of returning status zero if they
generated completions and non-zero if no matching completions could be added.

_absolute_command_paths
This function completes external commands as absolute paths (unlike _command_names
-e which completes their basenames). It takes no arguments.

_all_labels [ -x ] [ -12VJ ] tag name descr [ command arg ... ]
This is a convenient interface to the _next_label function below, implementing the
loop shown in the _next_label example. The command and its arguments are called to
generate the matches. The options stored in the parameter name will automatically
be inserted into the args passed to the command. Normally, they are put directly
after the command, but if one of the args is a single hyphen, they are inserted di-
rectly before that. If the hyphen is the last argument, it will be removed from
the argument list before the command is called. This allows _all_labels to be used
in almost all cases where the matches can be generated by a single call to the com-
padd builtin command or by a call to one of the utility functions.

For example:

local expl
...
if _requested foo; then
...
_all_labels foo expl '...' compadd ... - $matches
fi

Will complete the strings from the matches parameter, using compadd with additional
options which will take precedence over those generated by _all_labels.

_alternative [ -O name ] [ -C name ] spec ...
This function is useful in simple cases where multiple tags are available. Essen-
tially it implements a loop like the one described for the _tags function below.

The tags to use and the action to perform if a tag is requested are described using
the specs which are of the form: `tag:descr:action'. The tags are offered using
_tags and if the tag is requested, the action is executed with the given descrip-
tion descr. The actions are those accepted by the _arguments function (described
below), excluding the `->state' and `=...' forms.

For example, the action may be a simple function call:

_alternative \
'users:user:_users' \
'hosts:host:_hosts'

offers usernames and hostnames as possible matches, generated by the _users and
_hosts functions respectively.

Like _arguments, this function uses _all_labels to execute the actions, which will
loop over all sets of tags. Special handling is only required if there is an addi-
tional valid tag, for example inside a function called from _alternative.

The option `-O name' is used in the same way as by the _arguments function. In
other words, the elements of the name array will be passed to compadd when execut-
ing an action.

Like _tags this function supports the -C option to give a different name for the
argument context field.

_arguments [ -nswWCRS ] [ -A pat ] [ -O name ] [ -M matchspec ]
[ : ] spec ...
_arguments [ opt ... ] -- [ -l ] [ -i pats ] [ -s pair ]
[ helpspec ...]
This function can be used to give a complete specification for completion for a
command whose arguments follow standard UNIX option and argument conventions.

Options Overview

Options to _arguments itself must be in separate words, i.e. -s -w, not -sw. The
options are followed by specs that describe options and arguments of the analyzed
command. To avoid ambiguity, all options to _arguments itself may be separated
from the spec forms by a single colon.

The `--' form is used to intuit spec forms from the help output of the command be-
ing analyzed, and is described in detail below. The opts for the `--' form are
otherwise the same options as the first form. Note that `-s' following `--' has a
distinct meaning from `-s' preceding `--', and both may appear.

The option switches -s, -S, -A, -w, and -W affect how _arguments parses the ana-
lyzed command line's options. These switches are useful for commands with standard
argument parsing.

The options of _arguments have the following meanings:

-n With this option, _arguments sets the parameter NORMARG to the position of
the first normal argument in the $words array, i.e. the position after the
end of the options. If that argument has not been reached, NORMARG is set
to -1. The caller should declare `integer NORMARG' if the -n option is
passed; otherwise the parameter is not used.

-s Enable option stacking for single-letter options, whereby multiple sin-
gle-letter options may be combined into a single word. For example, the two
options `-x' and `-y' may be combined into a single word `-xy'. By default,
every word corresponds to a single option name (`-xy' is a single option
named `xy').

Options beginning with a single hyphen or plus sign are eligible for stack-
ing; words beginning with two hyphens are not.

Note that -s after -- has a different meaning, which is documented in the
segment entitled `Deriving spec forms from the help output'.

-w In combination with -s, allow option stacking even if one or more of the op-
tions take arguments. For example, if -x takes an argument, with no -s,
`-xy' is considered as a single (unhandled) option; with -s, -xy is an op-
tion with the argument `y'; with both -s and -w, -xy is the option -x and
the option -y with arguments to -x (and to -y, if it takes arguments) still
to come in subsequent words.

-W This option takes -w a stage further: it is possible to complete sin-
gle-letter options even after an argument that occurs in the same word.
However, it depends on the action performed whether options will really be
completed at this point. For more control, use a utility function like
_guard as part of the action.

-C Modify the curcontext parameter for an action of the form `->state'. This
is discussed in detail below.

-R Return status 300 instead of zero when a $state is to be handled, in the
`->string' syntax.

-S Do not complete options after a `--' appearing on the line, and ignore the
`--'. For example, with -S, in the line

foobar -x -- -y

the `-x' is considered an option, the `-y' is considered an argument, and
the `--' is considered to be neither.

-A pat Do not complete options after the first non-option argument on the line.
pat is a pattern matching all strings which are not to be taken as argu-
ments. For example, to make _arguments stop completing options after the
first normal argument, but ignoring all strings starting with a hyphen even
if they are not described by one of the optspecs, the form is `-A "-*"'.

-O name
Pass the elements of the array name as arguments to functions called to exe-
cute actions. This is discussed in detail below.

-M matchspec
Use the match specification matchspec for completing option names and val-
ues. The default matchspec allows partial word completion after `_' and
`-', such as completing `-f-b' to `-foo-bar'. The default matchspec is:
r:|[_-]=* r:|=*

specs: overview

Each of the following forms is a spec describing individual sets of options or ar-
guments on the command line being analyzed.

n:message:action
n::message:action
This describes the n'th normal argument. The message will be printed above
the matches generated and the action indicates what can be completed in this
position (see below). If there are two colons before the message the argu-
ment is optional. If the message contains only white space, nothing will be
printed above the matches unless the action adds an explanation string it-
self.

:message:action
::message:action
Similar, but describes the next argument, whatever number that happens to
be. If all arguments are specified in this form in the correct order the
numbers are unnecessary.

*:message:action
*::message:action
*:::message:action
This describes how arguments (usually non-option arguments, those not begin-
ning with - or +) are to be completed when neither of the first two forms
was provided. Any number of arguments can be completed in this fashion.

With two colons before the message, the words special array and the CURRENT
special parameter are modified to refer only to the normal arguments when
the action is executed or evaluated. With three colons before the message
they are modified to refer only to the normal arguments covered by this de-
scription.

optspec
optspec:...
This describes an option. The colon indicates handling for one or more ar-
guments to the option; if it is not present, the option is assumed to take
no arguments.

The following forms are available for the initial optspec, whether or not
the option has arguments.

*optspec
Here optspec is one of the remaining forms below. This indicates the
following optspec may be repeated. Otherwise if the corresponding
option is already present on the command line to the left of the cur-
sor it will not be offered again.

-optname
+optname
In the simplest form the optspec is just the option name beginning
with a minus or a plus sign, such as `-foo'. The first argument for
the option (if any) must follow as a separate word directly after the
option.

Either of `-+optname' and `+-optname' can be used to specify that
-optname and +optname are both valid.

In all the remaining forms, the leading `-' may be replaced by or
paired with `+' in this way.

-optname-
The first argument of the option must come directly after the option
name in the same word. For example, `-foo-:...' specifies that the
completed option and argument will look like `-fooarg'.

-optname+
The first argument may appear immediately after optname in the same
word, or may appear as a separate word after the option. For exam-
ple, `-foo+:...' specifies that the completed option and argument
will look like either `-fooarg' or `-foo arg'.

-optname=
The argument may appear as the next word, or in same word as the op-
tion name provided that it is separated from it by an equals sign,
for example `-foo=arg' or `-foo arg'.

-optname=-
The argument to the option must appear after an equals sign in the
same word, and may not be given in the next argument.

optspec[explanation]
An explanation string may be appended to any of the preceding forms
of optspec by enclosing it in brackets, as in `-q[query operation]'.

The verbose style is used to decide whether the explanation strings
are displayed with the option in a completion listing.

If no bracketed explanation string is given but the auto-description
style is set and only one argument is described for this optspec, the
value of the style is displayed, with any appearance of the sequence
`%d' in it replaced by the message of the first optarg that follows
the optspec; see below.

It is possible for options with a literal `+' or `=' to appear, but that
character must be quoted, for example `-\+'.

Each optarg following an optspec must take one of the following forms:

:message:action
::message:action
An argument to the option; message and action are treated as for or-
dinary arguments. In the first form, the argument is mandatory, and
in the second form it is optional.

This group may be repeated for options which take multiple arguments.
In other words, :message1:action1:message2:action2 specifies that the
option takes two arguments.

:*pattern:message:action
:*pattern::message:action
:*pattern:::message:action
This describes multiple arguments. Only the last optarg for an op-
tion taking multiple arguments may be given in this form. If the
pattern is empty (i.e. :*:), all the remaining words on the line are
to be completed as described by the action; otherwise, all the words
up to and including a word matching the pattern are to be completed
using the action.

Multiple colons are treated as for the `*:...' forms for ordinary ar-
guments: when the message is preceded by two colons, the words spe-
cial array and the CURRENT special parameter are modified during the
execution or evaluation of the action to refer only to the words af-
ter the option. When preceded by three colons, they are modified to
refer only to the words covered by this description.

Any literal colon in an optname, message, or action must be preceded by a back-
slash, `\:'.

Each of the forms above may be preceded by a list in parentheses of option names
and argument numbers. If the given option is on the command line, the options and
arguments indicated in parentheses will not be offered. For example, `(-two -three
1)-one:...' completes the option `-one'; if this appears on the command line, the
options -two and -three and the first ordinary argument will not be completed after
it. `(-foo):...' specifies an ordinary argument completion; -foo will not be com-
pleted if that argument is already present.

Other items may appear in the list of excluded options to indicate various other
items that should not be applied when the current specification is matched: a sin-
gle star (*) for the rest arguments (i.e. a specification of the form `*:...'); a
colon (:) for all normal (non-option-) arguments; and a hyphen (-) for all options.
For example, if `(*)' appears before an option and the option appears on the com-
mand line, the list of remaining arguments (those shown in the above table begin-
ning with `*:') will not be completed.

To aid in reuse of specifications, it is possible to precede any of the forms above
with `!'; then the form will no longer be completed, although if the option or ar-
gument appears on the command line they will be skipped as normal. The main use
for this is when the arguments are given by an array, and _arguments is called re-
peatedly for more specific contexts: on the first call `_arguments $global_options'
is used, and on subsequent calls `_arguments !$^global_options'.

specs: actions

In each of the forms above the action determines how completions should be gener-
ated. Except for the `->string' form below, the action will be executed by calling
the _all_labels function to process all tag labels. No special handling of tags is
needed unless a function call introduces a new one.

The functions called to execute actions will be called with the elements of the ar-
ray named by the `-O name' option as arguments. This can be used, for example, to
pass the same set of options for the compadd builtin to all actions.

The forms for action are as follows.

(single unquoted space)
This is useful where an argument is required but it is not possible or de-
sirable to generate matches for it. The message will be displayed but no
completions listed. Note that even in this case the colon at the end of the
message is needed; it may only be omitted when neither a message nor an ac-
tion is given.

(item1 item2 ...)
One of a list of possible matches, for example:

:foo:(foo bar baz)

((item1\:desc1 ...))
Similar to the above, but with descriptions for each possible match. Note
the backslash before the colon. For example,

:foo:((a\:bar b\:baz))

The matches will be listed together with their descriptions if the descrip-
tion style is set with the values tag in the context.

->string
In this form, _arguments processes the arguments and options and then re-
turns control to the calling function with parameters set to indicate the
state of processing; the calling function then makes its own arrangements
for generating completions. For example, functions that implement a state
machine can use this type of action.

Where _arguments encounters action in the `->string' format, it will strip
all leading and trailing whitespace from string and set the array state to
the set of all strings for which an action is to be performed. The elements
of the array state_descr are assigned the corresponding message field from
each optarg containing such an action.

By default and in common with all other well behaved completion functions,
_arguments returns status zero if it was able to add matches and non-zero
otherwise. However, if the -R option is given, _arguments will instead re-
turn a status of 300 to indicate that $state is to be handled.

In addition to $state and $state_descr, _arguments also sets the global pa-
rameters `context', `line' and `opt_args' as described below, and does not
reset any changes made to the special parameters such as PREFIX and words.
This gives the calling function the choice of resetting these parameters or
propagating changes in them.

A function calling _arguments with at least one action containing a
`->string' must therefore declare appropriate local parameters:

local context state state_descr line
typeset -A opt_args

to prevent _arguments from altering the global environment.

{eval-string}
A string in braces is evaluated as shell code to generate matches. If the
eval-string itself does not begin with an opening parenthesis or brace it is
split into separate words before execution.

= action
If the action starts with `= ' (an equals sign followed by a space), _argu-
ments will insert the contents of the argument field of the current context
as the new first element in the words special array and increment the value
of the CURRENT special parameter. This has the effect of inserting a dummy
word onto the completion command line while not changing the point at which
completion is taking place.

This is most useful with one of the specifiers that restrict the words on
the command line on which the action is to operate (the two- and three-colon
forms above). One particular use is when an action itself causes _arguments
on a restricted range; it is necessary to use this trick to insert an appro-
priate command name into the range for the second call to _arguments to be
able to parse the line.

word...
word...
This covers all forms other than those above. If the action starts with a
space, the remaining list of words will be invoked unchanged.

Otherwise it will be invoked with some extra strings placed after the first
word; these are to be passed down as options to the compadd builtin. They
ensure that the state specified by _arguments, in particular the descrip-
tions of options and arguments, is correctly passed to the completion com-
mand. These additional arguments are taken from the array parameter `expl';
this will be set up before executing the action and hence may be referred to
inside it, typically in an expansion of the form `$expl[@]' which preserves
empty elements of the array.

During the performance of the action the array `line' will be set to the normal ar-
guments from the command line, i.e. the words from the command line after the com-
mand name excluding all options and their arguments. Options are stored in the as-
sociative array `opt_args' with option names as keys and their arguments as the
values. For options that have more than one argument these are given as one
string, separated by colons. All colons and backslashes in the original arguments
are preceded with backslashes.

The parameter `context' is set when returning to the calling function to perform an
action of the form `->string'. It is set to an array of elements corresponding to
the elements of $state. Each element is a suitable name for the argument field of
the context: either a string of the form `option-opt-n' for the n'th argument of
the option -opt, or a string of the form `argument-n' for the n'th argument. For
`rest' arguments, that is those in the list at the end not handled by position, n
is the string `rest'. For example, when completing the argument of the -o option,
the name is `option-o-1', while for the second normal (non-option-) argument it is
`argument-2'.

Furthermore, during the evaluation of the action the context name in the curcontext
parameter is altered to append the same string that is stored in the context param-
eter.

The option -C tells _arguments to modify the curcontext parameter for an action of
the form `->state'. This is the standard parameter used to keep track of the cur-
rent context. Here it (and not the context array) should be made local to the
calling function to avoid passing back the modified value and should be initialised
to the current value at the start of the function:

local curcontext="$curcontext"

This is useful where it is not possible for multiple states to be valid together.

Grouping Options

Options can be grouped to simplify exclusion lists. A group is introduced with `+'
followed by a name for the group in the subsequent word. Whole groups can then be
referenced in an exclusion list or a group name can be used to disambiguate between
two forms of the same option. For example:

_arguments \
'(group2--x)-a' \
+ group1 \
-m \
'(group2)-n' \
+ group2 \
-x -y

If the name of a group is specified in the form `(name)' then only one value from
that group will ever be completed; more formally, all specifications are mutually
exclusive to all other specifications in that group. This is useful for defining
options that are aliases for each other. For example:

_arguments \
-a -b \
+ '(operation)' \
{-c,--compress}'[compress]' \
{-d,--decompress}'[decompress]' \
{-l,--list}'[list]'

If an option in a group appears on the command line, it is stored in the associa-
tive array `opt_args' with 'group-option' as a key. In the example above, a key
`operation--c' is used if the option `-c' is present on the command line.

Specifying Multiple Sets of Arguments

It is possible to specify multiple sets of options and arguments with the sets sep-
arated by single hyphens. This differs from groups in that sets are considered to
be mutually exclusive of each other.

Specifications before the first set and from any group are common to all sets. For
example:

_arguments \
-a \
- set1 \
-c \
- set2 \
-d \
':arg:(x2 y2)'

This defines two sets. When the command line contains the option `-c', the `-d'
option and the argument will not be considered possible completions. When it con-
tains `-d' or an argument, the option `-c' will not be considered. However, after
`-a' both sets will still be considered valid.

As for groups, the name of a set may appear in exclusion lists, either alone or
preceding a normal option or argument specification.

The completion code has to parse the command line separately for each set. This can
be slow so sets should only be used when necessary. A useful alternative is often
an option specification with rest-arguments (as in `-foo:*:...'); here the option
-foo swallows up all remaining arguments as described by the optarg definitions.

Deriving spec forms from the help output

The option `--' allows _arguments to work out the names of long options that sup-
port the `--help' option which is standard in many GNU commands. The command word
is called with the argument `--help' and the output examined for option names.
Clearly, it can be dangerous to pass this to commands which may not support this
option as the behaviour of the command is unspecified.

In addition to options, `_arguments --' will try to deduce the types of arguments
available for options when the form `--opt=val' is valid. It is also possible to
provide hints by examining the help text of the command and adding helpspec of the
form `pattern:message:action'; note that other _arguments spec forms are not used.
The pattern is matched against the help text for an option, and if it matches the
message and action are used as for other argument specifiers. The special case of
`*:' means both message and action are empty, which has the effect of causing op-
tions having no description in the help output to be ordered in listings ahead of
options that have a description.

For example:

_arguments -- '*\*:toggle:(yes no)' \
'*=FILE*:file:_files' \
'*=DIR*:directory:_files -/' \
'*=PATH*:directory:_files -/'

Here, `yes' and `no' will be completed as the argument of options whose description
ends in a star; file names will be completed for options that contain the substring
`=FILE' in the description; and directories will be completed for options whose de-
scription contains `=DIR' or `=PATH'. The last three are in fact the default and
so need not be given explicitly, although it is possible to override the use of
these patterns. A typical help text which uses this feature is:

-C, --directory=DIR change to directory DIR

so that the above specifications will cause directories to be completed after
`--directory', though not after `-C'.

Note also that _arguments tries to find out automatically if the argument for an
option is optional. This can be specified explicitly by doubling the colon before
the message.

If the pattern ends in `(-)', this will be removed from the pattern and the action
will be used only directly after the `=', not in the next word. This is the behav-
iour of a normal specification defined with the form `=-'.

By default, the command (with the option `--help') is run after resetting all the
locale categories (except for LC_CTYPE) to `C'. If the localized help output is
known to work, the option `-l' can be specified after the `_arguments --' so that
the command is run in the current locale.

The `_arguments --' can be followed by the option `-i patterns' to give patterns
for options which are not to be completed. The patterns can be given as the name
of an array parameter or as a literal list in parentheses. For example,

_arguments -- -i \
"(--(en|dis)able-FEATURE*)"

will cause completion to ignore the options `--enable-FEATURE' and `--disable-FEA-
TURE' (this example is useful with GNU configure).

The `_arguments --' form can also be followed by the option `-s pair' to describe
option aliases. The pair consists of a list of alternating patterns and corre-
sponding replacements, enclosed in parens and quoted so that it forms a single ar-
gument word in the _arguments call.

For example, some configure-script help output describes options only as `--en-
able-foo', but the script also accepts the negated form `--disable-foo'. To allow
completion of the second form:

_arguments -- -s "((#s)--enable- --disable-)"

Miscellaneous notes

Finally, note that _arguments generally expects to be the primary function handling
any completion for which it is used. It may have side effects which change the
treatment of any matches added by other functions called after it. To combine _ar-
guments with other functions, those functions should be called either before _argu-
ments, as an action within a spec, or in handlers for `->state' actions.

Here is a more general example of the use of _arguments:

_arguments '-l+:left border:' \
'-format:paper size:(letter A4)' \
'*-copy:output file:_files::resolution:(300 600)' \
':postscript file:_files -g \*.$ps\|eps$' \
'*:page number:'

This describes three options: `-l', `-format', and `-copy'. The first takes one
argument described as `left border' for which no completion will be offered because
of the empty action. Its argument may come directly after the `-l' or it may be
given as the next word on the line.

The `-format' option takes one argument in the next word, described as `paper size'
for which only the strings `letter' and `A4' will be completed.

The `-copy' option may appear more than once on the command line and takes two ar-
guments. The first is mandatory and will be completed as a filename. The second
is optional (because of the second colon before the description `resolution') and
will be completed from the strings `300' and `600'.

The last two descriptions say what should be completed as arguments. The first de-
scribes the first argument as a `postscript file' and makes files ending in `ps' or
`eps' be completed. The last description gives all other arguments the description
`page numbers' but does not offer completions.

_cache_invalid cache_identifier
This function returns status zero if the completions cache corresponding to the
given cache identifier needs rebuilding. It determines this by looking up the
cache-policy style for the current context. This should provide a function name
which is run with the full path to the relevant cache file as the only argument.

Example:

_example_caching_policy () {
# rebuild if cache is more than a week old
local -a oldp
oldp=( "$1"(Nm+7) )
(( $#oldp ))
}

_call_function return name [ arg ... ]
If a function name exists, it is called with the arguments args. The return argu-
ment gives the name of a parameter in which the return status from the function
name should be stored; if return is empty or a single hyphen it is ignored.

The return status of _call_function itself is zero if the function name exists and
was called and non-zero otherwise.

_call_program [ -l ] [ -p ] tag string ...
This function provides a mechanism for the user to override the use of an external
command. It looks up the command style with the supplied tag. If the style is
set, its value is used as the command to execute. The strings from the call to
_call_program, or from the style if set, are concatenated with spaces between them
and the resulting string is evaluated. The return status is the return status of
the command called.

By default, the command is run in an environment where all the locale categories
(except for LC_CTYPE) are reset to `C' by calling the utility function _comp_locale
(see below). If the option `-l' is given, the command is run with the current lo-
cale.

If the option `-p' is supplied it indicates that the command output is influenced
by the permissions it is run with. If the gain-privileges style is set to true,
_call_program will make use of commands such as sudo, if present on the com-
mand-line, to match the permissions to whatever the final command is likely to run
under. When looking up the gain-privileges and command styles, the command compo-
nent of the zstyle context will end with a slash (`/') followed by the command that
would be used to gain privileges.

_combination [ -s pattern ] tag style spec ... field opts ...
This function is used to complete combinations of values, for example pairs of
hostnames and usernames. The style argument gives the style which defines the
pairs; it is looked up in a context with the tag specified.

The style name consists of field names separated by hyphens, for example
`users-hosts-ports'. For each field for a value is already known, a spec of the
form `field=pattern' is given. For example, if the command line so far specifies a
user `pws', the argument `users=pws' should appear.

The next argument with no equals sign is taken as the name of the field for which
completions should be generated (presumably not one of the fields for which the
value is known).

The matches generated will be taken from the value of the style. These should con-
tain the possible values for the combinations in the appropriate order (users,
hosts, ports in the example above). The values for the different fields are sepa-
rated by colons. This can be altered with the option -s to _combination which
specifies a pattern. Typically this is a character class, as for example `-s
"[:@]"' in the case of the users-hosts style. Each `field=pattern' specification
restricts the completions which apply to elements of the style with appropriately
matching fields.

If no style with the given name is defined for the given tag, or if none of the
strings in style's value match, but a function name of the required field preceded
by an underscore is defined, that function will be called to generate the matches.
For example, if there is no `users-hosts-ports' or no matching hostname when a host
is required, the function `_hosts' will automatically be called.

If the same name is used for more than one field, in both the `field=pattern' and
the argument that gives the name of the field to be completed, the number of the
field (starting with one) may be given after the fieldname, separated from it by a
colon.

All arguments after the required field name are passed to compadd when generating
matches from the style value, or to the functions for the fields if they are
called.

_command_names [ -e | - ]
This function completes words that are valid at command position: names of aliases,
builtins, hashed commands, functions, and so on. With the -e flag, only hashed
commands are completed. The - flag is ignored.

_comp_locale
This function resets all the locale categories other than LC_CTYPE to `C' so that
the output from external commands can be easily analyzed by the completion system.
LC_CTYPE retains the current value (taking LC_ALL and LANG into account), ensuring
that non-ASCII characters in file names are still handled properly.

This function should normally be run only in a subshell, because the new locale is
exported to the environment. Typical usage would be `$(_comp_locale; command ...)'.

_completers [ -p ]
This function completes names of completers.

-p Include the leading underscore (`_') in the matches.

_describe [-12JVx] [ -oO | -t tag ] descr name1 [ name2 ] [ opt ... ]
[ -- name1 [ name2 ] [ opt ... ] ... ]
This function associates completions with descriptions. Multiple groups separated
by -- can be supplied, potentially with different completion options opts.

The descr is taken as a string to display above the matches if the format style for
the descriptions tag is set. This is followed by one or two names of arrays fol-
lowed by options to pass to compadd. The array name1 contains the possible comple-
tions with their descriptions in the form `completion:description'. Any literal
colons in completion must be quoted with a backslash. If a name2 is given, it
should have the same number of elements as name1; in this case the corresponding
elements are added as possible completions instead of the completion strings from
name1. The completion list will retain the descriptions from name1. Finally, a
set of completion options can appear.

If the option `-o' appears before the first argument, the matches added will be
treated as names of command options (N.B. not shell options), typically following a
`-', `--' or `+' on the command line. In this case _describe uses the prefix-hid-
den, prefix-needed and verbose styles to find out if the strings should be added as
completions and if the descriptions should be shown. Without the `-o' option, only
the verbose style is used to decide how descriptions are shown. If `-O' is used
instead of `-o', command options are completed as above but _describe will not han-
dle the prefix-needed style.

With the -t option a tag can be specified. The default is `values' or, if the -o
option is given, `options'.

The options -1, -2, -J, -V, -x are passed to _next_label.

If selected by the list-grouped style, strings with the same description will ap-
pear together in the list.

_describe uses the _all_labels function to generate the matches, so it does not
need to appear inside a loop over tag labels.

_description [ -x ] [ -12VJ ] tag name descr [ spec ... ]
This function is not to be confused with the previous one; it is used as a helper
function for creating options to compadd. It is buried inside many of the higher
level completion functions and so often does not need to be called directly.

The styles listed below are tested in the current context using the given tag. The
resulting options for compadd are put into the array named name (this is tradition-
ally `expl', but this convention is not enforced). The description for the corre-
sponding set of matches is passed to the function in descr.

The styles tested are: format, hidden, matcher, ignore-line, ignored-patterns,
group-name and sort. The format style is first tested for the given tag and then
for the descriptions tag if no value was found, while the remainder are only tested
for the tag given as the first argument. The function also calls _setup which
tests some more styles.

The string returned by the format style (if any) will be modified so that the se-
quence `%d' is replaced by the descr given as the third argument without any lead-
ing or trailing white space. If, after removing the white space, the descr is the
empty string, the format style will not be used and the options put into the name
array will not contain an explanation string to be displayed above the matches.

If _description is called with more than three arguments, the additional specs
should be of the form `char:str'. These supply escape sequence replacements for
the format style: every appearance of `%char' will be replaced by string.

If the -x option is given, the description will be passed to compadd using the -x
option instead of the default -X. This means that the description will be dis-
played even if there are no corresponding matches.

The options placed in the array name take account of the group-name style, so
matches are placed in a separate group where necessary. The group normally has its
elements sorted (by passing the option -J to compadd), but if an option starting
with `-V', `-J', `-1', or `-2' is passed to _description, that option will be in-
cluded in the array. Hence it is possible for the completion group to be unsorted
by giving the option `-V', `-1V', or `-2V'.

In most cases, the function will be used like this:

local expl
_description files expl file
compadd "$expl[@]" - "$files[@]"

Note the use of the parameter expl, the hyphen, and the list of matches. Almost
all calls to compadd within the completion system use a similar format; this en-
sures that user-specified styles are correctly passed down to the builtins which
implement the internals of completion.

_dir_list [ -s sep ] [ -S ]
Complete a list of directory names separated by colons (the same format as $PATH).

-s sep Use sep as separator between items. sep defaults to a colon (`:').

-S Add sep instead of slash (`/') as an autoremoveable suffix.

_dispatch context string ...
This sets the current context to context and looks for completion functions to han-
dle this context by hunting through the list of command names or special contexts
(as described above for compdef) given as strings. The first completion function
to be defined for one of the contexts in the list is used to generate matches.
Typically, the last string is -default- to cause the function for default comple-
tion to be used as a fallback.

The function sets the parameter $service to the string being tried, and sets the
context/command field (the fourth) of the $curcontext parameter to the context
given as the first argument.

_email_addresses [ -c ] [ -n plugin ]
Complete email addresses. Addresses are provided by plugins.

-c Complete bare localhost AT domain.tld addresses, without a name part or a com-
ment. Without this option, RFC822 `Firstname Lastname <address>' strings
are completed.

-n plugin
Complete aliases from plugin.

The following plugins are available by default: _email-ldap (see the filter style),
_email-local (completes user@hostname Unix addresses), _email-mail (completes
aliases from ~/.mailrc), _email-mush, _email-mutt, and _email-pine.

Addresses from the _email-foo plugin are added under the tag `email-foo'.

Writing plugins

Plugins are written as separate functions with names starting with `_email-'. They
are invoked with the -c option and compadd options. They should either do their
own completion or set the $reply array to a list of `alias:address' elements and
return 300. New plugins will be picked up and run automatically.

_files The function _files is a wrapper around _path_files. It supports all of the same
functionality, with some enhancements -- notably, it respects the list-dirs-first
style, and it allows users to override the behaviour of the -g and -/ options with
the file-patterns style. _files should therefore be preferred over _path_files in
most cases.

This function accepts the full set of options allowed by _path_files, described be-
low.

_gnu_generic
This function is a simple wrapper around the _arguments function described above.
It can be used to determine automatically the long options understood by commands
that produce a list when passed the option `--help'. It is intended to be used as
a top-level completion function in its own right. For example, to enable option
completion for the commands foo and bar, use

compdef _gnu_generic foo bar

after the call to compinit.

The completion system as supplied is conservative in its use of this function,
since it is important to be sure the command understands the option `--help'.

_guard [ options ] pattern descr
This function displays descr if pattern matches the string to be completed. It is
intended to be used in the action for the specifications passed to _arguments and
similar functions.

The return status is zero if the message was displayed and the word to complete is
not empty, and non-zero otherwise.

The pattern may be preceded by any of the options understood by compadd that are
passed down from _description, namely -M, -J, -V, -1, -2, -n, -F and -X. All of
these options will be ignored. This fits in conveniently with the argument-passing
conventions of actions for _arguments.

As an example, consider a command taking the options -n and -none, where -n must be
followed by a numeric value in the same word. By using:

_arguments '-n-: :_guard "[0-9]#" "numeric value"' '-none'

_arguments can be made to both display the message `numeric value' and complete op-
tions after `-n<TAB>'. If the `-n' is already followed by one or more digits (the
pattern passed to _guard) only the message will be displayed; if the `-n' is fol-
lowed by another character, only options are completed.

_message [ -r12 ] [ -VJ group ] descr
_message -e [ tag ] descr
The descr is used in the same way as the third argument to the _description func-
tion, except that the resulting string will always be shown whether or not matches
were generated. This is useful for displaying a help message in places where no
completions can be generated.

The format style is examined with the messages tag to find a message; the usual
tag, descriptions, is used only if the style is not set with the former.

If the -r option is given, no style is used; the descr is taken literally as the
string to display. This is most useful when the descr comes from a pre-processed
argument list which already contains an expanded description. Note that this op-
tion does not disable the `%'-sequence parsing done by compadd.

The -12VJ options and the group are passed to compadd and hence determine the group
the message string is added to.

The second -e form gives a description for completions with the tag tag to be shown
even if there are no matches for that tag. This form is called by _arguments in
the event that there is no action for an option specification. The tag can be
omitted and if so the tag is taken from the parameter $curtag; this is maintained
by the completion system and so is usually correct. Note that if there are no
matches at the time this function is called, compstate[insert] is cleared, so addi-
tional matches generated later are not inserted on the command line.

_multi_parts [ -i ] sep array
The argument sep is a separator character. The array may be either the name of an
array parameter or a literal array in the form `(foo bar)', a parenthesised list of
words separated by whitespace. The possible completions are the strings from the
array. However, each chunk delimited by sep will be completed separately. For ex-
ample, the _tar function uses `_multi_parts / patharray' to complete partial file
paths from the given array of complete file paths.

The -i option causes _multi_parts to insert a unique match even if that requires
multiple separators to be inserted. This is not usually the expected behaviour
with filenames, but certain other types of completion, for example those with a
fixed set of possibilities, may be more suited to this form.

Like other utility functions, this function accepts the `-V', `-J', `-1', `-2',
`-n', `-f', `-X', `-M', `-P', `-S', `-r', `-R', and `-q' options and passes them to
the compadd builtin.

_next_label [ -x ] [ -12VJ ] tag name descr [ option ... ]
This function is used to implement the loop over different tag labels for a partic-
ular tag as described above for the tag-order style. On each call it checks to see
if there are any more tag labels; if there is it returns status zero, otherwise
non-zero. As this function requires a current tag to be set, it must always follow
a call to _tags or _requested.

The -x12VJ options and the first three arguments are passed to the _description
function. Where appropriate the tag will be replaced by a tag label in this call.
Any description given in the tag-order style is preferred to the descr passed to
_next_label.

The options given after the descr are set in the parameter given by name, and hence
are to be passed to compadd or whatever function is called to add the matches.

Here is a typical use of this function for the tag foo. The call to _requested de-
termines if tag foo is required at all; the loop over _next_label handles any la-
bels defined for the tag in the tag-order style.

local expl ret=1
...
if _requested foo; then
...
while _next_label foo expl '...'; do
compadd "$expl[@]" ... && ret=0
done
...
fi
return ret

_normal [ -P | -p precommand ]
This is the standard function called to handle completion outside any special -con-
text-. It is called both to complete the command word and also the arguments for a
command. In the second case, _normal looks for a special completion for that com-
mand, and if there is none it uses the completion for the -default- context.

A second use is to reexamine the command line specified by the $words array and the
$CURRENT parameter after those have been modified. For example, the function _pre-
command, which completes after precommand specifiers such as nohup, removes the
first word from the words array, decrements the CURRENT parameter, then calls
`_normal -p $service'. The effect is that `nohup cmd ...' is treated in the same
way as `cmd ...'.

-P Reset the list of precommands. This option should be used if completing a
command line which allows internal commands (e.g. builtins and functions)
regardless of prior precommands (e.g. `zsh -c').

-p precommand
Append precommand to the list of precommands. This option should be used in
nearly all cases in which -P is not applicable.

If the command name matches one of the patterns given by one of the options -p or
-P to compdef, the corresponding completion function is called and then the parame-
ter _compskip is checked. If it is set completion is terminated at that point even
if no matches have been found. This is the same effect as in the -first- context.

_options
This can be used to complete the names of shell options. It provides a matcher
specification that ignores a leading `no', ignores underscores and allows up-
per-case letters to match their lower-case counterparts (for example, `glob',
`noglob', `NO_GLOB' are all completed). Any arguments are propagated to the com-
padd builtin.

_options_set and _options_unset
These functions complete only set or unset options, with the same matching specifi-
cation used in the _options function.

Note that you need to uncomment a few lines in the _main_complete function for
these functions to work properly. The lines in question are used to store the op-
tion settings in effect before the completion widget locally sets the options it
needs. Hence these functions are not generally used by the completion system.

_parameters
This is used to complete the names of shell parameters.

The option `-g pattern' limits the completion to parameters whose type matches the
pattern. The type of a parameter is that shown by `print ${(t)param}', hence judi-
cious use of `*' in pattern is probably necessary.

All other arguments are passed to the compadd builtin.

_path_files
This function is used throughout the completion system to complete filenames. It
allows completion of partial paths. For example, the string `/u/i/s/sig' may be
completed to `/usr/include/sys/signal.h'.

The options accepted by both _path_files and _files are:

-f Complete all filenames. This is the default.

-/ Specifies that only directories should be completed.

-g pattern
Specifies that only files matching the pattern should be completed.

-W paths
Specifies path prefixes that are to be prepended to the string from the com-
mand line to generate the filenames but that should not be inserted as com-
pletions nor shown in completion listings. Here, paths may be the name of
an array parameter, a literal list of paths enclosed in parentheses or an
absolute pathname.

-F ignored-files
This behaves as for the corresponding option to the compadd builtin. It
gives direct control over which filenames should be ignored. If the option
is not present, the ignored-patterns style is used.

Both _path_files and _files also accept the following options which are passed to
compadd: `-J', `-V', `-1', `-2', `-n', `-X', `-M', `-P', `-S', `-q', `-r', and
`-R'.

Finally, the _path_files function uses the styles expand, ambiguous, special-dirs,
list-suffixes and file-sort described above.

_pick_variant [ -b builtin-label ] [ -c command ] [ -r name ]
label=pattern ... label [ arg ... ]
This function is used to resolve situations where a single command name requires
more than one type of handling, either because it has more than one variant or be-
cause there is a name clash between two different commands.

The command to run is taken from the first element of the array words unless this
is overridden by the option -c. This command is run and its output is compared
with a series of patterns. Arguments to be passed to the command can be specified
at the end after all the other arguments. The patterns to try in order are given
by the arguments label=pattern; if the output of `command arg ...' contains pat-
tern, then label is selected as the label for the command variant. If none of the
patterns match, the final command label is selected and status 1 is returned.

If the `-b builtin-label' is given, the command is tested to see if it is provided
as a shell builtin, possibly autoloaded; if so, the label builtin-label is selected
as the label for the variant.

If the `-r name' is given, the label picked is stored in the parameter named name.

The results are also cached in the _cmd_variant associative array indexed by the
name of the command run.

_regex_arguments name spec ...
This function generates a completion function name which matches the specifications
specs, a set of regular expressions as described below. After running _regex_argu-
ments, the function name should be called as a normal completion function. The
pattern to be matched is given by the contents of the words array up to the current
cursor position joined together with null characters; no quotation is applied.

The arguments are grouped as sets of alternatives separated by `|', which are tried
one after the other until one matches. Each alternative consists of a one or more
specifications which are tried left to right, with each pattern matched being
stripped in turn from the command line being tested, until all of the group suc-
ceeds or until one fails; in the latter case, the next alternative is tried. This
structure can be repeated to arbitrary depth by using parentheses; matching pro-
ceeds from inside to outside.

A special procedure is applied if no test succeeds but the remaining command line
string contains no null character (implying the remaining word is the one for which
completions are to be generated). The completion target is restricted to the re-
maining word and any actions for the corresponding patterns are executed. In this
case, nothing is stripped from the command line string. The order of evaluation of
the actions can be determined by the tag-order style; the various formats supported
by _alternative can be used in action. The descr is used for setting up the array
parameter expl.

Specification arguments take one of following forms, in which metacharacters such
as `(', `)', `#' and `|' should be quoted.

/pattern/ [%lookahead%] [-guard] [:tag:descr:action]
This is a single primitive component. The function tests whether the com-
bined pattern `(#b)((#B)pattern)lookahead*' matches the command line string.
If so, `guard' is evaluated and its return status is examined to determine
if the test has succeeded. The pattern string `[]' is guaranteed never to
match. The lookahead is not stripped from the command line before the next
pattern is examined.

The argument starting with : is used in the same manner as an argument to
_alternative.

A component is used as follows: pattern is tested to see if the component
already exists on the command line. If it does, any following specifica-
tions are examined to find something to complete. If a component is reached
but no such pattern exists yet on the command line, the string containing
the action is used to generate matches to insert at that point.

/pattern/+ [%lookahead%] [-guard] [:tag:descr:action]
This is similar to `/pattern/ ...' but the left part of the command line
string (i.e. the part already matched by previous patterns) is also consid-
ered part of the completion target.

/pattern/- [%lookahead%] [-guard] [:tag:descr:action]
This is similar to `/pattern/ ...' but the actions of the current and previ-
ously matched patterns are ignored even if the following `pattern' matches
the empty string.

( spec )
Parentheses may be used to groups specs; note each parenthesis is a single
argument to _regex_arguments.

spec # This allows any number of repetitions of spec.

spec spec
The two specs are to be matched one after the other as described above.

spec | spec
Either of the two specs can be matched.

The function _regex_words can be used as a helper function to generate matches for
a set of alternative words possibly with their own arguments as a command line ar-
gument.

Examples:

_regex_arguments _tst /$'[^\0]#\0'/ \
/$'[^\0]#\0'/ :'compadd aaa'

This generates a function _tst that completes aaa as its only argument. The tag
and description for the action have been omitted for brevity (this works but is not
recommended in normal use). The first component matches the command word, which is
arbitrary; the second matches any argument. As the argument is also arbitrary,
any following component would not depend on aaa being present.

_regex_arguments _tst /$'[^\0]#\0'/ \
/$'aaa\0'/ :'compadd aaa'

This is a more typical use; it is similar, but any following patterns would only
match if aaa was present as the first argument.

_regex_arguments _tst /$'[^\0]#\0'/ $ \
/$'aaa\0'/ :'compadd aaa' \
/$'bbb\0'/ :'compadd bbb' $ \#

In this example, an indefinite number of command arguments may be completed. Odd
arguments are completed as aaa and even arguments as bbb. Completion fails unless
the set of aaa and bbb arguments before the current one is matched correctly.

_regex_arguments _tst /$'[^\0]#\0'/ \
$ /$'aaa\0'/ :'compadd aaa' \| \
/$'bbb\0'/ :'compadd bbb' $ \#

This is similar, but either aaa or bbb may be completed for any argument. In this
case _regex_words could be used to generate a suitable expression for the argu-
ments.

_regex_words tag description spec ...
This function can be used to generate arguments for the _regex_arguments command
which may be inserted at any point where a set of rules is expected. The tag and
description give a standard tag and description pertaining to the current context.
Each spec contains two or three arguments separated by a colon: note that there is
no leading colon in this case.

Each spec gives one of a set of words that may be completed at this point, together
with arguments. It is thus roughly equivalent to the _arguments function when used
in normal (non-regex) completion.

The part of the spec before the first colon is the word to be completed. This may
contain a *; the entire word, before and after the * is completed, but only the
text before the * is required for the context to be matched, so that further argu-
ments may be completed after the abbreviated form.

The second part of spec is a description for the word being completed.

The optional third part of the spec describes how words following the one being
completed are themselves to be completed. It will be evaluated in order to avoid
problems with quoting. This means that typically it contains a reference to an ar-
ray containing previously generated regex arguments.

The option -t term specifies a terminator for the word instead of the usual space.
This is handled as an auto-removable suffix in the manner of the option -s sep to
_values.

The result of the processing by _regex_words is placed in the array reply, which
should be made local to the calling function. If the set of words and arguments
may be matched repeatedly, a # should be appended to the generated array at that
point.

For example:

local -a reply
_regex_words mydb-commands 'mydb commands' \
'add:add an entry to mydb:$mydb_add_cmds' \
'show:show entries in mydb'
_regex_arguments _mydb "$reply[@]"
_mydb "$@"

This shows a completion function for a command mydb which takes two command argu-
ments, add and show. show takes no arguments, while the arguments for add have al-
ready been prepared in an array mydb_add_cmds, quite possibly by a previous call to
_regex_words.

_requested [ -x ] [ -12VJ ] tag [ name descr [ command [ arg ... ] ]
This function is called to decide whether a tag already registered by a call to
_tags (see below) has been requested by the user and hence completion should be
performed for it. It returns status zero if the tag is requested and non-zero oth-
erwise. The function is typically used as part of a loop over different tags as
follows:

_tags foo bar baz
while _tags; do
if _requested foo; then
... # perform completion for foo
fi
... # test the tags bar and baz in the same way
... # exit loop if matches were generated
done

Note that the test for whether matches were generated is not performed until the
end of the _tags loop. This is so that the user can set the tag-order style to
specify a set of tags to be completed at the same time.

If name and descr are given, _requested calls the _description function with these
arguments together with the options passed to _requested.

If command is given, the _all_labels function will be called immediately with the
same arguments. In simple cases this makes it possible to perform the test for the
tag and the matching in one go. For example:

local expl ret=1
_tags foo bar baz
while _tags; do
_requested foo expl 'description' \
compadd foobar foobaz && ret=0
...
(( ret )) || break
done

If the command is not compadd, it must nevertheless be prepared to handle the same
options.

_retrieve_cache cache_identifier
This function retrieves completion information from the file given by cache_identi-
fier, stored in a directory specified by the cache-path style which defaults to
~/.zcompcache. The return status is zero if retrieval was successful. It will
only attempt retrieval if the use-cache style is set, so you can call this function
without worrying about whether the user wanted to use the caching layer.

See _store_cache below for more details.

_sep_parts
This function is passed alternating arrays and separators as arguments. The arrays
specify completions for parts of strings to be separated by the separators. The
arrays may be the names of array parameters or a quoted list of words in parenthe-
ses. For example, with the array `hosts=(ftp news)' the call `_sep_parts '(foo
bar)' @ hosts' will complete the string `f' to `foo' and the string `b@n' to
`bar@news'.

This function accepts the compadd options `-V', `-J', `-1', `-2', `-n', `-X', `-M',
`-P', `-S', `-r', `-R', and `-q' and passes them on to the compadd builtin used to
add the matches.

_sequence [ -s sep ] [ -n max ] [ -d ] function [ - ] ...
This function is a wrapper to other functions for completing items in a separated
list. The same function is used to complete each item in the list. The separator is
specified with the -s option. If -s is omitted it will use `,'. Duplicate values
are not matched unless -d is specified. If there is a fixed or maximum number of
items in the list, this can be specified with the -n option.

Common compadd options are passed on to the function. It is possible to use compadd
directly with _sequence, though _values may be more appropriate in this situation.

_setup tag [ group ]
This function sets up the special parameters used by the completion system appro-
priately for the tag given as the first argument. It uses the styles list-colors,
list-packed, list-rows-first, last-prompt, accept-exact, menu and force-list.

The optional group supplies the name of the group in which the matches will be
placed. If it is not given, the tag is used as the group name.

This function is called automatically from _description and hence is not normally
called explicitly.

_store_cache cache_identifier param ...
This function, together with _retrieve_cache and _cache_invalid, implements a
caching layer which can be used in any completion function. Data obtained by
costly operations are stored in parameters; this function then dumps the values of
those parameters to a file. The data can then be retrieved quickly from that file
via _retrieve_cache, even in different instances of the shell.

The cache_identifier specifies the file which the data should be dumped to. The
file is stored in a directory specified by the cache-path style which defaults to
~/.zcompcache. The remaining params arguments are the parameters to dump to the
file.

The return status is zero if storage was successful. The function will only at-
tempt storage if the use-cache style is set, so you can call this function without
worrying about whether the user wanted to use the caching layer.

The completion function may avoid calling _retrieve_cache when it already has the
completion data available as parameters. However, in that case it should call
_cache_invalid to check whether the data in the parameters and in the cache are
still valid.

See the _perl_modules completion function for a simple example of the usage of the
caching layer.

_tags [ [ -C name ] tag ... ]
If called with arguments, these are taken to be the names of tags valid for comple-
tions in the current context. These tags are stored internally and sorted by using
the tag-order style.

Next, _tags is called repeatedly without arguments from the same completion func-
tion. This successively selects the first, second, etc. set of tags requested by
the user. The return status is zero if at least one of the tags is requested and
non-zero otherwise. To test if a particular tag is to be tried, the _requested
function should be called (see above).

If `-C name' is given, name is temporarily stored in the argument field (the fifth)
of the context in the curcontext parameter during the call to _tags; the field is
restored on exit. This allows _tags to use a more specific context without having
to change and reset the curcontext parameter (which has the same effect).

_tilde_files
Like _files, but resolve leading tildes according to the rules of filename expan-
sion, so the suggested completions don't start with a `~' even if the filename on
the command-line does.

_values [ -O name ] [ -s sep ] [ -S sep ] [ -wC ] desc spec ...
This is used to complete arbitrary keywords (values) and their arguments, or lists
of such combinations.

If the first argument is the option `-O name', it will be used in the same way as
by the _arguments function. In other words, the elements of the name array will be
passed to compadd when executing an action.

If the first argument (or the first argument after `-O name') is `-s', the next ar-
gument is used as the character that separates multiple values. This character is
automatically added after each value in an auto-removable fashion (see below); all
values completed by `_values -s' appear in the same word on the command line, un-
like completion using _arguments. If this option is not present, only a single
value will be completed per word.

Normally, _values will only use the current word to determine which values are al-
ready present on the command line and hence are not to be completed again. If the
-w option is given, other arguments are examined as well.

The first non-option argument, desc, is used as a string to print as a description
before listing the values.

All other arguments describe the possible values and their arguments in the same
format used for the description of options by the _arguments function (see above).
The only differences are that no minus or plus sign is required at the beginning,
values can have only one argument, and the forms of action beginning with an equal
sign are not supported.

The character separating a value from its argument can be set using the option -S
(like -s, followed by the character to use as the separator in the next argument).
By default the equals sign will be used as the separator between values and argu-
ments.

Example:

_values -s , 'description' \
'*foo[bar]' \
'(two)*one[number]:first count:' \
'two[another number]::second count:(1 2 3)'

This describes three possible values: `foo', `one', and `two'. The first is de-
scribed as `bar', takes no argument and may appear more than once. The second is
described as `number', may appear more than once, and takes one mandatory argument
described as `first count'; no action is specified, so it will not be completed.
The `(two)' at the beginning says that if the value `one' is on the line, the value
`two' will no longer be considered a possible completion. Finally, the last value
(`two') is described as `another number' and takes an optional argument described
as `second count' for which the completions (to appear after an `=') are `1', `2',
and `3'. The _values function will complete lists of these values separated by
commas.

Like _arguments, this function temporarily adds another context name component to
the arguments element (the fifth) of the current context while executing the ac-
tion. Here this name is just the name of the value for which the argument is com-
pleted.

The style verbose is used to decide if the descriptions for the values (but not
those for the arguments) should be printed.

The associative array val_args is used to report values and their arguments; this
works similarly to the opt_args associative array used by _arguments. Hence the
function calling _values should declare the local parameters state, state_descr,
line, context and val_args:

local context state state_descr line
typeset -A val_args

when using an action of the form `->string'. With this function the context param-
eter will be set to the name of the value whose argument is to be completed. Note
that for _values, the state and state_descr are scalars rather than arrays. Only a
single matching state is returned.

Note also that _values normally adds the character used as the separator between
values as an auto-removable suffix (similar to a `/' after a directory). However,
this is not possible for a `->string' action as the matches for the argument are
generated by the calling function. To get the usual behaviour, the calling func-
tion can add the separator x as a suffix by passing the options `-qS x' either di-
rectly or indirectly to compadd.

The option -C is treated in the same way as it is by _arguments. In that case the
parameter curcontext should be made local instead of context (as described above).

_wanted [ -x ] [ -C name ] [ -12VJ ] tag name descr command [ arg ...]
In many contexts, completion can only generate one particular set of matches, usu-
ally corresponding to a single tag. However, it is still necessary to decide
whether the user requires matches of this type. This function is useful in such a
case.

The arguments to _wanted are the same as those to _requested, i.e. arguments to be
passed to _description. However, in this case the command is not optional; all
the processing of tags, including the loop over both tags and tag labels and the
generation of matches, is carried out automatically by _wanted.

Hence to offer only one tag and immediately add the corresponding matches with the
given description:

local expl
_wanted tag expl 'description' \
compadd matches...

Note that, as for _requested, the command must be able to accept options to be
passed down to compadd.

Like _tags this function supports the -C option to give a different name for the
argument context field. The -x option has the same meaning as for _description.

_widgets [ -g pattern ]
This function completes names of zle widgets (see the section `Widgets' in zsh-
zle(1)). The pattern, if present, is matched against values of the $widgets spe-
cial parameter, documented in the section `The zsh/zleparameter Module' in zshmod-
ules(1).

COMPLETION SYSTEM VARIABLES
There are some standard variables, initialised by the _main_complete function and then
used from other functions.

The standard variables are:

_comp_caller_options
The completion system uses setopt to set a number of options. This allows functions
to be written without concern for compatibility with every possible combination of
user options. However, sometimes completion needs to know what the user's option
preferences are. These are saved in the _comp_caller_options associative array. Op-
tion names, spelled in lowercase without underscores, are mapped to one or other of
the strings `on' and `off'.

_comp_priv_prefix
Completion functions such as _sudo can set the _comp_priv_prefix array to a
command prefix that may then be used by _call_program to match the privi-
leges when calling programs to generate matches.

Two more features are offered by the _main_complete function. The arrays comppre-
funcs and comppostfuncs may contain names of functions that are to be called imme-
diately before or after completion has been tried. A function will only be called
once unless it explicitly reinserts itself into the array.

COMPLETION DIRECTORIES
In the source distribution, the files are contained in various subdirectories of the Com-
pletion directory. They may have been installed in the same structure, or into one single
function directory. The following is a description of the files found in the original di-
rectory structure. If you wish to alter an installed file, you will need to copy it to
some directory which appears earlier in your fpath than the standard directory where it
appears.

Base The core functions and special completion widgets automatically bound to keys. You
will certainly need most of these, though will probably not need to alter them.
Many of these are documented above.

Zsh Functions for completing arguments of shell builtin commands and utility functions
for this. Some of these are also used by functions from the Unix directory.

Unix Functions for completing arguments of external commands and suites of commands.
They may need modifying for your system, although in many cases some attempt is
made to decide which version of a command is present. For example, completion for
the mount command tries to determine the system it is running on, while completion
for many other utilities try to decide whether the GNU version of the command is in
use, and hence whether the --help option is supported.

X, AIX, BSD, ...
Completion and utility function for commands available only on some systems. These
are not arranged hierarchically, so, for example, both the Linux and Debian direc-
tories, as well as the X directory, may be useful on your system.

ZSHCOMPCTL(1) General Commands Manual ZSHCOMPCTL(1)

NAME
zshcompctl - zsh programmable completion

DESCRIPTION
This version of zsh has two ways of performing completion of words on the command line.
New users of the shell may prefer to use the newer and more powerful system based on shell
functions; this is described in zshcompsys(1), and the basic shell mechanisms which sup-
port it are described in zshcompwid(1). This manual entry describes the older compctl
command.

compctl [ -CDT ] options [ command ... ]
compctl [ -CDT ] options [ -x pattern options - ... -- ]
[ + options [ -x ... -- ] ... [+] ] [ command ... ]
compctl -M match-specs ...
compctl -L [ -CDTM ] [ command ... ]
compctl + command ...

Control the editor's completion behavior according to the supplied set of options. Vari-
ous editing commands, notably expand-or-complete-word, usually bound to tab, will attempt
to complete a word typed by the user, while others, notably delete-char-or-list, usually
bound to ^D in EMACS editing mode, list the possibilities; compctl controls what those
possibilities are. They may for example be filenames (the most common case, and hence the
default), shell variables, or words from a user-specified list.

COMMAND FLAGS
Completion of the arguments of a command may be different for each command or may use the
default. The behavior when completing the command word itself may also be separately
specified. These correspond to the following flags and arguments, all of which (except
for -L) may be combined with any combination of the options described subsequently in the
section `Option Flags':

command ...
controls completion for the named commands, which must be listed last on the com-
mand line. If completion is attempted for a command with a pathname containing
slashes and no completion definition is found, the search is retried with the last
pathname component. If the command starts with a =, completion is tried with the
pathname of the command.

Any of the command strings may be patterns of the form normally used for filename
generation. These should be quoted to protect them from immediate expansion; for
example the command string 'foo*' arranges for completion of the words of any com-
mand beginning with foo. When completion is attempted, all pattern completions are
tried in the reverse order of their definition until one matches. By default, com-
pletion then proceeds as normal, i.e. the shell will try to generate more matches
for the specific command on the command line; this can be overridden by including
-tn in the flags for the pattern completion.

Note that aliases are expanded before the command name is determined unless the
COMPLETE_ALIASES option is set. Commands may not be combined with the -C, -D or -T
flags.

-C controls completion when the command word itself is being completed. If no compctl
-C command has been issued, the names of any executable command (whether in the
path or specific to the shell, such as aliases or functions) are completed.

-D controls default completion behavior for the arguments of commands not assigned any
special behavior. If no compctl -D command has been issued, filenames are com-
pleted.

-T supplies completion flags to be used before any other processing is done, even be-
fore processing for compctls defined for specific commands. This is especially
useful when combined with extended completion (the -x flag, see the section `Ex-
tended Completion' below). Using this flag you can define default behavior which
will apply to all commands without exception, or you can alter the standard behav-
ior for all commands. For example, if your access to the user database is too slow
and/or it contains too many users (so that completion after `~' is too slow to be
usable), you can use

compctl -T -x 's[~] C[0,[^/]#]' -k friends -S/ -tn

to complete the strings in the array friends after a `~'. The C[...] argument is
necessary so that this form of ~-completion is not tried after the directory name
is finished.

-L lists the existing completion behavior in a manner suitable for putting into a
start-up script; the existing behavior is not changed. Any combination of the
above forms, or the -M flag (which must follow the -L flag), may be specified, oth-
erwise all defined completions are listed. Any other flags supplied are ignored.

no argument
If no argument is given, compctl lists all defined completions in an abbreviated
form; with a list of options, all completions with those flags set (not counting
extended completion) are listed.

If the + flag is alone and followed immediately by the command list, the completion behav-
ior for all the commands in the list is reset to the default. In other words, completion
will subsequently use the options specified by the -D flag.

The form with -M as the first and only option defines global matching specifications (see
zshcompwid). The match specifications given will be used for every completion attempt
(only when using compctl, not with the new completion system) and are tried in the order
in which they are defined until one generates at least one match. E.g.:

compctl -M '' 'm:{a-zA-Z}={A-Za-z}'

This will first try completion without any global match specifications (the empty string)
and, if that generates no matches, will try case insensitive completion.

OPTION FLAGS
[ -fcFBdeaRGovNAIOPZEnbjrzu/12 ]
[ -k array ] [ -g globstring ] [ -s subststring ]
[ -K function ]
[ -Q ] [ -P prefix ] [ -S suffix ]
[ -W file-prefix ] [ -H num pattern ]
[ -q ] [ -X explanation ] [ -Y explanation ]
[ -y func-or-var ] [ -l cmd ] [ -h cmd ] [ -U ]
[ -t continue ] [ -J name ] [ -V name ]
[ -M match-spec ]

The remaining options specify the type of command arguments to look for during completion.
Any combination of these flags may be specified; the result is a sorted list of all the
possibilities. The options are as follows.

Simple Flags
These produce completion lists made up by the shell itself:

-f Filenames and file system paths.

-/ Just file system paths.

-c Command names, including aliases, shell functions, builtins and reserved words.

-F Function names.

-B Names of builtin commands.

-m Names of external commands.

-w Reserved words.

-a Alias names.

-R Names of regular (non-global) aliases.

-G Names of global aliases.

-d This can be combined with -F, -B, -w, -a, -R and -G to get names of disabled func-
tions, builtins, reserved words or aliases.

-e This option (to show enabled commands) is in effect by default, but may be combined
with -d; -de in combination with -F, -B, -w, -a, -R and -G will complete names of
functions, builtins, reserved words or aliases whether or not they are disabled.

-o Names of shell options (see zshoptions(1)).

-v Names of any variable defined in the shell.

-N Names of scalar (non-array) parameters.

-A Array names.

-I Names of integer variables.

-O Names of read-only variables.

-p Names of parameters used by the shell (including special parameters).

-Z Names of shell special parameters.

-E Names of environment variables.

-n Named directories.

-b Key binding names.

-j Job names: the first word of the job leader's command line. This is useful with
the kill builtin.

-r Names of running jobs.

-z Names of suspended jobs.

-u User names.

Flags with Arguments
These have user supplied arguments to determine how the list of completions is to be made
up:

-k array
Names taken from the elements of $array (note that the `$' does not appear on the
command line). Alternatively, the argument array itself may be a set of space- or
comma-separated values in parentheses, in which any delimiter may be escaped with a
backslash; in this case the argument should be quoted. For example,

compctl -k "(cputime filesize datasize stacksize
coredumpsize resident descriptors)" limit

-g globstring
The globstring is expanded using filename globbing; it should be quoted to protect
it from immediate expansion. The resulting filenames are taken as the possible com-
pletions. Use `*(/)' instead of `*/' for directories. The fignore special parame-
ter is not applied to the resulting files. More than one pattern may be given sep-
arated by blanks. (Note that brace expansion is not part of globbing. Use the syn-
tax `(either|or)' to match alternatives.)

-s subststring
The subststring is split into words and these words are than expanded using all
shell expansion mechanisms (see zshexpn(1)). The resulting words are taken as pos-
sible completions. The fignore special parameter is not applied to the resulting
files. Note that -g is faster for filenames.

-K function
Call the given function to get the completions. Unless the name starts with an un-
derscore, the function is passed two arguments: the prefix and the suffix of the
word on which completion is to be attempted, in other words those characters before
the cursor position, and those from the cursor position onwards. The whole command
line can be accessed with the -c and -l flags of the read builtin. The function
should set the variable reply to an array containing the completions (one comple-
tion per element); note that reply should not be made local to the function. From
such a function the command line can be accessed with the -c and -l flags to the
read builtin. For example,

function whoson { reply=(`users`); }
compctl -K whoson talk

completes only logged-on users after `talk'. Note that `whoson' must return an ar-
ray, so `reply=`users`' would be incorrect.

-H num pattern
The possible completions are taken from the last num history lines. Only words
matching pattern are taken. If num is zero or negative the whole history is
searched and if pattern is the empty string all words are taken (as with `*'). A
typical use is

compctl -D -f + -H 0 ''

which forces completion to look back in the history list for a word if no filename
matches.

Control Flags
These do not directly specify types of name to be completed, but manipulate the options
that do:

-Q This instructs the shell not to quote any metacharacters in the possible comple-
tions. Normally the results of a completion are inserted into the command line
with any metacharacters quoted so that they are interpreted as normal characters.
This is appropriate for filenames and ordinary strings. However, for special ef-
fects, such as inserting a backquoted expression from a completion array (-k) so
that the expression will not be evaluated until the complete line is executed, this
option must be used.

-P prefix
The prefix is inserted just before the completed string; any initial part already
typed will be completed and the whole prefix ignored for completion purposes. For
example,

compctl -j -P "%" kill

inserts a `%' after the kill command and then completes job names.

-S suffix
When a completion is found the suffix is inserted after the completed string. In
the case of menu completion the suffix is inserted immediately, but it is still
possible to cycle through the list of completions by repeatedly hitting the same
key.

-W file-prefix
With directory file-prefix: for command, file, directory and globbing completion
(options -c, -f, -/, -g), the file prefix is implicitly added in front of the com-
pletion. For example,

compctl -/ -W ~/Mail maildirs

completes any subdirectories to any depth beneath the directory ~/Mail, although
that prefix does not appear on the command line. The file-prefix may also be of
the form accepted by the -k flag, i.e. the name of an array or a literal list in
parenthesis. In this case all the directories in the list will be searched for pos-
sible completions.

-q If used with a suffix as specified by the -S option, this causes the suffix to be
removed if the next character typed is a blank or does not insert anything or if
the suffix consists of only one character and the next character typed is the same
character; this the same rule used for the AUTO_REMOVE_SLASH option. The option is
most useful for list separators (comma, colon, etc.).

-l cmd This option restricts the range of command line words that are considered to be ar-
guments. If combined with one of the extended completion patterns `p[...]',
`r[...]', or `R[...]' (see the section `Extended Completion' below) the range is
restricted to the range of arguments specified in the brackets. Completion is then
performed as if these had been given as arguments to the cmd supplied with the op-
tion. If the cmd string is empty the first word in the range is instead taken as
the command name, and command name completion performed on the first word in the
range. For example,

compctl -x 'r[-exec,;]' -l '' -- find

completes arguments between `-exec' and the following `;' (or the end of the com-
mand line if there is no such string) as if they were a separate command line.

-h cmd Normally zsh completes quoted strings as a whole. With this option, completion can
be done separately on different parts of such strings. It works like the -l option
but makes the completion code work on the parts of the current word that are sepa-
rated by spaces. These parts are completed as if they were arguments to the given
cmd. If cmd is the empty string, the first part is completed as a command name, as
with -l.

-U Use the whole list of possible completions, whether or not they actually match the
word on the command line. The word typed so far will be deleted. This is most
useful with a function (given by the -K option) which can examine the word compo-
nents passed to it (or via the read builtin's -c and -l flags) and use its own cri-
teria to decide what matches. If there is no completion, the original word is re-
tained. Since the produced possible completions seldom have interesting common
prefixes and suffixes, menu completion is started immediately if AUTO_MENU is set
and this flag is used.

-y func-or-var
The list provided by func-or-var is displayed instead of the list of completions
whenever a listing is required; the actual completions to be inserted are not af-
fected. It can be provided in two ways. Firstly, if func-or-var begins with a $ it
defines a variable, or if it begins with a left parenthesis a literal array, which
contains the list. A variable may have been set by a call to a function using the
-K option. Otherwise it contains the name of a function which will be executed to
create the list. The function will be passed as an argument list all matching com-
pletions, including prefixes and suffixes expanded in full, and should set the ar-
ray reply to the result. In both cases, the display list will only be retrieved
after a complete list of matches has been created.

Note that the returned list does not have to correspond, even in length, to the
original set of matches, and may be passed as a scalar instead of an array. No
special formatting of characters is performed on the output in this case; in par-
ticular, newlines are printed literally and if they appear output in columns is
suppressed.

-X explanation
Print explanation when trying completion on the current set of options. A `%n' in
this string is replaced by the number of matches that were added for this explana-
tion string. The explanation only appears if completion was tried and there was no
unique match, or when listing completions. Explanation strings will be listed to-
gether with the matches of the group specified together with the -X option (using
the -J or -V option). If the same explanation string is given to multiple -X op-
tions, the string appears only once (for each group) and the number of matches
shown for the `%n' is the total number of all matches for each of these uses. In
any case, the explanation string will only be shown if there was at least one match
added for the explanation string.

The sequences %B, %b, %S, %s, %U, and %u specify output attributes (bold, standout,
and underline), %F, %f, %K, %k specify foreground and background colours, and
%{...%} can be used to include literal escape sequences as in prompts.

-Y explanation
Identical to -X, except that the explanation first undergoes expansion following
the usual rules for strings in double quotes. The expansion will be carried out
after any functions are called for the -K or -y options, allowing them to set vari-
ables.

-t continue
The continue-string contains a character that specifies which set of completion
flags should be used next. It is useful:

(i) With -T, or when trying a list of pattern completions, when compctl would usu-
ally continue with ordinary processing after finding matches; this can be sup-
pressed with `-tn'.

(ii) With a list of alternatives separated by +, when compctl would normally stop
when one of the alternatives generates matches. It can be forced to consider the
next set of completions by adding `-t+' to the flags of the alternative before the
`+'.

(iii) In an extended completion list (see below), when compctl would normally con-
tinue until a set of conditions succeeded, then use only the immediately following
flags. With `-t-', compctl will continue trying extended completions after the
next `-'; with `-tx' it will attempt completion with the default flags, in other
words those before the `-x'.

-J name
This gives the name of the group the matches should be placed in. Groups are listed
and sorted separately; likewise, menu completion will offer the matches in the
groups in the order in which the groups were defined. If no group name is explic-
itly given, the matches are stored in a group named default. The first time a group
name is encountered, a group with that name is created. After that all matches with
the same group name are stored in that group.

This can be useful with non-exclusive alternative completions. For example, in

compctl -f -J files -t+ + -v -J variables foo

both files and variables are possible completions, as the -t+ forces both sets of
alternatives before and after the + to be considered at once. Because of the -J
options, however, all files are listed before all variables.

-V name
Like -J, but matches within the group will not be sorted in listings nor in menu
completion. These unsorted groups are in a different name space from the sorted
ones, so groups defined as -J files and -V files are distinct.

-1 If given together with the -V option, makes only consecutive duplicates in the
group be removed. Note that groups with and without this flag are in different name
spaces.

-2 If given together with the -J or -V option, makes all duplicates be kept. Again,
groups with and without this flag are in different name spaces.

-M match-spec
This defines additional matching control specifications that should be used only
when testing words for the list of flags this flag appears in. The format of the
match-spec string is described in zshcompwid.

ALTERNATIVE COMPLETION
compctl [ -CDT ] options + options [ + ... ] [ + ] command ...

The form with `+' specifies alternative options. Completion is tried with the options be-
fore the first `+'. If this produces no matches completion is tried with the flags after
the `+' and so on. If there are no flags after the last `+' and a match has not been found
up to that point, default completion is tried. If the list of flags contains a -t with a
+ character, the next list of flags is used even if the current list produced matches.

Additional options are available that restrict completion to some part of the command
line; this is referred to as `extended completion'.

EXTENDED COMPLETION
compctl [ -CDT ] options -x pattern options - ... --
[ command ... ]
compctl [ -CDT ] options [ -x pattern options - ... -- ]
[ + options [ -x ... -- ] ... [+] ] [ command ... ]

The form with `-x' specifies extended completion for the commands given; as shown, it may
be combined with alternative completion using `+'. Each pattern is examined in turn; when
a match is found, the corresponding options, as described in the section `Option Flags'
above, are used to generate possible completions. If no pattern matches, the options
given before the -x are used.

Note that each pattern should be supplied as a single argument and should be quoted to
prevent expansion of metacharacters by the shell.

A pattern is built of sub-patterns separated by commas; it matches if at least one of
these sub-patterns matches (they are `or'ed). These sub-patterns are in turn composed of
other sub-patterns separated by white spaces which match if all of the sub-patterns match
(they are `and'ed). An element of the sub-patterns is of the form `c[...][...]', where
the pairs of brackets may be repeated as often as necessary, and matches if any of the
sets of brackets match (an `or'). The example below makes this clearer.

The elements may be any of the following:

s[string]...
Matches if the current word on the command line starts with one of the strings
given in brackets. The string is not removed and is not part of the completion.

S[string]...
Like s[string] except that the string is part of the completion.

p[from,to]...
Matches if the number of the current word is between one of the from and to pairs
inclusive. The comma and to are optional; to defaults to the same value as from.
The numbers may be negative: -n refers to the n'th last word on the line.

c[offset,string]...
Matches if the string matches the word offset by offset from the current word posi-
tion. Usually offset will be negative.

C[offset,pattern]...
Like c but using pattern matching instead.

w[index,string]...
Matches if the word in position index is equal to the corresponding string. Note
that the word count is made after any alias expansion.

W[index,pattern]...
Like w but using pattern matching instead.

n[index,string]...
Matches if the current word contains string. Anything up to and including the in-
dexth occurrence of this string will not be considered part of the completion, but
the rest will. index may be negative to count from the end: in most cases, index
will be 1 or -1. For example,

compctl -s '`users`' -x 'n[1,@]' -k hosts -- talk

will usually complete usernames, but if you insert an @ after the name, names from
the array hosts (assumed to contain hostnames, though you must make the array your-
self) will be completed. Other commands such as rcp can be handled similarly.

N[index,string]...
Like n except that the string will be taken as a character class. Anything up to
and including the indexth occurrence of any of the characters in string will not be
considered part of the completion.

m[min,max]...
Matches if the total number of words lies between min and max inclusive.

r[str1,str2]...
Matches if the cursor is after a word with prefix str1. If there is also a word
with prefix str2 on the command line after the one matched by str1 it matches only
if the cursor is before this word. If the comma and str2 are omitted, it matches if
the cursor is after a word with prefix str1.

R[str1,str2]...
Like r but using pattern matching instead.

q[str]...
Matches the word currently being completed is in single quotes and the str begins
with the letter `s', or if completion is done in double quotes and str starts with
the letter `d', or if completion is done in backticks and str starts with a `b'.

EXAMPLE
compctl -u -x 's[+] c[-1,-f],s[-f+]' \
-g '~/Mail/*(:t)' - 's[-f],c[-1,-f]' -f -- mail

This is to be interpreted as follows:

If the current command is mail, then

if ((the current word begins with + and the previous word is -f)
or (the current word begins with -f+)), then complete the
non-directory part (the `:t' glob modifier) of files in the directory
~/Mail; else

if the current word begins with -f or the previous word was -f, then
complete any file; else

complete user names.

ZSHMODULES(1) General Commands Manual ZSHMODULES(1)

NAME
zshmodules - zsh loadable modules

DESCRIPTION
Some optional parts of zsh are in modules, separate from the core of the shell. Each of
these modules may be linked in to the shell at build time, or can be dynamically linked
while the shell is running if the installation supports this feature. Modules are linked
at runtime with the zmodload command, see zshbuiltins(1).

The modules that are bundled with the zsh distribution are:

zsh/attr
Builtins for manipulating extended attributes (xattr).

zsh/cap
Builtins for manipulating POSIX.1e (POSIX.6) capability (privilege) sets.

zsh/clone
A builtin that can clone a running shell onto another terminal.

zsh/compctl
The compctl builtin for controlling completion.

zsh/complete
The basic completion code.

zsh/complist
Completion listing extensions.

zsh/computil
A module with utility builtins needed for the shell function based completion sys-
tem.

zsh/curses
curses windowing commands

zsh/datetime
Some date/time commands and parameters.

zsh/db/gdbm
Builtins for managing associative array parameters tied to GDBM databases.

zsh/deltochar
A ZLE function duplicating EMACS' zap-to-char.

zsh/example
An example of how to write a module.

zsh/files
Some basic file manipulation commands as builtins.

zsh/langinfo
Interface to locale information.

zsh/mapfile
Access to external files via a special associative array.

zsh/mathfunc
Standard scientific functions for use in mathematical evaluations.

zsh/nearcolor
Map colours to the nearest colour in the available palette.

zsh/newuser
Arrange for files for new users to be installed.

zsh/parameter
Access to internal hash tables via special associative arrays.

zsh/pcre
Interface to the PCRE library.

zsh/param/private
Builtins for managing private-scoped parameters in function context.

zsh/regex
Interface to the POSIX regex library.

zsh/sched
A builtin that provides a timed execution facility within the shell.

zsh/net/socket
Manipulation of Unix domain sockets

zsh/stat
A builtin command interface to the stat system call.

zsh/system
A builtin interface to various low-level system features.

zsh/net/tcp
Manipulation of TCP sockets

zsh/termcap
Interface to the termcap database.

zsh/terminfo
Interface to the terminfo database.

zsh/zftp
A builtin FTP client.

zsh/zle
The Zsh Line Editor, including the bindkey and vared builtins.

zsh/zleparameter
Access to internals of the Zsh Line Editor via parameters.

zsh/zprof
A module allowing profiling for shell functions.

zsh/zpty
A builtin for starting a command in a pseudo-terminal.

zsh/zselect
Block and return when file descriptors are ready.

zsh/zutil
Some utility builtins, e.g. the one for supporting configuration via styles.

THE ZSH/ATTR MODULE
The zsh/attr module is used for manipulating extended attributes. The -h option causes
all commands to operate on symbolic links instead of their targets. The builtins in this
module are:

zgetattr [ -h ] filename attribute [ parameter ]
Get the extended attribute attribute from the specified filename. If the optional
argument parameter is given, the attribute is set on that parameter instead of be-
ing printed to stdout.

zsetattr [ -h ] filename attribute value
Set the extended attribute attribute on the specified filename to value.

zdelattr [ -h ] filename attribute
Remove the extended attribute attribute from the specified filename.

zlistattr [ -h ] filename [ parameter ]
List the extended attributes currently set on the specified filename. If the op-
tional argument parameter is given, the list of attributes is set on that parameter
instead of being printed to stdout.

zgetattr and zlistattr allocate memory dynamically. If the attribute or list of at-
tributes grows between the allocation and the call to get them, they return 2. On all
other errors, 1 is returned. This allows the calling function to check for this case and
retry.

THE ZSH/CAP MODULE
The zsh/cap module is used for manipulating POSIX.1e (POSIX.6) capability sets. If the
operating system does not support this interface, the builtins defined by this module will
do nothing. The builtins in this module are:

cap [ capabilities ]
Change the shell's process capability sets to the specified capabilities, otherwise
display the shell's current capabilities.

getcap filename ...
This is a built-in implementation of the POSIX standard utility. It displays the
capability sets on each specified filename.

setcap capabilities filename ...
This is a built-in implementation of the POSIX standard utility. It sets the capa-
bility sets on each specified filename to the specified capabilities.

THE ZSH/CLONE MODULE
The zsh/clone module makes available one builtin command:

clone tty
Creates a forked instance of the current shell, attached to the specified tty. In
the new shell, the PID, PPID and TTY special parameters are changed appropriately.
$! is set to zero in the new shell, and to the new shell's PID in the original
shell.

The return status of the builtin is zero in both shells if successful, and non-zero
on error.

The target of clone should be an unused terminal, such as an unused virtual console
or a virtual terminal created by

xterm -e sh -c 'trap : INT QUIT TSTP; tty;
while :; do sleep 100000000; done'

Some words of explanation are warranted about this long xterm command line: when
doing clone on a pseudo-terminal, some other session ("session" meant as a unix
session group, or SID) is already owning the terminal. Hence the cloned zsh cannot
acquire the pseudo-terminal as a controlling tty. That means two things:

o the job control signals will go to the sh-started-by-xterm process group
(that's why we disable INT QUIT and TSTP with trap; otherwise the while loop
could get suspended or killed)

o the cloned shell will have job control disabled, and the job control keys
(control-C, control-\ and control-Z) will not work.

This does not apply when cloning to an unused vc.

Cloning to a used (and unprepared) terminal will result in two processes reading
simultaneously from the same terminal, with input bytes going randomly to either
process.

clone is mostly useful as a shell built-in replacement for openvt.

THE ZSH/COMPCTL MODULE
The zsh/compctl module makes available two builtin commands. compctl, is the old, depre-
cated way to control completions for ZLE. See zshcompctl(1). The other builtin command,
compcall can be used in user-defined completion widgets, see zshcompwid(1).

THE ZSH/COMPLETE MODULE
The zsh/complete module makes available several builtin commands which can be used in
user-defined completion widgets, see zshcompwid(1).

THE ZSH/COMPLIST MODULE
The zsh/complist module offers three extensions to completion listings: the ability to
highlight matches in such a list, the ability to scroll through long lists and a different
style of menu completion.

Colored completion listings
Whenever one of the parameters ZLS_COLORS or ZLS_COLOURS is set and the zsh/complist mod-
ule is loaded or linked into the shell, completion lists will be colored. Note, however,
that complist will not automatically be loaded if it is not linked in: on systems with
dynamic loading, `zmodload zsh/complist' is required.

The parameters ZLS_COLORS and ZLS_COLOURS describe how matches are highlighted. To turn
on highlighting an empty value suffices, in which case all the default values given below
will be used. The format of the value of these parameters is the same as used by the GNU
version of the ls command: a colon-separated list of specifications of the form
`name=value'. The name may be one of the following strings, most of which specify file
types for which the value will be used. The strings and their default values are:

no 0 for normal text (i.e. when displaying something other than a matched file)

fi 0 for regular files

di 32 for directories

ln 36 for symbolic links. If this has the special value target, symbolic links are
dereferenced and the target file used to determine the display format.

pi 31 for named pipes (FIFOs)

so 33 for sockets

bd 44;37
for block devices

cd 44;37
for character devices

or none
for a symlink to nonexistent file (default is the value defined for ln)

mi none
for a non-existent file (default is the value defined for fi); this code is cur-
rently not used

su 37;41
for files with setuid bit set

sg 30;43
for files with setgid bit set

tw 30;42
for world writable directories with sticky bit set

ow 34;43
for world writable directories without sticky bit set

sa none
for files with an associated suffix alias; this is only tested after specific suf-
fixes, as described below

st 37;44
for directories with sticky bit set but not world writable

ex 35 for executable files

lc \e[ for the left code (see below)

rc m for the right code

tc 0 for the character indicating the file type printed after filenames if the
LIST_TYPES option is set

sp 0 for the spaces printed after matches to align the next column

ec none
for the end code

Apart from these strings, the name may also be an asterisk (`*') followed by any string.
The value given for such a string will be used for all files whose name ends with the
string. The name may also be an equals sign (`=') followed by a pattern; the EX-
TENDED_GLOB option will be turned on for evaluation of the pattern. The value given for
this pattern will be used for all matches (not just filenames) whose display string are
matched by the pattern. Definitions for the form with the leading equal sign take prece-
dence over the values defined for file types, which in turn take precedence over the form
with the leading asterisk (file extensions).

The leading-equals form also allows different parts of the displayed strings to be colored
differently. For this, the pattern has to use the `(#b)' globbing flag and pairs of
parentheses surrounding the parts of the strings that are to be colored differently. In
this case the value may consist of more than one color code separated by equal signs. The
first code will be used for all parts for which no explicit code is specified and the fol-
lowing codes will be used for the parts matched by the sub-patterns in parentheses. For
example, the specification `=(#b)(?)*(?)=0=3=7' will be used for all matches which are at
least two characters long and will use the code `3' for the first character, `7' for the
last character and `0' for the rest.

All three forms of name may be preceded by a pattern in parentheses. If this is given,
the value will be used only for matches in groups whose names are matched by the pattern
given in the parentheses. For example, `(g*)m*=43' highlights all matches beginning with
`m' in groups whose names begin with `g' using the color code `43'. In case of the `lc',
`rc', and `ec' codes, the group pattern is ignored.

Note also that all patterns are tried in the order in which they appear in the parameter
value until the first one matches which is then used. Patterns may be matched against
completions, descriptions (possibly with spaces appended for padding), or lines consisting
of a completion followed by a description. For consistent coloring it may be necessary to
use more than one pattern or a pattern with backreferences.

When printing a match, the code prints the value of lc, the value for the file-type or the
last matching specification with a `*', the value of rc, the string to display for the
match itself, and then the value of ec if that is defined or the values of lc, no, and rc
if ec is not defined.

The default values are ISO 6429 (ANSI) compliant and can be used on vt100 compatible ter-
minals such as xterms. On monochrome terminals the default values will have no visible
effect. The colors function from the contribution can be used to get associative arrays
containing the codes for ANSI terminals (see the section `Other Functions' in zshcon-
trib(1)). For example, after loading colors, one could use `$color[red]' to get the code
for foreground color red and `$color[bg-green]' for the code for background color green.

If the completion system invoked by compinit is used, these parameters should not be set
directly because the system controls them itself. Instead, the list-colors style should
be used (see the section `Completion System Configuration' in zshcompsys(1)).

Scrolling in completion listings
To enable scrolling through a completion list, the LISTPROMPT parameter must be set. Its
value will be used as the prompt; if it is the empty string, a default prompt will be
used. The value may contain escapes of the form `%x'. It supports the escapes `%B',
`%b', `%S', `%s', `%U', `%u', `%F', `%f', `%K', `%k' and `%{...%}' used also in shell
prompts as well as three pairs of additional sequences: a `%l' or `%L' is replaced by the
number of the last line shown and the total number of lines in the form `number/total'; a
`%m' or `%M' is replaced with the number of the last match shown and the total number of
matches; and `%p' or `%P' is replaced with `Top', `Bottom' or the position of the first
line shown in percent of the total number of lines, respectively. In each of these cases
the form with the uppercase letter will be replaced with a string of fixed width, padded
to the right with spaces, while the lowercase form will not be padded.

If the parameter LISTPROMPT is set, the completion code will not ask if the list should be
shown. Instead it immediately starts displaying the list, stopping after the first
screenful, showing the prompt at the bottom, waiting for a keypress after temporarily
switching to the listscroll keymap. Some of the zle functions have a special meaning
while scrolling lists:

send-break
stops listing discarding the key pressed

accept-line, down-history, down-line-or-history
down-line-or-search, vi-down-line-or-history
scrolls forward one line

complete-word, menu-complete, expand-or-complete
expand-or-complete-prefix, menu-complete-or-expand
scrolls forward one screenful

accept-search
stop listing but take no other action

Every other character stops listing and immediately processes the key as usual. Any key
that is not bound in the listscroll keymap or that is bound to undefined-key is looked up
in the keymap currently selected.

As for the ZLS_COLORS and ZLS_COLOURS parameters, LISTPROMPT should not be set directly
when using the shell function based completion system. Instead, the list-prompt style
should be used.

Menu selection
The zsh/complist module also offers an alternative style of selecting matches from a list,
called menu selection, which can be used if the shell is set up to return to the last
prompt after showing a completion list (see the ALWAYS_LAST_PROMPT option in zshop-
tions(1)).

Menu selection can be invoked directly by the widget menu-select defined by this module.
This is a standard ZLE widget that can be bound to a key in the usual way as described in
zshzle(1).

Alternatively, the parameter MENUSELECT can be set to an integer, which gives the minimum
number of matches that must be present before menu selection is automatically turned on.
This second method requires that menu completion be started, either directly from a widget
such as menu-complete, or due to one of the options MENU_COMPLETE or AUTO_MENU being set.
If MENUSELECT is set, but is 0, 1 or empty, menu selection will always be started during
an ambiguous menu completion.

When using the completion system based on shell functions, the MENUSELECT parameter should
not be used (like the ZLS_COLORS and ZLS_COLOURS parameters described above). Instead,
the menu style should be used with the select=... keyword.

After menu selection is started, the matches will be listed. If there are more matches
than fit on the screen, only the first screenful is shown. The matches to insert into the
command line can be selected from this list. In the list one match is highlighted using
the value for ma from the ZLS_COLORS or ZLS_COLOURS parameter. The default value for this
is `7' which forces the selected match to be highlighted using standout mode on a
vt100-compatible terminal. If neither ZLS_COLORS nor ZLS_COLOURS is set, the same termi-
nal control sequence as for the `%S' escape in prompts is used.

If there are more matches than fit on the screen and the parameter MENUPROMPT is set, its
value will be shown below the matches. It supports the same escape sequences as LIST-
PROMPT, but the number of the match or line shown will be that of the one where the mark
is placed. If its value is the empty string, a default prompt will be used.

The MENUSCROLL parameter can be used to specify how the list is scrolled. If the parame-
ter is unset, this is done line by line, if it is set to `0' (zero), the list will scroll
half the number of lines of the screen. If the value is positive, it gives the number of
lines to scroll and if it is negative, the list will be scrolled the number of lines of
the screen minus the (absolute) value.

As for the ZLS_COLORS, ZLS_COLOURS and LISTPROMPT parameters, neither MENUPROMPT nor
MENUSCROLL should be set directly when using the shell function based completion system.
Instead, the select-prompt and select-scroll styles should be used.

The completion code sometimes decides not to show all of the matches in the list. These
hidden matches are either matches for which the completion function which added them ex-
plicitly requested that they not appear in the list (using the -n option of the compadd
builtin command) or they are matches which duplicate a string already in the list (because
they differ only in things like prefixes or suffixes that are not displayed). In the list
used for menu selection, however, even these matches are shown so that it is possible to
select them. To highlight such matches the hi and du capabilities in the ZLS_COLORS and
ZLS_COLOURS parameters are supported for hidden matches of the first and second kind, re-
spectively.

Selecting matches is done by moving the mark around using the zle movement functions.
When not all matches can be shown on the screen at the same time, the list will scroll up
and down when crossing the top or bottom line. The following zle functions have special
meaning during menu selection. Note that the following always perform the same task
within the menu selection map and cannot be replaced by user defined widgets, nor can the
set of functions be extended:

accept-line, accept-search
accept the current match and leave menu selection (but do not cause the command
line to be accepted)

send-break
leaves menu selection and restores the previous contents of the command line

redisplay, clear-screen
execute their normal function without leaving menu selection

accept-and-hold, accept-and-menu-complete
accept the currently inserted match and continue selection allowing to select the
next match to insert into the line

accept-and-infer-next-history
accepts the current match and then tries completion with menu selection again; in
the case of files this allows one to select a directory and immediately attempt to
complete files in it; if there are no matches, a message is shown and one can use
undo to go back to completion on the previous level, every other key leaves menu
selection (including the other zle functions which are otherwise special during
menu selection)

undo removes matches inserted during the menu selection by one of the three functions
before

down-history, down-line-or-history
vi-down-line-or-history, down-line-or-search
moves the mark one line down

up-history, up-line-or-history
vi-up-line-or-history, up-line-or-search
moves the mark one line up

forward-char, vi-forward-char
moves the mark one column right

backward-char, vi-backward-char
moves the mark one column left

forward-word, vi-forward-word
vi-forward-word-end, emacs-forward-word
moves the mark one screenful down

backward-word, vi-backward-word, emacs-backward-word
moves the mark one screenful up

vi-forward-blank-word, vi-forward-blank-word-end
moves the mark to the first line of the next group of matches

vi-backward-blank-word
moves the mark to the last line of the previous group of matches

beginning-of-history
moves the mark to the first line

end-of-history
moves the mark to the last line

beginning-of-buffer-or-history, beginning-of-line
beginning-of-line-hist, vi-beginning-of-line
moves the mark to the leftmost column

end-of-buffer-or-history, end-of-line
end-of-line-hist, vi-end-of-line
moves the mark to the rightmost column

complete-word, menu-complete, expand-or-complete
expand-or-complete-prefix, menu-expand-or-complete
moves the mark to the next match

reverse-menu-complete
moves the mark to the previous match

vi-insert
this toggles between normal and interactive mode; in interactive mode the keys
bound to self-insert and self-insert-unmeta insert into the command line as in nor-
mal editing mode but without leaving menu selection; after each character comple-
tion is tried again and the list changes to contain only the new matches; the com-
pletion widgets make the longest unambiguous string be inserted in the command line
and undo and backward-delete-char go back to the previous set of matches

history-incremental-search-forward
history-incremental-search-backward
this starts incremental searches in the list of completions displayed; in this
mode, accept-line only leaves incremental search, going back to the normal menu se-
lection mode

All movement functions wrap around at the edges; any other zle function not listed leaves
menu selection and executes that function. It is possible to make widgets in the above
list do the same by using the form of the widget with a `.' in front. For example, the
widget `.accept-line' has the effect of leaving menu selection and accepting the entire
command line.

During this selection the widget uses the keymap menuselect. Any key that is not defined
in this keymap or that is bound to undefined-key is looked up in the keymap currently se-
lected. This is used to ensure that the most important keys used during selection (namely
the cursor keys, return, and TAB) have sensible defaults. However, keys in the menuselect
keymap can be modified directly using the bindkey builtin command (see zshmodules(1)). For
example, to make the return key leave menu selection without accepting the match currently
selected one could call

bindkey -M menuselect '^M' send-break

after loading the zsh/complist module.

THE ZSH/COMPUTIL MODULE
The zsh/computil module adds several builtin commands that are used by some of the comple-
tion functions in the completion system based on shell functions (see zshcompsys(1) ).
Except for compquote these builtin commands are very specialised and thus not very inter-
esting when writing your own completion functions. In summary, these builtin commands
are:

comparguments
This is used by the _arguments function to do the argument and command line pars-
ing. Like compdescribe it has an option -i to do the parsing and initialize some
internal state and various options to access the state information to decide what
should be completed.

compdescribe
This is used by the _describe function to build the displays for the matches and to
get the strings to add as matches with their options. On the first call one of the
options -i or -I should be supplied as the first argument. In the first case, dis-
play strings without the descriptions will be generated, in the second case, the
string used to separate the matches from their descriptions must be given as the
second argument and the descriptions (if any) will be shown. All other arguments
are like the definition arguments to _describe itself.

Once compdescribe has been called with either the -i or the -I option, it can be
repeatedly called with the -g option and the names of four parameters as its argu-
ments. This will step through the different sets of matches and store the value of
compstate[list] in the first scalar, the options for compadd in the second array,
the matches in the third array, and the strings to be displayed in the completion
listing in the fourth array. The arrays may then be directly given to compadd to
register the matches with the completion code.

compfiles
Used by the _path_files function to optimize complex recursive filename generation
(globbing). It does three things. With the -p and -P options it builds the glob
patterns to use, including the paths already handled and trying to optimize the
patterns with respect to the prefix and suffix from the line and the match specifi-
cation currently used. The -i option does the directory tests for the ignore-par-
ents style and the -r option tests if a component for some of the matches are equal
to the string on the line and removes all other matches if that is true.

compgroups
Used by the _tags function to implement the internals of the group-order style.
This only takes its arguments as names of completion groups and creates the groups
for it (all six types: sorted and unsorted, both without removing duplicates, with
removing all duplicates and with removing consecutive duplicates).

compquote [ -p ] names ...
There may be reasons to write completion functions that have to add the matches us-
ing the -Q option to compadd and perform quoting themselves. Instead of interpret-
ing the first character of the all_quotes key of the compstate special association
and using the q flag for parameter expansions, one can use this builtin command.
The arguments are the names of scalar or array parameters and the values of these
parameters are quoted as needed for the innermost quoting level. If the -p option
is given, quoting is done as if there is some prefix before the values of the pa-
rameters, so that a leading equal sign will not be quoted.

The return status is non-zero in case of an error and zero otherwise.

comptags
comptry
These implement the internals of the tags mechanism.

compvalues
Like comparguments, but for the _values function.

THE ZSH/CURSES MODULE
The zsh/curses module makes available one builtin command and various parameters.

Builtin
zcurses init
zcurses end
zcurses addwin targetwin nlines ncols begin_y begin_x [ parentwin ]
zcurses delwin targetwin
zcurses refresh [ targetwin ... ]
zcurses touch targetwin ...
zcurses move targetwin new_y new_x
zcurses clear targetwin [ redraw | eol | bot ]
zcurses position targetwin array
zcurses char targetwin character
zcurses string targetwin string
zcurses border targetwin border
zcurses attr targetwin [ [+|-]attribute | fg_col/bg_col ] [...]
zcurses bg targetwin [ [+|-]attribute | fg_col/bg_col | @char ] [...]
zcurses scroll targetwin [ on | off | [+|-]lines ]
zcurses input targetwin [ param [ kparam [ mparam ] ] ]
zcurses mouse [ delay num | [+|-]motion ]
zcurses timeout targetwin intval
zcurses querychar targetwin [ param ]
zcurses resize height width [ endwin | nosave | endwin_nosave ]
Manipulate curses windows. All uses of this command should be bracketed by
`zcurses init' to initialise use of curses, and `zcurses end' to end it; omitting
`zcurses end' can cause the terminal to be in an unwanted state.

The subcommand addwin creates a window with nlines lines and ncols columns. Its
upper left corner will be placed at row begin_y and column begin_x of the screen.
targetwin is a string and refers to the name of a window that is not currently as-
signed. Note in particular the curses convention that vertical values appear be-
fore horizontal values.

If addwin is given an existing window as the final argument, the new window is cre-
ated as a subwindow of parentwin. This differs from an ordinary new window in that
the memory of the window contents is shared with the parent's memory. Subwindows
must be deleted before their parent. Note that the coordinates of subwindows are
relative to the screen, not the parent, as with other windows.

Use the subcommand delwin to delete a window created with addwin. Note that end
does not implicitly delete windows, and that delwin does not erase the screen image
of the window.

The window corresponding to the full visible screen is called stdscr; it always ex-
ists after `zcurses init' and cannot be delete with delwin.

The subcommand refresh will refresh window targetwin; this is necessary to make any
pending changes (such as characters you have prepared for output with char) visible
on the screen. refresh without an argument causes the screen to be cleared and re-
drawn. If multiple windows are given, the screen is updated once at the end.

The subcommand touch marks the targetwins listed as changed. This is necessary be-
fore refreshing windows if a window that was in front of another window (which may
be stdscr) is deleted.

The subcommand move moves the cursor position in targetwin to new coordinates new_y
and new_x. Note that the subcommand string (but not the subcommand char) advances
the cursor position over the characters added.

The subcommand clear erases the contents of targetwin. One (and no more than one)
of three options may be specified. With the option redraw, in addition the next
refresh of targetwin will cause the screen to be cleared and repainted. With the
option eol, targetwin is only cleared to the end of the current cursor line. With
the option bot, targetwin is cleared to the end of the window, i.e everything to
the right and below the cursor is cleared.

The subcommand position writes various positions associated with targetwin into the
array named array. These are, in order:
- The y and x coordinates of the cursor relative to the top left of targetwin
- The y and x coordinates of the top left of targetwin on the screen
- The size of targetwin in y and x dimensions.

Outputting characters and strings are achieved by char and string respectively.

To draw a border around window targetwin, use border. Note that the border is not
subsequently handled specially: in other words, the border is simply a set of
characters output at the edge of the window. Hence it can be overwritten, can
scroll off the window, etc.

The subcommand attr will set targetwin's attributes or foreground/background color
pair for any successive character output. Each attribute given on the line may be
prepended by a + to set or a - to unset that attribute; + is assumed if absent.
The attributes supported are blink, bold, dim, reverse, standout, and underline.

Each fg_col/bg_col attribute (to be read as `fg_col on bg_col') sets the foreground
and background color for character output. The color default is sometimes avail-
able (in particular if the library is ncurses), specifying the foreground or back-
ground color with which the terminal started. The color pair default/default is
always available. To use more than the 8 named colors (red, green, etc.) construct
the fg_col/bg_col pairs where fg_col and bg_col are decimal integers, e.g 128/200.
The maximum color value is 254 if the terminal supports 256 colors.

bg overrides the color and other attributes of all characters in the window. Its
usual use is to set the background initially, but it will overwrite the attributes
of any characters at the time when it is called. In addition to the arguments al-
lowed with attr, an argument @char specifies a character to be shown in otherwise
blank areas of the window. Owing to limitations of curses this cannot be a multi-
byte character (use of ASCII characters only is recommended). As the specified set
of attributes override the existing background, turning attributes off in the argu-
ments is not useful, though this does not cause an error.

The subcommand scroll can be used with on or off to enabled or disable scrolling of
a window when the cursor would otherwise move below the window due to typing or
output. It can also be used with a positive or negative integer to scroll the win-
dow up or down the given number of lines without changing the current cursor posi-
tion (which therefore appears to move in the opposite direction relative to the
window). In the second case, if scrolling is off it is temporarily turned on to
allow the window to be scrolled.

The subcommand input reads a single character from the window without echoing it
back. If param is supplied the character is assigned to the parameter param, else
it is assigned to the parameter REPLY.

If both param and kparam are supplied, the key is read in `keypad' mode. In this
mode special keys such as function keys and arrow keys return the name of the key
in the parameter kparam. The key names are the macros defined in the curses.h or
ncurses.h with the prefix `KEY_' removed; see also the description of the parameter
zcurses_keycodes below. Other keys cause a value to be set in param as before. On
a successful return only one of param or kparam contains a non-empty string; the
other is set to an empty string.

If mparam is also supplied, input attempts to handle mouse input. This is only
available with the ncurses library; mouse handling can be detected by checking for
the exit status of `zcurses mouse' with no arguments. If a mouse button is clicked
(or double- or triple-clicked, or pressed or released with a configurable delay
from being clicked) then kparam is set to the string MOUSE, and mparam is set to an
array consisting of the following elements:
- An identifier to discriminate different input devices; this is only rarely
useful.
- The x, y and z coordinates of the mouse click relative to the full screen,
as three elements in that order (i.e. the y coordinate is, unusually, after
the x coordinate). The z coordinate is only available for a few unusual in-
put devices and is otherwise set to zero.
- Any events that occurred as separate items; usually there will be just one.
An event consists of PRESSED, RELEASED, CLICKED, DOUBLE_CLICKED or
TRIPLE_CLICKED followed immediately (in the same element) by the number of
the button.
- If the shift key was pressed, the string SHIFT.
- If the control key was pressed, the string CTRL.
- If the alt key was pressed, the string ALT.

Not all mouse events may be passed through to the terminal window; most terminal
emulators handle some mouse events themselves. Note that the ncurses manual im-
plies that using input both with and without mouse handling may cause the mouse
cursor to appear and disappear.

The subcommand mouse can be used to configure the use of the mouse. There is no
window argument; mouse options are global. `zcurses mouse' with no arguments re-
turns status 0 if mouse handling is possible, else status 1. Otherwise, the possi-
ble arguments (which may be combined on the same command line) are as follows. de-
lay num sets the maximum delay in milliseconds between press and release events to
be considered as a click; the value 0 disables click resolution, and the default is
one sixth of a second. motion proceeded by an optional `+' (the default) or -
turns on or off reporting of mouse motion in addition to clicks, presses and re-
leases, which are always reported. However, it appears reports for mouse motion
are not currently implemented.

The subcommand timeout specifies a timeout value for input from targetwin. If int-
val is negative, `zcurses input' waits indefinitely for a character to be typed;
this is the default. If intval is zero, `zcurses input' returns immediately; if
there is typeahead it is returned, else no input is done and status 1 is returned.
If intval is positive, `zcurses input' waits intval milliseconds for input and if
there is none at the end of that period returns status 1.

The subcommand querychar queries the character at the current cursor position. The
return values are stored in the array named param if supplied, else in the array
reply. The first value is the character (which may be a multibyte character if the
system supports them); the second is the color pair in the usual fg_col/bg_col no-
tation, or 0 if color is not supported. Any attributes other than color that apply
to the character, as set with the subcommand attr, appear as additional elements.

The subcommand resize resizes stdscr and all windows to given dimensions (windows
that stick out from the new dimensions are resized down). The underlying curses ex-
tension (resize_term call) can be unavailable. To verify, zeroes can be used for
height and width. If the result of the subcommand is 0, resize_term is available (2
otherwise). Tests show that resizing can be normally accomplished by calling
zcurses end and zcurses refresh. The resize subcommand is provided for versatility.
Multiple system configurations have been checked and zcurses end and zcurses re-
fresh are still needed for correct terminal state after resize. To invoke them with
resize, use endwin argument. Using nosave argument will cause new terminal state
to not be saved internally by zcurses. This is also provided for versatility and
should normally be not needed.

Parameters
ZCURSES_COLORS
Readonly integer. The maximum number of colors the terminal supports. This value
is initialised by the curses library and is not available until the first time
zcurses init is run.

ZCURSES_COLOR_PAIRS
Readonly integer. The maximum number of color pairs fg_col/bg_col that may be de-
fined in `zcurses attr' commands; note this limit applies to all color pairs that
have been used whether or not they are currently active. This value is initialised
by the curses library and is not available until the first time zcurses init is
run.

zcurses_attrs
Readonly array. The attributes supported by zsh/curses; available as soon as the
module is loaded.

zcurses_colors
Readonly array. The colors supported by zsh/curses; available as soon as the mod-
ule is loaded.

zcurses_keycodes
Readonly array. The values that may be returned in the second parameter supplied
to `zcurses input' in the order in which they are defined internally by curses.
Not all function keys are listed, only F0; curses reserves space for F0 up to F63.

zcurses_windows
Readonly array. The current list of windows, i.e. all windows that have been cre-
ated with `zcurses addwin' and not removed with `zcurses delwin'.

THE ZSH/DATETIME MODULE
The zsh/datetime module makes available one builtin command:

strftime [ -s scalar ] format [ epochtime [ nanoseconds ] ]
strftime -r [ -q ] [ -s scalar ] format timestring
Output the date in the format specified. With no epochtime, the current system
date/time is used; optionally, epochtime may be used to specify the number of sec-
onds since the epoch, and nanoseconds may additionally be used to specify the num-
ber of nanoseconds past the second (otherwise that number is assumed to be 0). See
strftime(3) for details. The zsh extensions described in the section EXPANSION OF
PROMPT SEQUENCES in zshmisc(1) are also available.

-q Run quietly; suppress printing of all error messages described below. Er-
rors for invalid epochtime values are always printed.

-r With the option -r (reverse), use format to parse the input string
timestring and output the number of seconds since the epoch at which the
time occurred. The parsing is implemented by the system function strptime;
see strptime(3). This means that zsh format extensions are not available,
but for reverse lookup they are not required.

In most implementations of strftime any timezone in the timestring is ig-
nored and the local timezone declared by the TZ environment variable is
used; other parameters are set to zero if not present.

If timestring does not match format the command returns status 1 and prints
an error message. If timestring matches format but not all characters in
timestring were used, the conversion succeeds but also prints an error mes-
sage.

If either of the system functions strptime or mktime is not available, sta-
tus 2 is returned and an error message is printed.

-s scalar
Assign the date string (or epoch time in seconds if -r is given) to scalar
instead of printing it.

Note that depending on the system's declared integral time type, strftime may pro-
duce incorrect results for epoch times greater than 2147483647 which corresponds to
2038-01-19 03:14:07 +0000.

The zsh/datetime module makes available several parameters; all are readonly:

EPOCHREALTIME
A floating point value representing the number of seconds since the epoch. The no-
tional accuracy is to nanoseconds if the clock_gettime call is available and to mi-
croseconds otherwise, but in practice the range of double precision floating point
and shell scheduling latencies may be significant effects.

EPOCHSECONDS
An integer value representing the number of seconds since the epoch.

epochtime
An array value containing the number of seconds since the epoch in the first ele-
ment and the remainder of the time since the epoch in nanoseconds in the second el-
ement. To ensure the two elements are consistent the array should be copied or
otherwise referenced as a single substitution before the values are used. The fol-
lowing idiom may be used:

for secs nsecs in $epochtime; do
...
done

THE ZSH/DB/GDBM MODULE
The zsh/db/gdbm module is used to create "tied" associative arrays that interface to data-
base files. If the GDBM interface is not available, the builtins defined by this module
will report an error. This module is also intended as a prototype for creating additional
database interfaces, so the ztie builtin may move to a more generic module in the future.

The builtins in this module are:

ztie -d db/gdbm -f filename [ -r ] arrayname
Open the GDBM database identified by filename and, if successful, create the asso-
ciative array arrayname linked to the file. To create a local tied array, the pa-
rameter must first be declared, so commands similar to the following would be exe-
cuted inside a function scope:

local -A sampledb
ztie -d db/gdbm -f sample.gdbm sampledb

The -r option opens the database file for reading only, creating a parameter with
the readonly attribute. Without this option, using `ztie' on a file for which the
user does not have write permission is an error. If writable, the database is
opened synchronously so fields changed in arrayname are immediately written to
filename.

Changes to the file modes filename after it has been opened do not alter the state
of arrayname, but `typeset -r arrayname' works as expected.

zuntie [ -u ] arrayname ...
Close the GDBM database associated with each arrayname and then unset the parame-
ter. The -u option forces an unset of parameters made readonly with `ztie -r'.

This happens automatically if the parameter is explicitly unset or its local scope
(function) ends. Note that a readonly parameter may not be explicitly unset, so
the only way to unset a global parameter created with `ztie -r' is to use `zuntie
-u'.

zgdbmpath parametername
Put path to database file assigned to parametername into REPLY scalar.

zgdbm_tied
Array holding names of all tied parameters.

The fields of an associative array tied to GDBM are neither cached nor otherwise stored in
memory, they are read from or written to the database on each reference. Thus, for exam-
ple, the values in a readonly array may be changed by a second writer of the same database
file.

THE ZSH/DELTOCHAR MODULE
The zsh/deltochar module makes available two ZLE functions:

delete-to-char
Read a character from the keyboard, and delete from the cursor position up to and
including the next (or, with repeat count n, the nth) instance of that character.
Negative repeat counts mean delete backwards.

zap-to-char
This behaves like delete-to-char, except that the final occurrence of the character
itself is not deleted.

THE ZSH/EXAMPLE MODULE
The zsh/example module makes available one builtin command:

example [ -flags ] [ args ... ]
Displays the flags and arguments it is invoked with.

The purpose of the module is to serve as an example of how to write a module.

THE ZSH/FILES MODULE
The zsh/files module makes available some common commands for file manipulation as
builtins; these commands are probably not needed for many normal situations but can be
useful in emergency recovery situations with constrained resources. The commands do not
implement all features now required by relevant standards committees.

For all commands, a variant beginning zf_ is also available and loaded automatically. Us-
ing the features capability of zmodload will let you load only those names you want. Note
that it's possible to load only the builtins with zsh-specific names using the following
command:

zmodload -m -F zsh/files b:zf_\*

The commands loaded by default are:

chgrp [ -hRs ] group filename ...
Changes group of files specified. This is equivalent to chown with a user-spec ar-
gument of `:group'.

chmod [ -Rs ] mode filename ...
Changes mode of files specified.

The specified mode must be in octal.

The -R option causes chmod to recursively descend into directories, changing the
mode of all files in the directory after changing the mode of the directory itself.

The -s option is a zsh extension to chmod functionality. It enables paranoid be-
haviour, intended to avoid security problems involving a chmod being tricked into
affecting files other than the ones intended. It will refuse to follow symbolic
links, so that (for example) ``chmod 600 /tmp/foo/passwd'' can't accidentally chmod
/etc/passwd if /tmp/foo happens to be a link to /etc. It will also check where it
is after leaving directories, so that a recursive chmod of a deep directory tree
can't end up recursively chmoding /usr as a result of directories being moved up
the tree.

chown [ -hRs ] user-spec filename ...
Changes ownership and group of files specified.

The user-spec can be in four forms:

user change owner to user; do not change group
user:: change owner to user; do not change group
user: change owner to user; change group to user's primary group
user:group
change owner to user; change group to group
:group do not change owner; change group to group

In each case, the `:' may instead be a `.'. The rule is that if there is a `:'
then the separator is `:', otherwise if there is a `.' then the separator is `.',
otherwise there is no separator.

Each of user and group may be either a username (or group name, as appropriate) or
a decimal user ID (group ID). Interpretation as a name takes precedence, if there
is an all-numeric username (or group name).

If the target is a symbolic link, the -h option causes chown to set the ownership
of the link instead of its target.

The -R option causes chown to recursively descend into directories, changing the
ownership of all files in the directory after changing the ownership of the direc-
tory itself.

The -s option is a zsh extension to chown functionality. It enables paranoid be-
haviour, intended to avoid security problems involving a chown being tricked into
affecting files other than the ones intended. It will refuse to follow symbolic
links, so that (for example) ``chown luser /tmp/foo/passwd'' can't accidentally
chown /etc/passwd if /tmp/foo happens to be a link to /etc. It will also check
where it is after leaving directories, so that a recursive chown of a deep direc-
tory tree can't end up recursively chowning /usr as a result of directories being
moved up the tree.

ln [ -dfhins ] filename dest
ln [ -dfhins ] filename ... dir
Creates hard (or, with -s, symbolic) links. In the first form, the specified des-
tination is created, as a link to the specified filename. In the second form, each
of the filenames is taken in turn, and linked to a pathname in the specified direc-
tory that has the same last pathname component.

Normally, ln will not attempt to create hard links to directories. This check can
be overridden using the -d option. Typically only the super-user can actually suc-
ceed in creating hard links to directories. This does not apply to symbolic links
in any case.

By default, existing files cannot be replaced by links. The -i option causes the
user to be queried about replacing existing files. The -f option causes existing
files to be silently deleted, without querying. -f takes precedence.

The -h and -n options are identical and both exist for compatibility; either one
indicates that if the target is a symlink then it should not be dereferenced. Typ-
ically this is used in combination with -sf so that if an existing link points to a
directory then it will be removed, instead of followed. If this option is used
with multiple filenames and the target is a symbolic link pointing to a directory
then the result is an error.

mkdir [ -p ] [ -m mode ] dir ...
Creates directories. With the -p option, non-existing parent directories are first
created if necessary, and there will be no complaint if the directory already ex-
ists. The -m option can be used to specify (in octal) a set of file permissions
for the created directories, otherwise mode 777 modified by the current umask (see
umask(2)) is used.

mv [ -fi ] filename dest
mv [ -fi ] filename ... dir
Moves files. In the first form, the specified filename is moved to the specified
destination. In the second form, each of the filenames is taken in turn, and moved
to a pathname in the specified directory that has the same last pathname component.

By default, the user will be queried before replacing any file that the user cannot
write to, but writable files will be silently removed. The -i option causes the
user to be queried about replacing any existing files. The -f option causes any
existing files to be silently deleted, without querying. -f takes precedence.

Note that this mv will not move files across devices. Historical versions of mv,
when actual renaming is impossible, fall back on copying and removing files; if
this behaviour is desired, use cp and rm manually. This may change in a future
version.

rm [ -dfiRrs ] filename ...
Removes files and directories specified.

Normally, rm will not remove directories (except with the -R or -r options). The
-d option causes rm to try removing directories with unlink (see unlink(2)), the
same method used for files. Typically only the super-user can actually succeed in
unlinking directories in this way. -d takes precedence over -R and -r.

By default, the user will be queried before removing any file that the user cannot
write to, but writable files will be silently removed. The -i option causes the
user to be queried about removing any files. The -f option causes files to be
silently deleted, without querying, and suppresses all error indications. -f takes
precedence.

The -R and -r options cause rm to recursively descend into directories, deleting
all files in the directory before removing the directory with the rmdir system call
(see rmdir(2)).

The -s option is a zsh extension to rm functionality. It enables paranoid behav-
iour, intended to avoid common security problems involving a root-run rm being
tricked into removing files other than the ones intended. It will refuse to follow
symbolic links, so that (for example) ``rm /tmp/foo/passwd'' can't accidentally re-
move /etc/passwd if /tmp/foo happens to be a link to /etc. It will also check
where it is after leaving directories, so that a recursive removal of a deep direc-
tory tree can't end up recursively removing /usr as a result of directories being
moved up the tree.

rmdir dir ...
Removes empty directories specified.

sync Calls the system call of the same name (see sync(2)), which flushes dirty buffers
to disk. It might return before the I/O has actually been completed.

THE ZSH/LANGINFO MODULE
The zsh/langinfo module makes available one parameter:

langinfo
An associative array that maps langinfo elements to their values.

Your implementation may support a number of the following keys:

CODESET, D_T_FMT, D_FMT, T_FMT, RADIXCHAR, THOUSEP, YESEXPR, NOEXPR, CRNCYSTR, AB-
DAY_{1..7}, DAY_{1..7}, ABMON_{1..12}, MON_{1..12}, T_FMT_AMPM, AM_STR, PM_STR,
ERA, ERA_D_FMT, ERA_D_T_FMT, ERA_T_FMT, ALT_DIGITS

THE ZSH/MAPFILE MODULE
The zsh/mapfile module provides one special associative array parameter of the same name.

mapfile
This associative array takes as keys the names of files; the resulting value is the
content of the file. The value is treated identically to any other text coming
from a parameter. The value may also be assigned to, in which case the file in
question is written (whether or not it originally existed); or an element may be
unset, which will delete the file in question. For example, `vared mapfile[my-
file]' works as expected, editing the file `myfile'.

When the array is accessed as a whole, the keys are the names of files in the cur-
rent directory, and the values are empty (to save a huge overhead in memory). Thus
${(k)mapfile} has the same effect as the glob operator *(D), since files beginning
with a dot are not special. Care must be taken with expressions such as rm
${(k)mapfile}, which will delete every file in the current directory without the
usual `rm *' test.

The parameter mapfile may be made read-only; in that case, files referenced may not
be written or deleted.

A file may conveniently be read into an array as one line per element with the form
`array=("${(f@)mapfile[filename]}")'. The double quotes and the `@' are necessary
to prevent empty lines from being removed. Note that if the file ends with a new-
line, the shell will split on the final newline, generating an additional empty
field; this can be suppressed by using `array=("${(f@)${mapfile[file-
name]%$'\n'}}")'.

Limitations
Although reading and writing of the file in question is efficiently handled, zsh's inter-
nal memory management may be arbitrarily baroque; however, mapfile is usually very much
more efficient than anything involving a loop. Note in particular that the whole contents
of the file will always reside physically in memory when accessed (possibly multiple
times, due to standard parameter substitution operations). In particular, this means han-
dling of sufficiently long files (greater than the machine's swap space, or than the range
of the pointer type) will be incorrect.

No errors are printed or flagged for non-existent, unreadable, or unwritable files, as the
parameter mechanism is too low in the shell execution hierarchy to make this convenient.

It is unfortunate that the mechanism for loading modules does not yet allow the user to
specify the name of the shell parameter to be given the special behaviour.

THE ZSH/MATHFUNC MODULE
The zsh/mathfunc module provides standard mathematical functions for use when evaluating
mathematical formulae. The syntax agrees with normal C and FORTRAN conventions, for exam-
ple,

(( f = sin(0.3) ))

assigns the sine of 0.3 to the parameter f.

Most functions take floating point arguments and return a floating point value. However,
any necessary conversions from or to integer type will be performed automatically by the
shell. Apart from atan with a second argument and the abs, int and float functions, all
functions behave as noted in the manual page for the corresponding C function, except that
any arguments out of range for the function in question will be detected by the shell and
an error reported.

The following functions take a single floating point argument: acos, acosh, asin, asinh,
atan, atanh, cbrt, ceil, cos, cosh, erf, erfc, exp, expm1, fabs, floor, gamma, j0, j1,
lgamma, log, log10, log1p, log2, logb, sin, sinh, sqrt, tan, tanh, y0, y1. The atan func-
tion can optionally take a second argument, in which case it behaves like the C function
atan2. The ilogb function takes a single floating point argument, but returns an integer.

The function signgam takes no arguments, and returns an integer, which is the C variable
of the same name, as described in gamma(3). Note that it is therefore only useful immedi-
ately after a call to gamma or lgamma. Note also that `signgam()' and `signgam' are dis-
tinct expressions.

The functions min, max, and sum are defined not in this module but in the zmathfunc au-
toloadable function, described in the section `Mathematical Functions' in zshcontrib(1).

The following functions take two floating point arguments: copysign, fmod, hypot,
nextafter.

The following take an integer first argument and a floating point second argument: jn, yn.

The following take a floating point first argument and an integer second argument: ldexp,
scalb.

The function abs does not convert the type of its single argument; it returns the absolute
value of either a floating point number or an integer. The functions float and int con-
vert their arguments into a floating point or integer value (by truncation) respectively.

Note that the C pow function is available in ordinary math evaluation as the `**' operator
and is not provided here.

The function rand48 is available if your system's mathematical library has the function
erand48(3). It returns a pseudo-random floating point number between 0 and 1. It takes a
single string optional argument.

If the argument is not present, the random number seed is initialised by three calls to
the rand(3) function --- this produces the same random numbers as the next three values of
$RANDOM.

If the argument is present, it gives the name of a scalar parameter where the current ran-
dom number seed will be stored. On the first call, the value must contain at least twelve
hexadecimal digits (the remainder of the string is ignored), or the seed will be ini-
tialised in the same manner as for a call to rand48 with no argument. Subsequent calls to
rand48(param) will then maintain the seed in the parameter param as a string of twelve
hexadecimal digits, with no base signifier. The random number sequences for different pa-
rameters are completely independent, and are also independent from that used by calls to
rand48 with no argument.

For example, consider

print $(( rand48(seed) ))
print $(( rand48() ))
print $(( rand48(seed) ))

Assuming $seed does not exist, it will be initialised by the first call. In the second
call, the default seed is initialised; note, however, that because of the properties of
rand() there is a correlation between the seeds used for the two initialisations, so for
more secure uses, you should generate your own 12-byte seed. The third call returns to
the same sequence of random numbers used in the first call, unaffected by the intervening
rand48().

THE ZSH/NEARCOLOR MODULE
The zsh/nearcolor module replaces colours specified as hex triplets with the nearest
colour in the 88 or 256 colour palettes that are widely used by terminal emulators. By
default, 24-bit true colour escape codes are generated when colours are specified using
hex triplets. These are not supported by all terminals. The purpose of this module is to
make it easier to define colour preferences in a form that can work across a range of ter-
minal emulators.

Aside from the default colour, the ANSI standard for terminal escape codes provides for
eight colours. The bright attribute brings this to sixteen. These basic colours are com-
monly used in terminal applications due to being widely supported. Expanded 88 and 256
colour palettes are also common and, while the first sixteen colours vary somewhat between
terminals and configurations, these add a generally consistent and predictable set of
colours.

In order to use the zsh/nearcolor module, it only needs to be loaded. Thereafter, whenever
a colour is specified using a hex triplet, it will be compared against each of the avail-
able colours and the closest will be selected. The first sixteen colours are never matched
in this process due to being unpredictable.

It isn't possible to reliably detect support for true colour in the terminal emulator. It
is therefore recommended to be selective in loading the zsh/nearcolor module. For example,
the following checks the COLORTERM environment variable:

[[ $COLORTERM = *(24bit|truecolor)* ]] || zmodload zsh/nearcolor

Note that some terminals accept the true color escape codes but map them internally to a
more limited palette in a similar manner to the zsh/nearcolor module.

THE ZSH/NEWUSER MODULE
The zsh/newuser module is loaded at boot if it is available, the RCS option is set, and
the PRIVILEGED option is not set (all three are true by default). This takes place imme-
diately after commands in the global zshenv file (typically /etc/zsh/zshenv), if any, have
been executed. If the module is not available it is silently ignored by the shell; the
module may safely be removed from $MODULE_PATH by the administrator if it is not required.

On loading, the module tests if any of the start-up files .zshenv, .zprofile, .zshrc or
.zlogin exist in the directory given by the environment variable ZDOTDIR, or the user's
home directory if that is not set. The test is not performed and the module halts pro-
cessing if the shell was in an emulation mode (i.e. had been invoked as some other shell
than zsh).

If none of the start-up files were found, the module then looks for the file newuser first
in a sitewide directory, usually the parent directory of the site-functions directory, and
if that is not found the module searches in a version-specific directory, usually the par-
ent of the functions directory containing version-specific functions. (These directories
can be configured when zsh is built using the --enable-site-scriptdir=dir and --en-
able-scriptdir=dir flags to configure, respectively; the defaults are prefix/share/zsh and
prefix/share/zsh/$ZSH_VERSION where the default prefix is /usr/local.)

If the file newuser is found, it is then sourced in the same manner as a start-up file.
The file is expected to contain code to install start-up files for the user, however any
valid shell code will be executed.

The zsh/newuser module is then unconditionally unloaded.

Note that it is possible to achieve exactly the same effect as the zsh/newuser module by
adding code to /etc/zsh/zshenv. The module exists simply to allow the shell to make ar-
rangements for new users without the need for intervention by package maintainers and sys-
tem administrators.

The script supplied with the module invokes the shell function zsh-newuser-install. This
may be invoked directly by the user even if the zsh/newuser module is disabled. Note,
however, that if the module is not installed the function will not be installed either.
The function is documented in the section User Configuration Functions in zshcontrib(1).

THE ZSH/PARAMETER MODULE
The zsh/parameter module gives access to some of the internal hash tables used by the
shell by defining some special parameters.

options
The keys for this associative array are the names of the options that can be set
and unset using the setopt and unsetopt builtins. The value of each key is either
the string on if the option is currently set, or the string off if the option is
unset. Setting a key to one of these strings is like setting or unsetting the op-
tion, respectively. Unsetting a key in this array is like setting it to the value
off.

commands
This array gives access to the command hash table. The keys are the names of exter-
nal commands, the values are the pathnames of the files that would be executed when
the command would be invoked. Setting a key in this array defines a new entry in
this table in the same way as with the hash builtin. Unsetting a key as in `unset
"commands[foo]"' removes the entry for the given key from the command hash table.

functions
This associative array maps names of enabled functions to their definitions. Set-
ting a key in it is like defining a function with the name given by the key and the
body given by the value. Unsetting a key removes the definition for the function
named by the key.

dis_functions
Like functions but for disabled functions.

functions_source
This readonly associative array maps names of enabled functions to the name of the
file containing the source of the function.

For an autoloaded function that has already been loaded, or marked for autoload
with an absolute path, or that has had its path resolved with `functions -r', this
is the file found for autoloading, resolved to an absolute path.

For a function defined within the body of a script or sourced file, this is the
name of that file. In this case, this is the exact path originally used to that
file, which may be a relative path.

For any other function, including any defined at an interactive prompt or an au-
toload function whose path has not yet been resolved, this is the empty string.
However, the hash element is reported as defined just so long as the function is
present: the keys to this hash are the same as those to $functions.

dis_functions_source
Like functions_source but for disabled functions.

builtins
This associative array gives information about the builtin commands currently en-
abled. The keys are the names of the builtin commands and the values are either
`undefined' for builtin commands that will automatically be loaded from a module if
invoked or `defined' for builtin commands that are already loaded.

dis_builtins
Like builtins but for disabled builtin commands.

reswords
This array contains the enabled reserved words.

dis_reswords
Like reswords but for disabled reserved words.

patchars
This array contains the enabled pattern characters.

dis_patchars
Like patchars but for disabled pattern characters.

aliases
This maps the names of the regular aliases currently enabled to their expansions.

dis_aliases
Like aliases but for disabled regular aliases.

galiases
Like aliases, but for global aliases.

dis_galiases
Like galiases but for disabled global aliases.

saliases
Like raliases, but for suffix aliases.

dis_saliases
Like saliases but for disabled suffix aliases.

parameters
The keys in this associative array are the names of the parameters currently de-
fined. The values are strings describing the type of the parameter, in the same
format used by the t parameter flag, see zshexpn(1) . Setting or unsetting keys in
this array is not possible.

modules
An associative array giving information about modules. The keys are the names of
the modules loaded, registered to be autoloaded, or aliased. The value says which
state the named module is in and is one of the strings `loaded', `autoloaded', or
`alias:name', where name is the name the module is aliased to.

Setting or unsetting keys in this array is not possible.

dirstack
A normal array holding the elements of the directory stack. Note that the output of
the dirs builtin command includes one more directory, the current working direc-
tory.

history
This associative array maps history event numbers to the full history lines. Al-
though it is presented as an associative array, the array of all values (${his-
tory[@]}) is guaranteed to be returned in order from most recent to oldest history
event, that is, by decreasing history event number.

historywords
A special array containing the words stored in the history. These also appear in
most to least recent order.

jobdirs
This associative array maps job numbers to the directories from which the job was
started (which may not be the current directory of the job).

The keys of the associative arrays are usually valid job numbers, and these are the
values output with, for example, ${(k)jobdirs}. Non-numeric job references may be
used when looking up a value; for example, ${jobdirs[%+]} refers to the current
job.

jobtexts
This associative array maps job numbers to the texts of the command lines that were
used to start the jobs.

Handling of the keys of the associative array is as described for jobdirs above.

jobstates
This associative array gives information about the states of the jobs currently
known. The keys are the job numbers and the values are strings of the form
`job-state:mark:pid=state...'. The job-state gives the state the whole job is cur-
rently in, one of `running', `suspended', or `done'. The mark is `+' for the cur-
rent job, `-' for the previous job and empty otherwise. This is followed by one
`:pid=state' for every process in the job. The pids are, of course, the process IDs
and the state describes the state of that process.

Handling of the keys of the associative array is as described for jobdirs above.

nameddirs
This associative array maps the names of named directories to the pathnames they
stand for.

userdirs
This associative array maps user names to the pathnames of their home directories.

usergroups
This associative array maps names of system groups of which the current user is a
member to the corresponding group identifiers. The contents are the same as the
groups output by the id command.

funcfiletrace
This array contains the absolute line numbers and corresponding file names for the
point where the current function, sourced file, or (if EVAL_LINENO is set) eval
command was called. The array is of the same length as funcsourcetrace and func-
trace, but differs from funcsourcetrace in that the line and file are the point of
call, not the point of definition, and differs from functrace in that all values
are absolute line numbers in files, rather than relative to the start of a func-
tion, if any.

funcsourcetrace
This array contains the file names and line numbers of the points where the func-
tions, sourced files, and (if EVAL_LINENO is set) eval commands currently being ex-
ecuted were defined. The line number is the line where the `function name' or
`name ()' started. In the case of an autoloaded function the line number is re-
ported as zero. The format of each element is filename:lineno.

For functions autoloaded from a file in native zsh format, where only the body of
the function occurs in the file, or for files that have been executed by the source
or `.' builtins, the trace information is shown as filename:0, since the entire
file is the definition. The source file name is resolved to an absolute path when
the function is loaded or the path to it otherwise resolved.

Most users will be interested in the information in the funcfiletrace array in-
stead.

funcstack
This array contains the names of the functions, sourced files, and (if EVAL_LINENO
is set) eval commands. currently being executed. The first element is the name of
the function using the parameter.

The standard shell array zsh_eval_context can be used to determine the type of
shell construct being executed at each depth: note, however, that is in the oppo-
site order, with the most recent item last, and it is more detailed, for example
including an entry for toplevel, the main shell code being executed either interac-
tively or from a script, which is not present in $funcstack.

functrace
This array contains the names and line numbers of the callers corresponding to the
functions currently being executed. The format of each element is name:lineno.
Callers are also shown for sourced files; the caller is the point where the source
or `.' command was executed.

THE ZSH/PCRE MODULE
The zsh/pcre module makes some commands available as builtins:

pcre_compile [ -aimxs ] PCRE
Compiles a perl-compatible regular expression.

Option -a will force the pattern to be anchored. Option -i will compile a case-in-
sensitive pattern. Option -m will compile a multi-line pattern; that is, ^ and $
will match newlines within the pattern. Option -x will compile an extended pat-
tern, wherein whitespace and # comments are ignored. Option -s makes the dot
metacharacter match all characters, including those that indicate newline.

pcre_study
Studies the previously-compiled PCRE which may result in faster matching.

pcre_match [ -v var ] [ -a arr ] [ -n offset ] [ -b ] string
Returns successfully if string matches the previously-compiled PCRE.

Upon successful match, if the expression captures substrings within parentheses,
pcre_match will set the array match to those substrings, unless the -a option is
given, in which case it will set the array arr. Similarly, the variable MATCH will
be set to the entire matched portion of the string, unless the -v option is given,
in which case the variable var will be set. No variables are altered if there is
no successful match. A -n option starts searching for a match from the byte offset
position in string. If the -b option is given, the variable ZPCRE_OP will be set
to an offset pair string, representing the byte offset positions of the entire
matched portion within the string. For example, a ZPCRE_OP set to "32 45" indi-
cates that the matched portion began on byte offset 32 and ended on byte offset 44.
Here, byte offset position 45 is the position directly after the matched portion.
Keep in mind that the byte position isn't necessarily the same as the character po-
sition when UTF-8 characters are involved. Consequently, the byte offset positions
are only to be relied on in the context of using them for subsequent searches on
string, using an offset position as an argument to the -n option. This is mostly
used to implement the "find all non-overlapping matches" functionality.

A simple example of "find all non-overlapping matches":

string="The following zip codes: 78884 90210 99513"
pcre_compile -m "\d{5}"
accum=()
pcre_match -b -- $string
while [[ $? -eq 0 ]] do
b=($=ZPCRE_OP)
accum+=$MATCH
pcre_match -b -n $b[2] -- $string
done
print -l $accum

The zsh/pcre module makes available the following test condition:

expr -pcre-match pcre
Matches a string against a perl-compatible regular expression.

For example,

[[ "$text" -pcre-match ^d+$ ]] &&
print text variable contains only "d's".

If the REMATCH_PCRE option is set, the =~ operator is equivalent to -pcre-match,
and the NO_CASE_MATCH option may be used. Note that NO_CASE_MATCH never applies to
the pcre_match builtin, instead use the -i switch of pcre_compile.

THE ZSH/PARAM/PRIVATE MODULE
The zsh/param/private module is used to create parameters whose scope is limited to the
current function body, and not to other functions called by the current function.

This module provides a single autoloaded builtin:

private [ {+|-}AHUahlprtux ] [ {+|-}EFLRZi [ n ] ] [ name[=value] ... ]
The private builtin accepts all the same options and arguments as local (zsh-
builtins(1)) except for the `-T' option. Tied parameters may not be made private.

If used at the top level (outside a function scope), private creates a normal pa-
rameter in the same manner as declare or typeset. A warning about this is printed
if WARN_CREATE_GLOBAL is set (zshoptions(1)). Used inside a function scope, pri-
vate creates a local parameter similar to one declared with local, except having
special properties noted below.

Special parameters which expose or manipulate internal shell state, such as ARGC,
argv, COLUMNS, LINES, UID, EUID, IFS, PROMPT, RANDOM, SECONDS, etc., cannot be made
private unless the `-h' option is used to hide the special meaning of the parame-
ter. This may change in the future.

As with other typeset equivalents, private is both a builtin and a reserved word, so ar-
rays may be assigned with parenthesized word list name=(value...) syntax. However, the
reserved word `private' is not available until zsh/param/private is loaded, so care must
be taken with order of execution and parsing for function definitions which use private.
To compensate for this, the module also adds the option `-P' to the `local' builtin to de-
clare private parameters.

For example, this construction fails if zsh/param/private has not yet been loaded when
`bad_declaration' is defined:
bad_declaration() {
zmodload zsh/param/private
private array=( one two three )
}

This construction works because local is already a keyword, and the module is loaded be-
fore the statement is executed:
good_declaration() {
zmodload zsh/param/private
local -P array=( one two three )
}

The following is usable in scripts but may have trouble with autoload:
zmodload zsh/param/private
iffy_declaration() {
private array=( one two three )
}

The private builtin may always be used with scalar assignments and for declarations with-
out assignments.

Parameters declared with private have the following properties:

o Within the function body where it is declared, the parameter behaves as a local,
except as noted above for tied or special parameters.

o The type of a parameter declared private cannot be changed in the scope where it
was declared, even if the parameter is unset. Thus an array cannot be assigned to
a private scalar, etc.

o Within any other function called by the declaring function, the private parameter
does NOT hide other parameters of the same name, so for example a global parameter
of the same name is visible and may be assigned or unset. This includes calls to
anonymous functions, although that may also change in the future.

o An exported private remains in the environment of inner scopes but appears unset
for the current shell in those scopes. Generally, exporting private parameters
should be avoided.

Note that this differs from the static scope defined by compiled languages derived from C,
in that the a new call to the same function creates a new scope, i.e., the parameter is
still associated with the call stack rather than with the function definition. It differs
from ksh `typeset -S' because the syntax used to define the function has no bearing on
whether the parameter scope is respected.

THE ZSH/REGEX MODULE
The zsh/regex module makes available the following test condition:

expr -regex-match regex
Matches a string against a POSIX extended regular expression. On successful match,
matched portion of the string will normally be placed in the MATCH variable. If
there are any capturing parentheses within the regex, then the match array variable
will contain those. If the match is not successful, then the variables will not be
altered.

For example,

[[ alphabetical -regex-match ^a([^a]+)a([^a]+)a ]] &&
print -l $MATCH X $match

If the option REMATCH_PCRE is not set, then the =~ operator will automatically load
this module as needed and will invoke the -regex-match operator.

If BASH_REMATCH is set, then the array BASH_REMATCH will be set instead of MATCH
and match.

THE ZSH/SCHED MODULE
The zsh/sched module makes available one builtin command and one parameter.

sched [-o] [+]hh:mm[:ss] command ...
sched [-o] [+]seconds command ...
sched [ -item ]
Make an entry in the scheduled list of commands to execute. The time may be speci-
fied in either absolute or relative time, and either as hours, minutes and (option-
ally) seconds separated by a colon, or seconds alone. An absolute number of sec-
onds indicates the time since the epoch (1970/01/01 00:00); this is useful in com-
bination with the features in the zsh/datetime module, see the zsh/datetime module
entry in zshmodules(1).

With no arguments, prints the list of scheduled commands. If the scheduled command
has the -o flag set, this is shown at the start of the command.

With the argument `-item', removes the given item from the list. The numbering of
the list is continuous and entries are in time order, so the numbering can change
when entries are added or deleted.

Commands are executed either immediately before a prompt, or while the shell's line
editor is waiting for input. In the latter case it is useful to be able to produce
output that does not interfere with the line being edited. Providing the option -o
causes the shell to clear the command line before the event and redraw it after-
wards. This should be used with any scheduled event that produces visible output
to the terminal; it is not needed, for example, with output that updates a terminal
emulator's title bar.

To effect changes to the editor buffer when an event executes, use the `zle' com-
mand with no arguments to test whether the editor is active, and if it is, then use
`zle widget' to access the editor via the named widget.

The sched builtin is not made available by default when the shell starts in a mode
emulating another shell. It can be made available with the command `zmodload -F
zsh/sched b:sched'.

zsh_scheduled_events
A readonly array corresponding to the events scheduled by the sched builtin. The
indices of the array correspond to the numbers shown when sched is run with no ar-
guments (provided that the KSH_ARRAYS option is not set). The value of the array
consists of the scheduled time in seconds since the epoch (see the section `The
zsh/datetime Module' for facilities for using this number), followed by a colon,
followed by any options (which may be empty but will be preceded by a `-' other-
wise), followed by a colon, followed by the command to be executed.

The sched builtin should be used for manipulating the events. Note that this will
have an immediate effect on the contents of the array, so that indices may become
invalid.

THE ZSH/NET/SOCKET MODULE
The zsh/net/socket module makes available one builtin command:

zsocket [ -altv ] [ -d fd ] [ args ]
zsocket is implemented as a builtin to allow full use of shell command line edit-
ing, file I/O, and job control mechanisms.

Outbound Connections
zsocket [ -v ] [ -d fd ] filename
Open a new Unix domain connection to filename. The shell parameter REPLY will be
set to the file descriptor associated with that connection. Currently, only stream
connections are supported.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

File descriptors can be closed with normal shell syntax when no longer needed, for
example:

exec {REPLY}>&-

Inbound Connections
zsocket -l [ -v ] [ -d fd ] filename
zsocket -l will open a socket listening on filename. The shell parameter REPLY
will be set to the file descriptor associated with that listener. The file de-
scriptor remains open in subshells and forked external executables.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

zsocket -a [ -tv ] [ -d targetfd ] listenfd
zsocket -a will accept an incoming connection to the socket associated with lis-
tenfd. The shell parameter REPLY will be set to the file descriptor associated
with the inbound connection. The file descriptor remains open in subshells and
forked external executables.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

If -t is specified, zsocket will return if no incoming connection is pending. Oth-
erwise it will wait for one.

In order to elicit more verbose output, use -v.

THE ZSH/STAT MODULE
The zsh/stat module makes available one builtin command under two possible names:

zstat [ -gnNolLtTrs ] [ -f fd ] [ -H hash ] [ -A array ] [ -F fmt ]
[ +element ] [ file ... ]
stat ...
The command acts as a front end to the stat system call (see stat(2)). The same
command is provided with two names; as the name stat is often used by an external
command it is recommended that only the zstat form of the command is used. This
can be arranged by loading the module with the command `zmodload -F zsh/stat b:zs-
tat'.

If the stat call fails, the appropriate system error message printed and status 1
is returned. The fields of struct stat give information about the files provided
as arguments to the command. In addition to those available from the stat call, an
extra element `link' is provided. These elements are:

device The number of the device on which the file resides.

inode The unique number of the file on this device (`inode' number).

mode The mode of the file; that is, the file's type and access permissions. With
the -s option, this will be returned as a string corresponding to the first
column in the display of the ls -l command.

nlink The number of hard links to the file.

uid The user ID of the owner of the file. With the -s option, this is displayed
as a user name.

gid The group ID of the file. With the -s option, this is displayed as a group
name.

rdev The raw device number. This is only useful for special devices.

size The size of the file in bytes.

atime
mtime
ctime The last access, modification and inode change times of the file, respec-
tively, as the number of seconds since midnight GMT on 1st January, 1970.
With the -s option, these are printed as strings for the local time zone;
the format can be altered with the -F option, and with the -g option the
times are in GMT.

blksize
The number of bytes in one allocation block on the device on which the file
resides.

block The number of disk blocks used by the file.

link If the file is a link and the -L option is in effect, this contains the name
of the file linked to, otherwise it is empty. Note that if this element is
selected (``zstat +link'') then the -L option is automatically used.

A particular element may be selected by including its name preceded by a `+' in the
option list; only one element is allowed. The element may be shortened to any
unique set of leading characters. Otherwise, all elements will be shown for all
files.

Options:

-A array
Instead of displaying the results on standard output, assign them to an ar-
ray, one struct stat element per array element for each file in order. In
this case neither the name of the element nor the name of the files appears
in array unless the -t or -n options were given, respectively. If -t is
given, the element name appears as a prefix to the appropriate array ele-
ment; if -n is given, the file name appears as a separate array element pre-
ceding all the others. Other formatting options are respected.

-H hash
Similar to -A, but instead assign the values to hash. The keys are the ele-
ments listed above. If the -n option is provided then the name of the file
is included in the hash with key name.

-f fd Use the file on file descriptor fd instead of named files; no list of file
names is allowed in this case.

-F fmt Supplies a strftime (see strftime(3)) string for the formatting of the time
elements. The format string supports all of the zsh extensions described in
the section EXPANSION OF PROMPT SEQUENCES in zshmisc(1). The -s option is
implied.

-g Show the time elements in the GMT time zone. The -s option is implied.

-l List the names of the type elements (to standard output or an array as ap-
propriate) and return immediately; arguments, and options other than -A, are
ignored.

-L Perform an lstat (see lstat(2)) rather than a stat system call. In this
case, if the file is a link, information about the link itself rather than
the target file is returned. This option is required to make the link ele-
ment useful. It's important to note that this is the exact opposite from
ls(1), etc.

-n Always show the names of files. Usually these are only shown when output is
to standard output and there is more than one file in the list.

-N Never show the names of files.

-o If a raw file mode is printed, show it in octal, which is more useful for
human consumption than the default of decimal. A leading zero will be
printed in this case. Note that this does not affect whether a raw or for-
matted file mode is shown, which is controlled by the -r and -s options, nor
whether a mode is shown at all.

-r Print raw data (the default format) alongside string data (the -s format);
the string data appears in parentheses after the raw data.

-s Print mode, uid, gid and the three time elements as strings instead of num-
bers. In each case the format is like that of ls -l.

-t Always show the type names for the elements of struct stat. Usually these
are only shown when output is to standard output and no individual element
has been selected.

-T Never show the type names of the struct stat elements.

THE ZSH/SYSTEM MODULE
The zsh/system module makes available various builtin commands and parameters.

Builtins
syserror [ -e errvar ] [ -p prefix ] [ errno | errname ]
This command prints out the error message associated with errno, a system error
number, followed by a newline to standard error.

Instead of the error number, a name errname, for example ENOENT, may be used. The
set of names is the same as the contents of the array errnos, see below.

If the string prefix is given, it is printed in front of the error message, with no
intervening space.

If errvar is supplied, the entire message, without a newline, is assigned to the
parameter names errvar and nothing is output.

A return status of 0 indicates the message was successfully printed (although it
may not be useful if the error number was out of the system's range), a return sta-
tus of 1 indicates an error in the parameters, and a return status of 2 indicates
the error name was not recognised (no message is printed for this).

sysopen [ -arw ] [ -m permissions ] [ -o options ]
-u fd file
This command opens a file. The -r, -w and -a flags indicate whether the file should
be opened for reading, writing and appending, respectively. The -m option allows
the initial permissions to use when creating a file to be specified in octal form.
The file descriptor is specified with -u. Either an explicit file descriptor in the
range 0 to 9 can be specified or a variable name can be given to which the file de-
scriptor number will be assigned.

The -o option allows various system specific options to be specified as a
comma-separated list. The following is a list of possible options. Note that, de-
pending on the system, some may not be available.
cloexec
mark file to be closed when other programs are executed (else the file de-
scriptor remains open in subshells and forked external executables)

create
creat create file if it does not exist

excl create file, error if it already exists

noatime
suppress updating of the file atime

nofollow
fail if file is a symbolic link

sync request that writes wait until data has been physically written

truncate
trunc truncate file to size 0

To close the file, use one of the following:

exec {fd}<&-
exec {fd}>&-

sysread [ -c countvar ] [ -i infd ] [ -o outfd ]
[ -s bufsize ] [ -t timeout ] [ param ]
Perform a single system read from file descriptor infd, or zero if that is not
given. The result of the read is stored in param or REPLY if that is not given.
If countvar is given, the number of bytes read is assigned to the parameter named
by countvar.

The maximum number of bytes read is bufsize or 8192 if that is not given, however
the command returns as soon as any number of bytes was successfully read.

If timeout is given, it specifies a timeout in seconds, which may be zero to poll
the file descriptor. This is handled by the poll system call if available, other-
wise the select system call if available.

If outfd is given, an attempt is made to write all the bytes just read to the file
descriptor outfd. If this fails, because of a system error other than EINTR or be-
cause of an internal zsh error during an interrupt, the bytes read but not written
are stored in the parameter named by param if supplied (no default is used in this
case), and the number of bytes read but not written is stored in the parameter
named by countvar if that is supplied. If it was successful, countvar contains the
full number of bytes transferred, as usual, and param is not set.

The error EINTR (interrupted system call) is handled internally so that shell in-
terrupts are transparent to the caller. Any other error causes a return.

The possible return statuses are
0 At least one byte of data was successfully read and, if appropriate, writ-
ten.

1 There was an error in the parameters to the command. This is the only error
for which a message is printed to standard error.

2 There was an error on the read, or on polling the input file descriptor for
a timeout. The parameter ERRNO gives the error.

3 Data were successfully read, but there was an error writing them to outfd.
The parameter ERRNO gives the error.

4 The attempt to read timed out. Note this does not set ERRNO as this is not
a system error.

5 No system error occurred, but zero bytes were read. This usually indicates
end of file. The parameters are set according to the usual rules; no write
to outfd is attempted.

sysseek [ -u fd ] [ -w start|end|current ] offset
The current file position at which future reads and writes will take place is ad-
justed to the specified byte offset. The offset is evaluated as a math expression.
The -u option allows the file descriptor to be specified. By default the offset is
specified relative to the start or the file but, with the -w option, it is possible
to specify that the offset should be relative to the current position or the end of
the file.

syswrite [ -c countvar ] [ -o outfd ] data
The data (a single string of bytes) are written to the file descriptor outfd, or 1
if that is not given, using the write system call. Multiple write operations may
be used if the first does not write all the data.

If countvar is given, the number of byte written is stored in the parameter named
by countvar; this may not be the full length of data if an error occurred.

The error EINTR (interrupted system call) is handled internally by retrying; other-
wise an error causes the command to return. For example, if the file descriptor is
set to non-blocking output, an error EAGAIN (on some systems, EWOULDBLOCK) may re-
sult in the command returning early.

The return status may be 0 for success, 1 for an error in the parameters to the
command, or 2 for an error on the write; no error message is printed in the last
case, but the parameter ERRNO will reflect the error that occurred.

zsystem flock [ -t timeout ] [ -f var ] [-er] file
zsystem flock -u fd_expr
The builtin zsystem's subcommand flock performs advisory file locking (via the fc-
ntl(2) system call) over the entire contents of the given file. This form of lock-
ing requires the processes accessing the file to cooperate; its most obvious use is
between two instances of the shell itself.

In the first form the named file, which must already exist, is locked by opening a
file descriptor to the file and applying a lock to the file descriptor. The lock
terminates when the shell process that created the lock exits; it is therefore of-
ten convenient to create file locks within subshells, since the lock is automati-
cally released when the subshell exits. Note that use of the print builtin with
the -u option will, as a side effect, release the lock, as will redirection to the
file in the shell holding the lock. To work around this use a subshell, e.g.
`(print message) >> file'. Status 0 is returned if the lock succeeds, else status
1.

In the second form the file descriptor given by the arithmetic expression fd_expr
is closed, releasing a lock. The file descriptor can be queried by using the `-f
var' form during the lock; on a successful lock, the shell variable var is set to
the file descriptor used for locking. The lock will be released if the file de-
scriptor is closed by any other means, for example using `exec {var}>&-'; however,
the form described here performs a safety check that the file descriptor is in use
for file locking.

By default the shell waits indefinitely for the lock to succeed. The option -t
timeout specifies a timeout for the lock in seconds; currently this must be an in-
teger. The shell will attempt to lock the file once a second during this period.
If the attempt times out, status 2 is returned.

If the option -e is given, the file descriptor for the lock is preserved when the
shell uses exec to start a new process; otherwise it is closed at that point and
the lock released.

If the option -r is given, the lock is only for reading, otherwise it is for read-
ing and writing. The file descriptor is opened accordingly.

zsystem supports subcommand
The builtin zsystem's subcommand supports tests whether a given subcommand is sup-
ported. It returns status 0 if so, else status 1. It operates silently unless
there was a syntax error (i.e. the wrong number of arguments), in which case status
255 is returned. Status 1 can indicate one of two things: subcommand is known but
not supported by the current operating system, or subcommand is not known (possibly
because this is an older version of the shell before it was implemented).

Math Functions
systell(fd)
The systell math function returns the current file position for the file descriptor
passed as an argument.

Parameters
errnos A readonly array of the names of errors defined on the system. These are typically
macros defined in C by including the system header file errno.h. The index of each
name (assuming the option KSH_ARRAYS is unset) corresponds to the error number.
Error numbers num before the last known error which have no name are given the name
Enum in the array.

Note that aliases for errors are not handled; only the canonical name is used.

sysparams
A readonly associative array. The keys are:

pid Returns the process ID of the current process, even in subshells. Compare
$$, which returns the process ID of the main shell process.

ppid Returns the process ID of the parent of the current process, even in sub-
shells. Compare $PPID, which returns the process ID of the parent of the
main shell process.

procsubstpid
Returns the process ID of the last process started for process substitution,
i.e. the <(...) and >(...) expansions.

THE ZSH/NET/TCP MODULE
The zsh/net/tcp module makes available one builtin command:

ztcp [ -acflLtv ] [ -d fd ] [ args ]
ztcp is implemented as a builtin to allow full use of shell command line editing,
file I/O, and job control mechanisms.

If ztcp is run with no options, it will output the contents of its session table.

If it is run with only the option -L, it will output the contents of the session
table in a format suitable for automatic parsing. The option is ignored if given
with a command to open or close a session. The output consists of a set of lines,
one per session, each containing the following elements separated by spaces:

File descriptor
The file descriptor in use for the connection. For normal inbound (I) and
outbound (O) connections this may be read and written by the usual shell
mechanisms. However, it should only be close with `ztcp -c'.

Connection type
A letter indicating how the session was created:

Z A session created with the zftp command.

L A connection opened for listening with `ztcp -l'.

I An inbound connection accepted with `ztcp -a'.

O An outbound connection created with `ztcp host ...'.

The local host
This is usually set to an all-zero IP address as the address of the local-
host is irrelevant.

The local port
This is likely to be zero unless the connection is for listening.

The remote host
This is the fully qualified domain name of the peer, if available, else an
IP address. It is an all-zero IP address for a session opened for listen-
ing.

The remote port
This is zero for a connection opened for listening.

Outbound Connections
ztcp [ -v ] [ -d fd ] host [ port ]
Open a new TCP connection to host. If the port is omitted, it will default to port
23. The connection will be added to the session table and the shell parameter RE-
PLY will be set to the file descriptor associated with that connection.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

Inbound Connections
ztcp -l [ -v ] [ -d fd ] port
ztcp -l will open a socket listening on TCP port. The socket will be added to the
session table and the shell parameter REPLY will be set to the file descriptor as-
sociated with that listener.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

In order to elicit more verbose output, use -v.

ztcp -a [ -tv ] [ -d targetfd ] listenfd
ztcp -a will accept an incoming connection to the port associated with listenfd.
The connection will be added to the session table and the shell parameter REPLY
will be set to the file descriptor associated with the inbound connection.

If -d is specified, its argument will be taken as the target file descriptor for
the connection.

If -t is specified, ztcp will return if no incoming connection is pending. Other-
wise it will wait for one.

In order to elicit more verbose output, use -v.

Closing Connections
ztcp -cf [ -v ] [ fd ]
ztcp -c [ -v ] [ fd ]
ztcp -c will close the socket associated with fd. The socket will be removed from
the session table. If fd is not specified, ztcp will close everything in the ses-
sion table.

Normally, sockets registered by zftp (see zshmodules(1) ) cannot be closed this
way. In order to force such a socket closed, use -f.

In order to elicit more verbose output, use -v.

Example
Here is how to create a TCP connection between two instances of zsh. We need to pick an
unassigned port; here we use the randomly chosen 5123.

On host1,
zmodload zsh/net/tcp
ztcp -l 5123
listenfd=$REPLY
ztcp -a $listenfd
fd=$REPLY
The second from last command blocks until there is an incoming connection.

Now create a connection from host2 (which may, of course, be the same machine):
zmodload zsh/net/tcp
ztcp host1 5123
fd=$REPLY

Now on each host, $fd contains a file descriptor for talking to the other. For example,
on host1:
print This is a message >&$fd
and on host2:
read -r line <&$fd; print -r - $line
prints `This is a message'.

To tidy up, on host1:
ztcp -c $listenfd
ztcp -c $fd
and on host2
ztcp -c $fd

THE ZSH/TERMCAP MODULE
The zsh/termcap module makes available one builtin command:

echotc cap [ arg ... ]
Output the termcap value corresponding to the capability cap, with optional argu-
ments.

The zsh/termcap module makes available one parameter:

termcap
An associative array that maps termcap capability codes to their values.

THE ZSH/TERMINFO MODULE
The zsh/terminfo module makes available one builtin command:

echoti cap [ arg ]
Output the terminfo value corresponding to the capability cap, instantiated with
arg if applicable.

The zsh/terminfo module makes available one parameter:

terminfo
An associative array that maps terminfo capability names to their values.

THE ZSH/ZFTP MODULE
The zsh/zftp module makes available one builtin command:

zftp subcommand [ args ]
The zsh/zftp module is a client for FTP (file transfer protocol). It is imple-
mented as a builtin to allow full use of shell command line editing, file I/O, and
job control mechanisms. Often, users will access it via shell functions providing
a more powerful interface; a set is provided with the zsh distribution and is de-
scribed in zshzftpsys(1). However, the zftp command is entirely usable in its own
right.

All commands consist of the command name zftp followed by the name of a subcommand.
These are listed below. The return status of each subcommand is supposed to re-
flect the success or failure of the remote operation. See a description of the
variable ZFTP_VERBOSE for more information on how responses from the server may be
printed.

Subcommands
open host[:port] [ user [ password [ account ] ] ]
Open a new FTP session to host, which may be the name of a TCP/IP connected host or
an IP number in the standard dot notation. If the argument is in the form
host:port, open a connection to TCP port port instead of the standard FTP port 21.
This may be the name of a TCP service or a number: see the description of
ZFTP_PORT below for more information.

If IPv6 addresses in colon format are used, the host should be surrounded by quoted
square brackets to distinguish it from the port, for example
'[fe80::203:baff:fe02:8b56]'. For consistency this is allowed with all forms of
host.

Remaining arguments are passed to the login subcommand. Note that if no arguments
beyond host are supplied, open will not automatically call login. If no arguments
at all are supplied, open will use the parameters set by the params subcommand.

After a successful open, the shell variables ZFTP_HOST, ZFTP_PORT, ZFTP_IP and
ZFTP_SYSTEM are available; see `Variables' below.

login [ name [ password [ account ] ] ]
user [ name [ password [ account ] ] ]
Login the user name with parameters password and account. Any of the parameters
can be omitted, and will be read from standard input if needed (name is always
needed). If standard input is a terminal, a prompt for each one will be printed on
standard error and password will not be echoed. If any of the parameters are not
used, a warning message is printed.

After a successful login, the shell variables ZFTP_USER, ZFTP_ACCOUNT and ZFTP_PWD
are available; see `Variables' below.

This command may be re-issued when a user is already logged in, and the server will
first be reinitialized for a new user.

params [ host [ user [ password [ account ] ] ] ]
params -
Store the given parameters for a later open command with no arguments. Only those
given on the command line will be remembered. If no arguments are given, the pa-
rameters currently set are printed, although the password will appear as a line of
stars; the return status is one if no parameters were set, zero otherwise.

Any of the parameters may be specified as a `?', which may need to be quoted to
protect it from shell expansion. In this case, the appropriate parameter will be
read from stdin as with the login subcommand, including special handling of pass-
word. If the `?' is followed by a string, that is used as the prompt for reading
the parameter instead of the default message (any necessary punctuation and white-
space should be included at the end of the prompt). The first letter of the param-
eter (only) may be quoted with a `\'; hence an argument "\\$word" guarantees that
the string from the shell parameter $word will be treated literally, whether or not
it begins with a `?'.

If instead a single `-' is given, the existing parameters, if any, are deleted. In
that case, calling open with no arguments will cause an error.

The list of parameters is not deleted after a close, however it will be deleted if
the zsh/zftp module is unloaded.

For example,

zftp params ftp.elsewhere.xx juser '?Password for juser: '

will store the host ftp.elsewhere.xx and the user juser and then prompt the user
for the corresponding password with the given prompt.

test Test the connection; if the server has reported that it has closed the connection
(maybe due to a timeout), return status 2; if no connection was open anyway, return
status 1; else return status 0. The test subcommand is silent, apart from messages
printed by the $ZFTP_VERBOSE mechanism, or error messages if the connection closes.
There is no network overhead for this test.

The test is only supported on systems with either the select(2) or poll(2) system
calls; otherwise the message `not supported on this system' is printed instead.

The test subcommand will automatically be called at the start of any other subcom-
mand for the current session when a connection is open.

cd directory
Change the remote directory to directory. Also alters the shell variable ZFTP_PWD.

cdup Change the remote directory to the one higher in the directory tree. Note that cd
.. will also work correctly on non-UNIX systems.

dir [ arg ... ]
Give a (verbose) listing of the remote directory. The args are passed directly to
the server. The command's behaviour is implementation dependent, but a UNIX server
will typically interpret args as arguments to the ls command and with no arguments
return the result of `ls -l'. The directory is listed to standard output.

ls [ arg ... ]
Give a (short) listing of the remote directory. With no arg, produces a raw list
of the files in the directory, one per line. Otherwise, up to vagaries of the
server implementation, behaves similar to dir.

type [ type ]
Change the type for the transfer to type, or print the current type if type is ab-
sent. The allowed values are `A' (ASCII), `I' (Image, i.e. binary), or `B' (a syn-
onym for `I').

The FTP default for a transfer is ASCII. However, if zftp finds that the remote
host is a UNIX machine with 8-bit byes, it will automatically switch to using bi-
nary for file transfers upon open. This can subsequently be overridden.

The transfer type is only passed to the remote host when a data connection is es-
tablished; this command involves no network overhead.

ascii The same as type A.

binary The same as type I.

mode [ S | B ]
Set the mode type to stream (S) or block (B). Stream mode is the default; block
mode is not widely supported.

remote file ...
local [ file ... ]
Print the size and last modification time of the remote or local files. If there
is more than one item on the list, the name of the file is printed first. The
first number is the file size, the second is the last modification time of the file
in the format CCYYMMDDhhmmSS consisting of year, month, date, hour, minutes and
seconds in GMT. Note that this format, including the length, is guaranteed, so
that time strings can be directly compared via the [[ builtin's < and > operators,
even if they are too long to be represented as integers.

Not all servers support the commands for retrieving this information. In that
case, the remote command will print nothing and return status 2, compared with sta-
tus 1 for a file not found.

The local command (but not remote) may be used with no arguments, in which case the
information comes from examining file descriptor zero. This is the same file as
seen by a put command with no further redirection.

get file ...
Retrieve all files from the server, concatenating them and sending them to standard
output.

put file ...
For each file, read a file from standard input and send that to the remote host
with the given name.

append file ...
As put, but if the remote file already exists, data is appended to it instead of
overwriting it.

getat file point
putat file point
appendat file point
Versions of get, put and append which will start the transfer at the given point in
the remote file. This is useful for appending to an incomplete local file. How-
ever, note that this ability is not universally supported by servers (and is not
quite the behaviour specified by the standard).

delete file ...
Delete the list of files on the server.

mkdir directory
Create a new directory directory on the server.

rmdir directory
Delete the directory directory on the server.

rename old-name new-name
Rename file old-name to new-name on the server.

site arg ...
Send a host-specific command to the server. You will probably only need this if
instructed by the server to use it.

quote arg ...
Send the raw FTP command sequence to the server. You should be familiar with the
FTP command set as defined in RFC959 before doing this. Useful commands may in-
clude STAT and HELP. Note also the mechanism for returning messages as described
for the variable ZFTP_VERBOSE below, in particular that all messages from the con-
trol connection are sent to standard error.

close
quit Close the current data connection. This unsets the shell parameters ZFTP_HOST,
ZFTP_PORT, ZFTP_IP, ZFTP_SYSTEM, ZFTP_USER, ZFTP_ACCOUNT, ZFTP_PWD, ZFTP_TYPE and
ZFTP_MODE.

session [ sessname ]
Allows multiple FTP sessions to be used at once. The name of the session is an ar-
bitrary string of characters; the default session is called `default'. If this
command is called without an argument, it will list all the current sessions; with
an argument, it will either switch to the existing session called sessname, or cre-
ate a new session of that name.

Each session remembers the status of the connection, the set of connection-specific
shell parameters (the same set as are unset when a connection closes, as given in
the description of close), and any user parameters specified with the params sub-
command. Changing to a previous session restores those values; changing to a new
session initialises them in the same way as if zftp had just been loaded. The name
of the current session is given by the parameter ZFTP_SESSION.

rmsession [ sessname ]
Delete a session; if a name is not given, the current session is deleted. If the
current session is deleted, the earliest existing session becomes the new current
session, otherwise the current session is not changed. If the session being
deleted is the only one, a new session called `default' is created and becomes the
current session; note that this is a new session even if the session being deleted
is also called `default'. It is recommended that sessions not be deleted while
background commands which use zftp are still active.

Parameters
The following shell parameters are used by zftp. Currently none of them are special.

ZFTP_TMOUT
Integer. The time in seconds to wait for a network operation to complete before
returning an error. If this is not set when the module is loaded, it will be given
the default value 60. A value of zero turns off timeouts. If a timeout occurs on
the control connection it will be closed. Use a larger value if this occurs too
frequently.

ZFTP_IP
Readonly. The IP address of the current connection in dot notation.

ZFTP_HOST
Readonly. The hostname of the current remote server. If the host was opened as an
IP number, ZFTP_HOST contains that instead; this saves the overhead for a name
lookup, as IP numbers are most commonly used when a nameserver is unavailable.

ZFTP_PORT
Readonly. The number of the remote TCP port to which the connection is open (even
if the port was originally specified as a named service). Usually this is the
standard FTP port, 21.

In the unlikely event that your system does not have the appropriate conversion
functions, this appears in network byte order. If your system is little-endian,
the port then consists of two swapped bytes and the standard port will be reported
as 5376. In that case, numeric ports passed to zftp open will also need to be in
this format.

ZFTP_SYSTEM
Readonly. The system type string returned by the server in response to an FTP SYST
request. The most interesting case is a string beginning "UNIX Type: L8", which
ensures maximum compatibility with a local UNIX host.

ZFTP_TYPE
Readonly. The type to be used for data transfers , either `A' or `I'. Use the
type subcommand to change this.

ZFTP_USER
Readonly. The username currently logged in, if any.

ZFTP_ACCOUNT
Readonly. The account name of the current user, if any. Most servers do not re-
quire an account name.

ZFTP_PWD
Readonly. The current directory on the server.

ZFTP_CODE
Readonly. The three digit code of the last FTP reply from the server as a string.
This can still be read after the connection is closed, and is not changed when the
current session changes.

ZFTP_REPLY
Readonly. The last line of the last reply sent by the server. This can still be
read after the connection is closed, and is not changed when the current session
changes.

ZFTP_SESSION
Readonly. The name of the current FTP session; see the description of the session
subcommand.

ZFTP_PREFS
A string of preferences for altering aspects of zftp's behaviour. Each preference
is a single character. The following are defined:

P Passive: attempt to make the remote server initiate data transfers. This
is slightly more efficient than sendport mode. If the letter S occurs later
in the string, zftp will use sendport mode if passive mode is not available.

S Sendport: initiate transfers by the FTP PORT command. If this occurs be-
fore any P in the string, passive mode will never be attempted.

D Dumb: use only the bare minimum of FTP commands. This prevents the vari-
ables ZFTP_SYSTEM and ZFTP_PWD from being set, and will mean all connections
default to ASCII type. It may prevent ZFTP_SIZE from being set during a
transfer if the server does not send it anyway (many servers do).

If ZFTP_PREFS is not set when zftp is loaded, it will be set to a default of `PS',
i.e. use passive mode if available, otherwise fall back to sendport mode.

ZFTP_VERBOSE
A string of digits between 0 and 5 inclusive, specifying which responses from the
server should be printed. All responses go to standard error. If any of the num-
bers 1 to 5 appear in the string, raw responses from the server with reply codes
beginning with that digit will be printed to standard error. The first digit of
the three digit reply code is defined by RFC959 to correspond to:

1. A positive preliminary reply.

2. A positive completion reply.

3. A positive intermediate reply.

4. A transient negative completion reply.

5. A permanent negative completion reply.

It should be noted that, for unknown reasons, the reply `Service not available',
which forces termination of a connection, is classified as 421, i.e. `transient
negative', an interesting interpretation of the word `transient'.

The code 0 is special: it indicates that all but the last line of multiline
replies read from the server will be printed to standard error in a processed for-
mat. By convention, servers use this mechanism for sending information for the
user to read. The appropriate reply code, if it matches the same response, takes
priority.

If ZFTP_VERBOSE is not set when zftp is loaded, it will be set to the default value
450, i.e., messages destined for the user and all errors will be printed. A null
string is valid and specifies that no messages should be printed.

Functions
zftp_chpwd
If this function is set by the user, it is called every time the directory changes
on the server, including when a user is logged in, or when a connection is closed.
In the last case, $ZFTP_PWD will be unset; otherwise it will reflect the new direc-
tory.

zftp_progress
If this function is set by the user, it will be called during a get, put or append
operation each time sufficient data has been received from the host. During a get,
the data is sent to standard output, so it is vital that this function should write
to standard error or directly to the terminal, not to standard output.

When it is called with a transfer in progress, the following additional shell pa-
rameters are set:

ZFTP_FILE
The name of the remote file being transferred from or to.

ZFTP_TRANSFER
A G for a get operation and a P for a put operation.

ZFTP_SIZE
The total size of the complete file being transferred: the same as the first
value provided by the remote and local subcommands for a particular file.
If the server cannot supply this value for a remote file being retrieved, it
will not be set. If input is from a pipe the value may be incorrect and
correspond simply to a full pipe buffer.

ZFTP_COUNT
The amount of data so far transferred; a number between zero and $ZFTP_SIZE,
if that is set. This number is always available.

The function is initially called with ZFTP_TRANSFER set appropriately and
ZFTP_COUNT set to zero. After the transfer is finished, the function will be
called one more time with ZFTP_TRANSFER set to GF or PF, in case it wishes to tidy
up. It is otherwise never called twice with the same value of ZFTP_COUNT.

Sometimes the progress meter may cause disruption. It is up to the user to decide
whether the function should be defined and to use unfunction when necessary.

Problems
A connection may not be opened in the left hand side of a pipe as this occurs in a sub-
shell and the file information is not updated in the main shell. In the case of type or
mode changes or closing the connection in a subshell, the information is returned but
variables are not updated until the next call to zftp. Other status changes in subshells
will not be reflected by changes to the variables (but should be otherwise harmless).

Deleting sessions while a zftp command is active in the background can have unexpected ef-
fects, even if it does not use the session being deleted. This is because all shell sub-
processes share information on the state of all connections, and deleting a session
changes the ordering of that information.

On some operating systems, the control connection is not valid after a fork(), so that op-
erations in subshells, on the left hand side of a pipeline, or in the background are not
possible, as they should be. This is presumably a bug in the operating system.

THE ZSH/ZLE MODULE
The zsh/zle module contains the Zsh Line Editor. See zshzle(1).

THE ZSH/ZLEPARAMETER MODULE
The zsh/zleparameter module defines two special parameters that can be used to access in-
ternal information of the Zsh Line Editor (see zshzle(1)).

keymaps
This array contains the names of the keymaps currently defined.

widgets
This associative array contains one entry per widget. The name of the widget is the
key and the value gives information about the widget. It is either
the string `builtin' for builtin widgets,
a string of the form `user:name' for user-defined widgets,
where name is the name of the shell function implementing the widget,
a string of the form `completion:type:name'
for completion widgets,
or a null value if the widget is not yet fully defined. In the penultimate case,
type is the name of the builtin widget the completion widget imitates in its behav-
ior and name is the name of the shell function implementing the completion widget.

THE ZSH/ZPROF MODULE
When loaded, the zsh/zprof causes shell functions to be profiled. The profiling results
can be obtained with the zprof builtin command made available by this module. There is no
way to turn profiling off other than unloading the module.

zprof [ -c ]
Without the -c option, zprof lists profiling results to standard output. The for-
mat is comparable to that of commands like gprof.

At the top there is a summary listing all functions that were called at least once.
This summary is sorted in decreasing order of the amount of time spent in each.
The lines contain the number of the function in order, which is used in other parts
of the list in suffixes of the form `[num]', then the number of calls made to the
function. The next three columns list the time in milliseconds spent in the func-
tion and its descendants, the average time in milliseconds spent in the function
and its descendants per call and the percentage of time spent in all shell func-
tions used in this function and its descendants. The following three columns give
the same information, but counting only the time spent in the function itself. The
final column shows the name of the function.

After the summary, detailed information about every function that was invoked is
listed, sorted in decreasing order of the amount of time spent in each function and
its descendants. Each of these entries consists of descriptions for the functions
that called the function described, the function itself, and the functions that
were called from it. The description for the function itself has the same format
as in the summary (and shows the same information). The other lines don't show the
number of the function at the beginning and have their function named indented to
make it easier to distinguish the line showing the function described in the sec-
tion from the surrounding lines.

The information shown in this case is almost the same as in the summary, but only
refers to the call hierarchy being displayed. For example, for a calling function
the column showing the total running time lists the time spent in the described
function and its descendants only for the times when it was called from that par-
ticular calling function. Likewise, for a called function, this columns lists the
total time spent in the called function and its descendants only for the times when
it was called from the function described.

Also in this case, the column showing the number of calls to a function also shows
a slash and then the total number of invocations made to the called function.

As long as the zsh/zprof module is loaded, profiling will be done and multiple in-
vocations of the zprof builtin command will show the times and numbers of calls
since the module was loaded. With the -c option, the zprof builtin command will
reset its internal counters and will not show the listing.

THE ZSH/ZPTY MODULE
The zsh/zpty module offers one builtin:

zpty [ -e ] [ -b ] name [ arg ... ]
The arguments following name are concatenated with spaces between, then executed as
a command, as if passed to the eval builtin. The command runs under a newly as-
signed pseudo-terminal; this is useful for running commands non-interactively which
expect an interactive environment. The name is not part of the command, but is
used to refer to this command in later calls to zpty.

With the -e option, the pseudo-terminal is set up so that input characters are
echoed.

With the -b option, input to and output from the pseudo-terminal are made
non-blocking.

The shell parameter REPLY is set to the file descriptor assigned to the master side
of the pseudo-terminal. This allows the terminal to be monitored with ZLE descrip-
tor handlers (see zshzle(1)) or manipulated with sysread and syswrite (see THE
ZSH/SYSTEM MODULE in zshmodules(1)). Warning: Use of sysread and syswrite is not
recommended; use zpty -r and zpty -w unless you know exactly what you are doing.

zpty -d [ name ... ]
The second form, with the -d option, is used to delete commands previously started,
by supplying a list of their names. If no name is given, all commands are deleted.
Deleting a command causes the HUP signal to be sent to the corresponding process.

zpty -w [ -n ] name [ string ... ]
The -w option can be used to send the to command name the given strings as input
(separated by spaces). If the -n option is not given, a newline is added at the
end.

If no string is provided, the standard input is copied to the pseudo-terminal; this
may stop before copying the full input if the pseudo-terminal is non-blocking. The
exact input is always copied: the -n option is not applied.

Note that the command under the pseudo-terminal sees this input as if it were
typed, so beware when sending special tty driver characters such as word-erase,
line-kill, and end-of-file.

zpty -r [ -mt ] name [ param [ pattern ] ]
The -r option can be used to read the output of the command name. With only a name
argument, the output read is copied to the standard output. Unless the pseudo-ter-
minal is non-blocking, copying continues until the command under the pseudo-termi-
nal exits; when non-blocking, only as much output as is immediately available is
copied. The return status is zero if any output is copied.

When also given a param argument, at most one line is read and stored in the param-
eter named param. Less than a full line may be read if the pseudo-terminal is
non-blocking. The return status is zero if at least one character is stored in
param.

If a pattern is given as well, output is read until the whole string read matches
the pattern, even in the non-blocking case. The return status is zero if the
string read matches the pattern, or if the command has exited but at least one
character could still be read. If the option -m is present, the return status is
zero only if the pattern matches. As of this writing, a maximum of one megabyte of
output can be consumed this way; if a full megabyte is read without matching the
pattern, the return status is non-zero.

In all cases, the return status is non-zero if nothing could be read, and is 2 if
this is because the command has finished.

If the -r option is combined with the -t option, zpty tests whether output is
available before trying to read. If no output is available, zpty immediately re-
turns the status 1. When used with a pattern, the behaviour on a failed poll is
similar to when the command has exited: the return value is zero if at least one
character could still be read even if the pattern failed to match.

zpty -t name
The -t option without the -r option can be used to test whether the command name is
still running. It returns a zero status if the command is running and a non-zero
value otherwise.

zpty [ -L ]
The last form, without any arguments, is used to list the commands currently de-
fined. If the -L option is given, this is done in the form of calls to the zpty
builtin.

THE ZSH/ZSELECT MODULE
The zsh/zselect module makes available one builtin command:

zselect [ -rwe ] [ -t timeout ] [ -a array ] [ -A assoc ] [ fd ... ]
The zselect builtin is a front-end to the `select' system call, which blocks until
a file descriptor is ready for reading or writing, or has an error condition, with
an optional timeout. If this is not available on your system, the command prints
an error message and returns status 2 (normal errors return status 1). For more
information, see your systems documentation for select(3). Note there is no con-
nection with the shell builtin of the same name.

Arguments and options may be intermingled in any order. Non-option arguments are
file descriptors, which must be decimal integers. By default, file descriptors are
to be tested for reading, i.e. zselect will return when data is available to be
read from the file descriptor, or more precisely, when a read operation from the
file descriptor will not block. After a -r, -w and -e, the given file descriptors
are to be tested for reading, writing, or error conditions. These options and an
arbitrary list of file descriptors may be given in any order.

(The presence of an `error condition' is not well defined in the documentation for
many implementations of the select system call. According to recent versions of
the POSIX specification, it is really an exception condition, of which the only
standard example is out-of-band data received on a socket. So zsh users are un-
likely to find the -e option useful.)

The option `-t timeout' specifies a timeout in hundredths of a second. This may be
zero, in which case the file descriptors will simply be polled and zselect will re-
turn immediately. It is possible to call zselect with no file descriptors and a
non-zero timeout for use as a finer-grained replacement for `sleep'; note, however,
the return status is always 1 for a timeout.

The option `-a array' indicates that array should be set to indicate the file de-
scriptor(s) which are ready. If the option is not given, the array reply will be
used for this purpose. The array will contain a string similar to the arguments
for zselect. For example,

zselect -t 0 -r 0 -w 1

might return immediately with status 0 and $reply containing `-r 0 -w 1' to show
that both file descriptors are ready for the requested operations.

The option `-A assoc' indicates that the associative array assoc should be set to
indicate the file descriptor(s) which are ready. This option overrides the option
-a, nor will reply be modified. The keys of assoc are the file descriptors, and
the corresponding values are any of the characters `rwe' to indicate the condition.

The command returns status 0 if some file descriptors are ready for reading. If
the operation timed out, or a timeout of 0 was given and no file descriptors were
ready, or there was an error, it returns status 1 and the array will not be set
(nor modified in any way). If there was an error in the select operation the ap-
propriate error message is printed.

THE ZSH/ZUTIL MODULE
The zsh/zutil module only adds some builtins:

zstyle [ -L [ metapattern [ style ] ] ]
zstyle [ -e | - | -- ] pattern style string ...
zstyle -d [ pattern [ style ... ] ]
zstyle -g name [ pattern [ style ] ]
zstyle -{a|b|s} context style name [ sep ]
zstyle -{T|t} context style [ string ... ]
zstyle -m context style pattern
This builtin command is used to define and lookup styles. Styles are pairs of
names and values, where the values consist of any number of strings. They are
stored together with patterns and lookup is done by giving a string, called the
`context', which is matched against the patterns. The definition stored for the
most specific pattern that matches will be returned.

A pattern is considered to be more specific than another if it contains more compo-
nents (substrings separated by colons) or if the patterns for the components are
more specific, where simple strings are considered to be more specific than pat-
terns and complex patterns are considered to be more specific than the pattern `*'.
A `*' in the pattern will match zero or more characters in the context; colons are
not treated specially in this regard. If two patterns are equally specific, the
tie is broken in favour of the pattern that was defined first.

Example

For example, to define your preferred form of precipitation depending on which city
you're in, you might set the following in your zshrc:

zstyle ':weather:europe:*' preferred-precipitation rain
zstyle ':weather:europe:germany:* preferred-precipitation none
zstyle ':weather:europe:germany:*:munich' preferred-precipitation snow

Then, the fictional `weather' plugin might run under the hood a command such as

zstyle -s ":weather:${continent}:${country}:${county}:${city}" preferred-precipitation REPLY

in order to retrieve your preference into the scalar variable $REPLY.

Usage

The forms that operate on patterns are the following.

zstyle [ -L [ metapattern [ style ] ] ]
Without arguments, lists style definitions. Styles are shown in alphabetic
order and patterns are shown in the order zstyle will test them.

If the -L option is given, listing is done in the form of calls to zstyle.
The optional first argument, metapattern, is a pattern which will be matched
against the string supplied as pattern when the style was defined. Note:
this means, for example, `zstyle -L ":completion:*"' will match any supplied
pattern beginning `:completion:', not just ":completion:*": use ':comple-
tion:\*' to match that. The optional second argument limits the output to a
specific style (not a pattern). -L is not compatible with any other op-
tions.

zstyle [ - | -- | -e ] pattern style string ...
Defines the given style for the pattern with the strings as the value. If
the -e option is given, the strings will be concatenated (separated by spa-
ces) and the resulting string will be evaluated (in the same way as it is
done by the eval builtin command) when the style is looked up. In this case
the parameter `reply' must be assigned to set the strings returned after the
evaluation. Before evaluating the value, reply is unset, and if it is still
unset after the evaluation, the style is treated as if it were not set.

zstyle -d [ pattern [ style ... ] ]
Delete style definitions. Without arguments all definitions are deleted,
with a pattern all definitions for that pattern are deleted and if any
styles are given, then only those styles are deleted for the pattern.

zstyle -g name [ pattern [ style ] ]
Retrieve a style definition. The name is used as the name of an array in
which the results are stored. Without any further arguments, all patterns
defined are returned. With a pattern the styles defined for that pattern are
returned and with both a pattern and a style, the value strings of that com-
bination is returned.

The other forms can be used to look up or test styles for a given context.

zstyle -s context style name [ sep ]
The parameter name is set to the value of the style interpreted as a string.
If the value contains several strings they are concatenated with spaces (or
with the sep string if that is given) between them.

Return 0 if the style is set, 1 otherwise.

zstyle -b context style name
The value is stored in name as a boolean, i.e. as the string `yes' if the
value has only one string and that string is equal to one of `yes', `true',
`on', or `1'. If the value is any other string or has more than one string,
the parameter is set to `no'.

Return 0 if name is set to `yes', 1 otherwise.

zstyle -a context style name
The value is stored in name as an array. If name is declared as an associa-
tive array, the first, third, etc. strings are used as the keys and the
other strings are used as the values.

Return 0 if the style is set, 1 otherwise.

zstyle -t context style [ string ... ]
zstyle -T context style [ string ... ]
Test the value of a style, i.e. the -t option only returns a status (sets
$?). Without any string the return status is zero if the style is defined
for at least one matching pattern, has only one string in its value, and
that is equal to one of `true', `yes', `on' or `1'. If any strings are given
the status is zero if and only if at least one of the strings is equal to at
least one of the strings in the value. If the style is defined but doesn't
match, the return status is 1. If the style is not defined, the status is 2.

The -T option tests the values of the style like -t, but it returns status
zero (rather than 2) if the style is not defined for any matching pattern.

zstyle -m context style pattern
Match a value. Returns status zero if the pattern matches at least one of
the strings in the value.

zformat -f param format spec ...
zformat -a array sep spec ...
This builtin provides two different forms of formatting. The first form is selected
with the -f option. In this case the format string will be modified by replacing
sequences starting with a percent sign in it with strings from the specs. Each
spec should be of the form `char:string' which will cause every appearance of the
sequence `%char' in format to be replaced by the string. The `%' sequence may also
contain optional minimum and maximum field width specifications between the `%' and
the `char' in the form `%min.maxc', i.e. the minimum field width is given first and
if the maximum field width is used, it has to be preceded by a dot. Specifying a
minimum field width makes the result be padded with spaces to the right if the
string is shorter than the requested width. Padding to the left can be achieved by
giving a negative minimum field width. If a maximum field width is specified, the
string will be truncated after that many characters. After all `%' sequences for
the given specs have been processed, the resulting string is stored in the parame-
ter param.

The %-escapes also understand ternary expressions in the form used by prompts. The
% is followed by a `(' and then an ordinary format specifier character as described
above. There may be a set of digits either before or after the `('; these specify
a test number, which defaults to zero. Negative numbers are also allowed. An ar-
bitrary delimiter character follows the format specifier, which is followed by a
piece of `true' text, the delimiter character again, a piece of `false' text, and a
closing parenthesis. The complete expression (without the digits) thus looks like
`%(X.text1.text2)', except that the `.' character is arbitrary. The value given
for the format specifier in the char:string expressions is evaluated as a mathemat-
ical expression, and compared with the test number. If they are the same, text1 is
output, else text2 is output. A parenthesis may be escaped in text2 as %). Either
of text1 or text2 may contain nested %-escapes.

For example:

zformat -f REPLY "The answer is '%3(c.yes.no)'." c:3

outputs "The answer is 'yes'." to REPLY since the value for the format specifier c
is 3, agreeing with the digit argument to the ternary expression.

The second form, using the -a option, can be used for aligning strings. Here, the
specs are of the form `left:right' where `left' and `right' are arbitrary strings.
These strings are modified by replacing the colons by the sep string and padding
the left strings with spaces to the right so that the sep strings in the result
(and hence the right strings after them) are all aligned if the strings are printed
below each other. All strings without a colon are left unchanged and all strings
with an empty right string have the trailing colon removed. In both cases the
lengths of the strings are not used to determine how the other strings are to be
aligned. A colon in the left string can be escaped with a backslash. The result-
ing strings are stored in the array.

zregexparse
This implements some internals of the _regex_arguments function.

zparseopts [ -D -E -F -K -M ] [ -a array ] [ -A assoc ] [ - ] spec ...
This builtin simplifies the parsing of options in positional parameters, i.e. the
set of arguments given by $*. Each spec describes one option and must be of the
form `opt[=array]'. If an option described by opt is found in the positional pa-
rameters it is copied into the array specified with the -a option; if the optional
`=array' is given, it is instead copied into that array, which should be declared
as a normal array and never as an associative array.

Note that it is an error to give any spec without an `=array' unless one of the -a
or -A options is used.

Unless the -E option is given, parsing stops at the first string that isn't de-
scribed by one of the specs. Even with -E, parsing always stops at a positional
parameter equal to `-' or `--'. See also -F.

The opt description must be one of the following. Any of the special characters
can appear in the option name provided it is preceded by a backslash.

name
name+ The name is the name of the option without the leading `-'. To specify a
GNU-style long option, one of the usual two leading `-' must be included in
name; for example, a `--file' option is represented by a name of `-file'.

If a `+' appears after name, the option is appended to array each time it is
found in the positional parameters; without the `+' only the last occurrence
of the option is preserved.

If one of these forms is used, the option takes no argument, so parsing
stops if the next positional parameter does not also begin with `-' (unless
the -E option is used).

name:
name:-
name:: If one or two colons are given, the option takes an argument; with one
colon, the argument is mandatory and with two colons it is optional. The
argument is appended to the array after the option itself.

An optional argument is put into the same array element as the option name
(note that this makes empty strings as arguments indistinguishable). A
mandatory argument is added as a separate element unless the `:-' form is
used, in which case the argument is put into the same element.

A `+' as described above may appear between the name and the first colon.

In all cases, option-arguments must appear either immediately following the option
in the same positional parameter or in the next one. Even an optional argument may
appear in the next parameter, unless it begins with a `-'. There is no special
handling of `=' as with GNU-style argument parsers; given the spec `-foo:', the po-
sitional parameter `--foo=bar' is parsed as `--foo' with an argument of `=bar'.

When the names of two options that take no arguments overlap, the longest one wins,
so that parsing for the specs `-foo -foobar' (for example) is unambiguous. However,
due to the aforementioned handling of option-arguments, ambiguities may arise when
at least one overlapping spec takes an argument, as in `-foo: -foobar'. In that
case, the last matching spec wins.

The options of zparseopts itself cannot be stacked because, for example, the stack
`-DEK' is indistinguishable from a spec for the GNU-style long option `--DEK'. The
options of zparseopts itself are:

-a array
As described above, this names the default array in which to store the
recognised options.

-A assoc
If this is given, the options and their values are also put into an associa-
tive array with the option names as keys and the arguments (if any) as the
values.

-D If this option is given, all options found are removed from the positional
parameters of the calling shell or shell function, up to but not including
any not described by the specs. If the first such parameter is `-' or `--',
it is removed as well. This is similar to using the shift builtin.

-E This changes the parsing rules to not stop at the first string that isn't
described by one of the specs. It can be used to test for or (if used to-
gether with -D) extract options and their arguments, ignoring all other op-
tions and arguments that may be in the positional parameters. As indicated
above, parsing still stops at the first `-' or `--' not described by a spec,
but it is not removed when used with -D.

-F If this option is given, zparseopts immediately stops at the first op-
tion-like parameter not described by one of the specs, prints an error mes-
sage, and returns status 1. Removal (-D) and extraction (-E) are not per-
formed, and option arrays are not updated. This provides basic validation
for the given options.

Note that the appearance in the positional parameters of an option without
its required argument always aborts parsing and returns an error as de-
scribed above regardless of whether this option is used.

-K With this option, the arrays specified with the -a option and with the `=ar-
ray' forms are kept unchanged when none of the specs for them is used. Oth-
erwise the entire array is replaced when any of the specs is used. Individ-
ual elements of associative arrays specified with the -A option are pre-
served by -K. This allows assignment of default values to arrays before
calling zparseopts.

-M This changes the assignment rules to implement a map among equivalent option
names. If any spec uses the `=array' form, the string array is interpreted
as the name of another spec, which is used to choose where to store the val-
ues. If no other spec is found, the values are stored as usual. This
changes only the way the values are stored, not the way $* is parsed, so re-
sults may be unpredictable if the `name+' specifier is used inconsistently.

For example,

set -- -a -bx -c y -cz baz -cend
zparseopts a=foo b:=bar c+:=bar

will have the effect of

foo=(-a)
bar=(-b x -c y -c z)

The arguments from `baz' on will not be used.

As an example for the -E option, consider:

set -- -a x -b y -c z arg1 arg2
zparseopts -E -D b:=bar

will have the effect of

bar=(-b y)
set -- -a x -c z arg1 arg2

I.e., the option -b and its arguments are taken from the positional parameters and
put into the array bar.

The -M option can be used like this:

set -- -a -bx -c y -cz baz -cend
zparseopts -A bar -M a=foo b+: c:=b

to have the effect of

foo=(-a)
bar=(-a '' -b xyz)

ZSHCALSYS(1) General Commands Manual ZSHCALSYS(1)

NAME
zshcalsys - zsh calendar system

DESCRIPTION
The shell is supplied with a series of functions to replace and enhance the traditional
Unix calendar programme, which warns the user of imminent or future events, details of
which are stored in a text file (typically calendar in the user's home directory). The
version provided here includes a mechanism for alerting the user when an event is due.

In addition functions age, before and after are provided that can be used in a glob quali-
fier; they allow files to be selected based on their modification times.

The format of the calendar file and the dates used there in and in the age function are
described first, then the functions that can be called to examine and modify the calendar
file.

The functions here depend on the availability of the zsh/datetime module which is usually
installed with the shell. The library function strptime() must be available; it is
present on most recent operating systems.

FILE AND DATE FORMATS
Calendar File Format
The calendar file is by default ~/calendar. This can be configured by the calendar-file
style, see the section STYLES below. The basic format consists of a series of separate
lines, with no indentation, each including a date and time specification followed by a de-
scription of the event.

Various enhancements to this format are supported, based on the syntax of Emacs calendar
mode. An indented line indicates a continuation line that continues the description of
the event from the preceding line (note the date may not be continued in this way). An
initial ampersand (&) is ignored for compatibility.

An indented line on which the first non-whitespace character is # is not displayed with
the calendar entry, but is still scanned for information. This can be used to hide infor-
mation useful to the calendar system but not to the user, such as the unique identifier
used by calendar_add.

The Emacs extension that a date with no description may refer to a number of succeeding
events at different times is not supported.

Unless the done-file style has been altered, any events which have been processed are ap-
pended to the file with the same name as the calendar file with the suffix .done, hence
~/calendar.done by default.

An example is shown below.

Date Format
The format of the date and time is designed to allow flexibility without admitting ambigu-
ity. (The words `date' and `time' are both used in the documentation below; except where
specifically noted this implies a string that may include both a date and a time specifi-
cation.) Note that there is no localization support; month and day names must be in Eng-
lish and separator characters are fixed. Matching is case insensitive, and only the first
three letters of the names are significant, although as a special case a form beginning
"month" does not match "Monday". Furthermore, time zones are not handled; all times are
assumed to be local.

It is recommended that, rather than exploring the intricacies of the system, users find a
date format that is natural to them and stick to it. This will avoid unexpected effects.
Various key facts should be noted.

o In particular, note the confusion between month/day/year and day/month/year when
the month is numeric; these formats should be avoided if at all possible. Many al-
ternatives are available.

o The year must be given in full to avoid confusion, and only years from 1900 to 2099
inclusive are matched.

The following give some obvious examples; users finding here a format they like and not
subject to vagaries of style may skip the full description. As dates and times are
matched separately (even though the time may be embedded in the date), any date format may
be mixed with any format for the time of day provide the separators are clear (whitespace,
colons, commas).

2007/04/03 13:13
2007/04/03:13:13
2007/04/03 1:13 pm
3rd April 2007, 13:13
April 3rd 2007 1:13 p.m.
Apr 3, 2007 13:13
Tue Apr 03 13:13:00 2007
13:13 2007/apr/3

More detailed rules follow.

Times are parsed and extracted before dates. They must use colons to separate hours and
minutes, though a dot is allowed before seconds if they are present. This limits time
formats to the following:

o HH:MM[:SS[.FFFFF]] [am|pm|a.m.|p.m.]

o HH:MM.SS[.FFFFF] [am|pm|a.m.|p.m.]

Here, square brackets indicate optional elements, possibly with alternatives. Fractions
of a second are recognised but ignored. For absolute times (the normal format require by
the calendar file and the age, before and after functions) a date is mandatory but a time
of day is not; the time returned is at the start of the date. One variation is allowed:
if a.m. or p.m. or one of their variants is present, an hour without a minute is allowed,
e.g. 3 p.m..

Time zones are not handled, though if one is matched following a time specification it
will be removed to allow a surrounding date to be parsed. This only happens if the format
of the timezone is not too unusual. The following are examples of forms that are under-
stood:

+0100
GMT
GMT-7
CET+1CDT

Any part of the timezone that is not numeric must have exactly three capital letters in
the name.

Dates suffer from the ambiguity between DD/MM/YYYY and MM/DD/YYYY. It is recommended this
form is avoided with purely numeric dates, but use of ordinals, eg. 3rd/04/2007, will re-
solve the ambiguity as the ordinal is always parsed as the day of the month. Years must
be four digits (and the first two must be 19 or 20); 03/04/08 is not recognised. Other
numbers may have leading zeroes, but they are not required. The following are handled:

o YYYY/MM/DD

o YYYY-MM-DD

o YYYY/MNM/DD

o YYYY-MNM-DD

o DD[th|st|rd] MNM[,] [ YYYY ]

o MNM DD[th|st|rd][,] [ YYYY ]

o DD[th|st|rd]/MM[,] YYYY

o DD[th|st|rd]/MM/YYYY

o MM/DD[th|st|rd][,] YYYY

o MM/DD[th|st|rd]/YYYY

Here, MNM is at least the first three letters of a month name, matched case-insensitively.
The remainder of the month name may appear but its contents are irrelevant, so janissary,
febrile, martial, apricot, maybe, junta, etc. are happily handled.

Where the year is shown as optional, the current year is assumed. There are only two such
cases, the form Jun 20 or 14 September (the only two commonly occurring forms, apart from
a "the" in some forms of English, which isn't currently supported). Such dates will of
course become ambiguous in the future, so should ideally be avoided.

Times may follow dates with a colon, e.g. 1965/07/12:09:45; this is in order to provide a
format with no whitespace. A comma and whitespace are allowed, e.g. 1965/07/12, 09:45.
Currently the order of these separators is not checked, so illogical formats such as
1965/07/12, : ,09:45 will also be matched. For simplicity such variations are not shown
in the list above. Otherwise, a time is only recognised as being associated with a date
if there is only whitespace in between, or if the time was embedded in the date.

Days of the week are not normally scanned, but will be ignored if they occur at the start
of the date pattern only. However, in contexts where it is useful to specify dates rela-
tive to today, days of the week with no other date specification may be given. The day is
assumed to be either today or within the past week. Likewise, the words yesterday, today
and tomorrow are handled. All matches are case-insensitive. Hence if today is Monday,
then Sunday is equivalent to yesterday, Monday is equivalent to today, but Tuesday gives a
date six days ago. This is not generally useful within the calendar file. Dates in this
format may be combined with a time specification; for example Tomorrow, 8 p.m..

For example, the standard date format:

Fri Aug 18 17:00:48 BST 2006

is handled by matching HH:MM:SS and removing it together with the matched (but unused)
time zone. This leaves the following:

Fri Aug 18 2006

Fri is ignored and the rest is matched according to the standard rules.

Relative Time Format
In certain places relative times are handled. Here, a date is not allowed; instead a com-
bination of various supported periods are allowed, together with an optional time. The
periods must be in order from most to least significant.

In some cases, a more accurate calculation is possible when there is an anchor date: off-
sets of months or years pick the correct day, rather than being rounded, and it is possi-
ble to pick a particular day in a month as `(1st Friday)', etc., as described in more de-
tail below.

Anchors are available in the following cases. If one or two times are passed to the func-
tion calendar, the start time acts an anchor for the end time when the end time is rela-
tive (even if the start time is implicit). When examining calendar files, the scheduled
event being examined anchors the warning time when it is given explicitly by means of the
WARN keyword; likewise, the scheduled event anchors a repetition period when given by the
RPT keyword, so that specifications such as RPT 2 months, 3rd Thursday are handled prop-
erly. Finally, the -R argument to calendar_scandate directly provides an anchor for rela-
tive calculations.

The periods handled, with possible abbreviations are:

Years years, yrs, ys, year, yr, y, yearly. A year is 365.25 days unless there is an an-
chor.

Months months, mons, mnths, mths, month, mon, mnth, mth, monthly. Note that m, ms, mn,
mns are ambiguous and are not handled. A month is a period of 30 days rather than
a calendar month unless there is an anchor.

Weeks weeks, wks, ws, week, wk, w, weekly

Days days, dys, ds, day, dy, d, daily

Hours hours, hrs, hs, hour, hr, h, hourly

Minutes
minutes, mins, minute, min, but not m, ms, mn or mns

Seconds
seconds, secs, ss, second, sec, s

Spaces between the numbers are optional, but are required between items, although a comma
may be used (with or without spaces).

The forms yearly to hourly allow the number to be omitted; it is assumed to be 1. For ex-
ample, 1 d and daily are equivalent. Note that using those forms with plurals is confus-
ing; 2 yearly is the same as 2 years, not twice yearly, so it is recommended they only be
used without numbers.

When an anchor time is present, there is an extension to handle regular events in the form
of the nth someday of the month. Such a specification must occur immediately after any
year and month specification, but before any time of day, and must be in the form
n(th|st|rd) day, for example 1st Tuesday or 3rd Monday. As in other places, days are
matched case insensitively, must be in English, and only the first three letters are sig-
nificant except that a form beginning `month' does not match `Monday'. No attempt is made
to sanitize the resulting date; attempts to squeeze too many occurrences into a month will
push the day into the next month (but in the obvious fashion, retaining the correct day of
the week).

Here are some examples:

30 years 3 months 4 days 3:42:41
14 days 5 hours
Monthly, 3rd Thursday
4d,10hr

Example
Here is an example calendar file. It uses a consistent date format, as recommended above.

Feb 1, 2006 14:30 Pointless bureaucratic meeting
Mar 27, 2006 11:00 Mutual recrimination and finger pointing
Bring water pistol and waterproofs
Mar 31, 2006 14:00 Very serious managerial pontification
# UID 12C7878A9A50
Apr 10, 2006 13:30 Even more pointless blame assignment exercise WARN 30 mins
May 18, 2006 16:00 Regular moaning session RPT monthly, 3rd Thursday

The second entry has a continuation line. The third entry has a continuation line that
will not be shown when the entry is displayed, but the unique identifier will be used by
the calendar_add function when updating the event. The fourth entry will produce a warn-
ing 30 minutes before the event (to allow you to equip yourself appropriately). The fifth
entry repeats after a month on the 3rd Thursday, i.e. June 15, 2006, at the same time.

USER FUNCTIONS
This section describes functions that are designed to be called directly by the user. The
first part describes those functions associated with the user's calendar; the second part
describes the use in glob qualifiers.

Calendar system functions
calendar [ -abdDsv ] [ -C calfile ] [ -n num ] [ -S showprog ]
[ [ start ] end ]
calendar -r [ -abdDrsv ] [ -C calfile ] [ -n num ] [ -S showprog ]
[ start ]
Show events in the calendar.

With no arguments, show events from the start of today until the end of the next
working day after today. In other words, if today is Friday, Saturday, or Sunday,
show up to the end of the following Monday, otherwise show today and tomorrow.

If end is given, show events from the start of today up to the time and date given,
which is in the format described in the previous section. Note that if this is a
date the time is assumed to be midnight at the start of the date, so that effec-
tively this shows all events before the given date.

end may start with a +, in which case the remainder of the specification is a rela-
tive time format as described in the previous section indicating the range of time
from the start time that is to be included.

If start is also given, show events starting from that time and date. The word now
can be used to indicate the current time.

To implement an alert when events are due, include calendar -s in your ~/.zshrc
file.

Options:

-a Show all items in the calendar, regardless of the start and end.

-b Brief: don't display continuation lines (i.e. indented lines following the
line with the date/time), just the first line.

-B lines
Brief: display at most the first lines lines of the calendar entry. `-B 1'
is equivalent to `-b'.

-C calfile
Explicitly specify a calendar file instead of the value of the calendar-file
style or the default ~/calendar.

-d Move any events that have passed from the calendar file to the "done" file,
as given by the done-file style or the default which is the calendar file
with .done appended. This option is implied by the -s option.

-D Turns off the option -d, even if the -s option is also present.

-n num, -num
Show at least num events, if present in the calendar file, regardless of the
start and end.

-r Show all the remaining options in the calendar, ignoring the given end time.
The start time is respected; any argument given is treated as a start time.

-s Use the shell's sched command to schedule a timed event that will warn the
user when an event is due. Note that the sched command only runs if the
shell is at an interactive prompt; a foreground task blocks the scheduled
task from running until it is finished.

The timed event usually runs the programme calendar_show to show the event,
as described in the section UTILITY FUNCTIONS below.

By default, a warning of the event is shown five minutes before it is due.
The warning period can be configured by the style warn-time or for a single
calendar entry by including WARN reltime in the first line of the entry,
where reltime is one of the usual relative time formats.

A repeated event may be indicated by including RPT reldate in the first line
of the entry. After the scheduled event has been displayed it will be
re-entered into the calendar file at a time reldate after the existing
event. Note that this is currently the only use made of the repeat count,
so that it is not possible to query the schedule for a recurrence of an
event in the calendar until the previous event has passed.

If RPT is used, it is also possible to specify that certain recurrences of
an event are rescheduled or cancelled. This is done with the OCCURRENCE
keyword, followed by whitespace and the date and time of the occurrence in
the regular sequence, followed by whitespace and either the date and time of
the rescheduled event or the exact string CANCELLED. In this case the date
and time must be in exactly the "date with local time" format used by the
text/calendar MIME type (RFC 2445), <YYYY><MM><DD>T<hh><mm><ss> (note the
presence of the literal character T). The first word (the regular recur-
rence) may be something other than a proper date/time to indicate that the
event is additional to the normal sequence; a convention that retains the
formatting appearance is XXXXXXXXTXXXXXX.

Furthermore, it is useful to record the next regular recurrence (as then the
displayed date may be for a rescheduled event so cannot be used for calcu-
lating the regular sequence). This is specified by RECURRENCE and a time or
date in the same format. calendar_add adds such an indication when it en-
counters a recurring event that does not include one, based on the headline
date/time.

If calendar_add is used to update occurrences the UID keyword described
there should be present in both the existing entry and the added occurrence
in order to identify recurring event sequences.

For example,

Thu May 6, 2010 11:00 Informal chat RPT 1 week
# RECURRENCE 20100506T110000
# OCCURRENCE 20100513T110000 20100513T120000
# OCCURRENCE 20100520T110000 CANCELLED

The event that occurs at 11:00 on 13th May 2010 is rescheduled an hour
later. The event that occurs a week later is cancelled. The occurrences
are given on a continuation line starting with a # character so will not
usually be displayed as part of the event. As elsewhere, no account of time
zones is taken with the times. After the next event occurs the headline
date/time will be `Thu May 13, 2010 12:00' while the RECURRENCE date/time
will be `20100513T110000' (note that cancelled and moved events are not
taken account of in the RECURRENCE, which records what the next regular re-
currence is, but they are accounted for in the headline date/time).

It is safe to run calendar -s to reschedule an existing event (if the calen-
dar file has changed, for example), and also to have it running in multiples
instances of the shell since the calendar file is locked when in use.

By default, expired events are moved to the "done" file; see the -d option.
Use -D to prevent this.

-S showprog
Explicitly specify a programme to be used for showing events instead of the
value of the show-prog style or the default calendar_show.

-v Verbose: show more information about stages of processing. This is useful
for confirming that the function has successfully parsed the dates in the
calendar file.

calendar_add [ -BL ] event ...
Adds a single event to the calendar in the appropriate location. The event can
contain multiple lines, as described in the section Calendar File Format above.
Using this function ensures that the calendar file is sorted in date and time or-
der. It also makes special arrangements for locking the file while it is altered.
The old calendar is left in a file with the suffix .old.

The option -B indicates that backing up the calendar file will be handled by the
caller and should not be performed by calendar_add. The option -L indicates that
calendar_add does not need to lock the calendar file as it is already locked.
These options will not usually be needed by users.

If the style reformat-date is true, the date and time of the new entry will be
rewritten into the standard date format: see the descriptions of this style and
the style date-format.

The function can use a unique identifier stored with each event to ensure that up-
dates to existing events are treated correctly. The entry should contain the word
UID, followed by whitespace, followed by a word consisting entirely of hexadecimal
digits of arbitrary length (all digits are significant, including leading zeroes).
As the UID is not directly useful to the user, it is convenient to hide it on an
indented continuation line starting with a #, for example:

Aug 31, 2007 09:30 Celebrate the end of the holidays
# UID 045B78A0

The second line will not be shown by the calendar function.

It is possible to specify the RPT keyword followed by CANCELLED instead of a rela-
tive time. This causes any matched event or series of events to be cancelled (the
original event does not have to be marked as recurring in order to be cancelled by
this method). A UID is required in order to match an existing event in the calen-
dar.

calendar_add will attempt to manage recurrences and occurrences of repeating events
as described for event scheduling by calendar -s above. To reschedule or cancel a
single event calendar_add should be called with an entry that includes the correct
UID but does not include the RPT keyword as this is taken to mean the entry applies
to a series of repeating events and hence replaces all existing information. Each
rescheduled or cancelled occurrence must have an OCCURRENCE keyword in the entry
passed to calendar_add which will be merged into the calendar file. Any existing
reference to the occurrence is replaced. An occurrence that does not refer to a
valid existing event is added as a one-off occurrence to the same calendar entry.

calendar_edit
This calls the user's editor to edit the calendar file. If there are arguments,
they are taken as the editor to use (the file name is appended to the commands);
otherwise, the editor is given by the variable VISUAL, if set, else the variable
EDITOR.

If the calendar scheduler was running, then after editing the file calendar -s is
called to update it.

This function locks out the calendar system during the edit. Hence it should be
used to edit the calendar file if there is any possibility of a calendar event oc-
curring meanwhile. Note this can lead to another shell with calendar functions en-
abled hanging waiting for a lock, so it is necessary to quit the editor as soon as
possible.

calendar_parse calendar-entry
This is the internal function that analyses the parts of a calendar entry, which is
passed as the only argument. The function returns status 1 if the argument could
not be parsed as a calendar entry and status 2 if the wrong number of arguments
were passed; it also sets the parameter reply to an empty associative array. Oth-
erwise, it returns status 0 and sets elements of the associative array reply as
follows:

time The time as a string of digits in the same units as $EPOCHSECONDS
schedtime
The regularly scheduled time. This may differ from the actual event time
time if this is a recurring event and the next occurrence has been resched-
uled. Then time gives the actual time and schedtime the time of the regular
recurrence before modification.
text1 The text from the line not including the date and time of the event, but in-
cluding any WARN or RPT keywords and values.
warntime
Any warning time given by the WARN keyword as a string of digits containing
the time at which to warn in the same units as $EPOCHSECONDS. (Note this is
an absolute time, not the relative time passed down.) Not set no WARN key-
word and value were matched.
warnstr
The raw string matched after the WARN keyword, else unset.
rpttime
Any recurrence time given by the RPT keyword as a string of digits contain-
ing the time of the recurrence in the same units as $EPOCHSECONDS. (Note
this is an absolute time.) Not set if no RPT keyword and value were
matched.
schedrpttime
The next regularly scheduled occurrence of a recurring event before modifi-
cation. This may differ from rpttime, which is the actual time of the event
that may have been rescheduled from the regular time.
rptstr The raw string matched after the RPT keyword, else unset.
text2 The text from the line after removal of the date and any keywords and val-
ues.

calendar_showdate [ -r ] [ -f fmt ] date-spec ...
The given date-spec is interpreted and the corresponding date and time printed. If
the initial date-spec begins with a + or - it is treated as relative to the current
time; date-specs after the first are treated as relative to the date calculated so
far and a leading + is optional in that case. This allows one to use the system as
a date calculator. For example, calendar_showdate '+1 month, 1st Friday' shows the
date of the first Friday of next month.

With the option -r nothing is printed but the value of the date and time in seconds
since the epoch is stored in the parameter REPLY.

With the option -f fmt the given date/time conversion format is passed to strftime;
see notes on the date-format style below.

In order to avoid ambiguity with negative relative date specifications, options
must occur in separate words; in other words, -r and -f should not be combined in
the same word.

calendar_sort
Sorts the calendar file into date and time order. The old calendar is left in a
file with the suffix .old.

Glob qualifiers
age The function age can be autoloaded and use separately from the calendar system, al-
though it uses the function calendar_scandate for date formatting. It requires the
zsh/stat builtin, but uses only the builtin zstat.

age selects files having a given modification time for use as a glob qualifier.
The format of the date is the same as that understood by the calendar system, de-
scribed in the section FILE AND DATE FORMATS above.

The function can take one or two arguments, which can be supplied either directly
as command or arguments, or separately as shell parameters.

print *(e:age 2006/10/04 2006/10/09:)

The example above matches all files modified between the start of those dates. The
second argument may alternatively be a relative time introduced by a +:

print *(e:age 2006/10/04 +5d:)

The example above is equivalent to the previous example.

In addition to the special use of days of the week, today and yesterday, times with
no date may be specified; these apply to today. Obviously such uses become prob-
lematic around midnight.

print *(e-age 12:00 13:30-)

The example above shows files modified between 12:00 and 13:00 today.

print *(e:age 2006/10/04:)

The example above matches all files modified on that date. If the second argument
is omitted it is taken to be exactly 24 hours after the first argument (even if the
first argument contains a time).

print *(e-age 2006/10/04:10:15 2006/10/04:10:45-)

The example above supplies times. Note that whitespace within the time and date
specification must be quoted to ensure age receives the correct arguments, hence
the use of the additional colon to separate the date and time.

AGEREF=2006/10/04:10:15
AGEREF2=2006/10/04:10:45
print *(+age)

This shows the same example before using another form of argument passing. The
dates and times in the parameters AGEREF and AGEREF2 stay in effect until unset,
but will be overridden if any argument is passed as an explicit argument to age.
Any explicit argument causes both parameters to be ignored.

Instead of an explicit date and time, it's possible to use the modification time of
a file as the date and time for either argument by introducing the file name with a
colon:

print *(e-age :file1-)

matches all files created on the same day (24 hours starting from midnight) as
file1.

print *(e-age :file1 :file2-)

matches all files modified no earlier than file1 and no later than file2; precision
here is to the nearest second.

after
before The functions after and before are simpler versions of age that take just one argu-
ment. The argument is parsed similarly to an argument of age; if it is not given
the variable AGEREF is consulted. As the names of the functions suggest, a file
matches if its modification time is after or before the time and date specified.
If a time only is given the date is today.

The two following examples are therefore equivalent:
print *(e-after 12:00-)
print *(e-after today:12:00-)

STYLES
The zsh style mechanism using the zstyle command is describe in zshmodules(1). This is
the same mechanism used in the completion system.

The styles below are all examined in the context :datetime:function:, for example :date-
time:calendar:.

calendar-file
The location of the main calendar. The default is ~/calendar.

date-format
A strftime format string (see strftime(3)) with the zsh extensions providing vari-
ous numbers with no leading zero or space if the number is a single digit as de-
scribed for the %D{string} prompt format in the section EXPANSION OF PROMPT SE-
QUENCES in zshmisc(1).

This is used for outputting dates in calendar, both to support the -v option and
when adding recurring events back to the calendar file, and in calendar_showdate as
the final output format.

If the style is not set, the default used is similar the standard system format as
output by the date command (also known as `ctime format'): `%a %b %d %H:%M:%S %Z
%Y'.

done-file
The location of the file to which events which have passed are appended. The de-
fault is the calendar file location with the suffix .done. The style may be set to
an empty string in which case a "done" file will not be maintained.

reformat-date
Boolean, used by calendar_add. If it is true, the date and time of new entries
added to the calendar will be reformatted to the format given by the style
date-format or its default. Only the date and time of the event itself is refor-
matted; any subsidiary dates and times such as those associated with repeat and
warning times are left alone.

show-prog
The programme run by calendar for showing events. It will be passed the start time
and stop time of the events requested in seconds since the epoch followed by the
event text. Note that calendar -s uses a start time and stop time equal to one an-
other to indicate alerts for specific events.

The default is the function calendar_show.

warn-time
The time before an event at which a warning will be displayed, if the first line of
the event does not include the text EVENT reltime. The default is 5 minutes.

UTILITY FUNCTIONS
calendar_lockfiles
Attempt to lock the files given in the argument. To prevent problems with network
file locking this is done in an ad hoc fashion by attempting to create a symbolic
link to the file with the name file.lockfile. No other system level functions are
used for locking, i.e. the file can be accessed and modified by any utility that
does not use this mechanism. In particular, the user is not prevented from editing
the calendar file at the same time unless calendar_edit is used.

Three attempts are made to lock the file before giving up. If the module zsh/zse-
lect is available, the times of the attempts are jittered so that multiple in-
stances of the calling function are unlikely to retry at the same time.

The files locked are appended to the array lockfiles, which should be local to the
caller.

If all files were successfully locked, status zero is returned, else status one.

This function may be used as a general file locking function, although this will
only work if only this mechanism is used to lock files.

calendar_read
This is a backend used by various other functions to parse the calendar file, which
is passed as the only argument. The array calendar_entries is set to the list of
events in the file; no pruning is done except that ampersands are removed from the
start of the line. Each entry may contain multiple lines.

calendar_scandate
This is a generic function to parse dates and times that may be used separately
from the calendar system. The argument is a date or time specification as de-
scribed in the section FILE AND DATE FORMATS above. The parameter REPLY is set to
the number of seconds since the epoch corresponding to that date or time. By de-
fault, the date and time may occur anywhere within the given argument.

Returns status zero if the date and time were successfully parsed, else one.

Options:
-a The date and time are anchored to the start of the argument; they will not
be matched if there is preceding text.

-A The date and time are anchored to both the start and end of the argument;
they will not be matched if the is any other text in the argument.

-d Enable additional debugging output.

-m Minus. When -R anchor_time is also given the relative time is calculated
backwards from anchor_time.

-r The argument passed is to be parsed as a relative time.

-R anchor_time
The argument passed is to be parsed as a relative time. The time is rela-
tive to anchor_time, a time in seconds since the epoch, and the returned
value is the absolute time corresponding to advancing anchor_time by the
relative time given. This allows lengths of months to be correctly taken
into account. If the final day does not exist in the given month, the last
day of the final month is given. For example, if the anchor time is during
31st January 2007 and the relative time is 1 month, the final time is the
same time of day during 28th February 2007.

-s In addition to setting REPLY, set REPLY2 to the remainder of the argument
after the date and time have been stripped. This is empty if the option -A
was given.

-t Allow a time with no date specification. The date is assumed to be today.
The behaviour is unspecified if the iron tongue of midnight is tolling
twelve.

calendar_show
The function used by default to display events. It accepts a start time and end
time for events, both in epoch seconds, and an event description.

The event is always printed to standard output. If the command line editor is ac-
tive (which will usually be the case) the command line will be redisplayed after
the output.

If the parameter DISPLAY is set and the start and end times are the same (indicat-
ing a scheduled event), the function uses the command xmessage to display a window
with the event details.

BUGS
As the system is based entirely on shell functions (with a little support from the
zsh/datetime module) the mechanisms used are not as robust as those provided by a dedi-
cated calendar utility. Consequently the user should not rely on the shell for vital
alerts.

There is no calendar_delete function.

There is no localization support for dates and times, nor any support for the use of time
zones.

Relative periods of months and years do not take into account the variable number of days.

The calendar_show function is currently hardwired to use xmessage for displaying alerts on
X Window System displays. This should be configurable and ideally integrate better with
the desktop.

calendar_lockfiles hangs the shell while waiting for a lock on a file. If called from a
scheduled task, it should instead reschedule the event that caused it.

ZSHTCPSYS(1) General Commands Manual ZSHTCPSYS(1)

NAME
zshtcpsys - zsh tcp system

DESCRIPTION
A module zsh/net/tcp is provided to provide network I/O over TCP/IP from within the shell;
see its description in zshmodules(1). This manual page describes a function suite based
on the module. If the module is installed, the functions are usually installed at the
same time, in which case they will be available for autoloading in the default function
search path. In addition to the zsh/net/tcp module, the zsh/zselect module is used to im-
plement timeouts on read operations. For troubleshooting tips, consult the corresponding
advice for the zftp functions described in zshzftpsys(1).

There are functions corresponding to the basic I/O operations open, close, read and send,
named tcp_open etc., as well as a function tcp_expect for pattern match analysis of data
read as input. The system makes it easy to receive data from and send data to multiple
named sessions at once. In addition, it can be linked with the shell's line editor in
such a way that input data is automatically shown at the terminal. Other facilities
available including logging, filtering and configurable output prompts.

To use the system where it is available, it should be enough to `autoload -U tcp_open' and
run tcp_open as documented below to start a session. The tcp_open function will autoload
the remaining functions.

TCP USER FUNCTIONS
Basic I/O
tcp_open [ -qz ] host port [ sess ]
tcp_open [ -qz ] [ -s sess | -l sess[,...] ] ...
tcp_open [ -qz ] [ -a fd | -f fd ] [ sess ]
Open a new session. In the first and simplest form, open a TCP connection to host
host at port port; numeric and symbolic forms are understood for both.

If sess is given, this becomes the name of the session which can be used to refer
to multiple different TCP connections. If sess is not given, the function will in-
vent a numeric name value (note this is not the same as the file descriptor to
which the session is attached). It is recommended that session names not include
`funny' characters, where funny characters are not well-defined but certainly do
not include alphanumerics or underscores, and certainly do include whitespace.

In the second case, one or more sessions to be opened are given by name. A single
session name is given after -s and a comma-separated list after -l; both options
may be repeated as many times as necessary. A failure to open any session causes
tcp_open to abort. The host and port are read from the file .ztcp_sessions in the
same directory as the user's zsh initialisation files, i.e. usually the home direc-
tory, but $ZDOTDIR if that is set. The file consists of lines each giving a ses-
sion name and the corresponding host and port, in that order (note the session name
comes first, not last), separated by whitespace.

The third form allows passive and fake TCP connections. If the option -a is used,
its argument is a file descriptor open for listening for connections. No function
front-end is provided to open such a file descriptor, but a call to `ztcp -l port'
will create one with the file descriptor stored in the parameter $REPLY. The lis-
tening port can be closed with `ztcp -c fd'. A call to `tcp_open -a fd' will block
until a remote TCP connection is made to port on the local machine. At this point,
a session is created in the usual way and is largely indistinguishable from an ac-
tive connection created with one of the first two forms.

If the option -f is used, its argument is a file descriptor which is used directly
as if it were a TCP session. How well the remainder of the TCP function system
copes with this depends on what actually underlies this file descriptor. A regular
file is likely to be unusable; a FIFO (pipe) of some sort will work better, but
note that it is not a good idea for two different sessions to attempt to read from
the same FIFO at once.

If the option -q is given with any of the three forms, tcp_open will not print in-
formational messages, although it will in any case exit with an appropriate status.

If the line editor (zle) is in use, which is typically the case if the shell is in-
teractive, tcp_open installs a handler inside zle which will check for new data at
the same time as it checks for keyboard input. This is convenient as the shell
consumes no CPU time while waiting; the test is performed by the operating system.
Giving the option -z to any of the forms of tcp_open prevents the handler from be-
ing installed, so data must be read explicitly. Note, however, this is not neces-
sary for executing complete sets of send and read commands from a function, as zle
is not active at this point. Generally speaking, the handler is only active when
the shell is waiting for input at a command prompt or in the vared builtin. The
option has no effect if zle is not active; `[[ -o zle]]' will test for this.

The first session to be opened becomes the current session and subsequent calls to
tcp_open do not change it. The current session is stored in the parameter
$TCP_SESS; see below for more detail about the parameters used by the system.

The function tcp_on_open, if defined, is called when a session is opened. See the
description below.

tcp_close [ -qn ] [ -a | -l sess[,...] | sess ... ]
Close the named sessions, or the current session if none is given, or all open ses-
sions if -a is given. The options -l and -s are both handled for consistency with
tcp_open, although the latter is redundant.

If the session being closed is the current one, $TCP_SESS is unset, leaving no cur-
rent session, even if there are other sessions still open.

If the session was opened with tcp_open -f, the file descriptor is closed so long
as it is in the range 0 to 9 accessible directly from the command line. If the op-
tion -n is given, no attempt will be made to close file descriptors in this case.
The -n option is not used for genuine ztcp session; the file descriptors are always
closed with the session.

If the option -q is given, no informational messages will be printed.

tcp_read [ -bdq ] [ -t TO ] [ -T TO ]
[ -a | -u fd[,...] | -l sess[,...] | -s sess ... ]
Perform a read operation on the current session, or on a list of sessions if any
are given with -u, -l or -s, or all open sessions if the option -a is given. Any
of the -u, -l or -s options may be repeated or mixed together. The -u option spec-
ifies a file descriptor directly (only those managed by this system are useful),
the other two specify sessions as described for tcp_open above.

The function checks for new data available on all the sessions listed. Unless the
-b option is given, it will not block waiting for new data. Any one line of data
from any of the available sessions will be read, stored in the parameter $TCP_LINE,
and displayed to standard output unless $TCP_SILENT contains a non-empty string.
When printed to standard output the string $TCP_PROMPT will be shown at the start
of the line; the default form for this includes the name of the session being read.
See below for more information on these parameters. In this mode, tcp_read can be
called repeatedly until it returns status 2 which indicates all pending input from
all specified sessions has been handled.

With the option -b, equivalent to an infinite timeout, the function will block un-
til a line is available to read from one of the specified sessions. However, only
a single line is returned.

The option -d indicates that all pending input should be drained. In this case
tcp_read may process multiple lines in the manner given above; only the last is
stored in $TCP_LINE, but the complete set is stored in the array $tcp_lines. This
is cleared at the start of each call to tcp_read.

The options -t and -T specify a timeout in seconds, which may be a floating point
number for increased accuracy. With -t the timeout is applied before each line
read. With -T, the timeout applies to the overall operation, possibly including
multiple read operations if the option -d is present; without this option, there is
no distinction between -t and -T.

The function does not print informational messages, but if the option -q is given,
no error message is printed for a non-existent session.

A return status of 2 indicates a timeout or no data to read. Any other non-zero
return status indicates some error condition.

See tcp_log for how to control where data is sent by tcp_read.

tcp_send [ -cnq ] [ -s sess | -l sess[,...] ] data ...
tcp_send [ -cnq ] -a data ...
Send the supplied data strings to all the specified sessions in turn. The underly-
ing operation differs little from a `print -r' to the session's file descriptor,
although it attempts to prevent the shell from dying owing to a SIGPIPE caused by
an attempt to write to a defunct session.

The option -c causes tcp_send to behave like cat. It reads lines from standard in-
put until end of input and sends them in turn to the specified session(s) exactly
as if they were given as data arguments to individual tcp_send commands.

The option -n prevents tcp_send from putting a newline at the end of the data
strings.

The remaining options all behave as for tcp_read.

The data arguments are not further processed once they have been passed to
tcp_send; they are simply passed down to print -r.

If the parameter $TCP_OUTPUT is a non-empty string and logging is enabled then the
data sent to each session will be echoed to the log file(s) with $TCP_OUTPUT in
front where appropriate, much in the manner of $TCP_PROMPT.

Session Management
tcp_alias [ -q ] alias=sess ...
tcp_alias [ -q ] [ alias ... ]
tcp_alias -d [ -q ] alias ...
This function is not particularly well tested.

The first form creates an alias for a session name; alias can then be used to refer
to the existing session sess. As many aliases may be listed as required.

The second form lists any aliases specified, or all aliases if none.

The third form deletes all the aliases listed. The underlying sessions are not af-
fected.

The option -q suppresses an inconsistently chosen subset of error messages.

tcp_log [ -asc ] [ -n | -N ] [ logfile ]
With an argument logfile, all future input from tcp_read will be logged to the
named file. Unless -a (append) is given, this file will first be truncated or cre-
ated empty. With no arguments, show the current status of logging.

With the option -s, per-session logging is enabled. Input from tcp_read is output
to the file logfile.sess. As the session is automatically discriminated by the
filename, the contents are raw (no $TCP_PROMPT). The option -a applies as above.
Per-session logging and logging of all data in one file are not mutually exclusive.

The option -c closes all logging, both complete and per-session logs.

The options -n and -N respectively turn off or restore output of data read by
tcp_read to standard output; hence `tcp_log -cn' turns off all output by tcp_read.

The function is purely a convenient front end to setting the parameters $TCP_LOG,
$TCP_LOG_SESS, $TCP_SILENT, which are described below.

tcp_rename old new
Rename session old to session new. The old name becomes invalid.

tcp_sess [ sess [ command [ arg ... ] ] ]
With no arguments, list all the open sessions and associated file descriptors. The
current session is marked with a star. For use in functions, direct access to the
parameters $tcp_by_name, $tcp_by_fd and $TCP_SESS is probably more convenient; see
below.

With a sess argument, set the current session to sess. This is equivalent to
changing $TCP_SESS directly.

With additional arguments, temporarily set the current session while executing
`command arg ...'. command is re-evaluated so as to expand aliases etc., but the
remaining args are passed through as that appear to tcp_sess. The original session
is restored when tcp_sess exits.

Advanced I/O
tcp_command send-option ... send-argument ...
This is a convenient front-end to tcp_send. All arguments are passed to tcp_send,
then the function pauses waiting for data. While data is arriving at least every
$TCP_TIMEOUT (default 0.3) seconds, data is handled and printed out according to
the current settings. Status 0 is always returned.

This is generally only useful for interactive use, to prevent the display becoming
fragmented by output returned from the connection. Within a programme or function
it is generally better to handle reading data by a more explicit method.

tcp_expect [ -q ] [ -p var | -P var ] [ -t TO | -T TO ]
[ -a | -s sess | -l sess[,...] ] pattern ...
Wait for input matching any of the given patterns from any of the specified ses-
sions. Input is ignored until an input line matches one of the given patterns; at
this point status zero is returned, the matching line is stored in $TCP_LINE, and
the full set of lines read during the call to tcp_expect is stored in the array
$tcp_expect_lines.

Sessions are specified in the same way as tcp_read: the default is to use the cur-
rent session, otherwise the sessions specified by -a, -s, or -l are used.

Each pattern is a standard zsh extended-globbing pattern; note that it needs to be
quoted to avoid it being expanded immediately by filename generation. It must
match the full line, so to match a substring there must be a `*' at the start and
end. The line matched against includes the $TCP_PROMPT added by tcp_read. It is
possible to include the globbing flags `#b' or `#m' in the patterns to make back-
references available in the parameters $MATCH, $match, etc., as described in the
base zsh documentation on pattern matching.

Unlike tcp_read, the default behaviour of tcp_expect is to block indefinitely until
the required input is found. This can be modified by specifying a timeout with -t
or -T; these function as in tcp_read, specifying a per-read or overall timeout, re-
spectively, in seconds, as an integer or floating-point number. As tcp_read, the
function returns status 2 if a timeout occurs.

The function returns as soon as any one of the patterns given match. If the caller
needs to know which of the patterns matched, the option -p var can be used; on re-
turn, $var is set to the number of the pattern using ordinary zsh indexing, i.e.
the first is 1, and so on. Note the absence of a `$' in front of var. To avoid
clashes, the parameter cannot begin with `_expect'. The index -1 is used if there
is a timeout and 0 if there is no match.

The option -P var works similarly to -p, but instead of numerical indexes the regu-
lar arguments must begin with a prefix followed by a colon: that prefix is then
used as a tag to which var is set when the argument matches. The tag timeout is
used if there is a timeout and the empty string if there is no match. Note it is
acceptable for different arguments to start with the same prefix if the matches do
not need to be distinguished.

The option -q is passed directly down to tcp_read.

As all input is done via tcp_read, all the usual rules about output of lines read
apply. One exception is that the parameter $tcp_lines will only reflect the line
actually matched by tcp_expect; use $tcp_expect_lines for the full set of lines
read during the function call.

tcp_proxy
This is a simple-minded function to accept a TCP connection and execute a command
with I/O redirected to the connection. Extreme caution should be taken as there is
no security whatsoever and this can leave your computer open to the world. Ide-
ally, it should only be used behind a firewall.

The first argument is a TCP port on which the function will listen.

The remaining arguments give a command and its arguments to execute with standard
input, standard output and standard error redirected to the file descriptor on
which the TCP session has been accepted. If no command is given, a new zsh is
started. This gives everyone on your network direct access to your account, which
in many cases will be a bad thing.

The command is run in the background, so tcp_proxy can then accept new connections.
It continues to accept new connections until interrupted.

tcp_spam [ -ertv ] [ -a | -s sess | -l sess[,...] ] cmd [ arg ... ]
Execute `cmd [ arg ... ]' for each session in turn. Note this executes the command
and arguments; it does not send the command line as data unless the -t (transmit)
option is given.

The sessions may be selected explicitly with the standard -a, -s or -l options, or
may be chosen implicitly. If none of the three options is given the rules are:
first, if the array $tcp_spam_list is set, this is taken as the list of sessions,
otherwise all sessions are taken. Second, any sessions given in the array
$tcp_no_spam_list are removed from the list of sessions.

Normally, any sessions added by the `-a' flag or when all sessions are chosen im-
plicitly are spammed in alphabetic order; sessions given by the $tcp_spam_list ar-
ray or on the command line are spammed in the order given. The -r flag reverses
the order however it was arrived it.

The -v flag specifies that a $TCP_PROMPT will be output before each session. This
is output after any modification to TCP_SESS by the user-defined tcp_on_spam func-
tion described below. (Obviously that function is able to generate its own out-
put.)

If the option -e is present, the line given as `cmd [ arg ... ]' is executed using
eval, otherwise it is executed without any further processing.

tcp_talk
This is a fairly simple-minded attempt to force input to the line editor to go
straight to the default TCP_SESS.

An escape string, $TCP_TALK_ESCAPE, default `:', is used to allow access to normal
shell operation. If it is on its own at the start of the line, or followed only by
whitespace, the line editor returns to normal operation. Otherwise, the string and
any following whitespace are skipped and the remainder of the line executed as
shell input without any change of the line editor's operating mode.

The current implementation is somewhat deficient in terms of use of the command
history. For this reason, many users will prefer to use some form of alternative
approach for sending data easily to the current session. One simple approach is to
alias some special character (such as `%') to `tcp_command --'.

tcp_wait
The sole argument is an integer or floating point number which gives the seconds to
delay. The shell will do nothing for that period except wait for input on all TCP
sessions by calling tcp_read -a. This is similar to the interactive behaviour at
the command prompt when zle handlers are installed.

`One-shot' file transfer
tcp_point port
tcp_shoot host port
This pair of functions provide a simple way to transfer a file between two hosts
within the shell. Note, however, that bulk data transfer is currently done using
cat. tcp_point reads any data arriving at port and sends it to standard output;
tcp_shoot connects to port on host and sends its standard input. Any unused port
may be used; the standard mechanism for picking a port is to think of a random
four-digit number above 1024 until one works.

To transfer a file from host woodcock to host springes, on springes:

tcp_point 8091 >output_file

and on woodcock:

tcp_shoot springes 8091 <input_file

As these two functions do not require tcp_open to set up a TCP connection first,
they may need to be autoloaded separately.

TCP USER-DEFINED FUNCTIONS
Certain functions, if defined by the user, will be called by the function system in cer-
tain contexts. This facility depends on the module zsh/parameter, which is usually avail-
able in interactive shells as the completion system depends on it. None of the functions
need be defined; they simply provide convenient hooks when necessary.

Typically, these are called after the requested action has been taken, so that the various
parameters will reflect the new state.

tcp_on_alias alias fd
When an alias is defined, this function will be called with two arguments: the name
of the alias, and the file descriptor of the corresponding session.

tcp_on_awol sess fd
If the function tcp_fd_handler is handling input from the line editor and detects
that the file descriptor is no longer reusable, by default it removes it from the
list of file descriptors handled by this method and prints a message. If the func-
tion tcp_on_awol is defined it is called immediately before this point. It may re-
turn status 100, which indicates that the normal handling should still be per-
formed; any other return status indicates that no further action should be taken
and the tcp_fd_handler should return immediately with the given status. Typically
the action of tcp_on_awol will be to close the session.

The variable TCP_INVALIDATE_ZLE will be a non-empty string if it is necessary to
invalidate the line editor display using `zle -I' before printing output from the
function.

(`AWOL' is military jargon for `absent without leave' or some variation. It has no
pre-existing technical meaning known to the author.)

tcp_on_close sess fd
This is called with the name of a session being closed and the file descriptor
which corresponded to that session. Both will be invalid by the time the function
is called.

tcp_on_open sess fd
This is called after a new session has been defined with the session name and file
descriptor as arguments. If it returns a non-zero status, opening the session is
assumed to fail and the session is closed again; however, tcp_open will continue to
attempt to open any remaining sessions given on the command line.

tcp_on_rename oldsess fd newsess
This is called after a session has been renamed with the three arguments old ses-
sion name, file descriptor, new session name.

tcp_on_spam sess command ...
This is called once for each session spammed, just before a command is executed for
a session by tcp_spam. The arguments are the session name followed by the command
list to be executed. If tcp_spam was called with the option -t, the first command
will be tcp_send.

This function is called after $TCP_SESS is set to reflect the session to be
spammed, but before any use of it is made. Hence it is possible to alter the value
of $TCP_SESS within this function. For example, the session arguments to tcp_spam
could include extra information to be stripped off and processed in tcp_on_spam.

If the function sets the parameter $REPLY to `done', the command line is not exe-
cuted; in addition, no prompt is printed for the -v option to tcp_spam.

tcp_on_unalias alias fd
This is called with the name of an alias and the corresponding session's file de-
scriptor after an alias has been deleted.

TCP UTILITY FUNCTIONS
The following functions are used by the TCP function system but will rarely if ever need
to be called directly.

tcp_fd_handler
This is the function installed by tcp_open for handling input from within the line
editor, if that is required. It is in the format documented for the builtin `zle
-F' in zshzle(1) .

While active, the function sets the parameter TCP_HANDLER_ACTIVE to 1. This allows
shell code called internally (for example, by setting tcp_on_read) to tell if is
being called when the shell is otherwise idle at the editor prompt.

tcp_output [ -q ] -P prompt -F fd -S sess
This function is used for both logging and handling output to standard output, from
within tcp_read and (if $TCP_OUTPUT is set) tcp_send.

The prompt to use is specified by -P; the default is the empty string. It can con-
tain:
%c Expands to 1 if the session is the current session, otherwise 0. Used with
ternary expressions such as `%(c.-.+)' to output `+' for the current session
and `-' otherwise.

%f Replaced by the session's file descriptor.

%s Replaced by the session name.

%% Replaced by a single `%'.

The option -q suppresses output to standard output, but not to any log files which
are configured.

The -S and -F options are used to pass in the session name and file descriptor for
possible replacement in the prompt.

TCP USER PARAMETERS
Parameters follow the usual convention that uppercase is used for scalars and integers,
while lowercase is used for normal and associative array. It is always safe for user code
to read these parameters. Some parameters may also be set; these are noted explicitly.
Others are included in this group as they are set by the function system for the user's
benefit, i.e. setting them is typically not useful but is benign.

It is often also useful to make settable parameters local to a function. For example,
`local TCP_SILENT=1' specifies that data read during the function call will not be printed
to standard output, regardless of the setting outside the function. Likewise, `local
TCP_SESS=sess' sets a session for the duration of a function, and `local TCP_PROMPT='
specifies that no prompt is used for input during the function.

tcp_expect_lines
Array. The set of lines read during the last call to tcp_expect, including the
last ($TCP_LINE).

tcp_filter
Array. May be set directly. A set of extended globbing patterns which, if matched
in tcp_output, will cause the line not to be printed to standard output. The pat-
terns should be defined as described for the arguments to tcp_expect. Output of
line to log files is not affected.

TCP_HANDLER_ACTIVE
Scalar. Set to 1 within tcp_fd_handler to indicate to functions called recursively
that they have been called during an editor session. Otherwise unset.

TCP_LINE
The last line read by tcp_read, and hence also tcp_expect.

TCP_LINE_FD
The file descriptor from which $TCP_LINE was read. ${tcp_by_fd[$TCP_LINE_FD]} will
give the corresponding session name.

tcp_lines
Array. The set of lines read during the last call to tcp_read, including the last
($TCP_LINE).

TCP_LOG
May be set directly, although it is also controlled by tcp_log. The name of a file
to which output from all sessions will be sent. The output is proceeded by the
usual $TCP_PROMPT. If it is not an absolute path name, it will follow the user's
current directory.

TCP_LOG_SESS
May be set directly, although it is also controlled by tcp_log. The prefix for a
set of files to which output from each session separately will be sent; the full
filename is ${TCP_LOG_SESS}.sess. Output to each file is raw; no prompt is added.
If it is not an absolute path name, it will follow the user's current directory.

tcp_no_spam_list
Array. May be set directly. See tcp_spam for how this is used.

TCP_OUTPUT
May be set directly. If a non-empty string, any data sent to a session by tcp_send
will be logged. This parameter gives the prompt to be used in a file specified by
$TCP_LOG but not in a file generated from $TCP_LOG_SESS. The prompt string has the
same format as TCP_PROMPT and the same rules for its use apply.

TCP_PROMPT
May be set directly. Used as the prefix for data read by tcp_read which is printed
to standard output or to the log file given by $TCP_LOG, if any. Any `%s', `%f' or
`%%' occurring in the string will be replaced by the name of the session, the ses-
sion's underlying file descriptor, or a single `%', respectively. The expression
`%c' expands to 1 if the session being read is the current session, else 0; this is
most useful in ternary expressions such as `%(c.-.+)' which outputs `+' if the ses-
sion is the current one, else `-'.

If the prompt starts with %P, this is stripped and the complete result of the pre-
vious stage is passed through standard prompt %-style formatting before being out-
put.

TCP_READ_DEBUG
May be set directly. If this has non-zero length, tcp_read will give some limited
diagnostics about data being read.

TCP_SECONDS_START
This value is created and initialised to zero by tcp_open.

The functions tcp_read and tcp_expect use the shell's SECONDS parameter for their
own timing purposes. If that parameter is not of floating point type on entry to
one of the functions, it will create a local parameter SECONDS which is floating
point and set the parameter TCP_SECONDS_START to the previous value of $SECONDS.
If the parameter is already floating point, it is used without a local copy being
created and TCP_SECONDS_START is not set. As the global value is zero, the shell
elapsed time is guaranteed to be the sum of $SECONDS and $TCP_SECONDS_START.

This can be avoided by setting SECONDS globally to a floating point value using
`typeset -F SECONDS'; then the TCP functions will never make a local copy and never
set TCP_SECONDS_START to a non-zero value.

TCP_SESS
May be set directly. The current session; must refer to one of the sessions estab-
lished by tcp_open.

TCP_SILENT
May be set directly, although it is also controlled by tcp_log. If of non-zero
length, data read by tcp_read will not be written to standard output, though may
still be written to a log file.

tcp_spam_list
Array. May be set directly. See the description of the function tcp_spam for how
this is used.

TCP_TALK_ESCAPE
May be set directly. See the description of the function tcp_talk for how this is
used.

TCP_TIMEOUT
May be set directly. Currently this is only used by the function tcp_command, see
above.

TCP USER-DEFINED PARAMETERS
The following parameters are not set by the function system, but have a special effect if
set by the user.

tcp_on_read
This should be an associative array; if it is not, the behaviour is undefined.
Each key is the name of a shell function or other command, and the corresponding
value is a shell pattern (using EXTENDED_GLOB). Every line read from a TCP session
directly or indirectly using tcp_read (which includes lines read by tcp_expect) is
compared against the pattern. If the line matches, the command given in the key is
called with two arguments: the name of the session from which the line was read,
and the line itself.

If any function called to handle a line returns a non-zero status, the line is not
output. Thus a tcp_on_read handler containing only the instruction `return 1' can
be used to suppress output of particular lines (see, however, tcp_filter above).
However, the line is still stored in TCP_LINE and tcp_lines; this occurs after all
tcp_on_read processing.

TCP UTILITY PARAMETERS
These parameters are controlled by the function system; they may be read directly, but
should not usually be set by user code.

tcp_aliases
Associative array. The keys are the names of sessions established with tcp_open;
each value is a space-separated list of aliases which refer to that session.

tcp_by_fd
Associative array. The keys are session file descriptors; each value is the name
of that session.

tcp_by_name
Associative array. The keys are the names of sessions; each value is the file de-
scriptor associated with that session.

TCP EXAMPLES
Here is a trivial example using a remote calculator.

To create a calculator server on port 7337 (see the dc manual page for quite how infuriat-
ing the underlying command is):

tcp_proxy 7337 dc

To connect to this from the same host with a session also named `dc':

tcp_open localhost 7337 dc

To send a command to the remote session and wait a short while for output (assuming dc is
the current session):

tcp_command 2 4 + p

To close the session:

tcp_close

The tcp_proxy needs to be killed to be stopped. Note this will not usually kill any con-
nections which have already been accepted, and also that the port is not immediately
available for reuse.

The following chunk of code puts a list of sessions into an xterm header, with the current
session followed by a star.

print -n "\033]2;TCP:" ${(k)tcp_by_name:/$TCP_SESS/$TCP_SESS\*} "\a"

TCP BUGS
The function tcp_read uses the shell's normal read builtin. As this reads a complete line
at once, data arriving without a terminating newline can cause the function to block in-
definitely.

Though the function suite works well for interactive use and for data arriving in small
amounts, the performance when large amounts of data are being exchanged is likely to be
extremely poor.

ZSHZFTPSYS(1) General Commands Manual ZSHZFTPSYS(1)

NAME
zshzftpsys - zftp function front-end

DESCRIPTION
This describes the set of shell functions supplied with the source distribution as an in-
terface to the zftp builtin command, allowing you to perform FTP operations from the shell
command line or within functions or scripts. The interface is similar to a traditional
FTP client (e.g. the ftp command itself, see ftp(1)), but as it is entirely done within
the shell all the familiar completion, editing and globbing features, and so on, are
present, and macros are particularly simple to write as they are just ordinary shell func-
tions.

The prerequisite is that the zftp command, as described in zshmodules(1) , must be avail-
able in the version of zsh installed at your site. If the shell is configured to load new
commands at run time, it probably is: typing `zmodload zsh/zftp' will make sure (if that
runs silently, it has worked). If this is not the case, it is possible zftp was linked
into the shell anyway: to test this, type `which zftp' and if zftp is available you will
get the message `zftp: shell built-in command'.

Commands given directly with zftp builtin may be interspersed between the functions in
this suite; in a few cases, using zftp directly may cause some of the status information
stored in shell parameters to become invalid. Note in particular the description of the
variables $ZFTP_TMOUT, $ZFTP_PREFS and $ZFTP_VERBOSE for zftp.

INSTALLATION
You should make sure all the functions from the Functions/Zftp directory of the source
distribution are available; they all begin with the two letters `zf'. They may already
have been installed on your system; otherwise, you will need to find them and copy them.
The directory should appear as one of the elements of the $fpath array (this should al-
ready be the case if they were installed), and at least the function zfinit should be au-
toloaded; it will autoload the rest. Finally, to initialize the use of the system you
need to call the zfinit function. The following code in your .zshrc will arrange for
this; assume the functions are stored in the directory ~/myfns:

fpath=(~/myfns $fpath)
autoload -U zfinit
zfinit

Note that zfinit assumes you are using the zmodload method to load the zftp command. If
it is already built into the shell, change zfinit to zfinit -n. It is helpful (though not
essential) if the call to zfinit appears after any code to initialize the new completion
system, else unnecessary compctl commands will be given.

FUNCTIONS
The sequence of operations in performing a file transfer is essentially the same as that
in a standard FTP client. Note that, due to a quirk of the shell's getopts builtin, for
those functions that handle options you must use `--' rather than `-' to ensure the re-
maining arguments are treated literally (a single `-' is treated as an argument).

Opening a connection
zfparams [ host [ user [ password ... ] ] ]
Set or show the parameters for a future zfopen with no arguments. If no arguments
are given, the current parameters are displayed (the password will be shown as a
line of asterisks). If a host is given, and either the user or password is not,
they will be prompted for; also, any parameter given as `?' will be prompted for,
and if the `?' is followed by a string, that will be used as the prompt. As zfopen
calls zfparams to store the parameters, this usually need not be called directly.

A single argument `-' will delete the stored parameters. This will also cause the
memory of the last directory (and so on) on the other host to be deleted.

zfopen [ -1 ] [ host [ user [ password [ account ] ] ] ]
If host is present, open a connection to that host under username user with pass-
word password (and, on the rare occasions when it is necessary, account account).
If a necessary parameter is missing or given as `?' it will be prompted for. If
host is not present, use a previously stored set of parameters.

If the command was successful, and the terminal is compatible with xterm or is
sun-cmd, a summary will appear in the title bar, giving the local host:directory
and the remote host:directory; this is handled by the function zftp_chpwd, de-
scribed below.

Normally, the host, user and password are internally recorded for later re-opening,
either by a zfopen with no arguments, or automatically (see below). With the op-
tion `-1', no information is stored. Also, if an open command with arguments
failed, the parameters will not be retained (and any previous parameters will also
be deleted). A zfopen on its own, or a zfopen -1, never alters the stored parame-
ters.

Both zfopen and zfanon (but not zfparams) understand URLs of the form
ftp://host/path... as meaning to connect to the host, then change directory to path
(which must be a directory, not a file). The `ftp://' can be omitted; the trailing
`/' is enough to trigger recognition of the path. Note prefixes other than `ftp:'
are not recognized, and that all characters after the first slash beyond host are
significant in path.

zfanon [ -1 ] host
Open a connection host for anonymous FTP. The username used is `anonymous'. The
password (which will be reported the first time) is generated as user@host; this is
then stored in the shell parameter $EMAIL_ADDR which can alternatively be set manu-
ally to a suitable string.

Directory management
zfcd [ dir ]
zfcd -
zfcd old new
Change the current directory on the remote server: this is implemented to have
many of the features of the shell builtin cd.

In the first form with dir present, change to the directory dir. The command `zfcd
..' is treated specially, so is guaranteed to work on non-UNIX servers (note this
is handled internally by zftp). If dir is omitted, has the effect of `zfcd ~'.

The second form changes to the directory previously current.

The third form attempts to change the current directory by replacing the first oc-
currence of the string old with the string new in the current directory.

Note that in this command, and indeed anywhere a remote filename is expected, the
string which on the local host corresponds to `~' is converted back to a `~' before
being passed to the remote machine. This is convenient because of the way expan-
sion is performed on the command line before zfcd receives a string. For example,
suppose the command is `zfcd ~/foo'. The shell will expand this to a full path
such as `zfcd /home/user2/pws/foo'. At this stage, zfcd recognises the initial
path as corresponding to `~' and will send the directory to the remote host as
~/foo, so that the `~' will be expanded by the server to the correct remote host
directory. Other named directories of the form `~name' are not treated in this
fashion.

zfhere Change directory on the remote server to the one corresponding to the current local
directory, with special handling of `~' as in zfcd. For example, if the current
local directory is ~/foo/bar, then zfhere performs the effect of `zfcd ~/foo/bar'.

zfdir [ -rfd ] [ - ] [ dir-options ] [ dir ]
Produce a long directory listing. The arguments dir-options and dir are passed di-
rectly to the server and their effect is implementation dependent, but specifying a
particular remote directory dir is usually possible. The output is passed through
a pager given by the environment variable $PAGER, or `more' if that is not set.

The directory is usually cached for re-use. In fact, two caches are maintained.
One is for use when there is no dir-options or dir, i.e. a full listing of the cur-
rent remote directory; it is flushed when the current remote directory changes.
The other is kept for repeated use of zfdir with the same arguments; for example,
repeated use of `zfdir /pub/gnu' will only require the directory to be retrieved on
the first call. Alternatively, this cache can be re-viewed with the -r option. As
relative directories will confuse zfdir, the -f option can be used to force the
cache to be flushed before the directory is listed. The option -d will delete both
caches without showing a directory listing; it will also delete the cache of file
names in the current remote directory, if any.

zfls [ ls-options ] [ dir ]
List files on the remote server. With no arguments, this will produce a simple
list of file names for the current remote directory. Any arguments are passed di-
rectly to the server. No pager and no caching is used.

Status commands
zftype [ type ]
With no arguments, show the type of data to be transferred, usually ASCII or bi-
nary. With an argument, change the type: the types `A' or `ASCII' for ASCII data
and `B' or `BINARY', `I' or `IMAGE' for binary data are understood case-insensi-
tively.

zfstat [ -v ]
Show the status of the current or last connection, as well as the status of some of
zftp's status variables. With the -v option, a more verbose listing is produced by
querying the server for its version of events, too.

Retrieving files
The commands for retrieving files all take at least two options. -G suppresses remote
filename expansion which would otherwise be performed (see below for a more detailed de-
scription of that). -t attempts to set the modification time of the local file to that of
the remote file: see the description of the function zfrtime below for more information.

zfget [ -Gtc ] file1 ...
Retrieve all the listed files file1 ... one at a time from the remote server. If a
file contains a `/', the full name is passed to the remote server, but the file is
stored locally under the name given by the part after the final `/'. The option -c
(cat) forces all files to be sent as a single stream to standard output; in this
case the -t option has no effect.

zfuget [ -Gvst ] file1 ...
As zfget, but only retrieve files where the version on the remote server is newer
(has a later modification time), or where the local file does not exist. If the
remote file is older but the files have different sizes, or if the sizes are the
same but the remote file is newer, the user will usually be queried. With the op-
tion -s, the command runs silently and will always retrieve the file in either of
those two cases. With the option -v, the command prints more information about the
files while it is working out whether or not to transfer them.

zfcget [ -Gt ] file1 ...
As zfget, but if any of the local files exists, and is shorter than the correspond-
ing remote file, the command assumes that it is the result of a partially completed
transfer and attempts to transfer the rest of the file. This is useful on a poor
connection which keeps failing.

Note that this requires a commonly implemented, but non-standard, version of the
FTP protocol, so is not guaranteed to work on all servers.

zfgcp [ -Gt ] remote-file local-file
zfgcp [ -Gt ] rfile1 ... ldir
This retrieves files from the remote server with arguments behaving similarly to
the cp command.

In the first form, copy remote-file from the server to the local file local-file.

In the second form, copy all the remote files rfile1 ... into the local directory
ldir retaining the same basenames. This assumes UNIX directory semantics.

Sending files
zfput [ -r ] file1 ...
Send all the file1 ... given separately to the remote server. If a filename con-
tains a `/', the full filename is used locally to find the file, but only the base-
name is used for the remote file name.

With the option -r, if any of the files are directories they are sent recursively
with all their subdirectories, including files beginning with `.'. This requires
that the remote machine understand UNIX file semantics, since `/' is used as a di-
rectory separator.

zfuput [ -vs ] file1 ...
As zfput, but only send files which are newer than their remote equivalents, or if
the remote file does not exist. The logic is the same as for zfuget, but reversed
between local and remote files.

zfcput file1 ...
As zfput, but if any remote file already exists and is shorter than the local
equivalent, assume it is the result of an incomplete transfer and send the rest of
the file to append to the existing part. As the FTP append command is part of the
standard set, this is in principle more likely to work than zfcget.

zfpcp local-file remote-file
zfpcp lfile1 ... rdir
This sends files to the remote server with arguments behaving similarly to the cp
command.

With two arguments, copy local-file to the server as remote-file.

With more than two arguments, copy all the local files lfile1 ... into the existing
remote directory rdir retaining the same basenames. This assumes UNIX directory
semantics.

A problem arises if you attempt to use zfpcp lfile1 rdir, i.e. the second form of
copying but with two arguments, as the command has no simple way of knowing if rdir
corresponds to a directory or a filename. It attempts to resolve this in various
ways. First, if the rdir argument is `.' or `..' or ends in a slash, it is assumed
to be a directory. Secondly, if the operation of copying to a remote file in the
first form failed, and the remote server sends back the expected failure code 553
and a reply including the string `Is a directory', then zfpcp will retry using the
second form.

Closing the connection
zfclose
Close the connection.

Session management
zfsession [ -lvod ] [ sessname ]
Allows you to manage multiple FTP sessions at once. By default, connections take
place in a session called `default'; by giving the command `zfsession sessname' you
can change to a new or existing session with a name of your choice. The new ses-
sion remembers its own connection, as well as associated shell parameters, and also
the host/user parameters set by zfparams. Hence you can have different sessions
set up to connect to different hosts, each remembering the appropriate host, user
and password.

With no arguments, zfsession prints the name of the current session; with the op-
tion -l it lists all sessions which currently exist, and with the option -v it
gives a verbose list showing the host and directory for each session, where the
current session is marked with an asterisk. With -o, it will switch to the most
recent previous session.

With -d, the given session (or else the current one) is removed; everything to do
with it is completely forgotten. If it was the only session, a new session called
`default' is created and made current. It is safest not to delete sessions while
background commands using zftp are active.

zftransfer sess1:file1 sess2:file2
Transfer files between two sessions; no local copy is made. The file is read from
the session sess1 as file1 and written to session sess2 as file file2; file1 and
file2 may be relative to the current directories of the session. Either sess1 or
sess2 may be omitted (though the colon should be retained if there is a possibility
of a colon appearing in the file name) and defaults to the current session; file2
may be omitted or may end with a slash, in which case the basename of file1 will be
added. The sessions sess1 and sess2 must be distinct.

The operation is performed using pipes, so it is required that the connections
still be valid in a subshell, which is not the case under versions of some operat-
ing systems, presumably due to a system bug.

Bookmarks
The two functions zfmark and zfgoto allow you to `bookmark' the present location (host,
user and directory) of the current FTP connection for later use. The file to be used for
storing and retrieving bookmarks is given by the parameter $ZFTP_BMFILE; if not set when
one of the two functions is called, it will be set to the file .zfbkmarks in the directory
where your zsh startup files live (usually ~).

zfmark [ bookmark ]
If given an argument, mark the current host, user and directory under the name
bookmark for later use by zfgoto. If there is no connection open, use the values
for the last connection immediately before it was closed; it is an error if there
was none. Any existing bookmark under the same name will be silently replaced.

If not given an argument, list the existing bookmarks and the points to which they
refer in the form user@host:directory; this is the format in which they are stored,
and the file may be edited directly.

zfgoto [ -n ] bookmark
Return to the location given by bookmark, as previously set by zfmark. If the lo-
cation has user `ftp' or `anonymous', open the connection with zfanon, so that no
password is required. If the user and host parameters match those stored for the
current session, if any, those will be used, and again no password is required.
Otherwise a password will be prompted for.

With the option -n, the bookmark is taken to be a nickname stored by the ncftp pro-
gram in its bookmark file, which is assumed to be ~/.ncftp/bookmarks. The function
works identically in other ways. Note that there is no mechanism for adding or
modifying ncftp bookmarks from the zftp functions.

Other functions
Mostly, these functions will not be called directly (apart from zfinit), but are described
here for completeness. You may wish to alter zftp_chpwd and zftp_progress, in particular.

zfinit [ -n ]
As described above, this is used to initialize the zftp function system. The -n
option should be used if the zftp command is already built into the shell.

zfautocheck [ -dn ]
This function is called to implement automatic reopening behaviour, as described in
more detail below. The options must appear in the first argument; -n prevents the
command from changing to the old directory, while -d prevents it from setting the
variable do_close, which it otherwise does as a flag for automatically closing the
connection after a transfer. The host and directory for the last session are
stored in the variable $zflastsession, but the internal host/user/password parame-
ters must also be correctly set.

zfcd_match prefix suffix
This performs matching for completion of remote directory names. If the remote
server is UNIX, it will attempt to persuade the server to list the remote directory
with subdirectories marked, which usually works but is not guaranteed. On other
hosts it simply calls zfget_match and hence completes all files, not just directo-
ries. On some systems, directories may not even look like filenames.

zfget_match prefix suffix
This performs matching for completion of remote filenames. It caches files for the
current directory (only) in the shell parameter $zftp_fcache. It is in the form to
be called by the -K option of compctl, but also works when called from a wid-
get-style completion function with prefix and suffix set appropriately.

zfrglob varname
Perform remote globbing, as describes in more detail below. varname is the name of
a variable containing the pattern to be expanded; if there were any matches, the
same variable will be set to the expanded set of filenames on return.

zfrtime lfile rfile [ time ]
Set the local file lfile to have the same modification time as the remote file
rfile, or the explicit time time in FTP format CCYYMMDDhhmmSS for the GMT timezone.
This uses the shell's zsh/datetime module to perform the conversion from GMT to lo-
cal time.

zftp_chpwd
This function is called every time a connection is opened, or closed, or the remote
directory changes. This version alters the title bar of an xterm-compatible or
sun-cmd terminal emulator to reflect the local and remote hostnames and current di-
rectories. It works best when combined with the function chpwd. In particular, a
function of the form

chpwd() {
if [[ -n $ZFTP_USER ]]; then
zftp_chpwd
else
# usual chpwd e.g put host:directory in title bar
fi
}

fits in well.

zftp_progress
This function shows the status of the transfer. It will not write anything unless
the output is going to a terminal; however, if you transfer files in the back-
ground, you should turn off progress reports by hand using `zstyle ':zftp:*'
progress none'. Note also that if you alter it, any output must be to standard er-
ror, as standard output may be a file being received. The form of the progress me-
ter, or whether it is used at all, can be configured without altering the function,
as described in the next section.

zffcache
This is used to implement caching of files in the current directory for each ses-
sion separately. It is used by zfget_match and zfrglob.

MISCELLANEOUS FEATURES
Configuration
Various styles are available using the standard shell style mechanism, described in zsh-
modules(1). Briefly, the command `zstyle ':zftp:*' style value ...'. defines the style to
have value value; more than one value may be given, although that is not useful in the
cases described here. These values will then be used throughout the zftp function system.
For more precise control, the first argument, which gives a context in which the style ap-
plies, can be modified to include a particular function, as for example `:zftp:zfget': the
style will then have the given value only in the zfget function. Values for the same
style in different contexts may be set; the most specific function will be used, where
strings are held to be more specific than patterns, and longer patterns and shorter pat-
terns. Note that only the top level function name, as called by the user, is used; call-
ing of lower level functions is transparent to the user. Hence modifications to the title
bar in zftp_chpwd use the contexts :zftp:zfopen, :zftp:zfcd, etc., depending where it was
called from. The following styles are understood:

progress
Controls the way that zftp_progress reports on the progress of a transfer. If
empty, unset, or `none', no progress report is made; if `bar' a growing bar of in-
verse video is shown; if `percent' (or any other string, though this may change in
future), the percentage of the file transferred is shown. The bar meter requires
that the width of the terminal be available via the $COLUMNS parameter (normally
this is set automatically). If the size of the file being transferred is not
available, bar and percent meters will simply show the number of bytes transferred
so far.

When zfinit is run, if this style is not defined for the context :zftp:*, it will
be set to `bar'.

update Specifies the minimum time interval between updates of the progress meter in sec-
onds. No update is made unless new data has been received, so the actual time in-
terval is limited only by $ZFTP_TIMEOUT.

As described for progress, zfinit will force this to default to 1.

remote-glob
If set to `1', `yes' or `true', filename generation (globbing) is performed on the
remote machine instead of by zsh itself; see below.

titlebar
If set to `1', `yes' or `true', zftp_chpwd will put the remote host and remote di-
rectory into the titlebar of terminal emulators such as xterm or sun-cmd that allow
this.

As described for progress, zfinit will force this to default to 1.

chpwd If set to `1' `yes' or `true', zftp_chpwd will call the function chpwd when a con-
nection is closed. This is useful if the remote host details were put into the
terminal title bar by zftp_chpwd and your usual chpwd also modifies the title bar.

When zfinit is run, it will determine whether chpwd exists and if so it will set
the default value for the style to 1 if none exists already.

Note that there is also an associative array zfconfig which contains values used by the
function system. This should not be modified or overwritten.

Remote globbing
The commands for retrieving files usually perform filename generation (globbing) on their
arguments; this can be turned off by passing the option -G to each of the commands. Nor-
mally this operates by retrieving a complete list of files for the directory in question,
then matching these locally against the pattern supplied. This has the advantage that the
full range of zsh patterns (respecting the setting of the option EXTENDED_GLOB) can be
used. However, it means that the directory part of a filename will not be expanded and
must be given exactly. If the remote server does not support the UNIX directory seman-
tics, directory handling is problematic and it is recommended that globbing only be used
within the current directory. The list of files in the current directory, if retrieved,
will be cached, so that subsequent globs in the same directory without an intervening zfcd
are much faster.

If the remote-glob style (see above) is set, globbing is instead performed on the remote
host: the server is asked for a list of matching files. This is highly dependent on how
the server is implemented, though typically UNIX servers will provide support for basic
glob patterns. This may in some cases be faster, as it avoids retrieving the entire list
of directory contents.

Automatic and temporary reopening
As described for the zfopen command, a subsequent zfopen with no parameters will reopen
the connection to the last host (this includes connections made with the zfanon command).
Opened in this fashion, the connection starts in the default remote directory and will re-
main open until explicitly closed.

Automatic re-opening is also available. If a connection is not currently open and a com-
mand requiring a connection is given, the last connection is implicitly reopened. In this
case the directory which was current when the connection was closed again becomes the cur-
rent directory (unless, of course, the command given changes it). Automatic reopening
will also take place if the connection was close by the remote server for whatever reason
(e.g. a timeout). It is not available if the -1 option to zfopen or zfanon was used.

Furthermore, if the command issued is a file transfer, the connection will be closed after
the transfer is finished, hence providing a one-shot mode for transfers. This does not
apply to directory changing or listing commands; for example a zfdir may reopen a connec-
tion but will leave it open. Also, automatic closure will only ever happen in the same
command as automatic opening, i.e a zfdir directly followed by a zfget will never close
the connection automatically.

Information about the previous connection is given by the zfstat function. So, for exam-
ple, if that reports:

Session: default
Not connected.
Last session: ftp.bar.com:/pub/textfiles

then the command zfget file.txt will attempt to reopen a connection to ftp.bar.com, re-
trieve the file /pub/textfiles/file.txt, and immediately close the connection again. On
the other hand, zfcd .. will open the connection in the directory /pub and leave it open.

Note that all the above is local to each session; if you return to a previous session, the
connection for that session is the one which will be reopened.

Completion
Completion of local and remote files, directories, sessions and bookmarks is supported.
The older, compctl-style completion is defined when zfinit is called; support for the new
widget-based completion system is provided in the function Completion/Zsh/Command/_zftp,
which should be installed with the other functions of the completion system and hence
should automatically be available.

ZSHCONTRIB(1) General Commands Manual ZSHCONTRIB(1)

NAME
zshcontrib - user contributions to zsh

DESCRIPTION
The Zsh source distribution includes a number of items contributed by the user community.
These are not inherently a part of the shell, and some may not be available in every zsh
installation. The most significant of these are documented here. For documentation on
other contributed items such as shell functions, look for comments in the function source
files.

UTILITIES
Accessing On-Line Help
The key sequence ESC h is normally bound by ZLE to execute the run-help widget (see zsh-
zle(1)). This invokes the run-help command with the command word from the current input
line as its argument. By default, run-help is an alias for the man command, so this often
fails when the command word is a shell builtin or a user-defined function. By redefining
the run-help alias, one can improve the on-line help provided by the shell.

The helpfiles utility, found in the Util directory of the distribution, is a Perl program
that can be used to process the zsh manual to produce a separate help file for each shell
builtin and for many other shell features as well. The autoloadable run-help function,
found in Functions/Misc, searches for these helpfiles and performs several other tests to
produce the most complete help possible for the command.

Help files are installed by default to a subdirectory of /usr/share/zsh or /usr/lo-
cal/share/zsh.

To create your own help files with helpfiles, choose or create a directory where the indi-
vidual command help files will reside. For example, you might choose ~/zsh_help. If you
unpacked the zsh distribution in your home directory, you would use the commands:

mkdir ~/zsh_help
perl ~/zsh-5.8.1/Util/helpfiles ~/zsh_help

The HELPDIR parameter tells run-help where to look for the help files. When unset, it uses
the default installation path. To use your own set of help files, set this to the appro-
priate path in one of your startup files:

HELPDIR=~/zsh_help

To use the run-help function, you need to add lines something like the following to your
.zshrc or equivalent startup file:

unalias run-help
autoload run-help

Note that in order for `autoload run-help' to work, the run-help file must be in one of
the directories named in your fpath array (see zshparam(1)). This should already be the
case if you have a standard zsh installation; if it is not, copy Functions/Misc/run-help
to an appropriate directory.

Recompiling Functions
If you frequently edit your zsh functions, or periodically update your zsh installation to
track the latest developments, you may find that function digests compiled with the zcom-
pile builtin are frequently out of date with respect to the function source files. This
is not usually a problem, because zsh always looks for the newest file when loading a
function, but it may cause slower shell startup and function loading. Also, if a digest
file is explicitly used as an element of fpath, zsh won't check whether any of its source
files has changed.

The zrecompile autoloadable function, found in Functions/Misc, can be used to keep func-
tion digests up to date.

zrecompile [ -qt ] [ name ... ]
zrecompile [ -qt ] -p arg ... [ -- arg ... ]
This tries to find *.zwc files and automatically re-compile them if at least one of
the original files is newer than the compiled file. This works only if the names
stored in the compiled files are full paths or are relative to the directory that
contains the .zwc file.

In the first form, each name is the name of a compiled file or a directory contain-
ing *.zwc files that should be checked. If no arguments are given, the directories
and *.zwc files in fpath are used.

When -t is given, no compilation is performed, but a return status of zero (true)
is set if there are files that need to be re-compiled and non-zero (false) other-
wise. The -q option quiets the chatty output that describes what zrecompile is do-
ing.

Without the -t option, the return status is zero if all files that needed re-compi-
lation could be compiled and non-zero if compilation for at least one of the files
failed.

If the -p option is given, the args are interpreted as one or more sets of argu-
ments for zcompile, separated by `--'. For example:

zrecompile -p \
-R ~/.zshrc -- \
-M ~/.zcompdump -- \
~/zsh/comp.zwc ~/zsh/Completion/*/_*

This compiles ~/.zshrc into ~/.zshrc.zwc if that doesn't exist or if it is older
than ~/.zshrc. The compiled file will be marked for reading instead of mapping. The
same is done for ~/.zcompdump and ~/.zcompdump.zwc, but this compiled file is
marked for mapping. The last line re-creates the file ~/zsh/comp.zwc if any of the
files matching the given pattern is newer than it.

Without the -p option, zrecompile does not create function digests that do not al-
ready exist, nor does it add new functions to the digest.

The following shell loop is an example of a method for creating function digests for all
functions in your fpath, assuming that you have write permission to the directories:

for ((i=1; i <= $#fpath; ++i)); do
dir=$fpath[i]
zwc=${dir:t}.zwc
if [[ $dir == (.|..) || $dir == (.|..)/* ]]; then
continue
fi
files=($dir/*(N-.))
if [[ -w $dir:h && -n $files ]]; then
files=(${${(M)files%/*/*}#/})
if ( cd $dir:h &&
zrecompile -p -U -z $zwc $files ); then
fpath[i]=$fpath[i].zwc
fi
fi
done

The -U and -z options are appropriate for functions in the default zsh installation fpath;
you may need to use different options for your personal function directories.

Once the digests have been created and your fpath modified to refer to them, you can keep
them up to date by running zrecompile with no arguments.

Keyboard Definition
The large number of possible combinations of keyboards, workstations, terminals, emula-
tors, and window systems makes it impossible for zsh to have built-in key bindings for ev-
ery situation. The zkbd utility, found in Functions/Misc, can help you quickly create key
bindings for your configuration.

Run zkbd either as an autoloaded function, or as a shell script:

zsh -f ~/zsh-5.8.1/Functions/Misc/zkbd

When you run zkbd, it first asks you to enter your terminal type; if the default it offers
is correct, just press return. It then asks you to press a number of different keys to
determine characteristics of your keyboard and terminal; zkbd warns you if it finds any-
thing out of the ordinary, such as a Delete key that sends neither ^H nor ^?.

The keystrokes read by zkbd are recorded as a definition for an associative array named
key, written to a file in the subdirectory .zkbd within either your HOME or ZDOTDIR direc-
tory. The name of the file is composed from the TERM, VENDOR and OSTYPE parameters,
joined by hyphens.

You may read this file into your .zshrc or another startup file with the `source' or `.'
commands, then reference the key parameter in bindkey commands, like this:

source ${ZDOTDIR:-$HOME}/.zkbd/$TERM-$VENDOR-$OSTYPE
[[ -n ${key[Left]} ]] && bindkey "${key[Left]}" backward-char
[[ -n ${key[Right]} ]] && bindkey "${key[Right]}" forward-char
# etc.

Note that in order for `autoload zkbd' to work, the zkdb file must be in one of the direc-
tories named in your fpath array (see zshparam(1)). This should already be the case if
you have a standard zsh installation; if it is not, copy Functions/Misc/zkbd to an appro-
priate directory.

Dumping Shell State
Occasionally you may encounter what appears to be a bug in the shell, particularly if you
are using a beta version of zsh or a development release. Usually it is sufficient to
send a description of the problem to one of the zsh mailing lists (see zsh(1)), but some-
times one of the zsh developers will need to recreate your environment in order to track
the problem down.

The script named reporter, found in the Util directory of the distribution, is provided
for this purpose. (It is also possible to autoload reporter, but reporter is not in-
stalled in fpath by default.) This script outputs a detailed dump of the shell state, in
the form of another script that can be read with `zsh -f' to recreate that state.

To use reporter, read the script into your shell with the `.' command and redirect the
output into a file:

. ~/zsh-5.8.1/Util/reporter > zsh.report

You should check the zsh.report file for any sensitive information such as passwords and
delete them by hand before sending the script to the developers. Also, as the output can
be voluminous, it's best to wait for the developers to ask for this information before
sending it.

You can also use reporter to dump only a subset of the shell state. This is sometimes
useful for creating startup files for the first time. Most of the output from reporter is
far more detailed than usually is necessary for a startup file, but the aliases, options,
and zstyles states may be useful because they include only changes from the defaults. The
bindings state may be useful if you have created any of your own keymaps, because reporter
arranges to dump the keymap creation commands as well as the bindings for every keymap.

As is usual with automated tools, if you create a startup file with reporter, you should
edit the results to remove unnecessary commands. Note that if you're using the new com-
pletion system, you should not dump the functions state to your startup files with re-
porter; use the compdump function instead (see zshcompsys(1)).

reporter [ state ... ]
Print to standard output the indicated subset of the current shell state. The
state arguments may be one or more of:

all Output everything listed below.
aliases
Output alias definitions.
bindings
Output ZLE key maps and bindings.
completion
Output old-style compctl commands. New completion is covered by functions
and zstyles.
functions
Output autoloads and function definitions.
limits Output limit commands.
options
Output setopt commands.
styles Same as zstyles.
variables
Output shell parameter assignments, plus export commands for any environment
variables.
zstyles
Output zstyle commands.

If the state is omitted, all is assumed.

With the exception of `all', every state can be abbreviated by any prefix, even a single
letter; thus a is the same as aliases, z is the same as zstyles, etc.

Manipulating Hook Functions
add-zsh-hook [ -L | -dD ] [ -Uzk ] hook function
Several functions are special to the shell, as described in the section SPECIAL
FUNCTIONS, see zshmisc(1), in that they are automatically called at specific points
during shell execution. Each has an associated array consisting of names of func-
tions to be called at the same point; these are so-called `hook functions'. The
shell function add-zsh-hook provides a simple way of adding or removing functions
from the array.

hook is one of chpwd, periodic, precmd, preexec, zshaddhistory, zshexit, or zsh_di-
rectory_name, the special functions in question. Note that zsh_directory_name is
called in a different way from the other functions, but may still be manipulated as
a hook.

function is name of an ordinary shell function. If no options are given this will
be added to the array of functions to be executed in the given context. Functions
are invoked in the order they were added.

If the option -L is given, the current values for the hook arrays are listed with
typeset.

If the option -d is given, the function is removed from the array of functions to
be executed.

If the option -D is given, the function is treated as a pattern and any matching
names of functions are removed from the array of functions to be executed.

The options -U, -z and -k are passed as arguments to autoload for function. For
functions contributed with zsh, the options -Uz are appropriate.

add-zle-hook-widget [ -L | -dD ] [ -Uzk ] hook widgetname
Several widget names are special to the line editor, as described in the section
Special Widgets, see zshzle(1), in that they are automatically called at specific
points during editing. Unlike function hooks, these do not use a predefined array
of other names to call at the same point; the shell function add-zle-hook-widget
maintains a similar array and arranges for the special widget to invoke those addi-
tional widgets.

hook is one of isearch-exit, isearch-update, line-pre-redraw, line-init, line-fin-
ish, history-line-set, or keymap-select, corresponding to each of the special wid-
gets zle-isearch-exit, etc. The special widget names are also accepted as the hook
argument.

widgetname is the name of a ZLE widget. If no options are given this is added to
the array of widgets to be invoked in the given hook context. Widgets are invoked
in the order they were added, with
zle widgetname -Nw -- "$@"

Note that this means that the `WIDGET' special parameter tracks the widgetname when
the widget function is called, rather than tracking the name of the corresponding
special hook widget.

If the option -d is given, the widgetname is removed from the array of widgets to
be executed.

If the option -D is given, the widgetname is treated as a pattern and any matching
names of widgets are removed from the array.

If widgetname does not name an existing widget when added to the array, it is as-
sumed that a shell function also named widgetname is meant to provide the implemen-
tation of the widget. This name is therefore marked for autoloading, and the op-
tions -U, -z and -k are passed as arguments to autoload as with add-zsh-hook. The
widget is also created with `zle -N widgetname' to cause the corresponding function
to be loaded the first time the hook is called.

The arrays of widgetname are currently maintained in zstyle contexts, one for each
hook context, with a style of `widgets'. If the -L option is given, this set of
styles is listed with `zstyle -L'. This implementation may change, and the special
widgets that refer to the styles are created only if add-zle-hook-widget is called
to add at least one widget, so if this function is used for any hooks, then all
hooks should be managed only via this function.

REMEMBERING RECENT DIRECTORIES
The function cdr allows you to change the working directory to a previous working direc-
tory from a list maintained automatically. It is similar in concept to the directory
stack controlled by the pushd, popd and dirs builtins, but is more configurable, and as it
stores all entries in files it is maintained across sessions and (by default) between ter-
minal emulators in the current session. Duplicates are automatically removed, so that the
list reflects the single most recent use of each directory.

Note that the pushd directory stack is not actually modified or used by cdr unless you
configure it to do so as described in the configuration section below.

Installation
The system works by means of a hook function that is called every time the directory
changes. To install the system, autoload the required functions and use the add-zsh-hook
function described above:

autoload -Uz chpwd_recent_dirs cdr add-zsh-hook
add-zsh-hook chpwd chpwd_recent_dirs

Now every time you change directly interactively, no matter which command you use, the di-
rectory to which you change will be remembered in most-recent-first order.

Use
All direct user interaction is via the cdr function.

The argument to cdr is a number N corresponding to the Nth most recently changed-to direc-
tory. 1 is the immediately preceding directory; the current directory is remembered but
is not offered as a destination. Note that if you have multiple windows open 1 may refer
to a directory changed to in another window; you can avoid this by having per-terminal
files for storing directory as described for the recent-dirs-file style below.

If you set the recent-dirs-default style described below cdr will behave the same as cd if
given a non-numeric argument, or more than one argument. The recent directory list is up-
dated just the same however you change directory.

If the argument is omitted, 1 is assumed. This is similar to pushd's behaviour of swap-
ping the two most recent directories on the stack.

Completion for the argument to cdr is available if compinit has been run; menu selection
is recommended, using:

zstyle ':completion:*:*:cdr:*:*' menu selection

to allow you to cycle through recent directories; the order is preserved, so the first
choice is the most recent directory before the current one. The verbose style is also
recommended to ensure the directory is shown; this style is on by default so no action is
required unless you have changed it.

Options
The behaviour of cdr may be modified by the following options.

-l lists the numbers and the corresponding directories in abbreviated form (i.e. with
~ substitution reapplied), one per line. The directories here are not quoted (this
would only be an issue if a directory name contained a newline). This is used by
the completion system.

-r sets the variable reply to the current set of directories. Nothing is printed and
the directory is not changed.

-e allows you to edit the list of directories, one per line. The list can be edited
to any extent you like; no sanity checking is performed. Completion is available.
No quoting is necessary (except for newlines, where I have in any case no sympa-
thy); directories are in unabbreviated from and contain an absolute path, i.e. they
start with /. Usually the first entry should be left as the current directory.

-p 'pattern'
Prunes any items in the directory list that match the given extended glob pattern;
the pattern needs to be quoted from immediate expansion on the command line. The
pattern is matched against each completely expanded file name in the list; the full
string must match, so wildcards at the end (e.g. '*removeme*') are needed to remove
entries with a given substring.

If output is to a terminal, then the function will print the new list after pruning
and prompt for confirmation by the user. This output and confirmation step can be
skipped by using -P instead of -p.

Configuration
Configuration is by means of the styles mechanism that should be familiar from completion;
if not, see the description of the zstyle command in see zshmodules(1). The context for
setting styles should be ':chpwd:*' in case the meaning of the context is extended in fu-
ture, for example:

zstyle ':chpwd:*' recent-dirs-max 0

sets the value of the recent-dirs-max style to 0. In practice the style name is specific
enough that a context of '*' should be fine.

An exception is recent-dirs-insert, which is used exclusively by the completion system and
so has the usual completion system context (':completion:*' if nothing more specific is
needed), though again '*' should be fine in practice.

recent-dirs-default
If true, and the command is expecting a recent directory index, and either there is
more than one argument or the argument is not an integer, then fall through to
"cd". This allows the lazy to use only one command for directory changing. Com-
pletion recognises this, too; see recent-dirs-insert for how to control completion
when this option is in use.

recent-dirs-file
The file where the list of directories is saved. The default is ${ZDOT-
DIR:-$HOME}/.chpwd-recent-dirs, i.e. this is in your home directory unless you have
set the variable ZDOTDIR to point somewhere else. Directory names are saved in
$'...' quoted form, so each line in the file can be supplied directly to the shell
as an argument.

The value of this style may be an array. In this case, the first file in the list
will always be used for saving directories while any other files are left un-
touched. When reading the recent directory list, if there are fewer than the maxi-
mum number of entries in the first file, the contents of later files in the array
will be appended with duplicates removed from the list shown. The contents of the
two files are not sorted together, i.e. all the entries in the first file are shown
first. The special value + can appear in the list to indicate the default file
should be read at that point. This allows effects like the following:

zstyle ':chpwd:*' recent-dirs-file \
~/.chpwd-recent-dirs-${TTY##*/} +

Recent directories are read from a file numbered according to the terminal. If
there are insufficient entries the list is supplemented from the default file.

It is possible to use zstyle -e to make the directory configurable at run time:

zstyle -e ':chpwd:*' recent-dirs-file pick-recent-dirs-file
pick-recent-dirs-file() {
if [[ $PWD = ~/text/writing(|/*) ]]; then
reply=(~/.chpwd-recent-dirs-writing)
else
reply=(+)
fi
}

In this example, if the current directory is ~/text/writing or a directory under
it, then use a special file for saving recent directories, else use the default.

recent-dirs-insert
Used by completion. If recent-dirs-default is true, then setting this to true
causes the actual directory, rather than its index, to be inserted on the command
line; this has the same effect as using the corresponding index, but makes the his-
tory clearer and the line easier to edit. With this setting, if part of an argu-
ment was already typed, normal directory completion rather than recent directory
completion is done; this is because recent directory completion is expected to be
done by cycling through entries menu fashion.

If the value of the style is always, then only recent directories will be com-
pleted; in that case, use the cd command when you want to complete other directo-
ries.

If the value is fallback, recent directories will be tried first, then normal di-
rectory completion is performed if recent directory completion failed to find a
match.

Finally, if the value is both then both sets of completions are presented; the
usual tag mechanism can be used to distinguish results, with recent directories
tagged as recent-dirs. Note that the recent directories inserted are abbreviated
with directory names where appropriate.

recent-dirs-max
The maximum number of directories to save to the file. If this is zero or negative
there is no maximum. The default is 20. Note this includes the current directory,
which isn't offered, so the highest number of directories you will be offered is
one less than the maximum.

recent-dirs-prune
This style is an array determining what directories should (or should not) be added
to the recent list. Elements of the array can include:

parent Prune parents (more accurately, ancestors) from the recent list. If
present, changing directly down by any number of directories causes the cur-
rent directory to be overwritten. For example, changing from ~pws to
~pws/some/other/dir causes ~pws not to be left on the recent directory
stack. This only applies to direct changes to descendant directories; ear-
lier directories on the list are not pruned. For example, changing from
~pws/yet/another to ~pws/some/other/dir does not cause ~pws to be pruned.

pattern:pattern
Gives a zsh pattern for directories that should not be added to the recent
list (if not already there). This element can be repeated to add different
patterns. For example, 'pattern:/tmp(|/*)' stops /tmp or its descendants
from being added. The EXTENDED_GLOB option is always turned on for these
patterns.

recent-dirs-pushd
If set to true, cdr will use pushd instead of cd to change the directory, so the
directory is saved on the directory stack. As the directory stack is completely
separate from the list of files saved by the mechanism used in this file there is
no obvious reason to do this.

Use with dynamic directory naming
It is possible to refer to recent directories using the dynamic directory name syntax by
using the supplied function zsh_directory_name_cdr a hook:

autoload -Uz add-zsh-hook
add-zsh-hook -Uz zsh_directory_name zsh_directory_name_cdr

When this is done, ~[1] will refer to the most recent directory other than $PWD, and so
on. Completion after ~[... also works.

Details of directory handling
This section is for the curious or confused; most users will not need to know this infor-
mation.

Recent directories are saved to a file immediately and hence are preserved across ses-
sions. Note currently no file locking is applied: the list is updated immediately on in-
teractive commands and nowhere else (unlike history), and it is assumed you are only going
to change directory in one window at once. This is not safe on shared accounts, but in
any case the system has limited utility when someone else is changing to a different set
of directories behind your back.

To make this a little safer, only directory changes instituted from the command line, ei-
ther directly or indirectly through shell function calls (but not through subshells,
evals, traps, completion functions and the like) are saved. Shell functions should use cd
-q or pushd -q to avoid side effects if the change to the directory is to be invisible at
the command line. See the contents of the function chpwd_recent_dirs for more details.

ABBREVIATED DYNAMIC REFERENCES TO DIRECTORIES
The dynamic directory naming system is described in the subsection Dynamic named directo-
ries of the section Filename Expansion in expn(1). In this, a reference to ~[...] is ex-
panded by a function found by the hooks mechanism.

The contributed function zsh_directory_name_generic provides a system allowing the user to
refer to directories with only a limited amount of new code. It supports all three of the
standard interfaces for directory naming: converting from a name to a directory, convert-
ing in the reverse direction to find a short name, and completion of names.

The main feature of this function is a path-like syntax, combining abbreviations at multi-
ple levels separated by ":". As an example, ~[g:p:s] might specify:
g The top level directory for your git area. This first component has to match, or
the function will return indicating another directory name hook function should be
tried.

p The name of a project within your git area.

s The source area within that project. This allows you to collapse references to
long hierarchies to a very compact form, particularly if the hierarchies are simi-
lar across different areas of the disk.

Name components may be completed: if a description is shown at the top of the list of com-
pletions, it includes the path to which previous components expand, while the description
for an individual completion shows the path segment it would add. No additional configu-
ration is needed for this as the completion system is aware of the dynamic directory name
mechanism.

Usage
To use the function, first define a wrapper function for your specific case. We'll assume
it's to be autoloaded. This can have any name but we'll refer to it as zdn_mywrapper.
This wrapper function will define various variables and then call this function with the
same arguments that the wrapper function gets. This configuration is described below.

Then arrange for the wrapper to be run as a zsh_directory_name hook:

autoload -Uz add-zsh-hook zsh_diretory_name_generic zdn_mywrapper
add-zsh-hook -U zsh_directory_name zdn_mywrapper

Configuration
The wrapper function should define a local associative array zdn_top. Alternatively, this
can be set with a style called mapping. The context for the style is :zdn:wrapper-name
where wrapper-name is the function calling zsh_directory_name_generic; for example:

zstyle :zdn:zdn_mywrapper: mapping zdn_mywrapper_top

The keys in this associative array correspond to the first component of the name. The
values are matching directories. They may have an optional suffix with a slash followed
by a colon and the name of a variable in the same format to give the next component. (The
slash before the colon is to disambiguate the case where a colon is needed in the path for
a drive. There is otherwise no syntax for escaping this, so path components whose names
start with a colon are not supported.) A special component :default: specifies a variable
in the form /:var (the path section is ignored and so is usually empty) that will be used
for the next component if no variable is given for the path. Variables referred to within
zdn_top have the same format as zdn_top itself, but contain relative paths.

For example,

local -A zdn_top=(
g ~/git
ga ~/alternate/git
gs /scratch/$USER/git/:second2
:default: /:second1
)

This specifies the behaviour of a directory referred to as ~[g:...] or ~[ga:...] or
~[gs:...]. Later path components are optional; in that case ~[g] expands to ~/git, and so
on. gs expands to /scratch/$USER/git and uses the associative array second2 to match the
second component; g and ga use the associative array second1 to match the second compo-
nent.

When expanding a name to a directory, if the first component is not g or ga or gs, it is
not an error; the function simply returns 1 so that a later hook function can be tried.
However, matching the first component commits the function, so if a later component does
not match, an error is printed (though this still does not stop later hooks from being ex-
ecuted).

For components after the first, a relative path is expected, but note that multiple levels
may still appear. Here is an example of second1:

local -A second1=(
p myproject
s somproject
os otherproject/subproject/:third
)

The path as found from zdn_top is extended with the matching directory, so ~[g:p] becomes
~/git/myproject. The slash between is added automatically (it's not possible to have a
later component modify the name of a directory already matched). Only os specifies a
variable for a third component, and there's no :default:, so it's an error to use a name
like ~[g:p:x] or ~[ga:s:y] because there's nowhere to look up the x or y.

The associative arrays need to be visible within this function; the generic function
therefore uses internal variable names beginning _zdn_ in order to avoid clashes. Note
that the variable reply needs to be passed back to the shell, so should not be local in
the calling function.

The function does not test whether directories assembled by component actually exist; this
allows the system to work across automounted file systems. The error from the command
trying to use a non-existent directory should be sufficient to indicate the problem.

Complete example
Here is a full fictitious but usable autoloadable definition of the example function de-
fined by the code above. So ~[gs:p:s] expands to /scratch/$USER/git/myscratchpro-
ject/top/srcdir (with $USER also expanded).

local -A zdn_top=(
g ~/git
ga ~/alternate/git
gs /scratch/$USER/git/:second2
:default: /:second1
)

local -A second1=(
p myproject
s somproject
os otherproject/subproject/:third
)

local -A second2=(
p myscratchproject
s somescratchproject
)

local -A third=(
s top/srcdir
d top/documentation
)

# autoload not needed if you did this at initialisation...
autoload -Uz zsh_directory_name_generic
zsh_directory_name_generic "$@

It is also possible to use global associative arrays, suitably named, and set the style
for the context of your wrapper function to refer to this. Then your set up code would
contain the following:

typeset -A zdn_mywrapper_top=(...)
# ... and so on for other associative arrays ...
zstyle ':zdn:zdn_mywrapper:' mapping zdn_mywrapper_top
autoload -Uz add-zsh-hook zsh_directory_name_generic zdn_mywrapper
add-zsh-hook -U zsh_directory_name zdn_mywrapper

and the function zdn_mywrapper would contain only the following:

zsh_directory_name_generic "$@"

GATHERING INFORMATION FROM VERSION CONTROL SYSTEMS
In a lot of cases, it is nice to automatically retrieve information from version control
systems (VCSs), such as subversion, CVS or git, to be able to provide it to the user; pos-
sibly in the user's prompt. So that you can instantly tell which branch you are currently
on, for example.

In order to do that, you may use the vcs_info function.

The following VCSs are supported, showing the abbreviated name by which they are referred
to within the system:
Bazaar (bzr)
https://bazaar.canonical.com/
Codeville (cdv)
http://freecode.com/projects/codeville/
Concurrent Versioning System (cvs)
https://www.nongnu.org/cvs/
Darcs (darcs)
http://darcs.net/
Fossil (fossil)
https://fossil-scm.org/
Git (git)
https://git-scm.com/
GNU arch (tla)
https://www.gnu.org/software/gnu-arch/
Mercurial (hg)
https://www.mercurial-scm.org/
Monotone (mtn)
https://monotone.ca/
Perforce (p4)
https://www.perforce.com/
Subversion (svn)
https://subversion.apache.org/
SVK (svk)
https://svk.bestpractical.com/

There is also support for the patch management system quilt (https://savan-
nah.nongnu.org/projects/quilt). See Quilt Support below for details.

To load vcs_info:

autoload -Uz vcs_info

It can be used in any existing prompt, because it does not require any specific $psvar en-
tries to be available.

Quickstart
To get this feature working quickly (including colors), you can do the following (assum-
ing, you loaded vcs_info properly - see above):

zstyle ':vcs_info:*' actionformats \
'%F{5}(%f%s%F{5})%F{3}-%F{5}[%F{2}%b%F{3}|%F{1}%a%F{5}]%f '
zstyle ':vcs_info:*' formats \
'%F{5}(%f%s%F{5})%F{3}-%F{5}[%F{2}%b%F{5}]%f '
zstyle ':vcs_info:(sv[nk]|bzr):*' branchformat '%b%F{1}:%F{3}%r'
precmd () { vcs_info }
PS1='%F{5}[%F{2}%n%F{5}] %F{3}%3~ ${vcs_info_msg_0_}%f%# '

Obviously, the last two lines are there for demonstration. You need to call vcs_info from
your precmd function. Once that is done you need a single quoted '${vcs_info_msg_0_}' in
your prompt.

To be able to use '${vcs_info_msg_0_}' directly in your prompt like this, you will need to
have the PROMPT_SUBST option enabled.

Now call the vcs_info_printsys utility from the command line:

% vcs_info_printsys
## list of supported version control backends:
## disabled systems are prefixed by a hash sign (#)
bzr
cdv
cvs
darcs
fossil
git
hg
mtn
p4
svk
svn
tla
## flavours (cannot be used in the enable or disable styles; they
## are enabled and disabled with their master [git-svn -> git])
## they *can* be used in contexts: ':vcs_info:git-svn:*'.
git-p4
git-svn
hg-git
hg-hgsubversion
hg-hgsvn

You may not want all of these because there is no point in running the code to detect sys-
tems you do not use. So there is a way to disable some backends altogether:

zstyle ':vcs_info:*' disable bzr cdv darcs mtn svk tla

You may also pick a few from that list and enable only those:

zstyle ':vcs_info:*' enable git cvs svn

If you rerun vcs_info_printsys after one of these commands, you will see the backends
listed in the disable style (or backends not in the enable style - if you used that)
marked as disabled by a hash sign. That means the detection of these systems is skipped
completely. No wasted time there.

Configuration
The vcs_info feature can be configured via zstyle.

First, the context in which we are working:
:vcs_info:vcs-string:user-context:repo-root-name

vcs-string
is one of: git, git-svn, git-p4, hg, hg-git, hg-hgsubversion, hg-hgsvn, darcs, bzr,
cdv, mtn, svn, cvs, svk, tla, p4 or fossil. This is followed by
`.quilt-quilt-mode' in Quilt mode (see Quilt Support for details) and by
`+hook-name' while hooks are active (see Hooks in vcs_info for details).

Currently, hooks in quilt mode don't add the `.quilt-quilt-mode' information. This
may change in the future.

user-context
is a freely configurable string, assignable by the user as the first argument to
vcs_info (see its description below).

repo-root-name
is the name of a repository in which you want a style to match. So, if you want a
setting specific to /usr/src/zsh, with that being a CVS checkout, you can set
repo-root-name to zsh to make it so.

There are three special values for vcs-string: The first is named -init-, that is in ef-
fect as long as there was no decision what VCS backend to use. The second is -preinit-; it
is used before vcs_info is run, when initializing the data exporting variables. The third
special value is formats and is used by the vcs_info_lastmsg for looking up its styles.

The initial value of repo-root-name is -all- and it is replaced with the actual name, as
soon as it is known. Only use this part of the context for defining the formats, action-
formats or branchformat styles, as it is guaranteed that repo-root-name is set up cor-
rectly for these only. For all other styles, just use '*' instead.

There are two pre-defined values for user-context:
default
the one used if none is specified
command
used by vcs_info_lastmsg to lookup its styles

You can of course use ':vcs_info:*' to match all VCSs in all user-contexts at once.

This is a description of all styles that are looked up.

formats
A list of formats, used when actionformats is not used (which is most of the time).

actionformats
A list of formats, used if there is a special action going on in your current
repository; like an interactive rebase or a merge conflict.

branchformat
Some backends replace %b in the formats and actionformats styles above, not only by
a branch name but also by a revision number. This style lets you modify how that
string should look.

nvcsformats
These "formats" are set when we didn't detect a version control system for the cur-
rent directory or vcs_info was disabled. This is useful if you want vcs_info to
completely take over the generation of your prompt. You would do something like
PS1='${vcs_info_msg_0_}' to accomplish that.

hgrevformat
hg uses both a hash and a revision number to reference a specific changeset in a
repository. With this style you can format the revision string (see branchformat)
to include either or both. It's only useful when get-revision is true. Note, the
full 40-character revision id is not available (except when using the use-simple
option) because executing hg more than once per prompt is too slow; you may custom-
ize this behavior using hooks.

max-exports
Defines the maximum number of vcs_info_msg_*_ variables vcs_info will set.

enable A list of backends you want to use. Checked in the -init- context. If this list
contains an item called NONE no backend is used at all and vcs_info will do noth-
ing. If this list contains ALL, vcs_info will use all known backends. Only with ALL
in enable will the disable style have any effect. ALL and NONE are case insensi-
tive.

disable
A list of VCSs you don't want vcs_info to test for repositories (checked in the
-init- context, too). Only used if enable contains ALL.

disable-patterns
A list of patterns that are checked against $PWD. If a pattern matches, vcs_info
will be disabled. This style is checked in the :vcs_info:-init-:*:-all- context.

Say, ~/.zsh is a directory under version control, in which you do not want vcs_info
to be active, do:
zstyle ':vcs_info:*' disable-patterns "${(b)HOME}/.zsh(|/*)"

use-quilt
If enabled, the quilt support code is active in `addon' mode. See Quilt Support
for details.

quilt-standalone
If enabled, `standalone' mode detection is attempted if no VCS is active in a given
directory. See Quilt Support for details.

quilt-patch-dir
Overwrite the value of the $QUILT_PATCHES environment variable. See Quilt Support
for details.

quiltcommand
When quilt itself is called in quilt support, the value of this style is used as
the command name.

check-for-changes
If enabled, this style causes the %c and %u format escapes to show when the working
directory has uncommitted changes. The strings displayed by these escapes can be
controlled via the stagedstr and unstagedstr styles. The only backends that cur-
rently support this option are git, hg, and bzr (the latter two only support un-
staged).

For this style to be evaluated with the hg backend, the get-revision style needs to
be set and the use-simple style needs to be unset. The latter is the default; the
former is not.

With the bzr backend, lightweight checkouts only honor this style if the use-server
style is set.

Note, the actions taken if this style is enabled are potentially expensive (read:
they may be slow, depending on how big the current repository is). Therefore, it
is disabled by default.

check-for-staged-changes
This style is like check-for-changes, but it never checks the worktree files, only
the metadata in the .${vcs} dir. Therefore, this style initializes only the %c es-
cape (with stagedstr) but not the %u escape. This style is faster than
check-for-changes.

In the git backend, this style checks for changes in the index. Other backends do
not currently implement this style.

This style is disabled by default.

stagedstr
This string will be used in the %c escape if there are staged changes in the repos-
itory.

unstagedstr
This string will be used in the %u escape if there are unstaged changes in the
repository.

command
This style causes vcs_info to use the supplied string as the command to use as the
VCS's binary. Note, that setting this in ':vcs_info:*' is not a good idea.

If the value of this style is empty (which is the default), the used binary name is
the name of the backend in use (e.g. svn is used in an svn repository).

The repo-root-name part in the context is always the default -all- when this style
is looked up.

For example, this style can be used to use binaries from non-default installation
directories. Assume, git is installed in /usr/bin but your sysadmin installed a
newer version in /usr/local/bin. Instead of changing the order of your $PATH param-
eter, you can do this:
zstyle ':vcs_info:git:*:-all-' command /usr/local/bin/git

use-server
This is used by the Perforce backend (p4) to decide if it should contact the Per-
force server to find out if a directory is managed by Perforce. This is the only
reliable way of doing this, but runs the risk of a delay if the server name cannot
be found. If the server (more specifically, the host:port pair describing the
server) cannot be contacted, its name is put into the associative array
vcs_info_p4_dead_servers and is not contacted again during the session until it is
removed by hand. If you do not set this style, the p4 backend is only usable if
you have set the environment variable P4CONFIG to a file name and have correspond-
ing files in the root directories of each Perforce client. See comments in the
function VCS_INFO_detect_p4 for more detail.

The Bazaar backend (bzr) uses this to permit contacting the server about light-
weight checkouts, see the check-for-changes style.

use-simple
If there are two different ways of gathering information, you can select the sim-
pler one by setting this style to true; the default is to use the not-that-simple
code, which is potentially a lot slower but might be more accurate in all possible
cases. This style is used by the bzr and hg backends. In the case of hg it will in-
voke the external hexdump program to parse the binary dirstate cache file; this
method will not return the local revision number.

get-revision
If set to true, vcs_info goes the extra mile to figure out the revision of a repos-
itory's work tree (currently for the git and hg backends, where this kind of infor-
mation is not always vital). For git, the hash value of the currently checked out
commit is available via the %i expansion. With hg, the local revision number and
the corresponding global hash are available via %i.

get-mq If set to true, the hg backend will look for a Mercurial Queue (mq) patch direc-
tory. Information will be available via the `%m' replacement.

get-bookmarks
If set to true, the hg backend will try to get a list of current bookmarks. They
will be available via the `%m' replacement.

The default is to generate a comma-separated list of all bookmark names that refer
to the currently checked out revision. If a bookmark is active, its name is suf-
fixed an asterisk and placed first in the list.

use-prompt-escapes
Determines if we assume that the assembled string from vcs_info includes prompt es-
capes. (Used by vcs_info_lastmsg.)

debug Enable debugging output to track possible problems. Currently this style is only
used by vcs_info's hooks system.

hooks A list style that defines hook-function names. See Hooks in vcs_info below for de-
tails.

patch-format
nopatch-format
This pair of styles format the patch information used by the %m expando in formats
and actionformats for the git and hg backends. The value is subject to certain
%-expansions described below. The expanded value is made available in the global
backend_misc array as ${backend_misc[patches]} (also if a set-patch-format hook is
used).

get-unapplied
This boolean style controls whether a backend should attempt to gather a list of
unapplied patches (for example with Mercurial Queue patches).

Used by the quilt and hg backends.

The default values for these styles in all contexts are:

formats
" (%s)-[%b]%u%c-"
actionformats
" (%s)-[%b|%a]%u%c-"
branchformat
"%b:%r" (for bzr, svn, svk and hg)
nvcsformats
""
hgrevformat
"%r:%h"
max-exports
2
enable ALL
disable
(empty list)
disable-patterns
(empty list)
check-for-changes
false
check-for-staged-changes
false
stagedstr
(string: "S")
unstagedstr
(string: "U")
command
(empty string)
use-server
false
use-simple
false
get-revision
false
get-mq true
get-bookmarks
false
use-prompt-escapes
true
debug false
hooks (empty list)
use-quilt
false
quilt-standalone
false
quilt-patch-dir
empty - use $QUILT_PATCHES
quiltcommand
quilt
patch-format
backend dependent
nopatch-format
backend dependent
get-unapplied
false

In normal formats and actionformats the following replacements are done:

%s The VCS in use (git, hg, svn, etc.).
%b Information about the current branch.
%a An identifier that describes the action. Only makes sense in actionformats.
%i The current revision number or identifier. For hg the hgrevformat style may be used
to customize the output.
%c The string from the stagedstr style if there are staged changes in the repository.
%u The string from the unstagedstr style if there are unstaged changes in the reposi-
tory.
%R The base directory of the repository.
%r The repository name. If %R is /foo/bar/repoXY, %r is repoXY.
%S A subdirectory within a repository. If $PWD is /foo/bar/repoXY/beer/tasty, %S is
beer/tasty.
%m A "misc" replacement. It is at the discretion of the backend to decide what this
replacement expands to.

The hg and git backends use this expando to display patch information. hg sources
patch information from the mq extensions; git from in-progress rebase and
cherry-pick operations and from the stgit extension. The patch-format and
nopatch-format styles control the generated string. The former is used when at
least one patch from the patch queue has been applied, and the latter otherwise.

The hg backend displays bookmark information in this expando (in addition to mq in-
formation). See the get-mq and get-bookmarks styles. Both of these styles may be
enabled at the same time. If both are enabled, both resulting strings will be
shown separated by a semicolon (that cannot currently be customized).

The quilt `standalone' backend sets this expando to the same value as the %Q ex-
pando.

%Q Quilt series information. When quilt is used (either in `addon' mode or as a
`standalone' backend), this expando is set to quilt series' patch-format string.
The set-patch-format hook and nopatch-format style are honoured.

See Quilt Support below for details.

In branchformat these replacements are done:

%b The branch name.
%r The current revision number or the hgrevformat style for hg.

In hgrevformat these replacements are done:

%r The current local revision number.
%h The current global revision identifier.

In patch-format and nopatch-format these replacements are done:

%p The name of the top-most applied patch; may be overridden by the applied-string
hook.
%u The number of unapplied patches; may be overridden by the unapplied-string hook.
%n The number of applied patches.
%c The number of unapplied patches.
%a The number of all patches (%a = %n + %c).
%g The names of active mq guards (hg backend).
%G The number of active mq guards (hg backend).

Not all VCS backends have to support all replacements. For nvcsformats no replacements are
performed at all, it is just a string.

Oddities
If you want to use the %b (bold off) prompt expansion in formats, which expands %b itself,
use %%b. That will cause the vcs_info expansion to replace %%b with %b, so that zsh's
prompt expansion mechanism can handle it. Similarly, to hand down %b from branchformat,
use %%%%b. Sorry for this inconvenience, but it cannot be easily avoided. Luckily we do
not clash with a lot of prompt expansions and this only needs to be done for those.

When one of the gen-applied-string, gen-unapplied-string, and set-patch-format hooks is
defined, applying %-escaping (`foo=${foo//'%'/%%}') to the interpolated values for use in
the prompt is the responsibility of those hooks (jointly); when neither of those hooks is
defined, vcs_info handles escaping by itself. We regret this coupling, but it was re-
quired for backwards compatibility.

Quilt Support
Quilt is not a version control system, therefore this is not implemented as a backend. It
can help keeping track of a series of patches. People use it to keep a set of changes they
want to use on top of software packages (which is tightly integrated into the package
build process - the Debian project does this for a large number of packages). Quilt can
also help individual developers keep track of their own patches on top of real version
control systems.

The vcs_info integration tries to support both ways of using quilt by having two slightly
different modes of operation: `addon' mode and `standalone' mode).

Quilt integration is off by default; to enable it, set the use-quilt style, and add %Q to
your formats or actionformats style:
zstyle ':vcs_info:*' use-quilt true

Styles looked up from the Quilt support code include `.quilt-quilt-mode' in the vcs-string
part of the context, where quilt-mode is either addon or standalone. Example:
:vcs_info:git.quilt-addon:default:repo-root-name.

For `addon' mode to become active vcs_info must have already detected a real version con-
trol system controlling the directory. If that is the case, a directory that holds quilt's
patches needs to be found. That directory is configurable via the `QUILT_PATCHES' environ-
ment variable. If that variable exists its value is used, otherwise the value `patches' is
assumed. The value from $QUILT_PATCHES can be overwritten using the `quilt-patches' style.
(Note: you can use vcs_info to keep the value of $QUILT_PATCHES correct all the time via
the post-quilt hook).

When the directory in question is found, quilt is assumed to be active. To gather more in-
formation, vcs_info looks for a directory called `.pc'; Quilt uses that directory to track
its current state. If this directory does not exist we know that quilt has not done any-
thing to the working directory (read: no patches have been applied yet).

If patches are applied, vcs_info will try to find out which. If you want to know which
patches of a series are not yet applied, you need to activate the get-unapplied style in
the appropriate context.

vcs_info allows for very detailed control over how the gathered information is presented
(see the Configuration and Hooks in vcs_info sections), all of which are documented below.
Note there are a number of other patch tracking systems that work on top of a certain ver-
sion control system (like stgit for git, or mq for hg); the configuration for systems like
that are generally configured the same way as the quilt support.

If the quilt support is working in `addon' mode, the produced string is available as a
simple format replacement (%Q to be precise), which can be used in formats and actionfor-
mats; see below for details).

If, on the other hand, the support code is working in `standalone' mode, vcs_info will
pretend as if quilt were an actual version control system. That means that the version
control system identifier (which otherwise would be something like `svn' or `cvs') will be
set to `-quilt-'. This has implications on the used style context where this identifier is
the second element. vcs_info will have filled in a proper value for the "repository's"
root directory and the string containing the information about quilt's state will be
available as the `misc' replacement (and %Q for compatibility with `addon' mode).

What is left to discuss is how `standalone' mode is detected. The detection itself is a
series of searches for directories. You can have this detection enabled all the time in
every directory that is not otherwise under version control. If you know there is only a
limited set of trees where you would like vcs_info to try and look for Quilt in `stand-
alone' mode to minimise the amount of searching on every call to vcs_info, there are a
number of ways to do that:

Essentially, `standalone' mode detection is controlled by a style called `quilt-stand-
alone'. It is a string style and its value can have different effects. The simplest values
are: `always' to run detection every time vcs_info is run, and `never' to turn the detec-
tion off entirely.

If the value of quilt-standalone is something else, it is interpreted differently. If the
value is the name of a scalar variable the value of that variable is checked and that
value is used in the same `always'/`never' way as described above.

If the value of quilt-standalone is an array, the elements of that array are used as di-
rectory names under which you want the detection to be active.

If quilt-standalone is an associative array, the keys are taken as directory names under
which you want the detection to be active, but only if the corresponding value is the
string `true'.

Last, but not least, if the value of quilt-standalone is the name of a function, the func-
tion is called without arguments and the return value decides whether detection should be
active. A `0' return value is true; a non-zero return value is interpreted as false.

Note, if there is both a function and a variable by the name of quilt-standalone, the
function will take precedence.

Function Descriptions (Public API)
vcs_info [user-context]
The main function, that runs all backends and assembles all data into
${vcs_info_msg_*_}. This is the function you want to call from precmd if you want
to include up-to-date information in your prompt (see Variable Description below).
If an argument is given, that string will be used instead of default in the
user-context field of the style context.

vcs_info_hookadd
Statically registers a number of functions to a given hook. The hook needs to be
given as the first argument; what follows is a list of hook-function names to reg-
ister to the hook. The `+vi-' prefix needs to be left out here. See Hooks in
vcs_info below for details.

vcs_info_hookdel
Remove hook-functions from a given hook. The hook needs to be given as the first
non-option argument; what follows is a list of hook-function names to un-register
from the hook. If `-a' is used as the first argument, all occurrences of the func-
tions are unregistered. Otherwise only the last occurrence is removed (if a func-
tion was registered to a hook more than once). The `+vi-' prefix needs to be left
out here. See Hooks in vcs_info below for details.

vcs_info_lastmsg
Outputs the last ${vcs_info_msg_*_} value. Takes into account the value of the
use-prompt-escapes style in ':vcs_info:formats:command:-all-'. It also only prints
max-exports values.

vcs_info_printsys [user-context]
Prints a list of all supported version control systems. Useful to find out possible
contexts (and which of them are enabled) or values for the disable style.

vcs_info_setsys
Initializes vcs_info's internal list of available backends. With this function, you
can add support for new VCSs without restarting the shell.

All functions named VCS_INFO_* are for internal use only.

Variable Description
${vcs_info_msg_N_} (Note the trailing underscore)
Where N is an integer, e.g., vcs_info_msg_0_. These variables are the storage for
the informational message the last vcs_info call has assembled. These are strongly
connected to the formats, actionformats and nvcsformats styles described above.
Those styles are lists. The first member of that list gets expanded into
${vcs_info_msg_0_}, the second into ${vcs_info_msg_1_} and the Nth into
${vcs_info_msg_N-1_}. (See the max-exports style above.)

All variables named VCS_INFO_* are for internal use only.

Hooks in vcs_info
Hooks are places in vcs_info where you can run your own code. That code can communicate
with the code that called it and through that, change the system's behaviour.

For configuration, hooks change the style context:
:vcs_info:vcs-string+hook-name:user-context:repo-root-name

To register functions to a hook, you need to list them in the hooks style in the appropri-
ate context.

Example:
zstyle ':vcs_info:*+foo:*' hooks bar baz

This registers functions to the hook `foo' for all backends. In order to avoid namespace
problems, all registered function names are prepended by a `+vi-', so the actual functions
called for the `foo' hook are `+vi-bar' and `+vi-baz'.

If you would like to register a function to a hook regardless of the current context, you
may use the vcs_info_hookadd function. To remove a function that was added like that, the
vcs_info_hookdel function can be used.

If something seems weird, you can enable the `debug' boolean style in the proper context
and the hook-calling code will print what it tried to execute and whether the function in
question existed.

When you register more than one function to a hook, all functions are executed one after
another until one function returns non-zero or until all functions have been called. Con-
text-sensitive hook functions are executed before statically registered ones (the ones
added by vcs_info_hookadd).

You may pass data between functions via an associative array, user_data. For example:
+vi-git-myfirsthook(){
user_data[myval]=$myval
}
+vi-git-mysecondhook(){
# do something with ${user_data[myval]}
}

There are a number of variables that are special in hook contexts:

ret The return value that the hooks system will return to the caller. The default is an
integer `zero'. If and how a changed ret value changes the execution of the caller
depends on the specific hook. See the hook documentation below for details.

hook_com
An associated array which is used for bidirectional communication from the caller
to hook functions. The used keys depend on the specific hook.

context
The active context of the hook. Functions that wish to change this variable should
make it local scope first.

vcs The current VCS after it was detected. The same values as in the enable/disable
style are used. Available in all hooks except start-up.

Finally, the full list of currently available hooks:

start-up
Called after starting vcs_info but before the VCS in this directory is determined.
It can be used to deactivate vcs_info temporarily if necessary. When ret is set to
1, vcs_info aborts and does nothing; when set to 2, vcs_info sets up everything as
if no version control were active and exits.

pre-get-data
Same as start-up but after the VCS was detected.

gen-hg-bookmark-string
Called in the Mercurial backend when a bookmark string is generated; the get-revi-
sion and get-bookmarks styles must be true.

This hook gets the names of the Mercurial bookmarks that vcs_info collected from
`hg'.

If a bookmark is active, the key ${hook_com[hg-active-bookmark]} is set to its
name. The key is otherwise unset.

When setting ret to non-zero, the string in ${hook_com[hg-bookmark-string]} will be
used in the %m escape in formats and actionformats and will be available in the
global backend_misc array as ${backend_misc[bookmarks]}.

gen-applied-string
Called in the git (with stgit or during rebase or merge), and hg (with mq) backends
and in quilt support when the applied-string is generated; the use-quilt zstyle
must be true for quilt (the mq and stgit backends are active by default).

This hook gets the names of all applied patches which vcs_info collected so far in
the opposite order, which means that the first argument is the top-most patch and
so forth.

When setting ret to non-zero, the string in ${hook_com[applied-string]} will be
available as %p in the patch-format and nopatch-format styles. This hook is, in
concert with set-patch-format, responsible for %-escaping that value for use in the
prompt. (See the Oddities section.)

gen-unapplied-string
Called in the git (with stgit or during rebase), and hg (with mq) backend and in
quilt support when the unapplied-string is generated; the get-unapplied style must
be true.

This hook gets the names of all unapplied patches which vcs_info collected so far
in order, which means that the first argument is the patch next-in-line to be ap-
plied and so forth.

When setting ret to non-zero, the string in ${hook_com[unapplied-string]} will be
available as %u in the patch-format and nopatch-format styles. This hook is, in
concert with set-patch-format, responsible for %-escaping that value for use in the
prompt. (See the Oddities section.)

gen-mqguards-string
Called in the hg backend when guards-string is generated; the get-mq style must be
true (default).

This hook gets the names of any active mq guards.

When setting ret to non-zero, the string in ${hook_com[guards-string]} will be used
in the %g escape in the patch-format and nopatch-format styles.

no-vcs This hooks is called when no version control system was detected.

The `hook_com' parameter is not used.

post-backend
Called as soon as the backend has finished collecting information.

The `hook_com' keys available are as for the set-message hook.

post-quilt
Called after the quilt support is done. The following information is passed as ar-
guments to the hook: 1. the quilt-support mode (`addon' or `standalone'); 2. the
directory that contains the patch series; 3. the directory that holds quilt's sta-
tus information (the `.pc' directory) or the string "-nopc-" if that directory
wasn't found.

The `hook_com' parameter is not used.

set-branch-format
Called before `branchformat' is set. The only argument to the hook is the format
that is configured at this point.

The `hook_com' keys considered are `branch' and `revision'. They are set to the
values figured out so far by vcs_info and any change will be used directly when the
actual replacement is done.

If ret is set to non-zero, the string in ${hook_com[branch-replace]} will be used
unchanged as the `%b' replacement in the variables set by vcs_info.

set-hgrev-format
Called before a `hgrevformat' is set. The only argument to the hook is the format
that is configured at this point.

The `hook_com' keys considered are `hash' and `localrev'. They are set to the val-
ues figured out so far by vcs_info and any change will be used directly when the
actual replacement is done.

If ret is set to non-zero, the string in ${hook_com[rev-replace]} will be used un-
changed as the `%i' replacement in the variables set by vcs_info.

pre-addon-quilt
This hook is used when vcs_info's quilt functionality is active in "addon" mode
(quilt used on top of a real version control system). It is activated right before
any quilt specific action is taken.

Setting the `ret' variable in this hook to a non-zero value avoids any quilt spe-
cific actions from being run at all.

set-patch-format
This hook is used to control some of the possible expansions in patch-format and
nopatch-format styles with patch queue systems such as quilt, mqueue and the like.

This hook is used in the git, hg and quilt backends.

The hook allows the control of the %p (${hook_com[applied]}) and %u (${hook_com[un-
applied]}) expansion in all backends that use the hook. With the mercurial backend,
the %g (${hook_com[guards]}) expansion is controllable in addition to that.

If ret is set to non-zero, the string in ${hook_com[patch-replace]} will be used
unchanged instead of an expanded format from patch-format or nopatch-format.

This hook is, in concert with the gen-applied-string or gen-unapplied-string hooks
if they are defined, responsible for %-escaping the final patch-format value for
use in the prompt. (See the Oddities section.)

set-message
Called each time before a `vcs_info_msg_N_' message is set. It takes two argu-
ments; the first being the `N' in the message variable name, the second is the cur-
rently configured formats or actionformats.

There are a number of `hook_com' keys, that are used here: `action', `branch',
`base', `base-name', `subdir', `staged', `unstaged', `revision', `misc', `vcs' and
one `miscN' entry for each backend-specific data field (N starting at zero). They
are set to the values figured out so far by vcs_info and any change will be used
directly when the actual replacement is done.

Since this hook is triggered multiple times (once for each configured formats or
actionformats), each of the `hook_com' keys mentioned above (except for the miscN
entries) has an `_orig' counterpart, so even if you changed a value to your liking
you can still get the original value in the next run. Changing the `_orig' values
is probably not a good idea.

If ret is set to non-zero, the string in ${hook_com[message]} will be used un-
changed as the message by vcs_info.

If all of this sounds rather confusing, take a look at the Examples section below and also
in the Misc/vcs_info-examples file in the Zsh source. They contain some explanatory code.

Examples
Don't use vcs_info at all (even though it's in your prompt):
zstyle ':vcs_info:*' enable NONE

Disable the backends for bzr and svk:
zstyle ':vcs_info:*' disable bzr svk

Disable everything but bzr and svk:
zstyle ':vcs_info:*' enable bzr svk

Provide a special formats for git:
zstyle ':vcs_info:git:*' formats ' GIT, BABY! [%b]'
zstyle ':vcs_info:git:*' actionformats ' GIT ACTION! [%b|%a]'

All %x expansion in all sorts of formats (formats, actionformats, branchformat, you name
it) are done using the `zformat' builtin from the `zsh/zutil' module. That means you can
do everything with these %x items what zformat supports. In particular, if you want some-
thing that is really long to have a fixed width, like a hash in a mercurial branchformat,
you can do this: %12.12i. That'll shrink the 40 character hash to its 12 leading charac-
ters. The form is actually `%min.maxx'. More is possible. See the section `The zsh/zutil
Module' in zshmodules(1) for details.

Use the quicker bzr backend
zstyle ':vcs_info:bzr:*' use-simple true

If you do use use-simple, please report if it does `the-right-thing[tm]'.

Display the revision number in yellow for bzr and svn:
zstyle ':vcs_info:(svn|bzr):*' \
branchformat '%b%{'${fg[yellow]}'%}:%r'

If you want colors, make sure you enclose the color codes in %{...%} if you want to use
the string provided by vcs_info in prompts.

Here is how to print the VCS information as a command (not in a prompt):
alias vcsi='vcs_info command; vcs_info_lastmsg'

This way, you can even define different formats for output via vcs_info_lastmsg in the
':vcs_info:*:command:*' namespace.

Now as promised, some code that uses hooks: say, you'd like to replace the string `svn' by
`subversion' in vcs_info's %s formats replacement.

First, we will tell vcs_info to call a function when populating the message variables with
the gathered information:
zstyle ':vcs_info:*+set-message:*' hooks svn2subversion

Nothing happens. Which is reasonable, since we didn't define the actual function yet. To
see what the hooks subsystem is trying to do, enable the `debug' style:
zstyle ':vcs_info:*+*:*' debug true

That should give you an idea what is going on. Specifically, the function that we are
looking for is `+vi-svn2subversion'. Note, the `+vi-' prefix. So, everything is in order,
just as documented. When you are done checking out the debugging output, disable it again:
zstyle ':vcs_info:*+*:*' debug false

Now, let's define the function:
function +vi-svn2subversion() {
[[ ${hook_com[vcs_orig]} == svn ]] && hook_com[vcs]=subversion
}

Simple enough. And it could have even been simpler, if only we had registered our function
in a less generic context. If we do it only in the `svn' backend's context, we don't need
to test which the active backend is:
zstyle ':vcs_info:svn+set-message:*' hooks svn2subversion
function +vi-svn2subversion() {
hook_com[vcs]=subversion
}

And finally a little more elaborate example, that uses a hook to create a customised book-
mark string for the hg backend.

Again, we start off by registering a function:
zstyle ':vcs_info:hg+gen-hg-bookmark-string:*' hooks hgbookmarks

And then we define the `+vi-hgbookmarks' function:
function +vi-hgbookmarks() {
# The default is to connect all bookmark names by
# commas. This mixes things up a little.
# Imagine, there's one type of bookmarks that is
# special to you. Say, because it's *your* work.
# Those bookmarks look always like this: "sh/*"
# (because your initials are sh, for example).
# This makes the bookmarks string use only those
# bookmarks. If there's more than one, it
# concatenates them using commas.
# The bookmarks returned by `hg' are available in
# the function's positional parameters.
local s="${(Mj:,:)@:#sh/*}"
# Now, the communication with the code that calls
# the hook functions is done via the hook_com[]
# hash. The key at which the `gen-hg-bookmark-string'
# hook looks is `hg-bookmark-string'. So:
hook_com[hg-bookmark-string]=$s
# And to signal that we want to use the string we
# just generated, set the special variable `ret' to
# something other than the default zero:
ret=1
return 0
}

Some longer examples and code snippets which might be useful are available in the examples
file located at Misc/vcs_info-examples in the Zsh source directory.

This concludes our guided tour through zsh's vcs_info.

PROMPT THEMES
Installation
You should make sure all the functions from the Functions/Prompts directory of the source
distribution are available; they all begin with the string `prompt_' except for the spe-
cial function`promptinit'. You also need the `colors' and `add-zsh-hook' functions from
Functions/Misc. All these functions may already be installed on your system; if not, you
will need to find them and copy them. The directory should appear as one of the elements
of the fpath array (this should already be the case if they were installed), and at least
the function promptinit should be autoloaded; it will autoload the rest. Finally, to ini-
tialize the use of the system you need to call the promptinit function. The following
code in your .zshrc will arrange for this; assume the functions are stored in the direc-
tory ~/myfns:

fpath=(~/myfns $fpath)
autoload -U promptinit
promptinit

Theme Selection
Use the prompt command to select your preferred theme. This command may be added to your
.zshrc following the call to promptinit in order to start zsh with a theme already se-
lected.

prompt [ -c | -l ]
prompt [ -p | -h ] [ theme ... ]
prompt [ -s ] theme [ arg ... ]
Set or examine the prompt theme. With no options and a theme argument, the theme
with that name is set as the current theme. The available themes are determined at
run time; use the -l option to see a list. The special theme `random' selects at
random one of the available themes and sets your prompt to that.

In some cases the theme may be modified by one or more arguments, which should be
given after the theme name. See the help for each theme for descriptions of these
arguments.

Options are:

-c Show the currently selected theme and its parameters, if any.
-l List all available prompt themes.
-p Preview the theme named by theme, or all themes if no theme is given.
-h Show help for the theme named by theme, or for the prompt function if no
theme is given.
-s Set theme as the current theme and save state.

prompt_theme_setup
Each available theme has a setup function which is called by the prompt function to
install that theme. This function may define other functions as necessary to main-
tain the prompt, including functions used to preview the prompt or provide help for
its use. You should not normally call a theme's setup function directly.

Utility Themes
prompt off
The theme `off' sets all the prompt variables to minimal values with no special ef-
fects.

prompt default
The theme `default' sets all prompt variables to the same state as if an interac-
tive zsh was started with no initialization files.

prompt restore
The special theme `restore' erases all theme settings and sets prompt variables to
their state before the first time the `prompt' function was run, provided each
theme has properly defined its cleanup (see below).

Note that you can undo `prompt off' and `prompt default' with `prompt restore', but
a second restore does not undo the first.

Writing Themes
The first step for adding your own theme is to choose a name for it, and create a file
`prompt_name_setup' in a directory in your fpath, such as ~/myfns in the example above.
The file should at minimum contain assignments for the prompt variables that your theme
wishes to modify. By convention, themes use PS1, PS2, RPS1, etc., rather than the longer
PROMPT and RPROMPT.

The file is autoloaded as a function in the current shell context, so it may contain any
necessary commands to customize your theme, including defining additional functions. To
make some complex tasks easier, your setup function may also do any of the following:

Assign prompt_opts
The array prompt_opts may be assigned any of "bang", "cr", "percent", "sp", and/or
"subst" as values. The corresponding setopts (promptbang, etc.) are turned on, all
other prompt-related options are turned off. The prompt_opts array preserves se-
topts even beyond the scope of localoptions, should your function need that.

Modify precmd and preexec
Use of add-zsh-hook is recommended. The precmd and preexec hooks are automatically
adjusted if the prompt theme changes or is disabled.

Declare cleanup
If your function makes any other changes that should be undone when the theme is
disabled, your setup function may call
prompt_cleanup command
where command should be suitably quoted. If your theme is ever disabled or replaced by
another, command is executed with eval. You may declare more than one such cleanup hook.

Define preview
Define or autoload a function prompt_name_preview to display a simulated version of
your prompt. A simple default previewer is defined by promptinit for themes that
do not define their own. This preview function is called by `prompt -p'.

Provide help
Define or autoload a function prompt_name_help to display documentation or help
text for your theme. This help function is called by `prompt -h'.

ZLE FUNCTIONS
Widgets
These functions all implement user-defined ZLE widgets (see zshzle(1)) which can be bound
to keystrokes in interactive shells. To use them, your .zshrc should contain lines of the
form

autoload function
zle -N function

followed by an appropriate bindkey command to associate the function with a key sequence.
Suggested bindings are described below.

bash-style word functions
If you are looking for functions to implement moving over and editing words in the
manner of bash, where only alphanumeric characters are considered word characters,
you can use the functions described in the next section. The following is suffi-
cient:

autoload -U select-word-style
select-word-style bash

forward-word-match, backward-word-match
kill-word-match, backward-kill-word-match
transpose-words-match, capitalize-word-match
up-case-word-match, down-case-word-match
delete-whole-word-match, select-word-match
select-word-style, match-word-context, match-words-by-style
The first eight `-match' functions are drop-in replacements for the builtin widgets
without the suffix. By default they behave in a similar way. However, by the use
of styles and the function select-word-style, the way words are matched can be al-
tered. select-word-match is intended to be used as a text object in vi mode but
with custom word styles. For comparison, the widgets described in zshzle(1) under
Text Objects use fixed definitions of words, compatible with the vim editor.

The simplest way of configuring the functions is to use select-word-style, which
can either be called as a normal function with the appropriate argument, or invoked
as a user-defined widget that will prompt for the first character of the word style
to be used. The first time it is invoked, the first eight -match functions will
automatically replace the builtin versions, so they do not need to be loaded ex-
plicitly.

The word styles available are as follows. Only the first character is examined.

bash Word characters are alphanumeric characters only.

normal As in normal shell operation: word characters are alphanumeric characters
plus any characters present in the string given by the parameter $WORDCHARS.

shell Words are complete shell command arguments, possibly including complete
quoted strings, or any tokens special to the shell.

whitespace
Words are any set of characters delimited by whitespace.

default
Restore the default settings; this is usually the same as `normal'.

All but `default' can be input as an upper case character, which has the same ef-
fect but with subword matching turned on. In this case, words with upper case
characters are treated specially: each separate run of upper case characters, or an
upper case character followed by any number of other characters, is considered a
word. The style subword-range can supply an alternative character range to the de-
fault `[:upper:]'; the value of the style is treated as the contents of a `[...]'
pattern (note that the outer brackets should not be supplied, only those surround-
ing named ranges).

More control can be obtained using the zstyle command, as described in zshmod-
ules(1). Each style is looked up in the context :zle:widget where widget is the
name of the user-defined widget, not the name of the function implementing it, so
in the case of the definitions supplied by select-word-style the appropriate con-
texts are :zle:forward-word, and so on. The function select-word-style itself al-
ways defines styles for the context `:zle:*' which can be overridden by more spe-
cific (longer) patterns as well as explicit contexts.

The style word-style specifies the rules to use. This may have the following val-
ues.

normal Use the standard shell rules, i.e. alphanumerics and $WORDCHARS, unless
overridden by the styles word-chars or word-class.

specified
Similar to normal, but only the specified characters, and not also alphanu-
merics, are considered word characters.

unspecified
The negation of specified. The given characters are those which will not be
considered part of a word.

shell Words are obtained by using the syntactic rules for generating shell command
arguments. In addition, special tokens which are never command arguments
such as `()' are also treated as words.

whitespace
Words are whitespace-delimited strings of characters.

The first three of those rules usually use $WORDCHARS, but the value in the parame-
ter can be overridden by the style word-chars, which works in exactly the same way
as $WORDCHARS. In addition, the style word-class uses character class syntax to
group characters and takes precedence over word-chars if both are set. The
word-class style does not include the surrounding brackets of the character class;
for example, `-:[:alnum:]' is a valid word-class to include all alphanumerics plus
the characters `-' and `:'. Be careful including `]', `^' and `-' as these are
special inside character classes.

word-style may also have `-subword' appended to its value to turn on subword match-
ing, as described above.

The style skip-chars is mostly useful for transpose-words and similar functions.
If set, it gives a count of characters starting at the cursor position which will
not be considered part of the word and are treated as space, regardless of what
they actually are. For example, if

zstyle ':zle:transpose-words' skip-chars 1

has been set, and transpose-words-match is called with the cursor on the X of
fooXbar, where X can be any character, then the resulting expression is barXfoo.

Finer grained control can be obtained by setting the style word-context to an array
of pairs of entries. Each pair of entries consists of a pattern and a subcontext.
The shell argument the cursor is on is matched against each pattern in turn until
one matches; if it does, the context is extended by a colon and the corresponding
subcontext. Note that the test is made against the original word on the line, with
no stripping of quotes. Special handling is done between words: the current con-
text is examined and if it contains the string between the word is set to a single
space; else if it is contains the string back, the word before the cursor is con-
sidered, else the word after cursor is considered. Some examples are given below.

The style skip-whitespace-first is only used with the forward-word widget. If it
is set to true, then forward-word skips any non-word-characters, followed by any
non-word-characters: this is similar to the behaviour of other word-orientated wid-
gets, and also that used by other editors, however it differs from the standard zsh
behaviour. When using select-word-style the widget is set in the context :zle:* to
true if the word style is bash and false otherwise. It may be overridden by set-
ting it in the more specific context :zle:forward-word*.

It is possible to create widgets with specific behaviour by defining a new widget
implemented by the appropriate generic function, then setting a style for the con-
text of the specific widget. For example, the following defines a widget back-
ward-kill-space-word using backward-kill-word-match, the generic widget implement-
ing backward-kill-word behaviour, and ensures that the new widget always implements
space-delimited behaviour.

zle -N backward-kill-space-word backward-kill-word-match
zstyle :zle:backward-kill-space-word word-style space

The widget backward-kill-space-word can now be bound to a key.

Here are some further examples of use of the styles, actually taken from the sim-
plified interface in select-word-style:

zstyle ':zle:*' word-style standard
zstyle ':zle:*' word-chars ''

Implements bash-style word handling for all widgets, i.e. only alphanumerics are
word characters; equivalent to setting the parameter WORDCHARS empty for the given
context.

style ':zle:*kill*' word-style space

Uses space-delimited words for widgets with the word `kill' in the name. Neither
of the styles word-chars nor word-class is used in this case.

Here are some examples of use of the word-context style to extend the context.

zstyle ':zle:*' word-context \
"*/*" filename "[[:space:]]" whitespace
zstyle ':zle:transpose-words:whitespace' word-style shell
zstyle ':zle:transpose-words:filename' word-style normal
zstyle ':zle:transpose-words:filename' word-chars ''

This provides two different ways of using transpose-words depending on whether the
cursor is on whitespace between words or on a filename, here any word containing a
/. On whitespace, complete arguments as defined by standard shell rules will be
transposed. In a filename, only alphanumerics will be transposed. Elsewhere,
words will be transposed using the default style for :zle:transpose-words.

The word matching and all the handling of zstyle settings is actually implemented
by the function match-words-by-style. This can be used to create new user-defined
widgets. The calling function should set the local parameter curcontext to
:zle:widget, create the local parameter matched_words and call match-words-by-style
with no arguments. On return, matched_words will be set to an array with the ele-
ments: (1) the start of the line (2) the word before the cursor (3) any non-word
characters between that word and the cursor (4) any non-word character at the cur-
sor position plus any remaining non-word characters before the next word, including
all characters specified by the skip-chars style, (5) the word at or following the
cursor (6) any non-word characters following that word (7) the remainder of the
line. Any of the elements may be an empty string; the calling function should test
for this to decide whether it can perform its function.

If the variable matched_words is defined by the caller to match-words-by-style as
an associative array (local -A matched_words), then the seven values given above
should be retrieved from it as elements named start, word-before-cursor, ws-be-
fore-cursor, ws-after-cursor, word-after-cursor, ws-after-word, and end. In addi-
tion the element is-word-start is 1 if the cursor is on the start of a word or sub-
word, or on white space before it (the cases can be distinguished by testing the
ws-after-cursor element) and 0 otherwise. This form is recommended for future com-
patibility.

It is possible to pass options with arguments to match-words-by-style to override
the use of styles. The options are:
-w word-style
-s skip-chars
-c word-class
-C word-chars
-r subword-range

For example, match-words-by-style -w shell -c 0 may be used to extract the command
argument around the cursor.

The word-context style is implemented by the function match-word-context. This
should not usually need to be called directly.

bracketed-paste-magic
The bracketed-paste widget (see subsection Miscellaneous in zshzle(1)) inserts
pasted text literally into the editor buffer rather than interpret it as key-
strokes. This disables some common usages where the self-insert widget is replaced
in order to accomplish some extra processing. An example is the contributed
url-quote-magic widget described below.

The bracketed-paste-magic widget is meant to replace bracketed-paste with a wrapper
that re-enables these self-insert actions, and other actions as selected by
zstyles. Therefore this widget is installed with

autoload -Uz bracketed-paste-magic
zle -N bracketed-paste bracketed-paste-magic

Other than enabling some widget processing, bracketed-paste-magic attempts to
replicate bracketed-paste as faithfully as possible.

The following zstyles may be set to control processing of pasted text. All are
looked up in the context `:bracketed-paste-magic'.

active-widgets
A list of patterns matching widget names that should be activated during the
paste. All other key sequences are processed as self-insert-unmeta. The
default is `self-*' so any user-defined widgets named with that prefix are
active along with the builtin self-insert.

If this style is not set (explicitly deleted) or set to an empty value, no
widgets are active and the pasted text is inserted literally. If the value
includes `undefined-key', any unknown sequences are discarded from the
pasted text.

inactive-keys
The inverse of active-widgets, a list of key sequences that always use
self-insert-unmeta even when bound to an active widget. Note that this is a
list of literal key sequences, not patterns.

paste-init
A list of function names, called in widget context (but not as widgets).
The functions are called in order until one of them returns a non-zero sta-
tus. The parameter `PASTED' contains the initial state of the pasted text.
All other ZLE parameters such as `BUFFER' have their normal values and
side-effects, and full history is available, so for example paste-init func-
tions may move words from BUFFER into PASTED to make those words visible to
the active-widgets.

A non-zero return from a paste-init function does not prevent the paste it-
self from proceeding.

Loading bracketed-paste-magic defines backward-extend-paste, a helper func-
tion for use in paste-init.

zstyle :bracketed-paste-magic paste-init \
backward-extend-paste

When a paste would insert into the middle of a word or append text to a word
already on the line, backward-extend-paste moves the prefix from LBUFFER
into PASTED so that the active-widgets see the full word so far. This may
be useful with url-quote-magic.

paste-finish
Another list of function names called in order until one returns non-zero.
These functions are called after the pasted text has been processed by the
active-widgets, but before it is inserted into `BUFFER'. ZLE parameters
have their normal values and side-effects.

A non-zero return from a paste-finish function does not prevent the paste
itself from proceeding.

Loading bracketed-paste-magic also defines quote-paste, a helper function
for use in paste-finish.

zstyle :bracketed-paste-magic paste-finish \
quote-paste
zstyle :bracketed-paste-magic:finish quote-style \
qqq

When the pasted text is inserted into BUFFER, it is quoted per the
quote-style value. To forcibly turn off the built-in numeric prefix quoting
of bracketed-paste, use:

zstyle :bracketed-paste-magic:finish quote-style \
none

Important: During active-widgets processing of the paste (after paste-init and be-
fore paste-finish), BUFFER starts empty and history is restricted, so cursor mo-
tions, etc., may not pass outside of the pasted content. Text assigned to BUFFER
by the active widgets is copied back into PASTED before paste-finish.

copy-earlier-word
This widget works like a combination of insert-last-word and copy-prev-shell-word.
Repeated invocations of the widget retrieve earlier words on the relevant history
line. With a numeric argument N, insert the Nth word from the history line; N may
be negative to count from the end of the line.

If insert-last-word has been used to retrieve the last word on a previous history
line, repeated invocations will replace that word with earlier words from the same
line.

Otherwise, the widget applies to words on the line currently being edited. The
widget style can be set to the name of another widget that should be called to re-
trieve words. This widget must accept the same three arguments as in-
sert-last-word.

cycle-completion-positions
After inserting an unambiguous string into the command line, the new function based
completion system may know about multiple places in this string where characters
are missing or differ from at least one of the possible matches. It will then
place the cursor on the position it considers to be the most interesting one, i.e.
the one where one can disambiguate between as many matches as possible with as lit-
tle typing as possible.

This widget allows the cursor to be easily moved to the other interesting spots.
It can be invoked repeatedly to cycle between all positions reported by the comple-
tion system.

delete-whole-word-match
This is another function which works like the -match functions described immedi-
ately above, i.e. using styles to decide the word boundaries. However, it is not a
replacement for any existing function.

The basic behaviour is to delete the word around the cursor. There is no numeric
argument handling; only the single word around the cursor is considered. If the
widget contains the string kill, the removed text will be placed in the cutbuffer
for future yanking. This can be obtained by defining kill-whole-word-match as fol-
lows:

zle -N kill-whole-word-match delete-whole-word-match

and then binding the widget kill-whole-word-match.

up-line-or-beginning-search, down-line-or-beginning-search
These widgets are similar to the builtin functions up-line-or-search and
down-line-or-search: if in a multiline buffer they move up or down within the buf-
fer, otherwise they search for a history line matching the start of the current
line. In this case, however, they search for a line which matches the current line
up to the current cursor position, in the manner of history-beginning-search-back-
ward and -forward, rather than the first word on the line.

edit-command-line
Edit the command line using your visual editor, as in ksh.

bindkey -M vicmd v edit-command-line

expand-absolute-path
Expand the file name under the cursor to an absolute path, resolving symbolic
links. Where possible, the initial path segment is turned into a named directory
or reference to a user's home directory.

history-search-end
This function implements the widgets history-beginning-search-backward-end and his-
tory-beginning-search-forward-end. These commands work by first calling the corre-
sponding builtin widget (see `History Control' in zshzle(1)) and then moving the
cursor to the end of the line. The original cursor position is remembered and re-
stored before calling the builtin widget a second time, so that the same search is
repeated to look farther through the history.

Although you autoload only one function, the commands to use it are slightly dif-
ferent because it implements two widgets.

zle -N history-beginning-search-backward-end \
history-search-end
zle -N history-beginning-search-forward-end \
history-search-end
bindkey '\e^P' history-beginning-search-backward-end
bindkey '\e^N' history-beginning-search-forward-end

history-beginning-search-menu
This function implements yet another form of history searching. The text before
the cursor is used to select lines from the history, as for history-begin-
ning-search-backward except that all matches are shown in a numbered menu. Typing
the appropriate digits inserts the full history line. Note that leading zeroes
must be typed (they are only shown when necessary for removing ambiguity). The en-
tire history is searched; there is no distinction between forwards and backwards.

With a numeric argument, the search is not anchored to the start of the line; the
string typed by the use may appear anywhere in the line in the history.

If the widget name contains `-end' the cursor is moved to the end of the line in-
serted. If the widget name contains `-space' any space in the text typed is
treated as a wildcard and can match anything (hence a leading space is equivalent
to giving a numeric argument). Both forms can be combined, for example:

zle -N history-beginning-search-menu-space-end \
history-beginning-search-menu

history-pattern-search
The function history-pattern-search implements widgets which prompt for a pattern
with which to search the history backwards or forwards. The pattern is in the
usual zsh format, however the first character may be ^ to anchor the search to the
start of the line, and the last character may be $ to anchor the search to the end
of the line. If the search was not anchored to the end of the line the cursor is
positioned just after the pattern found.

The commands to create bindable widgets are similar to those in the example immedi-
ately above:

autoload -U history-pattern-search
zle -N history-pattern-search-backward history-pattern-search
zle -N history-pattern-search-forward history-pattern-search

incarg Typing the keystrokes for this widget with the cursor placed on or to the left of
an integer causes that integer to be incremented by one. With a numeric argument,
the number is incremented by the amount of the argument (decremented if the numeric
argument is negative). The shell parameter incarg may be set to change the default
increment to something other than one.

bindkey '^X+' incarg

incremental-complete-word
This allows incremental completion of a word. After starting this command, a list
of completion choices can be shown after every character you type, which you can
delete with ^H or DEL. Pressing return accepts the completion so far and returns
you to normal editing (that is, the command line is not immediately executed). You
can hit TAB to do normal completion, ^G to abort back to the state when you
started, and ^D to list the matches.

This works only with the new function based completion system.

bindkey '^Xi' incremental-complete-word

insert-composed-char
This function allows you to compose characters that don't appear on the keyboard to
be inserted into the command line. The command is followed by two keys correspond-
ing to ASCII characters (there is no prompt). For accented characters, the two
keys are a base character followed by a code for the accent, while for other spe-
cial characters the two characters together form a mnemonic for the character to be
inserted. The two-character codes are a subset of those given by RFC 1345 (see for
example http://www.faqs.org/rfcs/rfc1345.html).

The function may optionally be followed by up to two characters which replace one
or both of the characters read from the keyboard; if both characters are supplied,
no input is read. For example, insert-composed-char a: can be used within a widget
to insert an a with umlaut into the command line. This has the advantages over use
of a literal character that it is more portable.

For best results zsh should have been built with support for multibyte characters
(configured with --enable-multibyte); however, the function works for the limited
range of characters available in single-byte character sets such as ISO-8859-1.

The character is converted into the local representation and inserted into the com-
mand line at the cursor position. (The conversion is done within the shell, using
whatever facilities the C library provides.) With a numeric argument, the charac-
ter and its code are previewed in the status line

The function may be run outside zle in which case it prints the character (together
with a newline) to standard output. Input is still read from keystrokes.

See insert-unicode-char for an alternative way of inserting Unicode characters us-
ing their hexadecimal character number.

The set of accented characters is reasonably complete up to Unicode character
U+0180, the set of special characters less so. However, it is very sporadic from
that point. Adding new characters is easy, however; see the function define-com-
posed-chars. Please send any additions to zsh-workers AT zsh.org.

The codes for the second character when used to accent the first are as follows.
Note that not every character can take every accent.
! Grave.
' Acute.
> Circumflex.
? Tilde. (This is not ~ as RFC 1345 does not assume that character is present
on the keyboard.)
- Macron. (A horizontal bar over the base character.)
( Breve. (A shallow dish shape over the base character.)
. Dot above the base character, or in the case of i no dot, or in the case of
L and l a centered dot.
: Diaeresis (Umlaut).
c Cedilla.
_ Underline, however there are currently no underlined characters.
/ Stroke through the base character.
" Double acute (only supported on a few letters).
; Ogonek. (A little forward facing hook at the bottom right of the charac-
ter.)
< Caron. (A little v over the letter.)
0 Circle over the base character.
2 Hook over the base character.
9 Horn over the base character.

The most common characters from the Arabic, Cyrillic, Greek and Hebrew alphabets
are available; consult RFC 1345 for the appropriate sequences. In addition, a set
of two letter codes not in RFC 1345 are available for the double-width characters
corresponding to ASCII characters from ! to ~ (0x21 to 0x7e) by preceding the
character with ^, for example ^A for a double-width A.

The following other two-character sequences are understood.

ASCII characters
These are already present on most keyboards:
<( Left square bracket
// Backslash (solidus)
)> Right square bracket
(! Left brace (curly bracket)
!! Vertical bar (pipe symbol)
!) Right brace (curly bracket)
'? Tilde

Special letters
Characters found in various variants of the Latin alphabet:
ss Eszett (scharfes S)
D-, d- Eth
TH, th Thorn
kk Kra
'n 'n
NG, ng Ng
OI, oi Oi
yr yr
ED ezh

Currency symbols
Ct Cent
Pd Pound sterling (also lira and others)
Cu Currency
Ye Yen
Eu Euro (N.B. not in RFC 1345)

Punctuation characters
References to "right" quotes indicate the shape (like a 9 rather than 6)
rather than their grammatical use. (For example, a "right" low double quote
is used to open quotations in German.)
!I Inverted exclamation mark
BB Broken vertical bar
SE Section
Co Copyright
-a Spanish feminine ordinal indicator
<< Left guillemet
-- Soft hyphen
Rg Registered trade mark
PI Pilcrow (paragraph)
-o Spanish masculine ordinal indicator
>> Right guillemet
?I Inverted question mark
-1 Hyphen
-N En dash
-M Em dash
-3 Horizontal bar
:3 Vertical ellipsis
.3 Horizontal midline ellipsis
!2 Double vertical line
=2 Double low line
'6 Left single quote
'9 Right single quote
.9 "Right" low quote
9' Reversed "right" quote
"6 Left double quote
"9 Right double quote
:9 "Right" low double quote
9" Reversed "right" double quote
/- Dagger
/= Double dagger

Mathematical symbols
DG Degree
-2, +-, -+
- sign, +/- sign, -/+ sign
2S Superscript 2
3S Superscript 3
1S Superscript 1
My Micro
.M Middle dot
14 Quarter
12 Half
34 Three quarters
*X Multiplication
-: Division
%0 Per mille
FA, TE, /0
For all, there exists, empty set
dP, DE, NB
Partial derivative, delta (increment), del (nabla)
(-, -) Element of, contains
*P, +Z Product, sum
*-, Ob, Sb
Asterisk, ring, bullet
RT, 0(, 00
Root sign, proportional to, infinity

Other symbols
cS, cH, cD, cC
Card suits: spades, hearts, diamonds, clubs
Md, M8, M2, Mb, Mx, MX
Musical notation: crotchet (quarter note), quaver (eighth note), semiquavers
(sixteenth notes), flag sign, natural sign, sharp sign
Fm, Ml Female, male

Accents on their own
'> Circumflex (same as caret, ^)
'! Grave (same as backtick, `)
', Cedilla
': Diaeresis (Umlaut)
'm Macron
'' Acute

insert-files
This function allows you type a file pattern, and see the results of the expansion
at each step. When you hit return, all expansions are inserted into the command
line.

bindkey '^Xf' insert-files

insert-unicode-char
When first executed, the user inputs a set of hexadecimal digits. This is termi-
nated with another call to insert-unicode-char. The digits are then turned into
the corresponding Unicode character. For example, if the widget is bound to ^XU,
the character sequence `^XU 4 c ^XU' inserts L (Unicode U+004c).

See insert-composed-char for a way of inserting characters using a two-character
mnemonic.

narrow-to-region [ -p pre ] [ -P post ]
[ -S statepm | -R statepm | [ -l lbufvar ] [ -r rbufvar ] ]
[ -n ] [ start end ]
narrow-to-region-invisible
Narrow the editable portion of the buffer to the region between the cursor and the
mark, which may be in either order. The region may not be empty.

narrow-to-region may be used as a widget or called as a function from a user-de-
fined widget; by default, the text outside the editable area remains visible. A
recursive-edit is performed and the original widening status is then restored.
Various options and arguments are available when it is called as a function.

The options -p pretext and -P posttext may be used to replace the text before and
after the display for the duration of the function; either or both may be an empty
string.

If the option -n is also given, pretext or posttext will only be inserted if there
is text before or after the region respectively which will be made invisible.

Two numeric arguments may be given which will be used instead of the cursor and
mark positions.

The option -S statepm is used to narrow according to the other options while saving
the original state in the parameter with name statepm, while the option -R statepm
is used to restore the state from the parameter; note in both cases the name of the
parameter is required. In the second case, other options and arguments are irrele-
vant. When this method is used, no recursive-edit is performed; the calling widget
should call this function with the option -S, perform its own editing on the com-
mand line or pass control to the user via `zle recursive-edit', then call this
function with the option -R. The argument statepm must be a suitable name for an
ordinary parameter, except that parameters beginning with the prefix _ntr_ are re-
served for use within narrow-to-region. Typically the parameter will be local to
the calling function.

The options -l lbufvar and -r rbufvar may be used to specify parameters where the
widget will store the resulting text from the operation. The parameter lbufvar
will contain LBUFFER and rbufvar will contain RBUFFER. Neither of these two op-
tions may be used with -S or -R.

narrow-to-region-invisible is a simple widget which calls narrow-to-region with ar-
guments which replace any text outside the region with `...'. It does not take any
arguments.

The display is restored (and the widget returns) upon any zle command which would
usually cause the line to be accepted or aborted. Hence an additional such command
is required to accept or abort the current line.

The return status of both widgets is zero if the line was accepted, else non-zero.

Here is a trivial example of a widget using this feature.
local state
narrow-to-region -p $'Editing restricted region\n' \
-P '' -S state
zle recursive-edit
narrow-to-region -R state

predict-on
This set of functions implements predictive typing using history search. After
predict-on, typing characters causes the editor to look backward in the history for
the first line beginning with what you have typed so far. After predict-off, edit-
ing returns to normal for the line found. In fact, you often don't even need to
use predict-off, because if the line doesn't match something in the history, adding
a key performs standard completion, and then inserts itself if no completions were
found. However, editing in the middle of a line is liable to confuse prediction;
see the toggle style below.

With the function based completion system (which is needed for this), you should be
able to type TAB at almost any point to advance the cursor to the next ``interest-
ing'' character position (usually the end of the current word, but sometimes some-
where in the middle of the word). And of course as soon as the entire line is what
you want, you can accept with return, without needing to move the cursor to the end
first.

The first time predict-on is used, it creates several additional widget functions:

delete-backward-and-predict
Replaces the backward-delete-char widget. You do not need to bind this
yourself.
insert-and-predict
Implements predictive typing by replacing the self-insert widget. You do
not need to bind this yourself.
predict-off
Turns off predictive typing.

Although you autoload only the predict-on function, it is necessary to create a
keybinding for predict-off as well.

zle -N predict-on
zle -N predict-off
bindkey '^X^Z' predict-on
bindkey '^Z' predict-off

read-from-minibuffer
This is most useful when called as a function from inside a widget, but will work
correctly as a widget in its own right. It prompts for a value below the current
command line; a value may be input using all of the standard zle operations (and
not merely the restricted set available when executing, for example, exe-
cute-named-cmd). The value is then returned to the calling function in the parame-
ter $REPLY and the editing buffer restored to its previous state. If the read was
aborted by a keyboard break (typically ^G), the function returns status 1 and $RE-
PLY is not set.

If one argument is supplied to the function it is taken as a prompt, otherwise `? '
is used. If two arguments are supplied, they are the prompt and the initial value
of $LBUFFER, and if a third argument is given it is the initial value of $RBUFFER.
This provides a default value and starting cursor placement. Upon return the en-
tire buffer is the value of $REPLY.

One option is available: `-k num' specifies that num characters are to be read in-
stead of a whole line. The line editor is not invoked recursively in this case, so
depending on the terminal settings the input may not be visible, and only the input
keys are placed in $REPLY, not the entire buffer. Note that unlike the read
builtin num must be given; there is no default.

The name is a slight misnomer, as in fact the shell's own minibuffer is not used.
Hence it is still possible to call executed-named-cmd and similar functions while
reading a value.

replace-argument, replace-argument-edit
The function replace-argument can be used to replace a command line argument in the
current command line or, if the current command line is empty, in the last command
line executed (the new command line is not executed). Arguments are as delimited
by standard shell syntax,

If a numeric argument is given, that specifies the argument to be replaced. 0
means the command name, as in history expansion. A negative numeric argument
counts backward from the last word.

If no numeric argument is given, the current argument is replaced; this is the last
argument if the previous history line is being used.

The function prompts for a replacement argument.

If the widget contains the string edit, for example is defined as

zle -N replace-argument-edit replace-argument

then the function presents the current value of the argument for editing, otherwise
the editing buffer for the replacement is initially empty.

replace-string, replace-pattern
replace-string-again, replace-pattern-again
The function replace-string implements three widgets. If defined under the same
name as the function, it prompts for two strings; the first (source) string will be
replaced by the second everywhere it occurs in the line editing buffer.

If the widget name contains the word `pattern', for example by defining the widget
using the command `zle -N replace-pattern replace-string', then the matching is
performed using zsh patterns. All zsh extended globbing patterns can be used in
the source string; note that unlike filename generation the pattern does not need
to match an entire word, nor do glob qualifiers have any effect. In addition, the
replacement string can contain parameter or command substitutions. Furthermore, a
`&' in the replacement string will be replaced with the matched source string, and
a backquoted digit `\N' will be replaced by the Nth parenthesised expression
matched. The form `\{N}' may be used to protect the digit from following digits.

If the widget instead contains the word `regex' (or `regexp'), then the matching is
performed using regular expressions, respecting the setting of the option
RE_MATCH_PCRE (see the description of the function regexp-replace below). The spe-
cial replacement facilities described above for pattern matching are available.

By default the previous source or replacement string will not be offered for edit-
ing. However, this feature can be activated by setting the style edit-previous in
the context :zle:widget (for example, :zle:replace-string) to true. In addition, a
positive numeric argument forces the previous values to be offered, a negative or
zero argument forces them not to be.

The function replace-string-again can be used to repeat the previous replacement;
no prompting is done. As with replace-string, if the name of the widget contains
the word `pattern' or `regex', pattern or regular expression matching is performed,
else a literal string replacement. Note that the previous source and replacement
text are the same whether pattern, regular expression or string matching is used.

In addition, replace-string shows the previous replacement above the prompt, so
long as there was one during the current session; if the source string is empty,
that replacement will be repeated without the widget prompting for a replacement
string.

For example, starting from the line:

print This line contains fan and fond

and invoking replace-pattern with the source string `f(?)n' and the replacement
string `c\1r' produces the not very useful line:

print This line contains car and cord

The range of the replacement string can be limited by using the narrow-to-re-
gion-invisible widget. One limitation of the current version is that undo will cy-
cle through changes to the replacement and source strings before undoing the re-
placement itself.

send-invisible
This is similar to read-from-minibuffer in that it may be called as a function from
a widget or as a widget of its own, and interactively reads input from the key-
board. However, the input being typed is concealed and a string of asterisks (`*')
is shown instead. The value is saved in the parameter $INVISIBLE to which a refer-
ence is inserted into the editing buffer at the restored cursor position. If the
read was aborted by a keyboard break (typically ^G) or another escape from editing
such as push-line, $INVISIBLE is set to empty and the original buffer is restored
unchanged.

If one argument is supplied to the function it is taken as a prompt, otherwise
`Non-echoed text: ' is used (as in emacs). If a second and third argument are sup-
plied they are used to begin and end the reference to $INVISIBLE that is inserted
into the buffer. The default is to open with ${, then INVISIBLE, and close with },
but many other effects are possible.

smart-insert-last-word
This function may replace the insert-last-word widget, like so:

zle -N insert-last-word smart-insert-last-word

With a numeric argument, or when passed command line arguments in a call from an-
other widget, it behaves like insert-last-word, except that words in comments are
ignored when INTERACTIVE_COMMENTS is set.

Otherwise, the rightmost ``interesting'' word from the previous command is found
and inserted. The default definition of ``interesting'' is that the word contains
at least one alphabetic character, slash, or backslash. This definition may be
overridden by use of the match style. The context used to look up the style is the
widget name, so usually the context is :insert-last-word. However, you can bind
this function to different widgets to use different patterns:

zle -N insert-last-assignment smart-insert-last-word
zstyle :insert-last-assignment match '[[:alpha:]][][[:alnum:]]#=*'
bindkey '\e=' insert-last-assignment

If no interesting word is found and the auto-previous style is set to a true value,
the search continues upward through the history. When auto-previous is unset or
false (the default), the widget must be invoked repeatedly in order to search ear-
lier history lines.

transpose-lines
Only useful with a multi-line editing buffer; the lines here are lines within the
current on-screen buffer, not history lines. The effect is similar to the function
of the same name in Emacs.

Transpose the current line with the previous line and move the cursor to the start
of the next line. Repeating this (which can be done by providing a positive nu-
meric argument) has the effect of moving the line above the cursor down by a number
of lines.

With a negative numeric argument, requires two lines above the cursor. These two
lines are transposed and the cursor moved to the start of the previous line. Using
a numeric argument less than -1 has the effect of moving the line above the cursor
up by minus that number of lines.

url-quote-magic
This widget replaces the built-in self-insert to make it easier to type URLs as
command line arguments. As you type, the input character is analyzed and, if it
may need quoting, the current word is checked for a URI scheme. If one is found
and the current word is not already in quotes, a backslash is inserted before the
input character.

Styles to control quoting behavior:

url-metas
This style is looked up in the context `:url-quote-magic:scheme' (where
scheme is that of the current URL, e.g. "ftp"). The value is a string list-
ing the characters to be treated as globbing metacharacters when appearing
in a URL using that scheme. The default is to quote all zsh extended glob-
bing characters, excluding '<' and '>' but including braces (as in brace ex-
pansion). See also url-seps.

url-seps
Like url-metas, but lists characters that should be considered command sepa-
rators, redirections, history references, etc. The default is to quote the
standard set of shell separators, excluding those that overlap with the ex-
tended globbing characters, but including '<' and '>' and the first charac-
ter of $histchars.

url-globbers
This style is looked up in the context `:url-quote-magic'. The values form
a list of command names that are expected to do their own globbing on the
URL string. This implies that they are aliased to use the `noglob' modi-
fier. When the first word on the line matches one of the values and the URL
refers to a local file (see url-local-schema), only the url-seps characters
are quoted; the url-metas are left alone, allowing them to affect com-
mand-line parsing, completion, etc. The default values are a literal
`noglob' plus (when the zsh/parameter module is available) any commands
aliased to the helper function `urlglobber' or its alias `globurl'.

url-local-schema
This style is always looked up in the context `:urlglobber', even though it
is used by both url-quote-magic and urlglobber. The values form a list of
URI schema that should be treated as referring to local files by their real
local path names, as opposed to files which are specified relative to a
web-server-defined document root. The defaults are "ftp" and "file".

url-other-schema
Like url-local-schema, but lists all other URI schema upon which urlglobber
and url-quote-magic should act. If the URI on the command line does not
have a scheme appearing either in this list or in url-local-schema, it is
not magically quoted. The default values are "http", "https", and "ftp".
When a scheme appears both here and in url-local-schema, it is quoted dif-
ferently depending on whether the command name appears in url-globbers.

Loading url-quote-magic also defines a helper function `urlglobber' and aliases
`globurl' to `noglob urlglobber'. This function takes a local URL apart, attempts
to pattern-match the local file portion of the URL path, and then puts the results
back into URL format again.

vi-pipe
This function reads a movement command from the keyboard and then prompts for an
external command. The part of the buffer covered by the movement is piped to the
external command and then replaced by the command's output. If the movement command
is bound to vi-pipe, the current line is used.

The function serves as an example for reading a vi movement command from within a
user-defined widget.

which-command
This function is a drop-in replacement for the builtin widget which-command. It
has enhanced behaviour, in that it correctly detects whether or not the command
word needs to be expanded as an alias; if so, it continues tracing the command word
from the expanded alias until it reaches the command that will be executed.

The style whence is available in the context :zle:$WIDGET; this may be set to an
array to give the command and options that will be used to investigate the command
word found. The default is whence -c.

zcalc-auto-insert
This function is useful together with the zcalc function described in the section
Mathematical Functions. It should be bound to a key representing a binary operator
such as `+', `-', `*' or `/'. When running in zcalc, if the key occurs at the
start of the line or immediately following an open parenthesis, the text "ans " is
inserted before the representation of the key itself. This allows easy use of the
answer from the previous calculation in the current line. The text to be inserted
before the symbol typed can be modified by setting the variable ZCALC_AUTO_IN-
SERT_PREFIX.

Hence, for example, typing `+12' followed by return adds 12 to the previous result.

If zcalc is in RPN mode (-r option) the effect of this binding is automatically
suppressed as operators alone on a line are meaningful.

When not in zcalc, the key simply inserts the symbol itself.

Utility Functions
These functions are useful in constructing widgets. They should be loaded with `autoload
-U function' and called as indicated from user-defined widgets.

split-shell-arguments
This function splits the line currently being edited into shell arguments and
whitespace. The result is stored in the array reply. The array contains all the
parts of the line in order, starting with any whitespace before the first argument,
and finishing with any whitespace after the last argument. Hence (so long as the
option KSH_ARRAYS is not set) whitespace is given by odd indices in the array and
arguments by even indices. Note that no stripping of quotes is done; joining to-
gether all the elements of reply in order is guaranteed to produce the original
line.

The parameter REPLY is set to the index of the word in reply which contains the
character after the cursor, where the first element has index 1. The parameter RE-
PLY2 is set to the index of the character under the cursor in that word, where the
first character has index 1.

Hence reply, REPLY and REPLY2 should all be made local to the enclosing function.

See the function modify-current-argument, described below, for an example of how to
call this function.

modify-current-argument [ expr-using-$ARG | func ]
This function provides a simple method of allowing user-defined widgets to modify
the command line argument under the cursor (or immediately to the left of the cur-
sor if the cursor is between arguments).

The argument can be an expression which when evaluated operates on the shell param-
eter ARG, which will have been set to the command line argument under the cursor.
The expression should be suitably quoted to prevent it being evaluated too early.

Alternatively, if the argument does not contain the string ARG, it is assumed to be
a shell function, to which the current command line argument is passed as the only
argument. The function should set the variable REPLY to the new value for the com-
mand line argument. If the function returns non-zero status, so does the calling
function.

For example, a user-defined widget containing the following code converts the char-
acters in the argument under the cursor into all upper case:

modify-current-argument '${(U)ARG}'

The following strips any quoting from the current word (whether backslashes or one
of the styles of quotes), and replaces it with single quoting throughout:

modify-current-argument '${(qq)${(Q)ARG}}'

The following performs directory expansion on the command line argument and re-
places it by the absolute path:

expand-dir() {
REPLY=${~1}
REPLY=${REPLY:a}
}
modify-current-argument expand-dir

In practice the function expand-dir would probably not be defined within the widget
where modify-current-argument is called.

Styles
The behavior of several of the above widgets can be controlled by the use of the zstyle
mechanism. In particular, widgets that interact with the completion system pass along
their context to any completions that they invoke.

break-keys
This style is used by the incremental-complete-word widget. Its value should be a
pattern, and all keys matching this pattern will cause the widget to stop incremen-
tal completion without the key having any further effect. Like all styles used di-
rectly by incremental-complete-word, this style is looked up using the context
`:incremental'.

completer
The incremental-complete-word and insert-and-predict widgets set up their top-level
context name before calling completion. This allows one to define different sets
of completer functions for normal completion and for these widgets. For example,
to use completion, approximation and correction for normal completion, completion
and correction for incremental completion and only completion for prediction one
could use:

zstyle ':completion:*' completer \
_complete _correct _approximate
zstyle ':completion:incremental:*' completer \
_complete _correct
zstyle ':completion:predict:*' completer \
_complete

It is a good idea to restrict the completers used in prediction, because they may
be automatically invoked as you type. The _list and _menu completers should never
be used with prediction. The _approximate, _correct, _expand, and _match com-
pleters may be used, but be aware that they may change characters anywhere in the
word behind the cursor, so you need to watch carefully that the result is what you
intended.

cursor The insert-and-predict widget uses this style, in the context `:predict', to decide
where to place the cursor after completion has been tried. Values are:

complete
The cursor is left where it was when completion finished, but only if it is
after a character equal to the one just inserted by the user. If it is af-
ter another character, this value is the same as `key'.

key The cursor is left after the nth occurrence of the character just inserted,
where n is the number of times that character appeared in the word before
completion was attempted. In short, this has the effect of leaving the cur-
sor after the character just typed even if the completion code found out
that no other characters need to be inserted at that position.

Any other value for this style unconditionally leaves the cursor at the position
where the completion code left it.

list When using the incremental-complete-word widget, this style says if the matches
should be listed on every key press (if they fit on the screen). Use the context
prefix `:completion:incremental'.

The insert-and-predict widget uses this style to decide if the completion should be
shown even if there is only one possible completion. This is done if the value of
this style is the string always. In this case the context is `:predict' (not
`:completion:predict').

match This style is used by smart-insert-last-word to provide a pattern (using full EX-
TENDED_GLOB syntax) that matches an interesting word. The context is the name of
the widget to which smart-insert-last-word is bound (see above). The default be-
havior of smart-insert-last-word is equivalent to:

zstyle :insert-last-word match '*[[:alpha:]/\\]*'

However, you might want to include words that contain spaces:

zstyle :insert-last-word match '*[[:alpha:][:space:]/\\]*'

Or include numbers as long as the word is at least two characters long:

zstyle :insert-last-word match '*([[:digit:]]?|[[:alpha:]/\\])*'

The above example causes redirections like "2>" to be included.

prompt The incremental-complete-word widget shows the value of this style in the status
line during incremental completion. The string value may contain any of the fol-
lowing substrings in the manner of the PS1 and other prompt parameters:

%c Replaced by the name of the completer function that generated the matches
(without the leading underscore).

%l When the list style is set, replaced by `...' if the list of matches is too
long to fit on the screen and with an empty string otherwise. If the list
style is `false' or not set, `%l' is always removed.

%n Replaced by the number of matches generated.

%s Replaced by `-no match-', `-no prefix-', or an empty string if there is no
completion matching the word on the line, if the matches have no common pre-
fix different from the word on the line, or if there is such a common pre-
fix, respectively.

%u Replaced by the unambiguous part of all matches, if there is any, and if it
is different from the word on the line.

Like `break-keys', this uses the `:incremental' context.

stop-keys
This style is used by the incremental-complete-word widget. Its value is treated
similarly to the one for the break-keys style (and uses the same context: `:incre-
mental'). However, in this case all keys matching the pattern given as its value
will stop incremental completion and will then execute their usual function.

toggle This boolean style is used by predict-on and its related widgets in the context
`:predict'. If set to one of the standard `true' values, predictive typing is au-
tomatically toggled off in situations where it is unlikely to be useful, such as
when editing a multi-line buffer or after moving into the middle of a line and then
deleting a character. The default is to leave prediction turned on until an ex-
plicit call to predict-off.

verbose
This boolean style is used by predict-on and its related widgets in the context
`:predict'. If set to one of the standard `true' values, these widgets display a
message below the prompt when the predictive state is toggled. This is most useful
in combination with the toggle style. The default does not display these messages.

widget This style is similar to the command style: For widget functions that use zle to
call other widgets, this style can sometimes be used to override the widget which
is called. The context for this style is the name of the calling widget (not the
name of the calling function, because one function may be bound to multiple widget
names).

zstyle :copy-earlier-word widget smart-insert-last-word

Check the documentation for the calling widget or function to determine whether the
widget style is used.

EXCEPTION HANDLING
Two functions are provided to enable zsh to provide exception handling in a form that
should be familiar from other languages.

throw exception
The function throw throws the named exception. The name is an arbitrary string and
is only used by the throw and catch functions. An exception is for the most part
treated the same as a shell error, i.e. an unhandled exception will cause the shell
to abort all processing in a function or script and to return to the top level in
an interactive shell.

catch exception-pattern
The function catch returns status zero if an exception was thrown and the pattern
exception-pattern matches its name. Otherwise it returns status 1. exception-pat-
tern is a standard shell pattern, respecting the current setting of the EX-
TENDED_GLOB option. An alias catch is also defined to prevent the argument to the
function from matching filenames, so patterns may be used unquoted. Note that as
exceptions are not fundamentally different from other shell errors it is possible
to catch shell errors by using an empty string as the exception name. The shell
variable CAUGHT is set by catch to the name of the exception caught. It is possi-
ble to rethrow an exception by calling the throw function again once an exception
has been caught.

The functions are designed to be used together with the always construct described in zsh-
misc(1). This is important as only this construct provides the required support for ex-
ceptions. A typical example is as follows.

{
# "try" block
# ... nested code here calls "throw MyExcept"
} always {
# "always" block
if catch MyExcept; then
print "Caught exception MyExcept"
elif catch ''; then
print "Caught a shell error. Propagating..."
throw ''
fi
# Other exceptions are not handled but may be caught further
# up the call stack.
}

If all exceptions should be caught, the following idiom might be preferable.

{
# ... nested code here throws an exception
} always {
if catch *; then
case $CAUGHT in
(MyExcept)
print "Caught my own exception"
;;
(*)
print "Caught some other exception"
;;
esac
fi
}

In common with exception handling in other languages, the exception may be thrown by code
deeply nested inside the `try' block. However, note that it must be thrown inside the
current shell, not in a subshell forked for a pipeline, parenthesised current-shell con-
struct, or some form of command or process substitution.

The system internally uses the shell variable EXCEPTION to record the name of the excep-
tion between throwing and catching. One drawback of this scheme is that if the exception
is not handled the variable EXCEPTION remains set and may be incorrectly recognised as the
name of an exception if a shell error subsequently occurs. Adding unset EXCEPTION at the
start of the outermost layer of any code that uses exception handling will eliminate this
problem.

MIME FUNCTIONS
Three functions are available to provide handling of files recognised by extension, for
example to dispatch a file text.ps when executed as a command to an appropriate viewer.

zsh-mime-setup [ -fv ] [ -l [ suffix ... ] ]
zsh-mime-handler [ -l ] command argument ...
These two functions use the files ~/.mime.types and /etc/mime.types, which asso-
ciate types and extensions, as well as ~/.mailcap and /etc/mailcap files, which as-
sociate types and the programs that handle them. These are provided on many sys-
tems with the Multimedia Internet Mail Extensions.

To enable the system, the function zsh-mime-setup should be autoloaded and run.
This allows files with extensions to be treated as executable; such files be com-
pleted by the function completion system. The function zsh-mime-handler should not
need to be called by the user.

The system works by setting up suffix aliases with `alias -s'. Suffix aliases al-
ready installed by the user will not be overwritten.

For suffixes defined in lower case, upper case variants will also automatically be
handled (e.g. PDF is automatically handled if handling for the suffix pdf is de-
fined), but not vice versa.

Repeated calls to zsh-mime-setup do not override the existing mapping between suf-
fixes and executable files unless the option -f is given. Note, however, that this
does not override existing suffix aliases assigned to handlers other than
zsh-mime-handler.

Calling zsh-mime-setup with the option -l lists the existing mappings without al-
tering them. Suffixes to list (which may contain pattern characters that should be
quoted from immediate interpretation on the command line) may be given as addi-
tional arguments, otherwise all suffixes are listed.

Calling zsh-mime-setup with the option -v causes verbose output to be shown during
the setup operation.

The system respects the mailcap flags needsterminal and copiousoutput, see mail-
cap(4).

The functions use the following styles, which are defined with the zstyle builtin
command (see zshmodules(1)). They should be defined before zsh-mime-setup is run.
The contexts used all start with :mime:, with additional components in some cases.
It is recommended that a trailing * (suitably quoted) be appended to style patterns
in case the system is extended in future. Some examples are given below.

For files that have multiple suffixes, e.g. .pdf.gz, where the context includes the
suffix it will be looked up starting with the longest possible suffix until a match
for the style is found. For example, if .pdf.gz produces a match for the handler,
that will be used; otherwise the handler for .gz will be used. Note that, owing to
the way suffix aliases work, it is always required that there be a handler for the
shortest possible suffix, so in this example .pdf.gz can only be handled if .gz is
also handled (though not necessarily in the same way). Alternatively, if no han-
dling for .gz on its own is needed, simply adding the command

alias -s gz=zsh-mime-handler

to the initialisation code is sufficient; .gz will not be handled on its own, but
may be in combination with other suffixes.

current-shell
If this boolean style is true, the mailcap handler for the context in ques-
tion is run using the eval builtin instead of by starting a new sh process.
This is more efficient, but may not work in the occasional cases where the
mailcap handler uses strict POSIX syntax.

disown If this boolean style is true, mailcap handlers started in the background
will be disowned, i.e. not subject to job control within the parent shell.
Such handlers nearly always produce their own windows, so the only likely
harmful side effect of setting the style is that it becomes harder to kill
jobs from within the shell.

execute-as-is
This style gives a list of patterns to be matched against files passed for
execution with a handler program. If the file matches the pattern, the en-
tire command line is executed in its current form, with no handler. This is
useful for files which might have suffixes but nonetheless be executable in
their own right. If the style is not set, the pattern *(*) *(/) is used;
hence executable files are executed directly and not passed to a handler,
and the option AUTO_CD may be used to change to directories that happen to
have MIME suffixes.

execute-never
This style is useful in combination with execute-as-is. It is set to an ar-
ray of patterns corresponding to full paths to files that should never be
treated as executable, even if the file passed to the MIME handler matches
execute-as-is. This is useful for file systems that don't handle execute
permission or that contain executables from another operating system. For
example, if /mnt/windows is a Windows mount, then

zstyle ':mime:*' execute-never '/mnt/windows/*'

will ensure that any files found in that area will be executed as MIME types
even if they are executable. As this example shows, the complete file name
is matched against the pattern, regardless of how the file was passed to the
handler. The file is resolved to a full path using the :P modifier de-
scribed in the subsection Modifiers in zshexpn(1); this means that symbolic
links are resolved where possible, so that links into other file systems be-
have in the correct fashion.

file-path
Used if the style find-file-in-path is true for the same context. Set to an
array of directories that are used for searching for the file to be handled;
the default is the command path given by the special parameter path. The
shell option PATH_DIRS is respected; if that is set, the appropriate path
will be searched even if the name of the file to be handled as it appears on
the command line contains a `/'. The full context is :mime:.suffix:, as de-
scribed for the style handler.

find-file-in-path
If set, allows files whose names do not contain absolute paths to be
searched for in the command path or the path specified by the file-path
style. If the file is not found in the path, it is looked for locally
(whether or not the current directory is in the path); if it is not found
locally, the handler will abort unless the handle-nonexistent style is set.
Files found in the path are tested as described for the style execute-as-is.
The full context is :mime:.suffix:, as described for the style handler.

flags Defines flags to go with a handler; the context is as for the handler style,
and the format is as for the flags in mailcap.

handle-nonexistent
By default, arguments that don't correspond to files are not passed to the
MIME handler in order to prevent it from intercepting commands found in the
path that happen to have suffixes. This style may be set to an array of ex-
tended glob patterns for arguments that will be passed to the handler even
if they don't exist. If it is not explicitly set it defaults to [[:al-
pha:]]#:/* which allows URLs to be passed to the MIME handler even though
they don't exist in that format in the file system. The full context is
:mime:.suffix:, as described for the style handler.

handler
Specifies a handler for a suffix; the suffix is given by the context as
:mime:.suffix:, and the format of the handler is exactly that in mailcap.
Note in particular the `.' and trailing colon to distinguish this use of the
context. This overrides any handler specified by the mailcap files. If the
handler requires a terminal, the flags style should be set to include the
word needsterminal, or if the output is to be displayed through a pager (but
not if the handler is itself a pager), it should include copiousoutput.

mailcap
A list of files in the format of ~/.mailcap and /etc/mailcap to be read dur-
ing setup, replacing the default list which consists of those two files.
The context is :mime:. A + in the list will be replaced by the default
files.

mailcap-priorities
This style is used to resolve multiple mailcap entries for the same MIME
type. It consists of an array of the following elements, in descending or-
der of priority; later entries will be used if earlier entries are unable to
resolve the entries being compared. If none of the tests resolve the en-
tries, the first entry encountered is retained.

files The order of files (entries in the mailcap style) read. Earlier
files are preferred. (Note this does not resolve entries in the same
file.)

priority
The priority flag from the mailcap entry. The priority is an integer
from 0 to 9 with the default value being 5.

flags The test given by the mailcap-prio-flags option is used to resolve
entries.

place Later entries are preferred; as the entries are strictly ordered,
this test always succeeds.

Note that as this style is handled during initialisation, the context is al-
ways :mime:, with no discrimination by suffix.

mailcap-prio-flags
This style is used when the keyword flags is encountered in the list of
tests specified by the mailcap-priorities style. It should be set to a list
of patterns, each of which is tested against the flags specified in the
mailcap entry (in other words, the sets of assignments found with some en-
tries in the mailcap file). Earlier patterns in the list are preferred to
later ones, and matched patterns are preferred to unmatched ones.

mime-types
A list of files in the format of ~/.mime.types and /etc/mime.types to be
read during setup, replacing the default list which consists of those two
files. The context is :mime:. A + in the list will be replaced by the de-
fault files.

never-background
If this boolean style is set, the handler for the given context is always
run in the foreground, even if the flags provided in the mailcap entry sug-
gest it need not be (for example, it doesn't require a terminal).

pager If set, will be used instead of $PAGER or more to handle suffixes where the
copiousoutput flag is set. The context is as for handler, i.e. :mime:.suf-
fix: for handling a file with the given suffix.

Examples:

zstyle ':mime:*' mailcap ~/.mailcap /usr/local/etc/mailcap
zstyle ':mime:.txt:' handler less %s
zstyle ':mime:.txt:' flags needsterminal

When zsh-mime-setup is subsequently run, it will look for mailcap entries in the
two files given. Files of suffix .txt will be handled by running `less file.txt'.
The flag needsterminal is set to show that this program must run attached to a ter-
minal.

As there are several steps to dispatching a command, the following should be
checked if attempting to execute a file by extension .ext does not have the ex-
pected effect.

The command `alias -s ext' should show `ps=zsh-mime-handler'. If it shows some-
thing else, another suffix alias was already installed and was not overwritten. If
it shows nothing, no handler was installed: this is most likely because no handler
was found in the .mime.types and mailcap combination for .ext files. In that case,
appropriate handling should be added to ~/.mime.types and mailcap.

If the extension is handled by zsh-mime-handler but the file is not opened cor-
rectly, either the handler defined for the type is incorrect, or the flags associ-
ated with it are in appropriate. Running zsh-mime-setup -l will show the handler
and, if there are any, the flags. A %s in the handler is replaced by the file
(suitably quoted if necessary). Check that the handler program listed lists and
can be run in the way shown. Also check that the flags needsterminal or copi-
ousoutput are set if the handler needs to be run under a terminal; the second flag
is used if the output should be sent to a pager. An example of a suitable mailcap
entry for such a program is:

text/html; /usr/bin/lynx '%s'; needsterminal

Running `zsh-mime-handler -l command line' prints the command line that would be
executed, simplified to remove the effect of any flags, and quoted so that the out-
put can be run as a complete zsh command line. This is used by the completion sys-
tem to decide how to complete after a file handled by zsh-mime-setup.

pick-web-browser
This function is separate from the two MIME functions described above and can be
assigned directly to a suffix:

autoload -U pick-web-browser
alias -s html=pick-web-browser

It is provided as an intelligent front end to dispatch a web browser. It may be
run as either a function or a shell script. The status 255 is returned if no
browser could be started.

Various styles are available to customize the choice of browsers:

browser-style
The value of the style is an array giving preferences in decreasing order
for the type of browser to use. The values of elements may be

running
Use a GUI browser that is already running when an X Window display is
available. The browsers listed in the x-browsers style are tried in
order until one is found; if it is, the file will be displayed in
that browser, so the user may need to check whether it has appeared.
If no running browser is found, one is not started. Browsers other
than Firefox, Opera and Konqueror are assumed to understand the
Mozilla syntax for opening a URL remotely.

x Start a new GUI browser when an X Window display is available.
Search for the availability of one of the browsers listed in the
x-browsers style and start the first one that is found. No check is
made for an already running browser.

tty Start a terminal-based browser. Search for the availability of one
of the browsers listed in the tty-browsers style and start the first
one that is found.

If the style is not set the default running x tty is used.

x-browsers
An array in decreasing order of preference of browsers to use when running
under the X Window System. The array consists of the command name under
which to start the browser. They are looked up in the context :mime: (which
may be extended in future, so appending `*' is recommended). For example,

zstyle ':mime:*' x-browsers opera konqueror firefox

specifies that pick-web-browser should first look for a running instance of
Opera, Konqueror or Firefox, in that order, and if it fails to find any
should attempt to start Opera. The default is firefox mozilla netscape
opera konqueror.

tty-browsers
An array similar to x-browsers, except that it gives browsers to use when no
X Window display is available. The default is elinks links lynx.

command
If it is set this style is used to pick the command used to open a page for
a browser. The context is :mime:browser:new:$browser: to start a new
browser or :mime:browser:running:$browser: to open a URL in a browser al-
ready running on the current X display, where $browser is the value matched
in the x-browsers or tty-browsers style. The escape sequence %b in the
style's value will be replaced by the browser, while %u will be replaced by
the URL. If the style is not set, the default for all new instances is
equivalent to %b %u and the defaults for using running browsers are equiva-
lent to the values kfmclient openURL %u for Konqueror, firefox -new-tab %u
for Firefox, opera -newpage %u for Opera, and %b -remote "openUrl(%u)" for
all others.

MATHEMATICAL FUNCTIONS
zcalc [ -erf ] [ expression ... ]
A reasonably powerful calculator based on zsh's arithmetic evaluation facility.
The syntax is similar to that of formulae in most programming languages; see the
section `Arithmetic Evaluation' in zshmisc(1) for details.

Non-programmers should note that, as in many other programming languages, expres-
sions involving only integers (whether constants without a `.', variables contain-
ing such constants as strings, or variables declared to be integers) are by default
evaluated using integer arithmetic, which is not how an ordinary desk calculator
operates. To force floating point operation, pass the option -f; see further notes
below.

If the file ~/.zcalcrc exists it will be sourced inside the function once it is set
up and about to process the command line. This can be used, for example, to set
shell options; emulate -L zsh and setopt extendedglob are in effect at this point.
Any failure to source the file if it exists is treated as fatal. As with other
initialisation files, the directory $ZDOTDIR is used instead of $HOME if it is set.

The mathematical library zsh/mathfunc will be loaded if it is available; see the
section `The zsh/mathfunc Module' in zshmodules(1). The mathematical functions
correspond to the raw system libraries, so trigonometric functions are evaluated
using radians, and so on.

Each line typed is evaluated as an expression. The prompt shows a number, which
corresponds to a positional parameter where the result of that calculation is
stored. For example, the result of the calculation on the line preceded by `4> '
is available as $4. The last value calculated is available as ans. Full command
line editing, including the history of previous calculations, is available; the
history is saved in the file ~/.zcalc_history. To exit, enter a blank line or type
`:q' on its own (`q' is allowed for historical compatibility).

A line ending with a single backslash is treated in the same fashion as it is in
command line editing: the backslash is removed, the function prompts for more in-
put (the prompt is preceded by `...' to indicate this), and the lines are combined
into one to get the final result. In addition, if the input so far contains more
open than close parentheses zcalc will prompt for more input.

If arguments are given to zcalc on start up, they are used to prime the first few
positional parameters. A visual indication of this is given when the calculator
starts.

The constants PI (3.14159...) and E (2.71828...) are provided. Parameter assign-
ment is possible, but note that all parameters will be put into the global name-
space unless the :local special command is used. The function creates local vari-
ables whose names start with _, so users should avoid doing so. The variables ans
(the last answer) and stack (the stack in RPN mode) may be referred to directly;
stack is an array but elements of it are numeric. Various other special variables
are used locally with their standard meaning, for example compcontext, match, mbe-
gin, mend, psvar.

The output base can be initialised by passing the option `-#base', for example
`zcalc -#16' (the `#' may have to be quoted, depending on the globbing options
set).

If the option `-e' is set, the function runs non-interactively: the arguments are
treated as expressions to be evaluated as if entered interactively line by line.

If the option `-f' is set, all numbers are treated as floating point, hence for ex-
ample the expression `3/4' evaluates to 0.75 rather than 0. Options must appear in
separate words.

If the option `-r' is set, RPN (Reverse Polish Notation) mode is entered. This has
various additional properties:
Stack Evaluated values are maintained in a stack; this is contained in an array
named stack with the most recent value in ${stack[1]}.

Operators and functions
If the line entered matches an operator (+, -, *, /, **, ^, | or &) or a
function supplied by the zsh/mathfunc library, the bottom element or ele-
ments of the stack are popped to use as the argument or arguments. The
higher elements of stack (least recent) are used as earlier arguments. The
result is then pushed into ${stack[1]}.

Expressions
Other expressions are evaluated normally, printed, and added to the stack as
numeric values. The syntax within expressions on a single line is normal
shell arithmetic (not RPN).

Stack listing
If an integer follows the option -r with no space, then on every evaluation
that many elements of the stack, where available, are printed instead of
just the most recent result. Hence, for example, zcalc -r4 shows $stack[4]
to $stack[1] each time results are printed.

Duplication: =
The pseudo-operator = causes the most recent element of the stack to be du-
plicated onto the stack.

pop The pseudo-function pop causes the most recent element of the stack to be
popped. A `>' on its own has the same effect.

>ident The expression > followed (with no space) by a shell identifier causes the
most recent element of the stack to be popped and assigned to the variable
with that name. The variable is local to the zcalc function.

<ident The expression < followed (with no space) by a shell identifier causes the
value of the variable with that name to be pushed onto the stack. ident may
be an integer, in which case the previous result with that number (as shown
before the > in the standard zcalc prompt) is put on the stack.

Exchange: xy
The pseudo-function xy causes the most recent two elements of the stack to
be exchanged. `<>' has the same effect.

The prompt is configurable via the parameter ZCALCPROMPT, which undergoes standard
prompt expansion. The index of the current entry is stored locally in the first
element of the array psvar, which can be referred to in ZCALCPROMPT as `%1v'. The
default prompt is `%1v> '.

The variable ZCALC_ACTIVE is set within the function and can be tested by nested
functions; it has the value rpn if RPN mode is active, else 1.

A few special commands are available; these are introduced by a colon. For back-
ward compatibility, the colon may be omitted for certain commands. Completion is
available if compinit has been run.

The output precision may be specified within zcalc by special commands familiar
from many calculators.
:norm The default output format. It corresponds to the printf %g specification.
Typically this shows six decimal digits.

:sci digits
Scientific notation, corresponding to the printf %g output format with the
precision given by digits. This produces either fixed point or exponential
notation depending on the value output.

:fix digits
Fixed point notation, corresponding to the printf %f output format with the
precision given by digits.

:eng digits
Exponential notation, corresponding to the printf %E output format with the
precision given by digits.

:raw Raw output: this is the default form of the output from a math evaluation.
This may show more precision than the number actually possesses.

Other special commands:
:!line...
Execute line... as a normal shell command line. Note that it is executed in
the context of the function, i.e. with local variables. Space is optional
after :!.

:local arg ...
Declare variables local to the function. Other variables may be used, too,
but they will be taken from or put into the global scope.

:function name [ body ]
Define a mathematical function or (with no body) delete it. :function may
be abbreviated to :func or simply :f. The name may contain the same charac-
ters as a shell function name. The function is defined using zmathfuncdef,
see below.

Note that zcalc takes care of all quoting. Hence for example:

:f cube $1 * $1 * $1

defines a function to cube the sole argument. Functions so defined, or in-
deed any functions defined directly or indirectly using functions -M, are
available to execute by typing only the name on the line in RPN mode; this
pops the appropriate number of arguments off the stack to pass to the func-
tion, i.e. 1 in the case of the example cube function. If there are op-
tional arguments only the mandatory arguments are supplied by this means.

[#base]
This is not a special command, rather part of normal arithmetic syntax; how-
ever, when this form appears on a line by itself the default output radix is
set to base. Use, for example, `[#16]' to display hexadecimal output pre-
ceded by an indication of the base, or `[##16]' just to display the raw num-
ber in the given base. Bases themselves are always specified in decimal.
`[#]' restores the normal output format. Note that setting an output base
suppresses floating point output; use `[#]' to return to normal operation.

$var Print out the value of var literally; does not affect the calculation. To
use the value of var, omit the leading `$'.

See the comments in the function for a few extra tips.

min(arg, ...)
max(arg, ...)
sum(arg, ...)
zmathfunc
The function zmathfunc defines the three mathematical functions min, max, and sum.
The functions min and max take one or more arguments. The function sum takes zero
or more arguments. Arguments can be of different types (ints and floats).

Not to be confused with the zsh/mathfunc module, described in the section `The
zsh/mathfunc Module' in zshmodules(1).

zmathfuncdef [ mathfunc [ body ] ]
A convenient front end to functions -M.

With two arguments, define a mathematical function named mathfunc which can be used
in any form of arithmetic evaluation. body is a mathematical expression to imple-
ment the function. It may contain references to position parameters $1, $2, ...
to refer to mandatory parameters and ${1:-defvalue} ... to refer to optional pa-
rameters. Note that the forms must be strictly adhered to for the function to cal-
culate the correct number of arguments. The implementation is held in a shell
function named zsh_math_func_mathfunc; usually the user will not need to refer to
the shell function directly. Any existing function of the same name is silently
replaced.

With one argument, remove the mathematical function mathfunc as well as the shell
function implementation.

With no arguments, list all mathfunc functions in a form suitable for restoring the
definition. The functions have not necessarily been defined by zmathfuncdef.

USER CONFIGURATION FUNCTIONS
The zsh/newuser module comes with a function to aid in configuring shell options for new
users. If the module is installed, this function can also be run by hand. It is avail-
able even if the module's default behaviour, namely running the function for a new user
logging in without startup files, is inhibited.

zsh-newuser-install [ -f ]
The function presents the user with various options for customizing their initial-
ization scripts. Currently only ~/.zshrc is handled. $ZDOTDIR/.zshrc is used in-
stead if the parameter ZDOTDIR is set; this provides a way for the user to config-
ure a file without altering an existing .zshrc.

By default the function exits immediately if it finds any of the files .zshenv,
.zprofile, .zshrc, or .zlogin in the appropriate directory. The option -f is re-
quired in order to force the function to continue. Note this may happen even if
.zshrc itself does not exist.

As currently configured, the function will exit immediately if the user has root
privileges; this behaviour cannot be overridden.

Once activated, the function's behaviour is supposed to be self-explanatory. Menus
are present allowing the user to alter the value of options and parameters. Sug-
gestions for improvements are always welcome.

When the script exits, the user is given the opportunity to save the new file or
not; changes are not irreversible until this point. However, the script is careful
to restrict changes to the file only to a group marked by the lines `# Lines con-
figured by zsh-newuser-install' and `# End of lines configured by zsh-newuser-in-
stall'. In addition, the old version of .zshrc is saved to a file with the suffix
.zni appended.

If the function edits an existing .zshrc, it is up to the user to ensure that the
changes made will take effect. For example, if control usually returns early from
the existing .zshrc the lines will not be executed; or a later initialization file
may override options or parameters, and so on. The function itself does not at-
tempt to detect any such conflicts.

OTHER FUNCTIONS
There are a large number of helpful functions in the Functions/Misc directory of the zsh
distribution. Most are very simple and do not require documentation here, but a few are
worthy of special mention.

Descriptions
colors This function initializes several associative arrays to map color names to (and
from) the ANSI standard eight-color terminal codes. These are used by the prompt
theme system (see above). You seldom should need to run colors more than once.

The eight base colors are: black, red, green, yellow, blue, magenta, cyan, and
white. Each of these has codes for foreground and background. In addition there
are seven intensity attributes: bold, faint, standout, underline, blink, reverse,
and conceal. Finally, there are seven codes used to negate attributes: none (reset
all attributes to the defaults), normal (neither bold nor faint), no-standout,
no-underline, no-blink, no-reverse, and no-conceal.

Some terminals do not support all combinations of colors and intensities.

The associative arrays are:

color
colour Map all the color names to their integer codes, and integer codes to the
color names. The eight base names map to the foreground color codes, as do
names prefixed with `fg-', such as `fg-red'. Names prefixed with `bg-',
such as `bg-blue', refer to the background codes. The reverse mapping from
code to color yields base name for foreground codes and the bg- form for
backgrounds.

Although it is a misnomer to call them `colors', these arrays also map the
other fourteen attributes from names to codes and codes to names.

fg
fg_bold
fg_no_bold
Map the eight basic color names to ANSI terminal escape sequences that set
the corresponding foreground text properties. The fg sequences change the
color without changing the eight intensity attributes.

bg
bg_bold
bg_no_bold
Map the eight basic color names to ANSI terminal escape sequences that set
the corresponding background properties. The bg sequences change the color
without changing the eight intensity attributes.

In addition, the scalar parameters reset_color and bold_color are set to the ANSI
terminal escapes that turn off all attributes and turn on bold intensity, respec-
tively.

fned [ -x num ] name
Same as zed -f. This function does not appear in the zsh distribution, but can be
created by linking zed to the name fned in some directory in your fpath.

is-at-least needed [ present ]
Perform a greater-than-or-equal-to comparison of two strings having the format of a
zsh version number; that is, a string of numbers and text with segments separated
by dots or dashes. If the present string is not provided, $ZSH_VERSION is used.
Segments are paired left-to-right in the two strings with leading non-number parts
ignored. If one string has fewer segments than the other, the missing segments are
considered zero.

This is useful in startup files to set options and other state that are not avail-
able in all versions of zsh.

is-at-least 3.1.6-15 && setopt NO_GLOBAL_RCS
is-at-least 3.1.0 && setopt HIST_REDUCE_BLANKS
is-at-least 2.6-17 || print "You can't use is-at-least here."

nslookup [ arg ... ]
This wrapper function for the nslookup command requires the zsh/zpty module (see
zshmodules(1)). It behaves exactly like the standard nslookup except that it pro-
vides customizable prompts (including a right-side prompt) and completion of
nslookup commands, host names, etc. (if you use the function-based completion sys-
tem). Completion styles may be set with the context prefix `:completion:nslookup'.

See also the pager, prompt and rprompt styles below.

regexp-replace var regexp replace
Use regular expressions to perform a global search and replace operation on a vari-
able. POSIX extended regular expressions are used, unless the option RE_MATCH_PCRE
has been set, in which case Perl-compatible regular expressions are used (this re-
quires the shell to be linked against the pcre library).

var is the name of the variable containing the string to be matched. The variable
will be modified directly by the function. The variables MATCH, MBEGIN, MEND,
match, mbegin, mend should be avoided as these are used by the regular expression
code.

regexp is the regular expression to match against the string.

replace is the replacement text. This can contain parameter, command and arith-
metic expressions which will be replaced: in particular, a reference to $MATCH
will be replaced by the text matched by the pattern.

The return status is 0 if at least one match was performed, else 1.

run-help cmd
This function is designed to be invoked by the run-help ZLE widget, in place of the
default alias. See `Accessing On-Line Help' above for setup instructions.

In the discussion which follows, if cmd is a file system path, it is first reduced
to its rightmost component (the file name).

Help is first sought by looking for a file named cmd in the directory named by the
HELPDIR parameter. If no file is found, an assistant function, alias, or command
named run-help-cmd is sought. If found, the assistant is executed with the rest of
the current command line (everything after the command name cmd) as its arguments.
When neither file nor assistant is found, the external command `man cmd' is run.

An example assistant for the "ssh" command:

run-help-ssh() {
emulate -LR zsh
local -a args
# Delete the "-l username" option
zparseopts -D -E -a args l:
# Delete other options, leaving: host command
args=(${@:#-*})
if [[ ${#args} -lt 2 ]]; then
man ssh
else
run-help $args[2]
fi
}

Several of these assistants are provided in the Functions/Misc directory. These
must be autoloaded, or placed as executable scripts in your search path, in order
to be found and used by run-help.

run-help-git
run-help-ip
run-help-openssl
run-help-p4
run-help-sudo
run-help-svk
run-help-svn
Assistant functions for the git, ip, openssl, p4, sudo, svk, and svn, com-
mands.

tetris Zsh was once accused of not being as complete as Emacs, because it lacked a Tetris
game. This function was written to refute this vicious slander.

This function must be used as a ZLE widget:

autoload -U tetris
zle -N tetris
bindkey keys tetris

To start a game, execute the widget by typing the keys. Whatever command line you
were editing disappears temporarily, and your keymap is also temporarily replaced
by the Tetris control keys. The previous editor state is restored when you quit
the game (by pressing `q') or when you lose.

If you quit in the middle of a game, the next invocation of the tetris widget will
continue where you left off. If you lost, it will start a new game.

tetriscurses
This is a port of the above to zcurses. The input handling is improved a bit so
that moving a block sideways doesn't automatically advance a timestep, and the
graphics use unicode block graphics.

This version does not save the game state between invocations, and is not invoked
as a widget, but rather as:

autoload -U tetriscurses
tetriscurses

zargs [ option ... -- ] [ input ... ] [ -- command [ arg ... ] ]
This function has a similar purpose to GNU xargs. Instead of reading lines of ar-
guments from the standard input, it takes them from the command line. This is use-
ful because zsh, especially with recursive glob operators, often can construct a
command line for a shell function that is longer than can be accepted by an exter-
nal command.

The option list represents options of the zargs command itself, which are the same
as those of xargs. The input list is the collection of strings (often file names)
that become the arguments of the command, analogous to the standard input of xargs.
Finally, the arg list consists of those arguments (usually options) that are passed
to the command each time it runs. The arg list precedes the elements from the in-
put list in each run. If no command is provided, then no arg list may be provided,
and in that event the default command is `print' with arguments `-r --'.

For example, to get a long ls listing of all non-hidden plain files in the current
directory or its subdirectories:

autoload -U zargs
zargs -- **/*(.) -- ls -ld --

The first and third occurrences of `--' are used to mark the end of options for
zargs and ls respectively to guard against filenames starting with `-', while the
second is used to separate the list of files from the command to run (`ls -ld --').

The first `--' would also be needed if there was a chance the list might be empty
as in:

zargs -r -- ./*.back(#qN) -- rm -f

In the event that the string `--' is or may be an input, the -e option may be used
to change the end-of-inputs marker. Note that this does not change the end-of-op-
tions marker. For example, to use `..' as the marker:

zargs -e.. -- **/*(.) .. ls -ld --

This is a good choice in that example because no plain file can be named `..', but
the best end-marker depends on the circumstances.

The options -i, -I, -l, -L, and -n differ slightly from their usage in xargs.
There are no input lines for zargs to count, so -l and -L count through the input
list, and -n counts the number of arguments passed to each execution of command,
including any arg list. Also, any time -i or -I is used, each input is processed
separately as if by `-L 1'.

For details of the other zargs options, see xargs(1) (but note the difference in
function between zargs and xargs) or run zargs with the --help option.

zed [ -f [ -x num ] ] name
zed -b This function uses the ZLE editor to edit a file or function.

Only one name argument is allowed. If the -f option is given, the name is taken to
be that of a function; if the function is marked for autoloading, zed searches for
it in the fpath and loads it. Note that functions edited this way are installed
into the current shell, but not written back to the autoload file. In this case
the -x option specifies that leading tabs indenting the function according to syn-
tax should be converted into the given number of spaces; `-x 2' is consistent with
the layout of functions distributed with the shell.

Without -f, name is the path name of the file to edit, which need not exist; it is
created on write, if necessary.

While editing, the function sets the main keymap to zed and the vi command keymap
to zed-vicmd. These will be copied from the existing main and vicmd keymaps if
they do not exist the first time zed is run. They can be used to provide special
key bindings used only in zed.

If it creates the keymap, zed rebinds the return key to insert a line break and
`^X^W' to accept the edit in the zed keymap, and binds `ZZ' to accept the edit in
the zed-vicmd keymap.

The bindings alone can be installed by running `zed -b'. This is suitable for
putting into a startup file. Note that, if rerun, this will overwrite the existing
zed and zed-vicmd keymaps.

Completion is available, and styles may be set with the context prefix `:comple-
tion:zed'.

A zle widget zed-set-file-name is available. This can be called by name from
within zed using `\ex zed-set-file-name' (note, however, that because of zed's re-
bindings you will have to type ^j at the end instead of the return key), or can be
bound to a key in either of the zed or zed-vicmd keymaps after `zed -b' has been
run. When the widget is called, it prompts for a new name for the file being
edited. When zed exits the file will be written under that name and the original
file will be left alone. The widget has no effect with `zed -f'.

While zed-set-file-name is running, zed uses the keymap zed-normal-keymap, which is
linked from the main keymap in effect at the time zed initialised its bindings.
(This is to make the return key operate normally.) The result is that if the main
keymap has been changed, the widget won't notice. This is not a concern for most
users.

zcp [ -finqQvwW ] srcpat dest
zln [ -finqQsvwW ] srcpat dest
Same as zmv -C and zmv -L, respectively. These functions do not appear in the zsh
distribution, but can be created by linking zmv to the names zcp and zln in some
directory in your fpath.

zkbd See `Keyboard Definition' above.

zmv [ -finqQsvwW ] [ -C | -L | -M | -{p|P} program ] [ -o optstring ]
srcpat dest
Move (usually, rename) files matching the pattern srcpat to corresponding files
having names of the form given by dest, where srcpat contains parentheses surround-
ing patterns which will be replaced in turn by $1, $2, ... in dest. For example,

zmv '(*).lis' '$1.txt'

renames `foo.lis' to `foo.txt', `my.old.stuff.lis' to `my.old.stuff.txt', and so
on.

The pattern is always treated as an EXTENDED_GLOB pattern. Any file whose name is
not changed by the substitution is simply ignored. Any error (a substitution re-
sulted in an empty string, two substitutions gave the same result, the destination
was an existing regular file and -f was not given) causes the entire function to
abort without doing anything.

In addition to pattern replacement, the variable $f can be referrred to in the sec-
ond (replacement) argument. This makes it possible to use variable substitution to
alter the argument; see examples below.

Options:

-f Force overwriting of destination files. Not currently passed down to the
mv/cp/ln command due to vagaries of implementations (but you can use -o-f to
do that).
-i Interactive: show each line to be executed and ask the user whether to exe-
cute it. `Y' or `y' will execute it, anything else will skip it. Note that
you just need to type one character.
-n No execution: print what would happen, but don't do it.
-q Turn bare glob qualifiers off: now assumed by default, so this has no ef-
fect.
-Q Force bare glob qualifiers on. Don't turn this on unless you are actually
using glob qualifiers in a pattern.
-s Symbolic, passed down to ln; only works with -L.
-v Verbose: print each command as it's being executed.
-w Pick out wildcard parts of the pattern, as described above, and implicitly
add parentheses for referring to them.
-W Just like -w, with the addition of turning wildcards in the replacement pat-
tern into sequential ${1} .. ${N} references.
-C
-L
-M Force cp, ln or mv, respectively, regardless of the name of the function.
-p program
Call program instead of cp, ln or mv. Whatever it does, it should at least
understand the form `program -- oldname newname' where oldname and newname
are filenames generated by zmv. program will be split into words, so might
be e.g. the name of an archive tool plus a copy or rename subcommand.
-P program
As -p program, except that program does not accept a following -- to indi-
cate the end of options. In this case filenames must already be in a sane
form for the program in question.
-o optstring
The optstring is split into words and passed down verbatim to the cp, ln or
mv command called to perform the work. It should probably begin with a `-'.

Further examples:

zmv -v '(* *)' '${1// /_}'

For any file in the current directory with at least one space in the name, replace
every space by an underscore and display the commands executed.

zmv -v '* *' '${f// /_}'

This does exactly the same by referring to the file name stored in $f.

For more complete examples and other implementation details, see the zmv source
file, usually located in one of the directories named in your fpath, or in Func-
tions/Misc/zmv in the zsh distribution.

zrecompile
See `Recompiling Functions' above.

zstyle+ context style value [ + subcontext style value ... ]
This makes defining styles a bit simpler by using a single `+' as a special token
that allows you to append a context name to the previously used context name. Like
this:

zstyle+ ':foo:bar' style1 value1 \
+':baz' style2 value2 \
+':frob' style3 value3

This defines style1 with value1 for the context :foo:bar as usual, but it also de-
fines style2 with value2 for the context :foo:bar:baz and style3 with value3 for
:foo:bar:frob. Any subcontext may be the empty string to re-use the first context
unchanged.

Styles
insert-tab
The zed function sets this style in context `:completion:zed:*' to turn off comple-
tion when TAB is typed at the beginning of a line. You may override this by set-
ting your own value for this context and style.

pager The nslookup function looks up this style in the context `:nslookup' to determine
the program used to display output that does not fit on a single screen.

prompt
rprompt
The nslookup function looks up this style in the context `:nslookup' to set the
prompt and the right-side prompt, respectively. The usual expansions for the PS1
and RPS1 parameters may be used (see EXPANSION OF PROMPT SEQUENCES in zshmisc(1)).

ZSHALL(1) General Commands Manual ZSHALL(1)

FILES
$ZDOTDIR/.zshenv
$ZDOTDIR/.zprofile
$ZDOTDIR/.zshrc
$ZDOTDIR/.zlogin
$ZDOTDIR/.zlogout
${TMPPREFIX}* (default is /tmp/zsh*)
/etc/zsh/zshenv
/etc/zsh/zprofile
/etc/zsh/zshrc
/etc/zsh/zlogin
/etc/zsh/zlogout (installation-specific - /etc is the default)

SEE ALSO
sh(1), csh(1), tcsh(1), rc(1), bash(1), ksh(1)

IEEE Standard for information Technology - Portable Operating System Interface (POSIX) -
Part 2: Shell and Utilities, IEEE Inc, 1993, ISBN 1-55937-255-9.

zsh 5.8.1 February 12, 2022 ZSHALL(1)

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