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TCSH(1)                              General Commands Manual                              TCSH(1)

NAME
       tcsh - C shell with file name completion and command line editing

SYNOPSIS
       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l

DESCRIPTION
       tcsh  is  an  enhanced  but  completely  compatible  version of the Berkeley UNIX C shell,
       csh(1).  It is a command language interpreter usable both as an  interactive  login  shell
       and a shell script command processor.  It includes a command-line editor (see The command-
       line editor), programmable word completion (see Completion and listing), spelling  correc-
       tion  (see  Spelling correction), a history mechanism (see History substitution), job con-
       trol (see Jobs) and a C-like syntax.  The NEW FEATURES section  describes  major  enhance-
       ments  of  tcsh  over  csh(1).  Throughout this manual, features of tcsh not found in most
       csh(1) implementations (specifically, the 4.4BSD csh) are labeled with `(+)', and features
       which are present in csh(1) but not usually documented are labeled with `(u)'.

   Argument list processing
       If  the first argument (argument 0) to the shell is `-' then it is a login shell.  A login
       shell can be also specified by invoking the shell with the -l flag as the only argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from option processing, causing any further shell arguments  to  be
           treated  as  non-option arguments.  The remaining arguments will not be interpreted as
           shell options.  This may be used to pass options to a shell script  without  confusion
           or  possible subterfuge.  The shell will not run a set-user ID script without this op-
           tion.

       -c  Commands are read from the following argument (which must be present, and  must  be  a
           single  argument),  stored  in the command shell variable for reference, and executed.
           Any remaining arguments are placed in the argv shell variable.

       -d  The shell loads the directory stack from ~/.cshdirs as  described  under  Startup  and
           shutdown, whether or not it is a login shell. (+)

       -Dname[=value]
           Sets the environment variable name to value. (Domain/OS only) (+)

       -e  The shell exits if any invoked command terminates abnormally or yields a non-zero exit
           status.

       -f  The shell does not load any resource or startup files, or perform any command hashing,
           and thus starts faster.

       -F  The shell uses fork(2) instead of vfork(2) to spawn processes. (+)

       -i  The  shell  is  interactive and prompts for its top-level input, even if it appears to
           not be a terminal.  Shells are interactive without this option  if  their  inputs  and
           outputs are terminals.

       -l  The shell is a login shell.  Applicable only if -l is the only flag specified.

       -m  The  shell  loads  ~/.tcshrc  even if it does not belong to the effective user.  Newer
           versions of su(1) can pass -m to the shell. (+)

       -n  The shell parses commands but does not execute them.  This  aids  in  debugging  shell
           scripts.

       -q  The  shell  accepts  SIGQUIT (see Signal handling) and behaves when it is used under a
           debugger.  Job control is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line of input.  A `\' may be used to escape  the
           newline at the end of this line and continue onto another line.

       -v  Sets the verbose shell variable, so that command input is echoed after history substi-
           tution.

       -x  Sets the echo shell variable, so that commands are echoed  immediately  before  execu-
           tion.

       -V  Sets the verbose shell variable even before executing ~/.tcshrc.

       -X  Is to -x as -V is to -v.

       --help
           Print a help message on the standard output and exit. (+)

       --version
           Print  the version/platform/compilation options on the standard output and exit.  This
           information is also contained in the version shell variable. (+)

       After processing of flag arguments, if arguments remain but none of the -c, -i, -s, or  -t
       options  were  given,  the  first  argument is taken as the name of a file of commands, or
       ``script'', to be executed.  The shell opens this file and saves its name for possible re-
       substitution by `$0'.  Because many systems use either the standard version 6 or version 7
       shells whose shell scripts are not compatible with this  shell,  the  shell  uses  such  a
       `standard'  shell  to execute a script whose first character is not a `#', i.e., that does
       not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A login shell begins by executing  commands  from  the  system  files  /etc/csh.cshrc  and
       /etc/csh.login.   It then executes commands from files in the user's home directory: first
       ~/.tcshrc (+) or, if ~/.tcshrc is not found, ~/.cshrc, then the contents of ~/.history (or
       the  value  of the histfile shell variable) are loaded into memory, then ~/.login, and fi-
       nally ~/.cshdirs (or the value of the dirsfile shell variable) (+).  The  shell  may  read
       /etc/csh.login  before instead of after /etc/csh.cshrc, and ~/.login before instead of af-
       ter ~/.tcshrc or ~/.cshrc and ~/.history, if so compiled; see the version shell  variable.
       (+)

       Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on startup.

       For examples of startup files, please consult http://tcshrc.sourceforge.net.

       Commands  like  stty(1)  and tset(1), which need be run only once per login, usually go in
       one's ~/.login file.  Users who need to use the same set of files  with  both  csh(1)  and
       tcsh  can  have  only a ~/.cshrc which checks for the existence of the tcsh shell variable
       (q.v.) before using tcsh-specific commands, or can have both a ~/.cshrc  and  a  ~/.tcshrc
       which  sources  (see  the builtin command) ~/.cshrc.  The rest of this manual uses `~/.tc-
       shrc' to mean `~/.tcshrc or, if ~/.tcshrc is not found, ~/.cshrc'.

       In the normal case, the shell begins reading commands from the terminal, prompting with `>
       '.   (Processing of arguments and the use of the shell to process files containing command
       scripts are described later.)  The shell repeatedly reads a line of command input,  breaks
       it  into words, places it on the command history list, parses it and executes each command
       in the line.

       One can log out by typing `^D' on an empty line, `logout' or `login' or  via  the  shell's
       autologout  mechanism  (see the autologout shell variable).  When a login shell terminates
       it sets the logout shell variable to `normal' or `automatic' as appropriate, then executes
       commands  from  the files /etc/csh.logout and ~/.logout.  The shell may drop DTR on logout
       if so compiled; see the version shell variable.

       The names of the system login and logout files vary from system to system for  compatibil-
       ity with different csh(1) variants; see FILES.

   Editing
       We  first  describe The command-line editor.  The Completion and listing and Spelling cor-
       rection sections describe two sets of functionality that are implemented  as  editor  com-
       mands but which deserve their own treatment.  Finally, Editor commands lists and describes
       the editor commands specific to the shell and their default bindings.

   The command-line editor (+)
       Command-line input can be edited using key sequences much like those used in  emacs(1)  or
       vi(1).   The editor is active only when the edit shell variable is set, which it is by de-
       fault in interactive shells.  The bindkey builtin can display  and  change  key  bindings.
       emacs(1)-style  key bindings are used by default (unless the shell was compiled otherwise;
       see the version shell variable), but bindkey can change the key  bindings  to  vi(1)-style
       bindings en masse.

       The shell always binds the arrow keys (as defined in the TERMCAP environment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       unless  doing  so would alter another single-character binding.  One can set the arrow key
       escape sequences to the empty string with settc to prevent these bindings.  The ANSI/VT100
       sequences for arrow keys are always bound.

       Other  key bindings are, for the most part, what emacs(1) and vi(1) users would expect and
       can easily be displayed by bindkey, so there is no need  to  list  them  here.   Likewise,
       bindkey  can list the editor commands with a short description of each.  Certain key bind-
       ings have different behavior depending if emacs(1) or vi(1) style bindings are being used;
       see vimode for more information.

       Note  that  editor  commands  do not have the same notion of a ``word'' as does the shell.
       The editor delimits words with any non-alphanumeric characters not in the  shell  variable
       wordchars, while the shell recognizes only whitespace and some of the characters with spe-
       cial meanings to it, listed under Lexical structure.

   Completion and listing (+)
       The shell is often able to complete words when given a unique abbreviation.  Type part  of
       a  word  (for  example `ls /usr/lost') and hit the tab key to run the complete-word editor
       command.  The shell completes the filename `/usr/lost'  to  `/usr/lost+found/',  replacing
       the  incomplete  word with the complete word in the input buffer.  (Note the terminal `/';
       completion adds a `/' to the end of completed directories and a space to the end of  other
       completed  words, to speed typing and provide a visual indicator of successful completion.
       The addsuffix shell variable can be unset to prevent this.)  If no match is found (perhaps
       `/usr/lost+found'  doesn't  exist),  the terminal bell rings.  If the word is already com-
       plete (perhaps there is a `/usr/lost' on your system, or perhaps you were thinking too far
       ahead  and  typed  the whole thing) a `/' or space is added to the end if it isn't already
       there.

       Completion works anywhere in the line, not at just the end; completed text pushes the rest
       of  the  line  to the right.  Completion in the middle of a word often results in leftover
       characters to the right of the cursor that need to be deleted.

       Commands and variables can be completed  in  much  the  same  way.   For  example,  typing
       `em[tab]' would complete `em' to `emacs' if emacs were the only command on your system be-
       ginning with `em'.  Completion can find a command in any directory in path or if  given  a
       full  pathname.   Typing `echo $ar[tab]' would complete `$ar' to `$argv' if no other vari-
       able began with `ar'.

       The shell parses the input buffer to determine whether  the  word  you  want  to  complete
       should  be completed as a filename, command or variable.  The first word in the buffer and
       the first word following `;', `|', `|&', `&&' or `||' is considered to be  a  command.   A
       word  beginning with `$' is considered to be a variable.  Anything else is a filename.  An
       empty line is `completed' as a filename.

       You can list the possible completions of a word at any time by  typing  `^D'  to  run  the
       delete-char-or-list-or-eof editor command.  The shell lists the possible completions using
       the ls-F builtin (q.v.)  and reprints the prompt and unfinished command line, for example:

           > ls /usr/l[^D]
           lbin/       lib/        local/      lost+found/
           > ls /usr/l

       If the autolist shell variable is set, the shell lists  the  remaining  choices  (if  any)
       whenever completion fails:

           > set autolist
           > nm /usr/lib/libt[tab]
           libtermcap.a@ libtermlib.a@
           > nm /usr/lib/libterm

       If  autolist is set to `ambiguous', choices are listed only when completion fails and adds
       no new characters to the word being completed.

       A filename to be completed can contain variables, your own or others' home directories ab-
       breviated  with  `~'  (see  Filename substitution) and directory stack entries abbreviated
       with `=' (see Directory stack substitution).  For example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/

       or

           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note that variables can also be expanded explicitly with the expand-variables editor  com-
       mand.

       delete-char-or-list-or-eof  lists  at only the end of the line; in the middle of a line it
       deletes the character under the cursor and on an empty line it logs one  out  or,  if  ig-
       noreeof  is  set,  does  nothing.  `M-^D', bound to the editor command list-choices, lists
       completion possibilities anywhere on a line, and list-choices (or any one of  the  related
       editor commands that do or don't delete, list and/or log out, listed under delete-char-or-
       list-or-eof) can be bound to `^D' with the bindkey builtin command if so desired.

       The complete-word-fwd and complete-word-back editor commands (not bound to any keys by de-
       fault)  can be used to cycle up and down through the list of possible completions, replac-
       ing the current word with the next or previous word in the list.

       The shell variable fignore can be set to a list of suffixes to be ignored  by  completion.
       Consider the following:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o
           > emacs ma[tab]
           > emacs main.c

       `main.c~'  and  `main.o'  are ignored by completion (but not listing), because they end in
       suffixes in fignore.  Note that a `\' was needed in front of `~' to prevent it from  being
       expanded to home as described under Filename substitution.  fignore is ignored if only one
       completion is possible.

       If the complete shell variable is set to `enhance', completion 1) ignores case and 2) con-
       siders  periods,  hyphens and underscores (`.', `-' and `_') to be word separators and hy-
       phens and underscores to be equivalent.  If you had the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and typed `mail -f c.l.c[tab]', it would be completed to `mail  -f  comp.lang.c',  and  ^D
       would   list   `comp.lang.c'   and  `comp.lang.c++'.   `mail  -f  c..c++[^D]'  would  list
       `comp.lang.c++' and `comp.std.c++'.  Typing `rm a--file[^D]' in the following directory

           A_silly_file    a-hyphenated-file    another_silly_file

       would list all three files, because case is ignored and hyphens and underscores are equiv-
       alent.  Periods, however, are not equivalent to hyphens or underscores.

       If  the  complete  shell variable is set to `Enhance', completion ignores case and differ-
       ences between a hyphen and an underscore word separator only when the user types a  lower-
       case  character  or  a  hyphen.  Entering an uppercase character or an underscore will not
       match the  corresponding  lowercase  character  or  hyphen  word  separator.   Typing  `rm
       a--file[^D]'  in  the  directory of the previous example would still list all three files,
       but typing `rm A--file' would match only `A_silly_file' and typing `rm a__file[^D]'  would
       match just `A_silly_file' and `another_silly_file' because the user explicitly used an up-
       percase or an underscore character.

       Completion and listing are affected by several other shell variables: recexact can be  set
       to  complete  on the shortest possible unique match, even if more typing might result in a
       longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just beeps, because `fo' could expand to `fod' or `foo', but if we type another `o',

           > rm foo[tab]
           > rm foo

       the completion completes on `foo', even though `food' and `foonly' also match.  autoexpand
       can  be set to run the expand-history editor command before each completion attempt, auto-
       correct can be set to spelling-correct the word to be completed (see Spelling  correction)
       before  each  completion attempt and correct can be set to complete commands automatically
       after one hits `return'.  matchbeep can be set to make completion beep or not  beep  in  a
       variety of situations, and nobeep can be set to never beep at all.  nostat can be set to a
       list of directories and/or patterns that match directories to prevent the completion mech-
       anism  from stat(2)ing those directories.  listmax and listmaxrows can be set to limit the
       number of items and rows (respectively) that are  listed  without  asking  first.   recog-
       nize_only_executables can be set to make the shell list only executables when listing com-
       mands, but it is quite slow.

       Finally, the complete builtin command can be used to tell the shell how to complete  words
       other than filenames, commands and variables.  Completion and listing do not work on glob-
       patterns (see Filename substitution), but the list-glob and  expand-glob  editor  commands
       perform equivalent functions for glob-patterns.

   Spelling correction (+)
       The  shell can sometimes correct the spelling of filenames, commands and variable names as
       well as completing and listing them.

       Individual words can be spelling-corrected with the  spell-word  editor  command  (usually
       bound  to M-s and M-S) and the entire input buffer with spell-line (usually bound to M-$).
       The correct shell variable can be set to `cmd' to correct the command  name  or  `all'  to
       correct  the  entire line each time return is typed, and autocorrect can be set to correct
       the word to be completed before each completion attempt.

       When spelling correction is invoked in any of these ways and the  shell  thinks  that  any
       part of the command line is misspelled, it prompts with the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One  can  answer  `y' or space to execute the corrected line, `e' to leave the uncorrected
       command in the input buffer, `a' to abort the command as if `^C' had been  hit,  and  any-
       thing else to execute the original line unchanged.

       Spelling  correction  recognizes  user-defined  completions (see the complete builtin com-
       mand).  If an input word in a position for which a completion is defined resembles a  word
       in  the completion list, spelling correction registers a misspelling and suggests the lat-
       ter word as a correction.  However, if the input word does not match any of  the  possible
       completions for that position, spelling correction does not register a misspelling.

       Like  completion,  spelling correction works anywhere in the line, pushing the rest of the
       line to the right and possibly leaving extra characters to the right of the cursor.

   Editor commands (+)
       `bindkey' lists key bindings and `bindkey -l' lists and briefly describes editor commands.
       Only  new  or especially interesting editor commands are described here.  See emacs(1) and
       vi(1) for descriptions of each editor's key bindings.

       The character or characters to which each command is bound by default is given  in  paren-
       theses.   `^character' means a control character and `M-character' a meta character, typed
       as escape-character on terminals without a meta key.  Case counts, but commands  that  are
       bound  to  letters  by  default  are bound to both lower- and uppercase letters for conve-
       nience.

       backward-char (^B, left)
               Move back a character.  Cursor behavior modified by vimode.

       backward-delete-word (M-^H, M-^?)
               Cut from beginning of current word to cursor - saved in cut buffer.  Word boundary
               behavior modified by vimode.

       backward-word (M-b, M-B)
               Move  to beginning of current word.  Word boundary and cursor behavior modified by
               vimode.

       beginning-of-line (^A, home)
               Move to beginning of line.  Cursor behavior modified by vimode.

       capitalize-word (M-c, M-C)
               Capitalize the characters from cursor to end of current word.  Word  boundary  be-
               havior modified by vimode.

       complete-word (tab)
               Completes a word as described under Completion and listing.

       complete-word-back (not bound)
               Like complete-word-fwd, but steps up from the end of the list.

       complete-word-fwd (not bound)
               Replaces the current word with the first word in the list of possible completions.
               May be repeated to step down through the list.  At the end of the list, beeps  and
               reverts to the incomplete word.

       complete-word-raw (^X-tab)
               Like complete-word, but ignores user-defined completions.

       copy-prev-word (M-^_)
               Copies  the previous word in the current line into the input buffer.  See also in-
               sert-last-word.  Word boundary behavior modified by vimode.

       dabbrev-expand (M-/)
               Expands the current word to the most recent preceding one for which the current is
               a  leading  substring,  wrapping around the history list (once) if necessary.  Re-
               peating dabbrev-expand without any intervening typing changes to the next previous
               word etc., skipping identical matches much like history-search-backward does.

       delete-char (bound to `Del' if using the standard /etc/csh.cshrc)
               Deletes  the  character  under  the  cursor.  See also delete-char-or-list-or-eof.
               Cursor behavior modified by vimode.

       delete-char-or-eof (not bound)
               Does delete-char if there is a character under the cursor  or  end-of-file  on  an
               empty line.  See also delete-char-or-list-or-eof.  Cursor behavior modified by vi-
               mode.

       delete-char-or-list (not bound)
               Does delete-char if there is a character under the cursor or list-choices  at  the
               end of the line.  See also delete-char-or-list-or-eof.

       delete-char-or-list-or-eof (^D)
               Does delete-char if there is a character under the cursor, list-choices at the end
               of the line or end-of-file on an empty line.  See also those three commands,  each
               of  which  does  only a single action, and delete-char-or-eof, delete-char-or-list
               and list-or-eof, each of which does a different two out of the three.

       delete-word (M-d, M-D)
               Cut from cursor to end of current word - save in cut buffer.  Word boundary behav-
               ior modified by vimode.

       down-history (down-arrow, ^N)
               Like up-history, but steps down, stopping at the original input line.

       downcase-word (M-l, M-L)
               Lowercase the characters from cursor to end of current word.  Word boundary behav-
               ior modified by vimode.

       end-of-file (not bound)
               Signals an end of file, causing the shell to exit unless the ignoreeof shell vari-
               able (q.v.) is set to prevent this.  See also delete-char-or-list-or-eof.

       end-of-line (^E, end)
               Move cursor to end of line.  Cursor behavior modified by vimode.

       expand-history (M-space)
               Expands history substitutions in the current word.  See History substitution.  See
               also magic-space, toggle-literal-history and the autoexpand shell variable.

       expand-glob (^X-*)
               Expands the glob-pattern to the left of the cursor.  See Filename substitution.

       expand-line (not bound)
               Like expand-history, but expands history substitutions in each word in  the  input
               buffer.

       expand-variables (^X-$)
               Expands the variable to the left of the cursor.  See Variable substitution.

       forward-char (^F, right)
               Move forward one character.  Cursor behavior modified by vimode.

       forward-word (M-f, M-F)
               Move  forward  to end of current word.  Word boundary and cursor behavior modified
               by vimode.

       history-search-backward (M-p, M-P)
               Searches backwards through the history list for a command beginning with the  cur-
               rent  contents  of  the input buffer up to the cursor and copies it into the input
               buffer.  The search string may be a glob-pattern (see Filename substitution)  con-
               taining `*', `?', `[]' or `{}'.  up-history and down-history will proceed from the
               appropriate point in the history list.  Emacs mode only.  See also history-search-
               forward and i-search-back.

       history-search-forward (M-n, M-N)
               Like history-search-backward, but searches forward.

       i-search-back (not bound)
               Searches  backward  like  history-search-backward, copies the first match into the
               input buffer with the cursor positioned at the end of  the  pattern,  and  prompts
               with  `bck:  '  and the first match.  Additional characters may be typed to extend
               the search, i-search-back may be typed to continue searching with  the  same  pat-
               tern,  wrapping around the history list if necessary, (i-search-back must be bound
               to a single character for this to work) or one of the following special characters
               may be typed:

                   ^W      Appends the rest of the word under the cursor to the search pattern.
                   delete (or any character bound to backward-delete-char)
                           Undoes  the effect of the last character typed and deletes a character
                           from the search pattern if appropriate.
                   ^G      If the previous search was successful, aborts the entire  search.   If
                           not, goes back to the last successful search.
                   escape  Ends the search, leaving the current line in the input buffer.

               Any  other character not bound to self-insert-command terminates the search, leav-
               ing the current line in the input buffer, and is then interpreted as normal input.
               In particular, a carriage return causes the current line to be executed.  See also
               i-search-fwd and history-search-backward.  Word boundary behavior modified by  vi-
               mode.

       i-search-fwd (not bound)
               Like  i-search-back, but searches forward.  Word boundary behavior modified by vi-
               mode.

       insert-last-word (M-_)
               Inserts the last word of the previous input line (`!$')  into  the  input  buffer.
               See also copy-prev-word.

       list-choices (M-^D)
               Lists  completion  possibilities  as  described under Completion and listing.  See
               also delete-char-or-list-or-eof and list-choices-raw.

       list-choices-raw (^X-^D)
               Like list-choices, but ignores user-defined completions.

       list-glob (^X-g, ^X-G)
               Lists (via the ls-F builtin) matches to the glob-pattern (see  Filename  substitu-
               tion) to the left of the cursor.

       list-or-eof (not bound)
               Does  list-choices or end-of-file on an empty line.  See also delete-char-or-list-
               or-eof.

       magic-space (not bound)
               Expands history substitutions in the current line, like  expand-history,  and  in-
               serts  a  space.  magic-space is designed to be bound to the space bar, but is not
               bound by default.

       normalize-command (^X-?)
               Searches for the current word in PATH and, if it is found, replaces  it  with  the
               full path to the executable.  Special characters are quoted.  Aliases are expanded
               and quoted but commands within aliases are not.  This command is useful with  com-
               mands that take commands as arguments, e.g., `dbx' and `sh -x'.

       normalize-path (^X-n, ^X-N)
               Expands  the  current word as described under the `expand' setting of the symlinks
               shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current input line and looks for a stopped job where the file name  por-
               tion  of its first word is found in the editors shell variable.  If editors is not
               set, then the file name portion of the EDITOR environment variable (`ed' if unset)
               and  the  VISUAL environment variable (`vi' if unset) will be used.  If such a job
               is found, it is restarted as if `fg %job' had been typed.  This is used to  toggle
               back and forth between an editor and the shell easily.  Some people bind this com-
               mand to `^Z' so they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the current command, using the same notion of  `cur-
               rent command' as the completion routines, and prints it.  There is no way to use a
               pager; run-help is designed for short help files.  If the special  alias  helpcom-
               mand  is defined, it is run with the command name as a sole argument.  Else, docu-
               mentation should be in a file named command.help, command.1, command.6,  command.8
               or command, which should be in one of the directories listed in the HPATH environ-
               ment variable.  If there is more than one help file only the first is printed.

       self-insert-command (text characters)
               In insert mode (the default), inserts the typed character into the input line  af-
               ter the character under the cursor.  In overwrite mode, replaces the character un-
               der the cursor with the typed character.  The input mode is normally preserved be-
               tween  lines,  but  the  inputmode shell variable can be set to `insert' or `over-
               write' to put the editor in that mode at the beginning of  each  line.   See  also
               overwrite-mode.

       sequence-lead-in (arrow prefix, meta prefix, ^X)
               Indicates that the following characters are part of a multi-key sequence.  Binding
               a command to a multi-key sequence really creates two bindings: the first character
               to  sequence-lead-in  and the whole sequence to the command.  All sequences begin-
               ning with a character bound to sequence-lead-in are  effectively  bound  to  unde-
               fined-key unless bound to another command.

       spell-line (M-$)
               Attempts  to  correct  the  spelling of each word in the input buffer, like spell-
               word, but ignores words whose first character is one of `-', `!', `^' or  `%',  or
               which  contain `\', `*' or `?', to avoid problems with switches, substitutions and
               the like.  See Spelling correction.

       spell-word (M-s, M-S)
               Attempts to correct the spelling of the current word as described  under  Spelling
               correction.  Checks each component of a word which appears to be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands  or  `unexpands'  history substitutions in the input buffer.  See also ex-
               pand-history and the autoexpand shell variable.

       undefined-key (any unbound key)
               Beeps.

       up-history (up-arrow, ^P)
               Copies the previous entry in the history list into the input buffer.   If  histlit
               is  set,  uses  the literal form of the entry.  May be repeated to step up through
               the history list, stopping at the top.

       upcase-word (M-u, M-U)
               Uppercase the characters from cursor to end of current word.  Word boundary behav-
               ior modified by vimode.

       vi-beginning-of-next-word (not bound)
               Vi goto the beginning of next word.  Word boundary and cursor behavior modified by
               vimode.

       vi-eword (not bound)
               Vi move to the end of the current word.  Word boundary behavior  modified  by  vi-
               mode.

       vi-search-back (?)
               Prompts  with  `?'  for a search string (which may be a glob-pattern, as with his-
               tory-search-backward), searches for it and copies it into the input  buffer.   The
               bell  rings  if  no match is found.  Hitting return ends the search and leaves the
               last match in the input buffer.  Hitting escape ends the search and  executes  the
               match.  vi mode only.

       vi-search-fwd (/)
               Like vi-search-back, but searches forward.

       which-command (M-?)
               Does a which (see the description of the builtin command) on the first word of the
               input buffer.

       yank-pop (M-y)
               When executed immediately after a yank or another yank-pop,  replaces  the  yanked
               string  with  the next previous string from the killring. This also has the effect
               of rotating the killring, such that this string will be considered  the  most  re-
               cently  killed  by a later yank command. Repeating yank-pop will cycle through the
               killring any number of times.

   Lexical structure
       The shell splits input lines into words at blanks and tabs.  The special  characters  `&',
       `|',  `;', `<', `>', `(', and `)' and the doubled characters `&&', `||', `<<' and `>>' are
       always separate words, whether or not they are surrounded by whitespace.

       When the shell's input is not a terminal, the character `#' is taken to begin  a  comment.
       Each  `#'  and  the rest of the input line on which it appears is discarded before further
       parsing.

       A special character (including a blank or tab) may be prevented from  having  its  special
       meaning, and possibly made part of another word, by preceding it with a backslash (`\') or
       enclosing it in single (`''), double (`"') or backward (``') quotes.  When  not  otherwise
       quoted  a  newline  preceded by a `\' is equivalent to a blank, but inside quotes this se-
       quence results in a newline.

       Furthermore, all Substitutions (see below) except History substitution can be prevented by
       enclosing  the strings (or parts of strings) in which they appear with single quotes or by
       quoting the crucial character(s) (e.g., `$' or ``' for Variable  substitution  or  Command
       substitution  respectively) with `\'.  (Alias substitution is no exception: quoting in any
       way any character of a word for which an alias has been defined prevents  substitution  of
       the  alias.  The usual way of quoting an alias is to precede it with a backslash.) History
       substitution is prevented by backslashes but not by single quotes.   Strings  quoted  with
       double  or  backward  quotes  undergo  Variable substitution and Command substitution, but
       other substitutions are prevented.

       Text inside single or double quotes becomes a single word (or part of  one).   Metacharac-
       ters in these strings, including blanks and tabs, do not form separate words.  Only in one
       special case (see Command substitution below) can a double-quoted string  yield  parts  of
       more  than  one  word;  single-quoted strings never do.  Backward quotes are special: they
       signal Command substitution (q.v.), which may result in more than one word.

       Quoting complex strings, particularly strings which themselves contain quoting characters,
       can be confusing.  Remember that quotes need not be used as they are in human writing!  It
       may be easier to quote not an entire string, but only those parts of the string which need
       quoting, using different types of quoting to do so if appropriate.

       The backslash_quote shell variable (q.v.) can be set to make backslashes always quote `\',
       `'', and `"'.  (+) This may make complex quoting tasks easier, but it can cause syntax er-
       rors in csh(1) scripts.

   Substitutions
       We  now  describe the various transformations the shell performs on the input in the order
       in which they occur.  We note in passing the data structures involved and the commands and
       variables  which  affect them.  Remember that substitutions can be prevented by quoting as
       described under Lexical structure.

   History substitution
       Each command, or ``event'', input from the terminal is saved in  the  history  list.   The
       previous command is always saved, and the history shell variable can be set to a number to
       save that many commands.  The histdup shell variable can be  set  to  not  save  duplicate
       events or consecutive duplicate events.

       Saved commands are numbered sequentially from 1 and stamped with the time.  It is not usu-
       ally necessary to use event numbers, but the current event number can be made part of  the
       prompt by placing an `!' in the prompt shell variable.

       The  shell  actually  saves  history  in  expanded and literal (unexpanded) forms.  If the
       histlit shell variable is set, commands that display and store  history  use  the  literal
       form.

       The history builtin command can print, store in a file, restore and clear the history list
       at any time, and the savehist and histfile shell variables can be set to store the history
       list automatically on logout and restore it on login.

       History  substitutions introduce words from the history list into the input stream, making
       it easy to repeat commands, repeat arguments of a previous command in the current command,
       or  fix  spelling mistakes in the previous command with little typing and a high degree of
       confidence.

       History substitutions begin with the character `!'.  They may begin anywhere in the  input
       stream,  but  they  do  not nest.  The `!' may be preceded by a `\' to prevent its special
       meaning; for convenience, a `!' is passed unchanged when it is followed by a  blank,  tab,
       newline, `=' or `('.  History substitutions also occur when an input line begins with `^'.
       This special abbreviation will be described later.  The characters used to signal  history
       substitution  (`!'  and  `^') can be changed by setting the histchars shell variable.  Any
       input line which contains a history substitution is printed before it is executed.

       A history substitution may have an ``event specification'', which indicates the event from
       which  words  are  to be taken, a ``word designator'', which selects particular words from
       the chosen event, and/or a ``modifier'', which manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An offset, referring to the event n before the current event
           #       The current event.  This should be used carefully in csh(1), where there is no
                   check for recursion.  tcsh allows 10 levels of recursion.  (+)
           !       The previous event (equivalent to `-1')
           s       The most recent event whose first word begins with the string s
           ?s?     The  most  recent  event  which  contains the string s.  The second `?' can be
                   omitted if it is immediately followed by a newline.

       For example, consider this bit of someone's history list:

            9  8:30    nroff -man wumpus.man
           10  8:31    cp wumpus.man wumpus.man.old
           11  8:36    vi wumpus.man
           12  8:37    diff wumpus.man.old wumpus.man

       The commands are shown with their event numbers and time stamps.  The current event, which
       we  haven't typed in yet, is event 13.  `!11' and `!-2' refer to event 11.  `!!' refers to
       the previous event, 12.  `!!' can be abbreviated `!' if it is followed by `:' (`:' is  de-
       scribed  below).   `!n' refers to event 9, which begins with `n'.  `!?old?' also refers to
       event 12, which contains `old'.  Without word designators or modifiers history  references
       simply  expand  to  the  entire  event, so we might type `!cp' to redo the copy command or
       `!!|more' if the `diff' output scrolled off the top of the screen.

       History references may be insulated from the surrounding text with  braces  if  necessary.
       For example, `!vdoc' would look for a command beginning with `vdoc', and, in this example,
       not find one, but `!{v}doc' would expand unambiguously to  `vi  wumpus.mandoc'.   Even  in
       braces, history substitutions do not nest.

       (+)  While  csh(1)  expands, for example, `!3d' to event 3 with the letter `d' appended to
       it, tcsh expands it to the last event beginning with `3d'; only completely  numeric  argu-
       ments  are  treated  as  event numbers.  This makes it possible to recall events beginning
       with numbers.  To expand `!3d' as in csh(1) say `!{3}d'.

       To select words from an event we can follow the event specification by a `:' and a  desig-
       nator  for  the  desired words.  The words of an input line are numbered from 0, the first
       (usually command) word being 0, the second word (first argument) being 1, etc.  The  basic
       word designators are:

           0       The first (command) word
           n       The nth argument
           ^       The first argument, equivalent to `1'
           $       The last argument
           %       The word matched by an ?s? search
           x-y     A range of words
           -y      Equivalent to `0-y'
           *       Equivalent to `^-$', but returns nothing if the event contains only 1 word
           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word (`$')

       Selected  words  are inserted into the command line separated by single blanks.  For exam-
       ple, the `diff' command in the previous example might have been typed  as  `diff  !!:1.old
       !!:1'  (using  `:1'  to  select the first argument from the previous event) or `diff !-2:2
       !-2:1' to select and swap the arguments from the `cp' command.  If we  didn't  care  about
       the  order  of  the  `diff' we might have said `diff !-2:1-2' or simply `diff !-2:*'.  The
       `cp' command might have been written `cp wumpus.man !#:1.old', using `#' to refer  to  the
       current event.  `!n:- hurkle.man' would reuse the first two words from the `nroff' command
       to say `nroff -man hurkle.man'.

       The `:' separating the event specification from the word designator can be omitted if  the
       argument  selector  begins with a `^', `$', `*', `%' or `-'.  For example, our `diff' com-
       mand might have been `diff !!^.old !!^' or, equivalently, `diff !!$.old !!$'.  However, if
       `!!' is abbreviated `!', an argument selector beginning with `-' will be interpreted as an
       event specification.

       A history reference may have a word designator but no event specification.  It then refer-
       ences  the  previous  command.   Continuing  our `diff' example, we could have said simply
       `diff !^.old !^' or, to get the arguments in the opposite order, just `diff !*'.

       The word or words in a history reference can be edited, or ``modified'', by  following  it
       with one or more modifiers, each preceded by a `:':

           h       Remove a trailing pathname component, leaving the head.
           t       Remove all leading pathname components, leaving the tail.
           r       Remove a filename extension `.xxx', leaving the root name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute  l for r.  l is simply a string like r, not a regular expression as
                   in the eponymous ed(1) command.  Any character may be used as the delimiter in
                   place  of  `/';  a `\' can be used to quote the delimiter inside l and r.  The
                   character `&' in the r is replaced by l; `\' also quotes `&'.  If l  is  empty
                   (``''),  the l from a previous substitution or the s from a previous search or
                   event number in event specification is used.  The trailing  delimiter  may  be
                   omitted if it is immediately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply the following modifier once to each word.
           a (+)   Apply  the following modifier as many times as possible to a single word.  `a'
                   and `g' can be used together to apply a modifier globally.  With the `s' modi-
                   fier,  only  the  patterns contained in the original word are substituted, not
                   patterns that contain any substitution result.
           p       Print the new command line but do not execute it.
           q       Quote the substituted words, preventing further substitutions.
           x       Like q, but break into words at blanks, tabs and newlines.

       Modifiers are applied to only the first modifiable word (unless `g' is used).   It  is  an
       error for no word to be modifiable.

       For  example,  the  `diff' command might have been written as `diff wumpus.man.old !#^:r',
       using `:r' to remove `.old' from the first argument on the same line  (`!#^').   We  could
       say `echo hello out there', then `echo !*:u' to capitalize `hello', `echo !*:au' to say it
       out loud, or `echo !*:agu' to really shout.  We might follow `mail -s "I forgot  my  pass-
       word" rot' with `!:s/rot/root' to correct the spelling of `root' (but see Spelling correc-
       tion for a different approach).

       There is a special abbreviation for substitutions.  `^', when it is the first character on
       an  input  line, is equivalent to `!:s^'.  Thus we might have said `^rot^root' to make the
       spelling correction in the previous example.  This is the only history substitution  which
       does not explicitly begin with `!'.

       (+)  In  csh  as such, only one modifier may be applied to each history or variable expan-
       sion.  In tcsh, more than one may be used, for example

           % mv wumpus.man /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In csh, the result would be `wumpus.1:r'.  A substitution followed by a colon may need  to
       be insulated from it with braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The  first  attempt  would  succeed in csh but fails in tcsh, because tcsh expects another
       modifier after the second colon rather than `$'.

       Finally, history can be accessed through the editor as well as through  the  substitutions
       just described.  The up- and down-history, history-search-backward and -forward, i-search-
       back and -fwd, vi-search-back and -fwd, copy-prev-word and  insert-last-word  editor  com-
       mands search for events in the history list and copy them into the input buffer.  The tog-
       gle-literal-history editor command switches between the expanded and literal forms of his-
       tory  lines  in the input buffer.  expand-history and expand-line expand history substitu-
       tions in the current word and in the entire input buffer respectively.

   Alias substitution
       The shell maintains a list of aliases which can be set, unset and printed by the alias and
       unalias  commands.  After a command line is parsed into simple commands (see Commands) the
       first word of each command, left-to-right, is checked to see if it has an alias.   If  so,
       the  first  word  is replaced by the alias.  If the alias contains a history reference, it
       undergoes History substitution (q.v.) as though the original command were the previous in-
       put  line.   If  the alias does not contain a history reference, the argument list is left
       untouched.

       Thus if the alias for `ls' were `ls -l' the command `ls /usr' would become `ls  -l  /usr',
       the  argument  list  here  being  undisturbed.   If  the  alias for `lookup' were `grep !^
       /etc/passwd' then `lookup bill' would become `grep bill /etc/passwd'.  Aliases can be used
       to  introduce  parser  metasyntax.   For  example,  `alias print 'pr \!* | lpr'' defines a
       ``command'' (`print') which pr(1)s its arguments to the line printer.

       Alias substitution is repeated until the first word of the command has no  alias.   If  an
       alias  substitution  does  not  change  the  first word (as in the previous example) it is
       flagged to prevent a loop.  Other loops are detected and cause an error.

       Some aliases are referred to by the shell; see Special aliases.

   Variable substitution
       The shell maintains a list of variables, each of which has as value a list of zero or more
       words.   The values of shell variables can be displayed and changed with the set and unset
       commands.  The system maintains its own list of ``environment'' variables.  These  can  be
       displayed and changed with printenv, setenv and unsetenv.

       (+)  Variables may be made read-only with `set -r' (q.v.).  Read-only variables may not be
       modified or unset; attempting to do so will cause an error.  Once made read-only, a  vari-
       able  cannot be made writable, so `set -r' should be used with caution.  Environment vari-
       ables cannot be made read-only.

       Some variables are set by the shell or referred to by it.  For instance, the argv variable
       is  an image of the shell's argument list, and words of this variable's value are referred
       to in special ways.  Some of the variables referred to by the shell are toggles; the shell
       does  not  care  what their value is, only whether they are set or not.  For instance, the
       verbose variable is a toggle which causes command input to be echoed.  The -v command line
       option sets this variable.  Special shell variables lists all variables which are referred
       to by the shell.

       Other operations treat variables numerically.  The `@' command  permits  numeric  calcula-
       tions  to  be  performed and the result assigned to a variable.  Variable values are, how-
       ever, always represented as (zero or more) strings.  For the purposes  of  numeric  opera-
       tions,  the  null  string is considered to be zero, and the second and subsequent words of
       multi-word values are ignored.

       After the input line is aliased and parsed, and before each command is executed,  variable
       substitution  is  performed  keyed  by `$' characters.  This expansion can be prevented by
       preceding the `$' with a `\' except within `"'s where it always occurs,  and  within  `''s
       where it never occurs.  Strings quoted by ``' are interpreted later (see Command substitu-
       tion below) so `$' substitution does not occur there until later, if at  all.   A  `$'  is
       passed unchanged if followed by a blank, tab, or end-of-line.

       Input/output  redirections  are recognized before variable expansion, and are variable ex-
       panded separately.  Otherwise, the command name and entire argument list are expanded  to-
       gether.  It is thus possible for the first (command) word (to this point) to generate more
       than one word, the first of which becomes the command name, and the rest of  which  become
       arguments.

       Unless enclosed in `"' or given the `:q' modifier the results of variable substitution may
       eventually be command and filename substituted.  Within `"', a variable whose  value  con-
       sists  of  multiple  words  expands to a (portion of a) single word, with the words of the
       variable's value separated by blanks.  When the `:q' modifier is applied to a substitution
       the  variable will expand to multiple words with each word separated by a blank and quoted
       to prevent later command or filename substitution.

       The following metasequences are provided for introducing variable values  into  the  shell
       input.  Except as noted, it is an error to reference a variable which is not set.

       $name
       ${name} Substitutes  the  words  of the value of variable name, each separated by a blank.
               Braces insulate name from following characters which would otherwise  be  part  of
               it.   Shell  variables have names consisting of letters and digits starting with a
               letter.  The underscore character is considered a letter.  If name is not a  shell
               variable,  but is set in the environment, then that value is returned (but some of
               the other forms given below are not available in this case).
       $name[selector]
       ${name[selector]}
               Substitutes only the selected words from the value of name.  The selector is  sub-
               jected to `$' substitution and may consist of a single number or two numbers sepa-
               rated by a `-'.  The first word of a variable's value is  numbered  `1'.   If  the
               first  number  of  a range is omitted it defaults to `1'.  If the last member of a
               range is omitted it defaults to `$#name'.  The selector `*' selects all words.  It
               is  not  an  error for a range to be empty if the second argument is omitted or in
               range.
       $0      Substitutes the name of the file from which command input is being read.  An error
               occurs if the name is not known.
       $number
       ${number}
               Equivalent to `$argv[number]'.
       $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

       The `:' modifiers described under History substitution, except for `:p', can be applied to
       the substitutions above.  More than one may be used.  (+) Braces may be needed to insulate
       a variable substitution from a literal colon just as with History substitution (q.v.); any
       modifiers must appear within the braces.

       The following substitutions can not be modified with `:' modifiers.

       $?name
       ${?name}
               Substitutes the string `1' if name is set, `0' if it is not.
       $?0     Substitutes `1' if the current input filename is known, `0' if it is not.   Always
               `0' in interactive shells.
       $#name
       ${#name}
               Substitutes the number of words in name.
       $#      Equivalent to `$#argv'.  (+)
       $%name
       ${%name}
               Substitutes the number of characters in name.  (+)
       $%number
       ${%number}
               Substitutes the number of characters in $argv[number].  (+)
       $?      Equivalent to `$status'.  (+)
       $$      Substitutes the (decimal) process number of the (parent) shell.
       $!      Substitutes the (decimal) process number of the last background process started by
               this shell.  (+)
       $_      Substitutes the command line of the last command executed.  (+)
       $<      Substitutes a line from the standard input, with no further interpretation  there-
               after.  It can be used to read from the keyboard in a shell script.  (+) While csh
               always quotes $<, as if it were equivalent to `$<:q', tcsh does not.  Furthermore,
               when  tcsh is waiting for a line to be typed the user may type an interrupt to in-
               terrupt the sequence into which the line is to be substituted, but  csh  does  not
               allow this.

       The  editor  command  expand-variables,  normally bound to `^X-$', can be used to interac-
       tively expand individual variables.

   Command, filename and directory stack substitution
       The remaining substitutions are applied selectively to the arguments of builtin  commands.
       This means that portions of expressions which are not evaluated are not subjected to these
       expansions.  For commands which are not internal to the shell, the command name is substi-
       tuted  separately from the argument list.  This occurs very late, after input-output redi-
       rection is performed, and in a child of the main shell.

   Command substitution
       Command substitution is indicated by a command enclosed in ``'.  The output  from  such  a
       command  is  broken  into  separate words at blanks, tabs and newlines, and null words are
       discarded.  The output is variable and command substituted and put in place of the  origi-
       nal string.

       Command  substitutions  inside  double  quotes (`"') retain blanks and tabs; only newlines
       force new words.  The single final newline does not force a new word in any case.   It  is
       thus possible for a command substitution to yield only part of a word, even if the command
       outputs a complete line.

       By default, the shell since version 6.12 replaces all newline and carriage return  charac-
       ters  in the command by spaces.  If this is switched off by unsetting csubstnonl, newlines
       separate commands as usual.

   Filename substitution
       If a word contains any of the characters `*', `?', `[' or `{' or begins with the character
       `~' it is a candidate for filename substitution, also known as ``globbing''.  This word is
       then regarded as a pattern (``glob-pattern''), and replaced with an alphabetically  sorted
       list of file names which match the pattern.

       In  matching  filenames,  the  character `.' at the beginning of a filename or immediately
       following a `/', as well as the character `/' must be matched  explicitly  (unless  either
       globdot  or globstar or both are set(+)).  The character `*' matches any string of charac-
       ters, including the null string.  The character `?' matches any single character.  The se-
       quence  `[...]'  matches  any  one  of the characters enclosed.  Within `[...]', a pair of
       characters separated by `-' matches any character lexically between the two.

       (+) Some glob-patterns can be negated: The sequence `[^...]' matches any single  character
       not specified by the characters and/or ranges of characters in the braces.

       An entire glob-pattern can also be negated with `^':

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns  which do not use `?', `*', or `[]' or which use `{}' or `~' (below) are not
       negated correctly.

       The metanotation `a{b,c,d}e' is a shorthand for `abe ace  ade'.   Left-to-right  order  is
       preserved:     `/usr/source/s1/{oldls,ls}.c'     expands     to    `/usr/source/s1/oldls.c
       /usr/source/s1/ls.c'.  The results of matches are sorted separately at a low level to pre-
       serve  this  order: `../{memo,*box}' might expand to `../memo ../box ../mbox'.  (Note that
       `memo' was not sorted with the results of matching `*box'.)  It is not an error when  this
       construct  expands  to files which do not exist, but it is possible to get an error from a
       command to which the expanded list is passed.  This construct may be nested.  As a special
       case the words `{', `}' and `{}' are passed undisturbed.

       The  character  `~'  at  the beginning of a filename refers to home directories.  Standing
       alone, i.e., `~', it expands to the invoker's home directory as reflected in the value  of
       the  home  shell  variable.  When followed by a name consisting of letters, digits and `-'
       characters the shell searches for a user with that name and substitutes their home  direc-
       tory;  thus  `~ken' might expand to `/usr/ken' and `~ken/chmach' to `/usr/ken/chmach'.  If
       the character `~' is followed by a character other than a letter or `/' or  appears  else-
       where  than  at  the  beginning of a word, it is left undisturbed.  A command like `setenv
       MANPATH /usr/man:/usr/local/man:~/lib/man' does not, therefore, do home directory  substi-
       tution as one might hope.

       It  is  an  error for a glob-pattern containing `*', `?', `[' or `~', with or without `^',
       not to match any files.  However, only one pattern in a list of glob-patterns must match a
       file  (so  that, e.g., `rm *.a *.c *.o' would fail only if there were no files in the cur-
       rent directory ending in `.a', `.c', or `.o'), and if the nonomatch shell variable is  set
       a  pattern (or list of patterns) which matches nothing is left unchanged rather than caus-
       ing an error.

       The globstar shell variable can be set to allow `**' or `***' as a file glob pattern  that
       matches  any  string of characters including `/', recursively traversing any existing sub-
       directories.  For example, `ls **.c' will list all the .c files in the  current  directory
       tree.   If  used  by itself, it will match zero or more sub-directories (e.g. `ls /usr/in-
       clude/**/time.h' will list any file named `time.h' in the /usr/include directory tree; `ls
       /usr/include/**time.h'  will  match  any file in the /usr/include directory tree ending in
       `time.h'; and `ls /usr/include/**time**.h' will match any .h file with `time' either in  a
       subdirectory  name  or  in  the filename itself).  To prevent problems with recursion, the
       `**' glob-pattern will not descend into a symbolic link containing a directory.  To  over-
       ride this, use `***' (+)

       The noglob shell variable can be set to prevent filename substitution, and the expand-glob
       editor command, normally bound to `^X-*', can be used to interactively  expand  individual
       filename substitutions.

   Directory stack substitution (+)
       The  directory stack is a list of directories, numbered from zero, used by the pushd, popd
       and dirs builtin commands (q.v.).  dirs can print, store in a file, restore and clear  the
       directory  stack  at any time, and the savedirs and dirsfile shell variables can be set to
       store the directory stack automatically on logout and restore it on login.   The  dirstack
       shell  variable can be examined to see the directory stack and set to put arbitrary direc-
       tories into the directory stack.

       The character `=' followed by one or more digits expands to  an  entry  in  the  directory
       stack.  The special case `=-' expands to the last directory in the stack.  For example,

           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           /usr/spool/uucp
           > echo =0/calendar
           /usr/bin/calendar
           > echo =-
           /usr/accts/sys

       The  noglob  and nonomatch shell variables and the expand-glob editor command apply to di-
       rectory stack as well as filename substitutions.

   Other substitutions (+)
       There are several more transformations involving filenames, not strictly  related  to  the
       above  but  mentioned  here for completeness.  Any filename may be expanded to a full path
       when the symlinks variable (q.v.) is set to `expand'.  Quoting  prevents  this  expansion,
       and  the  normalize-path  editor  command does it on demand.  The normalize-command editor
       command expands commands in PATH into full paths on demand.  Finally, cd and pushd  inter-
       pret `-' as the old working directory (equivalent to the shell variable owd).  This is not
       a substitution at all, but an abbreviation recognized by only  those  commands.   Nonethe-
       less, it too can be prevented by quoting.

   Commands
       The  next three sections describe how the shell executes commands and deals with their in-
       put and output.

   Simple commands, pipelines and sequences
       A simple command is a sequence of words, the first of which specifies the  command  to  be
       executed.   A  series  of  simple commands joined by `|' characters forms a pipeline.  The
       output of each command in a pipeline is connected to the input of the next.

       Simple commands and pipelines may be joined into sequences with `;', and will be  executed
       sequentially.  Commands and pipelines can also be joined into sequences with `||' or `&&',
       indicating, as in the C language, that the second is to be  executed  only  if  the  first
       fails or succeeds respectively.

       A  simple command, pipeline or sequence may be placed in parentheses, `()', to form a sim-
       ple command, which may in turn be a component of a pipeline or sequence.  A command, pipe-
       line  or sequence can be executed without waiting for it to terminate by following it with
       an `&'.

   Builtin and non-builtin command execution
       Builtin commands are executed within the shell.  If any component of a pipeline except the
       last is a builtin command, the pipeline is executed in a subshell.

       Parenthesized commands are always executed in a subshell.

           (cd; pwd); pwd

       thus  prints  the home directory, leaving you where you were (printing this after the home
       directory), while

           cd; pwd

       leaves you in the home directory.  Parenthesized commands are most often used  to  prevent
       cd from affecting the current shell.

       When  a  command to be executed is found not to be a builtin command the shell attempts to
       execute the command via execve(2).  Each word in the variable path names  a  directory  in
       which  the  shell  will  look for the command.  If the shell is not given a -f option, the
       shell hashes the names in these directories into an internal table so that it will try  an
       execve(2) in only a directory where there is a possibility that the command resides there.
       This greatly speeds command location when a large number of directories are present in the
       search path. This hashing mechanism is not used:

       1.  If hashing is turned explicitly off via unhash.

       2.  If the shell was given a -f argument.

       3.  For each directory component of path which does not begin with a `/'.

       4.  If the command contains a `/'.

       In  the above four cases the shell concatenates each component of the path vector with the
       given command name to form a path name of a file which it then attempts to execute it.  If
       execution is successful, the search stops.

       If  the  file  has execute permissions but is not an executable to the system (i.e., it is
       neither an executable binary nor a script that specifies its interpreter), then it is  as-
       sumed  to  be a file containing shell commands and a new shell is spawned to read it.  The
       shell special alias may be set to specify an interpreter other than the shell itself.

       On systems which do not understand the `#!' script interpreter convention the shell may be
       compiled to emulate it; see the version shell variable.  If so, the shell checks the first
       line of the file to see if it is of the form `#!interpreter arg ...'.  If it is, the shell
       starts interpreter with the given args and feeds the file to it on standard input.

   Input/output
       The  standard  input and standard output of a command may be redirected with the following
       syntax:

       < name  Open file name (which is first variable, command and  filename  expanded)  as  the
               standard input.
       << word Read  the  shell  input up to a line which is identical to word.  word is not sub-
               jected to variable, filename or command substitution, and each input line is  com-
               pared  to  word  before  any  substitutions are done on this input line.  Unless a
               quoting `\', `"', `' or ``' appears in word variable and command  substitution  is
               performed  on the intervening lines, allowing `\' to quote `$', `\' and ``'.  Com-
               mands which are substituted have all blanks, tabs, and newlines preserved,  except
               for the final newline which is dropped.  The resultant text is placed in an anony-
               mous temporary file which is given to the command as standard input.
       > name
       >! name
       >& name
       >&! name
               The file name is used as standard output.  If the file does not exist then  it  is
               created; if the file exists, it is truncated, its previous contents being lost.

               If the shell variable noclobber is set, then the file must not exist or be a char-
               acter special file (e.g., a terminal or `/dev/null') or an  error  results.   This
               helps  prevent accidental destruction of files.  In this case the `!' forms can be
               used to suppress this check.  If notempty is given in noclobber, `>' is allowed on
               empty  files;  if ask is set, an interacive confirmation is presented, rather than
               an error.

               The forms involving `&' route the diagnostic output into  the  specified  file  as
               well  as the standard output.  name is expanded in the same way as `<' input file-
               names are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like `>', but appends output to the end of name.  If the shell variable  noclobber
               is set, then it is an error for the file not to exist, unless one of the `!' forms
               is given.

       A command receives the environment in which the shell was invoked as modified by  the  in-
       put-output  parameters  and  the presence of the command in a pipeline.  Thus, unlike some
       previous shells, commands run from a file of shell commands have no access to the text  of
       the  commands  by  default;  rather they receive the original standard input of the shell.
       The `<<' mechanism should be used to present inline  data.   This  permits  shell  command
       scripts  to function as components of pipelines and allows the shell to block read its in-
       put.  Note that the default standard input for a command run detached  is  not  the  empty
       file  /dev/null,  but the original standard input of the shell.  If this is a terminal and
       if the process attempts to read from the terminal, then the process  will  block  and  the
       user will be notified (see Jobs).

       Diagnostic output may be directed through a pipe with the standard output.  Simply use the
       form `|&' rather than just `|'.

       The shell cannot presently redirect diagnostic output without  also  redirecting  standard
       output,  but  `(command  >  output-file) >& error-file' is often an acceptable workaround.
       Either output-file or error-file may be `/dev/tty' to send output to the terminal.

   Features
       Having described how the shell accepts, parses and executes command lines, we now turn  to
       a variety of its useful features.

   Control flow
       The  shell contains a number of commands which can be used to regulate the flow of control
       in command files (shell scripts) and (in limited but useful  ways)  from  terminal  input.
       These commands all operate by forcing the shell to reread or skip in its input and, due to
       the implementation, restrict the placement of some of the commands.

       The foreach, switch, and while statements, as well as the  if-then-else  form  of  the  if
       statement,  require  that the major keywords appear in a single simple command on an input
       line as shown below.

       If the shell's input is not seekable, the shell buffers up input whenever a loop is  being
       read and performs seeks in this internal buffer to accomplish the rereading implied by the
       loop.  (To the extent that this allows, backward gotos will succeed  on  non-seekable  in-
       puts.)

   Expressions
       The if, while and exit builtin commands use expressions with a common syntax.  The expres-
       sions can include any of the operators described in the next three  sections.   Note  that
       the @ builtin command (q.v.) has its own separate syntax.

   Logical, arithmetical and comparison operators
       These operators are similar to those of C and have the same precedence.  They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here  the  precedence  increases  to the right, `==' `!=' `=~' and `!~', `<=' `>=' `<' and
       `>', `<<' and `>>', `+' and `-', `*' `/' and `%' being, in groups, at the same level.  The
       `=='  `!='  `=~' and `!~' operators compare their arguments as strings; all others operate
       on numbers.  The operators `=~' and `!~' are like `!=' and `==' except that the right hand
       side  is a glob-pattern (see Filename substitution) against which the left hand operand is
       matched.  This reduces the need for use of the switch builtin  command  in  shell  scripts
       when all that is really needed is pattern matching.

       Null or missing arguments are considered `0'.  The results of all expressions are strings,
       which represent decimal numbers.  It is important to note that no two components of an ex-
       pression  can  appear  in the same word; except when adjacent to components of expressions
       which are syntactically significant to the parser (`&' `|' `<' `>' `(' `)') they should be
       surrounded by spaces.

   Command exit status
       Commands  can  be executed in expressions and their exit status returned by enclosing them
       in braces (`{}').  Remember that the braces should be separated from the words of the com-
       mand by spaces.  Command executions succeed, returning true, i.e., `1', if the command ex-
       its with status 0, otherwise they fail, returning false, i.e., `0'.  If more detailed sta-
       tus  information  is required then the command should be executed outside of an expression
       and the status shell variable examined.

   File inquiry operators
       Some of these operators perform true/false tests on files and related objects.   They  are
       of the form -op file, where op is one of

           r   Read access
           w   Write access
           x   Execute access
           X   Executable in the path or shell builtin, e.g., `-X ls' and `-X ls-F' are generally
               true, but `-X /bin/ls' is not (+)
           e   Existence
           o   Ownership
           z   Zero size
           s   Non-zero size (+)
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)
           g   Set-group-ID bit is set (+)
           k   Sticky bit is set (+)
           t   file (which must be a digit) is an open file descriptor for a terminal device (+)
           R   Has been migrated (Convex only) (+)
           L   Applies subsequent operators in a multiple-operator test to a symbolic link rather
               than to the file to which the link points (+) *

       file is command and filename expanded and then tested to see if it has the specified rela-
       tionship to the real user.  If file does not exist or is inaccessible or, for  the  opera-
       tors  indicated  by  `*', if the specified file type does not exist on the current system,
       then all inquiries return false, i.e., `0'.

       These operators may be combined for conciseness: `-xy file' is equivalent to `-x  file  &&
       -y  file'.   (+)  For example, `-fx' is true (returns `1') for plain executable files, but
       not for directories.

       L may be used in a multiple-operator test to apply subsequent operators to a symbolic link
       rather  than  to the file to which the link points.  For example, `-lLo' is true for links
       owned by the invoking user.  Lr, Lw and Lx are always true for links and  false  for  non-
       links.   L  has  a  different  meaning when it is the last operator in a multiple-operator
       test; see below.

       It is possible but not useful, and sometimes misleading, to combine operators which expect
       file  to  be  a file with operators which do not (e.g., X and t).  Following L with a non-
       file operator can lead to particularly strange results.

       Other operators return other information, i.e., not just `0' or `1'.  (+)  They  have  the
       same format as before; op may be one of

           A       Last file access time, as the number of seconds since the epoch
           A:      Like A, but in timestamp format, e.g., `Fri May 14 16:36:10 1993'
           M       Last file modification time
           M:      Like M, but in timestamp format
           C       Last inode modification time
           C:      Like C, but in timestamp format
           D       Device number
           I       Inode number
           F       Composite file identifier, in the form device:inode
           L       The name of the file pointed to by a symbolic link
           N       Number of (hard) links
           P       Permissions, in octal, without leading zero
           P:      Like P, with leading zero
           Pmode   Equivalent  to  `-P  file  &  mode', e.g., `-P22 file' returns `22' if file is
                   writable by group and other, `20' if by group only, and `0' if by neither
           Pmode:  Like Pmode, with leading zero
           U       Numeric userid
           U:      Username, or the numeric userid if the username is unknown
           G       Numeric groupid
           G:      Groupname, or the numeric groupid if the groupname is unknown
           Z       Size, in bytes

       Only one of these operators may appear in a multiple-operator test, and  it  must  be  the
       last.  Note that L has a different meaning at the end of and elsewhere in a multiple-oper-
       ator test.  Because `0' is a valid return value for many of these operators, they  do  not
       return `0' when they fail: most return `-1', and F returns `:'.

       If  the  shell is compiled with POSIX defined (see the version shell variable), the result
       of a file inquiry is based on the permission bits of the file and not on the result of the
       access(2)  system  call.  For example, if one tests a file with -w whose permissions would
       ordinarily allow writing but which is on a file system mounted read-only,  the  test  will
       succeed in a POSIX shell but fail in a non-POSIX shell.

       File inquiry operators can also be evaluated with the filetest builtin command (q.v.) (+).

   Jobs
       The  shell associates a job with each pipeline.  It keeps a table of current jobs, printed
       by the jobs command, and assigns them small integer numbers.  When a job is started  asyn-
       chronously with `&', the shell prints a line 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 you are running a job and wish to do something else you may hit the suspend  key  (usu-
       ally  `^Z'),  which  sends a STOP signal to the current job.  The shell will then normally
       indicate that the job has been `Suspended' and print  another  prompt.   If  the  listjobs
       shell variable is set, all jobs will be listed like the jobs builtin command; if it is set
       to `long' the listing will be in long format, like `jobs -l'.  You can then manipulate the
       state  of  the suspended job.  You can put it in the ``background'' with the bg command or
       run some other commands and eventually bring the job back into the ``foreground'' with fg.
       (See  also the run-fg-editor editor command.)  A `^Z' takes effect immediately and is like
       an interrupt in that pending output and unread input are discarded when it is typed.   The
       wait builtin command causes the shell to wait for all background jobs to complete.

       The `^]' key sends a delayed suspend signal, which does not generate a STOP signal until a
       program attempts to read(2) it, to the current job.  This can usefully be typed ahead when
       you  have  prepared some commands for a job which you wish to stop after it has read them.
       The `^Y' key performs this function in csh(1); in tcsh, `^Y' is an editing command.  (+)

       A job being run in the background stops if it tries to read from the terminal.  Background
       jobs  are  normally allowed to produce output, but this can be disabled by giving the com-
       mand `stty tostop'.  If you set this tty option, then background jobs will stop when  they
       try to produce output like they do when they try to read input.

       There  are several ways to refer to jobs in the shell.  The character `%' introduces a job
       name.  If you wish to refer to job number 1, you can name it as `%1'.  Just naming  a  job
       brings  it to the foreground; thus `%1' is a synonym for `fg %1', bringing job 1 back into
       the foreground.  Similarly, saying `%1 &' resumes job 1 in the background, just  like  `bg
       %1'.  A job can also be named by an unambiguous prefix of the string typed in to start it:
       `%ex' would normally restart a suspended ex(1) job, if there were only one  suspended  job
       whose name began with the string `ex'.  It is also possible to say `%?string' to specify a
       job whose text contains string, if there is only one such job.

       The shell maintains a notion of the current and previous jobs.  In  output  pertaining  to
       jobs, the current job is marked with a `+' and the previous job with a `-'.  The abbrevia-
       tions `%+', `%', and (by analogy with the syntax of the history mechanism) `%%' all  refer
       to the current job, and `%-' refers to the previous job.

       The  job  control mechanism requires that the stty(1) option `new' be set on some systems.
       It is an artifact from a `new' implementation of the tty driver which allows generation of
       interrupt  characters  from  the keyboard to tell jobs to stop.  See stty(1) and the setty
       builtin command for details on setting options in the new tty driver.

   Status reporting
       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, but only right be-
       fore it prints a prompt.  This is done so that it does not otherwise  disturb  your  work.
       If,  however,  you set the shell variable notify, the shell will notify you immediately of
       changes of status in background jobs.  There is also a shell command notify which marks  a
       single process so that its status changes will be immediately reported.  By default notify
       marks the current process; simply say `notify' after starting a background job to mark it.

       When you try to leave the shell while jobs are stopped, you will be warned that `There are
       suspended jobs.' You may use the jobs command to see what they are.  If you do this or im-
       mediately try to exit again, the shell will not warn you a second time, and the  suspended
       jobs will be terminated.

   Automatic, periodic and timed events (+)
       There  are  various  ways  to run commands and take other actions automatically at various
       times in the ``life cycle'' of the shell.  They are summarized here, and described in  de-
       tail under the appropriate Builtin commands, Special shell variables and Special aliases.

       The  sched  builtin command puts commands in a scheduled-event list, to be executed by the
       shell at a given time.

       The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special aliases can be set, re-
       spectively,  to  execute  commands when the shell wants to ring the bell, when the working
       directory changes, every tperiod minutes, before each prompt, before each command gets ex-
       ecuted, after each command gets executed, and when a job is started or is brought into the
       foreground.

       The autologout shell variable can be set to log out or lock the shell after a given number
       of minutes of inactivity.

       The mail shell variable can be set to check for new mail periodically.

       The  printexitvalue  shell  variable can be set to print the exit status of commands which
       exit with a status other than zero.

       The rmstar shell variable can be set to ask the user, when `rm *' is typed, if that is re-
       ally what was meant.

       The  time  shell variable can be set to execute the time builtin command after the comple-
       tion of any process that takes more than a given number of CPU seconds.

       The watch and who shell variables can be set to report when selected users log in or  out,
       and the log builtin command reports on those users at any time.

   Native Language System support (+)
       The  shell  is  eight  bit clean (if so compiled; see the version shell variable) and thus
       supports character sets needing this capability.  NLS support differs depending on whether
       or  not  the  shell  was compiled to use the system's NLS (again, see version).  In either
       case, 7-bit ASCII is the default character code (e.g., the classification of which charac-
       ters  are  printable) and sorting, and changing the LANG or LC_CTYPE environment variables
       causes a check for possible changes in these respects.

       When using the system's NLS, the setlocale(3) function is called to determine  appropriate
       character  code/classification and sorting (e.g., a 'en_CA.UTF-8' would yield "UTF-8" as a
       character code).  This function typically examines the LANG and LC_CTYPE environment vari-
       ables; refer to the system documentation for further details.  When not using the system's
       NLS, the shell simulates it by assuming that the ISO 8859-1 character set is used whenever
       either of the LANG and LC_CTYPE variables are set, regardless of their values.  Sorting is
       not affected for the simulated NLS.

       In addition, with both real and simulated NLS,  all  printable  characters  in  the  range
       \200-\377,  i.e.,  those  that have M-char bindings, are automatically rebound to self-in-
       sert-command.  The corresponding binding for the escape-char sequence,  if  any,  is  left
       alone.   These  characters  are  not  rebound if the NOREBIND environment variable is set.
       This may be useful for the simulated NLS or a primitive real NLS which  assumes  full  ISO
       8859-1.   Otherwise,  all  M-char  bindings in the range \240-\377 are effectively undone.
       Explicitly rebinding the relevant keys with bindkey is of course still possible.

       Unknown characters (i.e., those that are neither printable  nor  control  characters)  are
       printed  in  the format \nnn.  If the tty is not in 8 bit mode, other 8 bit characters are
       printed by converting them to ASCII and using standout mode.  The shell never changes  the
       7/8 bit mode of the tty and tracks user-initiated changes of 7/8 bit mode.  NLS users (or,
       for that matter, those who want to use a meta key) may need to explicitly set the tty in 8
       bit mode through the appropriate stty(1) command in, e.g., the ~/.login file.

   OS variant support (+)
       A  number of new builtin commands are provided to support features in particular operating
       systems.  All are described in detail in the Builtin commands section.

       On systems that support TCF (aix-ibm370, aix-ps2), getspath and setspath get and  set  the
       system  execution  path, getxvers and setxvers get and set the experimental version prefix
       and migrate migrates processes between sites.  The jobs builtin prints the site  on  which
       each job is executing.

       Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD operating system.

       Under  Domain/OS, inlib adds shared libraries to the current environment, rootnode changes
       the rootnode and ver changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

       Under Harris CX/UX, ucb or att runs a command under the specified universe.

       Under Convex/OS, warp prints or sets the universe.

       The VENDOR, OSTYPE and MACHTYPE environment variables indicate  respectively  the  vendor,
       operating system and machine type (microprocessor class or machine model) of the system on
       which the shell thinks it is running.  These are particularly useful  when  sharing  one's
       home directory between several types of machines; one can, for example,

           set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in  one's ~/.login and put executables compiled for each machine in the appropriate direc-
       tory.

       The version shell variable indicates what options were chosen when the shell was compiled.

       Note also the newgrp builtin, the afsuser and echo_style shell variables and  the  system-
       dependent locations of the shell's input files (see FILES).

   Signal handling
       Login  shells  ignore  interrupts when reading the file ~/.logout.  The shell ignores quit
       signals unless started with -q.  Login shells catch the terminate  signal,  but  non-login
       shells  inherit  the terminate behavior from their parents.  Other signals have the values
       which the shell inherited from its parent.

       In shell scripts, the shell's handling of interrupt and  terminate  signals  can  be  con-
       trolled with onintr, and its handling of hangups can be controlled with hup and nohup.

       The shell exits on a hangup (see also the logout shell variable).  By default, the shell's
       children do too, but the shell does not send them a hangup when it  exits.   hup  arranges
       for  the shell to send a hangup to a child when it exits, and nohup sets a child to ignore
       hangups.

   Terminal management (+)
       The shell uses three different sets of terminal (``tty'') modes: `edit', used  when  edit-
       ing,  `quote',  used  when  quoting literal characters, and `execute', used when executing
       commands.  The shell holds some settings in each mode constant, so  commands  which  leave
       the  tty  in  a  confused  state  do not interfere with the shell.  The shell also matches
       changes in the speed and padding of the tty.  The list of tty modes that are kept constant
       can  be  examined and modified with the setty builtin.  Note that although the editor uses
       CBREAK mode (or its equivalent), it takes typed-ahead characters anyway.

       The echotc, settc and telltc commands can be used to manipulate and debug  terminal  capa-
       bilities from the command line.

       On  systems  that support SIGWINCH or SIGWINDOW, the shell adapts to window resizing auto-
       matically and adjusts the environment variables LINES and COLUMNS if set.  If the environ-
       ment  variable  TERMCAP contains li# and co# fields, the shell adjusts them to reflect the
       new window size.

REFERENCE
       The next sections of this manual describe all of the available Builtin  commands,  Special
       aliases and Special shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @
       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints the values of all shell variables.

               The  second  form  assigns  the value of expr to name.  The third form assigns the
               value of expr to the index'th component of name; both name and its index'th compo-
               nent must already exist.

               expr  may  contain  the  operators `*', `+', etc., as in C.  If expr contains `<',
               `>', `&' or `' then at least that part of expr must be placed within  `()'.   Note
               that the syntax of expr has nothing to do with that described under Expressions.

               The  fourth  and  fifth forms increment (`++') or decrement (`--') name or its in-
               dex'th component.

               The space between `@' and name is required.  The spaces between name and  `='  and
               between  `='  and expr are optional.  Components of expr must be separated by spa-
               ces.

       alias [name [wordlist]]
               Without arguments, prints all aliases.  With name,  prints  the  alias  for  name.
               With  name  and wordlist, assigns wordlist as the alias of name.  wordlist is com-
               mand and filename substituted.  name may not be `alias' or  `unalias'.   See  also
               the unalias builtin command.

       alloc   Shows  the  amount of dynamic memory acquired, broken down into used and free mem-
               ory.  With an argument shows the number of free and used blocks in each size cate-
               gory.   The  categories  start  at size 8 and double at each step.  This command's
               output may vary across system types, because systems other than the VAX may use  a
               different memory allocator.

       bg [%job ...]
               Puts  the  specified  jobs (or, without arguments, the current job) into the back-
               ground, continuing each if it is stopped.  job may be a number, a string, `', `%',
               `+' or `-' as described under Jobs.

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without  options,  the  first  form lists all bound keys and the editor command to
               which each is bound, the second form lists the editor  command  to  which  key  is
               bound  and  the  third  form binds the editor command command to key.  Options in-
               clude:

               -l  Lists all editor commands and a short description of each.
               -d  Binds all keys to the standard bindings for the default editor, as per -e  and
                   -v below.
               -e  Binds all keys to emacs(1)-style bindings.  Unsets vimode.
               -v  Binds all keys to vi(1)-style bindings.  Sets vimode.
               -a  Lists or changes key-bindings in the alternative key map.  This is the key map
                   used in vimode command mode.
               -b  key is interpreted as a control character written ^character (e.g.,  `^A')  or
                   C-character (e.g., `C-A'), a meta character written M-character (e.g., `M-A'),
                   a function key written F-string (e.g., `F-string'), or an extended prefix  key
                   written X-character (e.g., `X-A').
               -k  key  is  interpreted as a symbolic arrow key name, which may be one of `down',
                   `up', `left' or `right'.
               -r  Removes key's binding.  Be careful: `bindkey -r' does not bind key to self-in-
                   sert-command (q.v.), it unbinds key completely.
               -c  command  is  interpreted as a builtin or external command instead of an editor
                   command.
               -s  command is taken as a literal string and treated as terminal input when key is
                   typed.  Bound keys in command are themselves reinterpreted, and this continues
                   for ten levels of interpretation.
               --  Forces a break from option processing, so the next word is taken as  key  even
                   if it begins with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key may be a single character or a string.  If a command is bound to a string, the
               first character of the string is bound to sequence-lead-in and the  entire  string
               is bound to the command.

               Control characters in key can be literal (they can be typed by preceding them with
               the editor command quoted-insert, normally bound to `^V') or written caret-charac-
               ter  style,  e.g.,  `^A'.  Delete is written `^?'  (caret-question mark).  key and
               command can contain backslashed  escape  sequences  (in  the  style  of  System  V
               echo(1)) as follows:

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The ASCII character corresponding to the octal number nnn

               `\'  nullifies  the special meaning of the following character, if it has any, no-
               tably `\' and `^'.

       bs2cmd bs2000-command (+)
               Passes bs2000-command to the BS2000 command interpreter for execution.  Only  non-
               interactive  commands  can be executed, and it is not possible to execute any com-
               mand that would overlay the image of the current process, like /EXECUTE or  /CALL-
               PROCEDURE. (BS2000 only)

       break   Causes  execution  to  resume  after  the  end of the nearest enclosing foreach or
               while.  The remaining commands on the  current  line  are  executed.   Multi-level
               breaks are thus possible by writing them all on one line.

       breaksw Causes a break from a switch, resuming after the endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A synonym for the logout builtin command.  Available only if the shell was so com-
               piled; see the version shell variable.

       case label:
               A label in a switch statement as discussed below.

       cd [-p] [-l] [-n|-v] [I--] [name]
               If a directory name is given, changes the shell's working directory to  name.   If
               not,  changes  to  home,  unless the cdtohome variable is not set, in which case a
               name is required.  If name is `-' it is interpreted as the previous working direc-
               tory  (see Other substitutions).  (+) If name is not a subdirectory of the current
               directory (and does not begin with `/', `./' or  `../'),  each  component  of  the
               variable  cdpath is checked to see if it has a subdirectory name.  Finally, if all
               else fails but name is a shell variable whose value begins with `/' or  '.',  then
               this is tried to see if it is a directory, and the -p option is implied.

               With  -p,  prints  the  final  directory stack, just like dirs.  The -l, -n and -v
               flags have the same effect on cd as on dirs, and they  imply  -p.   (+)  Using  --
               forces  a  break from option processing so the next word is taken as the directory
               name even if it begins with '-'. (+)

               See also the implicitcd and cdtohome shell variables.

       chdir   A synonym for the cd builtin command.

       complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
               Without arguments, lists all completions.  With  command,  lists  completions  for
               command.  With command and word etc., defines completions.

               command  may be a full command name or a glob-pattern (see Filename substitution).
               It can begin with `-' to indicate that completion should be used only when command
               is ambiguous.

               word specifies which word relative to the current word is to be completed, and may
               be one of the following:

                   c   Current-word completion.  pattern is a glob-pattern which must  match  the
                       beginning  of  the  current  word on the command line.  pattern is ignored
                       when completing the current word.
                   C   Like c, but includes pattern when completing the current word.
                   n   Next-word completion.  pattern is a glob-pattern which must match the  be-
                       ginning of the previous word on the command line.
                   N   Like  n,  but  must match the beginning of the word two before the current
                       word.
                   p   Position-dependent completion.  pattern is a numeric range, with the  same
                       syntax used to index shell variables, which must include the current word.

               list, the list of possible completions, may be one of the following:

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands (builtin or external commands)
                   C       External commands which begin with the supplied path prefix
                   d       Directories
                   D       Directories which begin with the supplied path prefix
                   e       Environment variables
                   f       Filenames
                   F       Filenames which begin with the supplied path prefix
                   g       Groupnames
                   j       Jobs
                   l       Limits
                   n       Nothing
                   s       Shell variables
                   S       Signals
                   t       Plain (``text'') files
                   T       Plain (``text'') files which begin with the supplied path prefix
                   v       Any variables
                   u       Usernames
                   x       Like n, but prints select when list-choices is used.
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select is an optional glob-pattern.  If given, words from only list that match se-
               lect are considered and the fignore shell variable is  ignored.   The  last  three
               types of completion may not have a select pattern, and x uses select as an explan-
               atory message when the list-choices editor command is used.

               suffix is a single character to be appended to a successful completion.  If  null,
               no character is appended.  If omitted (in which case the fourth delimiter can also
               be omitted), a slash is appended to directories and a space to other words.

               command invoked from `...` version has additional environment  variable  set,  the
               variable name is COMMAND_LINE and contains (as its name indicates) contents of the
               current (already typed in) command line. One can examine and use contents  of  the
               COMMAND_LINE variable in her custom script to build more sophisticated completions
               (see completion for svn(1) included in this package).

               Now for some examples.  Some commands  take  only  directories  as  arguments,  so
               there's no point completing plain files.

                   > complete cd 'p/1/d/'

               completes  only  the  first  word following `cd' (`p/1') with a directory.  p-type
               completion can also be used to narrow down command completion:

                   > co[^D]
                   complete compress
                   > complete -co* 'p/0/(compress)/'
                   > co[^D]
                   > compress

               This completion completes commands (words in position 0, `p/0') which  begin  with
               `co' (thus matching `co*') to `compress' (the only word in the list).  The leading
               `-' indicates that this completion is to be used with only ambiguous commands.

                   > complete find 'n/-user/u/'

               is an example of n-type completion.  Any word  following  `find'  and  immediately
               following `-user' is completed from the list of users.

                   > complete cc 'c/-I/d/'

               demonstrates  c-type  completion.  Any word following `cc' and beginning with `-I'
               is completed as a directory.  `-I' is not taken as part of the  directory  because
               we used lowercase c.

               Different lists are useful with different commands.

                   > complete alias 'p/1/a/'
                   > complete man 'p/*/c/'
                   > complete set 'p/1/s/'
                   > complete true 'p/1/x:Truth has no options./'

               These  complete  words  following  `alias'  with aliases, `man' with commands, and
               `set' with shell variables.  `true' doesn't have any options, so  x  does  nothing
               when  completion  is  attempted and prints `Truth has no options.' when completion
               choices are listed.

               Note that the man example, and several other examples below, could  just  as  well
               have used 'c/*' or 'n/*' as 'p/*'.

               Words can be completed from a variable evaluated at completion time,

                   > complete ftp 'p/1/$hostnames/'
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^C]
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

               or from a command run at completion time:

                   > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note that the complete command does not itself quote its arguments, so the braces,
               space and `$' in `{print $1}' must be quoted explicitly.

               One command can have multiple completions:

                   > complete dbx 'p/2/(core)/' 'p/*/c/'

               completes the second argument to `dbx' with the word `core' and  all  other  argu-
               ments  with commands.  Note that the positional completion is specified before the
               next-word completion.  Because completions are evaluated from left  to  right,  if
               the  next-word completion were specified first it would always match and the posi-
               tional completion would never be executed.  This is a common mistake when defining
               a completion.

               The select pattern is useful when a command takes files with only particular forms
               as arguments.  For example,

                   > complete cc 'p/*/f:*.[cao]/'

               completes `cc' arguments to files ending in only `.c', `.a', or `.o'.  select  can
               also  exclude  files, using negation of a glob-pattern as described under Filename
               substitution.  One might use

                   > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

               to exclude precious source code from `rm' completion.  Of course, one could  still
               type  excluded  names manually or override the completion mechanism using the com-
               plete-word-raw or list-choices-raw editor commands (q.v.).

               The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'  respectively,  but
               they  use  the select argument in a different way: to restrict completion to files
               beginning with a particular path prefix.  For example, the Elm mail  program  uses
               `=' as an abbreviation for one's mail directory.  One might use

                   > complete elm c@=@F:$HOME/Mail/@

               to  complete `elm -f =' as if it were `elm -f ~/Mail/'.  Note that we used `@' in-
               stead of `/' to avoid confusion with the select argument, and we used `$HOME'  in-
               stead  of `~' because home directory substitution works at only the beginning of a
               word.

               suffix is used to add a nonstandard suffix (not space or `/' for  directories)  to
               completed words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes  arguments  to `finger' from the list of users, appends an `@', and then
               completes after the `@' from the `hostnames' variable.  Note again  the  order  in
               which the completions are specified.

               Finally, here's a complex example for inspiration:

                   > complete find \
                   'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   'n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   'n/-type/(b c d f l p s)/' \
                   'c/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \
                   'p/*/d/'

               This  completes  words  following  `-name', `-newer', `-cpio' or `ncpio' (note the
               pattern which matches both) to files, words following `-exec'  or  `-ok'  to  com-
               mands,  words  following  `user'  and `group' to users and groups respectively and
               words following `-fstype' or `-type' to members of the given lists.  It also  com-
               pletes the switches themselves from the given list (note the use of c-type comple-
               tion) and completes anything not otherwise completed to a directory.  Whew.

               Remember that programmed completions are ignored if the word being completed is  a
               tilde  substitution  (beginning with `~') or a variable (beginning with `$').  See
               also the uncomplete builtin command.

       continue
               Continues execution of the nearest enclosing while or foreach.  The  rest  of  the
               commands on the current line are executed.

       default:
               Labels  the default case in a switch statement.  It should come after all case la-
               bels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The first form prints the directory stack.  The top of the stack is  at  the  left
               and  the  first  directory in the stack is the current directory.  With -l, `~' or
               `~name' in the output is expanded explicitly to home or the pathname of  the  home
               directory  for  user name.  (+) With -n, entries are wrapped before they reach the
               edge of the screen.  (+) With -v, entries are printed one per  line,  preceded  by
               their stack positions.  (+) If more than one of -n or -v is given, -v takes prece-
               dence.  -p is accepted but does nothing.

               With -S, the second form saves the directory stack to filename as a series  of  cd
               and  pushd  commands.   With -L, the shell sources filename, which is presumably a
               directory stack file saved by the -S option or the savedirs mechanism.  In  either
               case, dirsfile is used if filename is not given and ~/.cshdirs is used if dirsfile
               is unset.

               Note that login shells do the equivalent of `dirs -L' on startup and, if  savedirs
               is  set, `dirs -S' before exiting.  Because only ~/.tcshrc is normally sourced be-
               fore ~/.cshdirs, dirsfile should be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes each word to the shell's standard output, separated by  spaces  and  termi-
               nated  with  a  newline.   The echo_style shell variable may be set to emulate (or
               not) the flags and escape sequences of the BSD and/or System V versions  of  echo;
               see echo(1).

       echotc [-sv] arg ... (+)
               Exercises  the  terminal  capabilities  (see  termcap(5))  in  args.  For example,
               'echotc home' sends the cursor to the home position, 'echotc cm 3 10' sends it  to
               column  3  and row 10, and 'echotc ts 0; echo "This is a test."; echotc fs' prints
               "This is a test."  in the status line.

               If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the value of that  ca-
               pability  ("yes"  or  "no" indicating that the terminal does or does not have that
               capability).  One might use this to make the output from a shell script less  ver-
               bose  on  slow  terminals,  or  limit command output to the number of lines on the
               screen:

                   > set history=`echotc lines`
                   > @ history--

               Termcap strings may contain wildcards which will not echo correctly.   One  should
               use  double  quotes when setting a shell variable to a terminal capability string,
               as in the following example that places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With -s, nonexistent capabilities return the empty string rather than  causing  an
               error.  With -v, messages are verbose.

       else
       end
       endif
       endsw   See the description of the foreach, if, switch, and while statements below.

       eval arg ...
               Treats  the  arguments as input to the shell and executes the resulting command(s)
               in the context of the current shell.  This is usually  used  to  execute  commands
               generated  as  the result of command or variable substitution, because parsing oc-
               curs before these substitutions.  See tset(1) for a sample use of eval.

       exec command
               Executes the specified command in place of the current shell.

       exit [expr]
               The shell exits either with the value of the specified expr (an expression, as de-
               scribed under Expressions) or, without expr, with the value 0.

       fg [%job ...]
               Brings  the specified jobs (or, without arguments, the current job) into the fore-
               ground, continuing each if it is stopped.  job may be a number, a string, `', `%',
               `+' or `-' as described under Jobs.  See also the run-fg-editor editor command.

       filetest -op file ... (+)
               Applies op (which is a file inquiry operator as described under File inquiry oper-
               ators) to each file and returns the results as a space-separated list.

       foreach name (wordlist)
       ...
       end     Successively sets the variable name to each member of wordlist  and  executes  the
               sequence of commands between this command and the matching end.  (Both foreach and
               end must appear alone on separate lines.)  The builtin  command  continue  may  be
               used  to  continue the loop prematurely and the builtin command break to terminate
               it prematurely.  When this command is read from the terminal,  the  loop  is  read
               once prompting with `foreach? ' (or prompt2) before any statements in the loop are
               executed.  If you make a mistake typing in a loop at the terminal you can  rub  it
               out.

       getspath (+)
               Prints the system execution path.  (TCF only)

       getxvers (+)
               Prints the experimental version prefix.  (TCF only)

       glob wordlist
               Like  echo,  but  the  `-n' parameter is not recognized and words are delimited by
               null characters in the output.  Useful for programs which wish to use the shell to
               filename expand a list of words.

       goto word
               word  is  filename  and command-substituted to yield a string of the form `label'.
               The shell rewinds its input as much as possible, searches for a line of  the  form
               `label:',  possibly preceded by blanks or tabs, and continues execution after that
               line.

       hashstat
               Prints a statistics line indicating how effective the internal hash table has been
               at  locating commands (and avoiding exec's).  An exec is attempted for each compo-
               nent of the path where the hash function indicates a possible  hit,  and  in  each
               component which does not begin with a `/'.

               On machines without vfork(2), prints only the number and size of hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The  first  form prints the history event list.  If n is given only the n most re-
               cent events are printed or saved.  With -h, the history list  is  printed  without
               leading numbers.  If -T is specified, timestamps are printed also in comment form.
               (This can be used to produce files suitable  for  loading  with  'history  -L'  or
               'source  -h'.)   With  -r,  the order of printing is most recent first rather than
               oldest first.

               With -S, the second form saves the history list to filename.  If the first word of
               the savehist shell variable is set to a number, at most that many lines are saved.
               If the second word of savehist is set to `merge', the history list is merged  with
               the  existing history file instead of replacing it (if there is one) and sorted by
               time stamp.  (+) Merging is intended for an environment like the X  Window  System
               with  several  shells  in  simultaneous  use.   If  the second word of savehist is
               `merge' and the third word is set to `lock', the history file update will be seri-
               alized  with other shell sessions that would possibly like to merge history at ex-
               actly the same time.

               With -L, the shell appends filename, which is presumably a history list  saved  by
               the  -S option or the savehist mechanism, to the history list.  -M is like -L, but
               the contents of filename are merged into the history list and sorted by timestamp.
               In  either  case, histfile is used if filename is not given and ~/.history is used
               if histfile is unset.  `history -L' is exactly like 'source  -h'  except  that  it
               does not require a filename.

               Note  that login shells do the equivalent of `history -L' on startup and, if save-
               hist is set, `history -S' before exiting.   Because  only  ~/.tcshrc  is  normally
               sourced  before ~/.history, histfile should be set in ~/.tcshrc rather than ~/.lo-
               gin.

               If histlit is set, the first and second forms print and save  the  literal  (unex-
               panded) form of the history list.

               The last form clears the history list.

       hup [command] (+)
               With  command, runs command such that it will exit on a hangup signal and arranges
               for the shell to send it a hangup signal when the shell exits.  Note that commands
               may  set  their  own  response  to  hangups, overriding hup.  Without an argument,
               causes the non-interactive shell only to exit on a hangup for the remainder of the
               script.  See also Signal handling and the nohup builtin command.

       if (expr) command
               If  expr (an expression, as described under Expressions) evaluates true, then com-
               mand is executed.  Variable substitution on command happens  early,  at  the  same
               time  it  does  for the rest of the if command.  command must be a simple command,
               not an alias, a pipeline, a command list or a parenthesized command list,  but  it
               may  have  arguments.   Input/output  redirection occurs even if expr is false and
               command is thus not executed; this is a bug.

       if (expr) then
       ...
       else if (expr2) then
       ...
       else
       ...
       endif   If the specified expr is true then the commands to the first  else  are  executed;
               otherwise if expr2 is true then the commands to the second else are executed, etc.
               Any number of else-if pairs are possible; only one endif is needed.  The else part
               is  likewise  optional.  (The words else and endif must appear at the beginning of
               input lines; the if must appear alone on its input line or after an else.)

       inlib shared-library ... (+)
               Adds each shared-library to the current environment.  There is no way to remove  a
               shared library.  (Domain/OS only)

       jobs [-l]
               Lists  the  active jobs.  With -l, lists process IDs in addition to the normal in-
               formation.  On TCF systems, prints the site on which each job is executing.

       kill [-s signal] %job|pid ...
       kill -l The first and second forms sends the specified signal (or, if none is  given,  the
               TERM (terminate) signal) to the specified jobs or processes.  job may be a number,
               a string, `', `%', `+' or `-' as described under Jobs.  Signals are  either  given
               by  number  or  by name (as given in /usr/include/signal.h, stripped of the prefix
               `SIG').  There is no default job; saying just `kill' does not send a signal to the
               current  job.   If the signal being sent is TERM (terminate) or HUP (hangup), then
               the job or process is sent a CONT (continue) signal as well.  The third form lists
               the signal names.

       limit [-h] [resource [maximum-use]]
               Limits  the  consumption by the current process and each process it creates to not
               individually exceed maximum-use on the specified resource.  If no  maximum-use  is
               given,  then the current limit is printed; if no resource is given, then all limi-
               tations are given.  If the -h flag is given, the hard limits are used  instead  of
               the current limits.  The hard limits impose a ceiling on the values of the current
               limits.  Only the super-user may raise the hard limits, but a user  may  lower  or
               raise the current limits within the legal range.

               Controllable resources currently include (if supported by the OS):

               cputime
                      the maximum number of cpu-seconds to be used by each process

               filesize
                      the largest single file which can be created

               datasize
                      the  maximum  growth of the data+stack region via sbrk(2) beyond the end of
                      the program text

               stacksize
                      the maximum size of the automatically-extended stack region

               coredumpsize
                      the size of the largest core dump that will be created

               memoryuse
                      the maximum amount of physical memory a process may have allocated to it at
                      a given time

               vmemoryuse
                      the  maximum amount of virtual memory a process may have allocated to it at
                      a given time (address space)

               vmemoryuse
                      the maximum amount of virtual memory a process may have allocated to it  at
                      a given time

               heapsize
                      the maximum amount of memory a process may allocate per brk() system call

               descriptors or openfiles
                      the maximum number of open files for this process

               pseudoterminals
                      the maximum number of pseudo-terminals for this user

               kqueues
                      the maximum number of kqueues allocated for this process

               concurrency
                      the maximum number of threads for this process

               memorylocked
                      the maximum size which a process may lock into memory using mlock(2)

               maxproc
                      the maximum number of simultaneous processes for this user id

               maxthread
                      the maximum number of simultaneous threads (lightweight processes) for this
                      user id

               threads
                      the maximum number of threads for this process

               sbsize the maximum size of socket buffer usage for this user

               swapsize
                      the maximum amount of swap space reserved or used for this user

               maxlocks
                      the maximum number of locks for this user

               posixlocks
                      the maximum number of POSIX advisory locks for this user

               maxsignal
                      the maximum number of pending signals for this user

               maxmessage
                      the maximum number of bytes in POSIX mqueues for this user

               maxnice
                      the maximum nice  priority  the  user  is  allowed  to  raise  mapped  from
                      [19...-20] to [0...39] for this user

               maxrtprio
                      the  maximum  realtime  priority for this user maxrttime the timeout for RT
                      tasks in microseconds for this user.

               maximum-use may be given as a (floating point or integer)  number  followed  by  a
               scale  factor.   For  all  limits  other  than cputime the default scale is `k' or
               `kilobytes' (1024 bytes); a scale factor of `m' or `megabytes' or  `g'  or  `giga-
               bytes'  may also be used.  For cputime the default scaling is `seconds', while `m'
               for minutes or `h' for hours, or a time of the form  `mm:ss'  giving  minutes  and
               seconds may be used.

               If  maximum-use   is `unlimited', then the limitation on the specified resource is
               removed (this is equivalent to the unlimit builtin command).

               For both resource names and scale factors, unambiguous prefixes of the names  suf-
               fice.

       log (+) Prints the watch shell variable and reports on each user indicated in watch who is
               logged in, regardless of when they last logged in.  See also watchlog.

       login   Terminates a login shell, replacing it with an instance of /bin/login. This is one
               way to log off, included for compatibility with sh(1).

       logout  Terminates a login shell.  Especially useful if ignoreeof is set.

       ls-F [-switch ...] [file ...] (+)
               Lists  files  like  `ls  -F', but much faster.  It identifies each type of special
               file in the listing with a special character:

               /   Directory
               *   Executable
               #   Block device
               %   Character device
               |   Named pipe (systems with named pipes only)
               =   Socket (systems with sockets only)
               @   Symbolic link (systems with symbolic links only)
               +   Hidden directory (AIX only) or context dependent (HP/UX only)
               :   Network special (HP/UX only)

               If the listlinks shell variable is set, symbolic links are identified in more  de-
               tail (on only systems that have them, of course):

               @   Symbolic link to a non-directory
               >   Symbolic link to a directory
               &   Symbolic link to nowhere

               listlinks  also  slows down ls-F and causes partitions holding files pointed to by
               symbolic links to be mounted.

               If the listflags shell variable is set to `x', `a'  or  `A',  or  any  combination
               thereof (e.g., `xA'), they are used as flags to ls-F, making it act like `ls -xF',
               `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA').  On machines where `ls  -C'
               is  not the default, ls-F acts like `ls -CF', unless listflags contains an `x', in
               which case it acts like `ls -xF'.  ls-F passes its arguments to  ls(1)  if  it  is
               given any switches, so `alias ls ls-F' generally does the right thing.

               The  ls-F  builtin can list files using different colors depending on the filetype
               or extension.  See the color shell variable and the  LS_COLORS  environment  vari-
               able.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The  first  form  migrates the process or job to the site specified or the default
               site determined by the system path.  The second form  is  equivalent  to  `migrate
               -site  $$':  it migrates the current process to the specified site.  Migrating the
               shell itself can cause unexpected behavior, because the shell  does  not  like  to
               lose its tty.  (TCF only)

       newgrp [-] [group] (+)
               Equivalent  to  `exec  newgrp'; see newgrp(1).  Available only if the shell was so
               compiled; see the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to number, or, without  number,  to  4.
               With  command,  runs command at the appropriate priority.  The greater the number,
               the less cpu the process gets.  The super-user may specify  negative  priority  by
               using  `nice -number ...'.  Command is always executed in a sub-shell, and the re-
               strictions placed on commands in simple if statements apply.

       nohup [command]
               With command, runs command such that it will ignore  hangup  signals.   Note  that
               commands  may set their own response to hangups, overriding nohup.  Without an ar-
               gument, causes the non-interactive shell only to ignore hangups for the  remainder
               of the script.  See also Signal handling and the hup builtin command.

       notify [%job ...]
               Causes  the  shell to notify the user asynchronously when the status of any of the
               specified jobs (or, without %job, the current job) changes, instead of waiting un-
               til  the  next prompt as is usual.  job may be a number, a string, `', `%', `+' or
               `-' as described under Jobs.  See also the notify shell variable.

       onintr [-|label]
               Controls the action of the shell on interrupts.  Without arguments,  restores  the
               default  action of the shell on interrupts, which is to terminate shell scripts or
               to return to the terminal command input level.  With `-', causes all interrupts to
               be ignored.  With label, causes the shell to execute a `goto label' when an inter-
               rupt is received or a child process terminates because it was interrupted.

               onintr is ignored if the shell is running detached and  in  system  startup  files
               (see FILES), where interrupts are disabled anyway.

       popd [-p] [-l] [-n|-v] [+n]
               Without  arguments, pops the directory stack and returns to the new top directory.
               With a number `+n', discards the n'th entry in the stack.

               Finally, all forms of popd print the final directory stack, just like  dirs.   The
               pushdsilent shell variable can be set to prevent this and the -p flag can be given
               to override pushdsilent.  The -l, -n and -v flags have the same effect on popd  as
               on dirs.  (+)

       printenv [name] (+)
               Prints  the names and values of all environment variables or, with name, the value
               of the environment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without arguments, exchanges the top two elements  of  the  directory  stack.   If
               pushdtohome  is  set,  pushd  without arguments does `pushd ~', like cd.  (+) With
               name, pushes the current working directory onto the directory stack and changes to
               name.   If  name  is  `-' it is interpreted as the previous working directory (see
               Filename substitution).  (+) If dunique is set, pushd  removes  any  instances  of
               name from the stack before pushing it onto the stack.  (+) With a number `+n', ro-
               tates the nth element of the directory stack around to  be  the  top  element  and
               changes  to  it.   If dextract is set, however, `pushd +n' extracts the nth direc-
               tory, pushes it onto the top of the stack and changes to it.  (+)

               Finally, all forms of pushd print the final directory stack, just like dirs.   The
               pushdsilent shell variable can be set to prevent this and the -p flag can be given
               to override pushdsilent.  The -l, -n and -v flags have the same effect on pushd as
               on dirs.  (+)

       rehash  Causes  the  internal  hash  table  of the contents of the directories in the path
               variable to be recomputed.  This is needed if the autorehash shell variable is not
               set  and  new  commands  are added to directories in path while you are logged in.
               With autorehash, a new command will be found automatically, except in the  special
               case where another command of the same name which is located in a different direc-
               tory already exists in the hash table.  Also flushes the cache of home directories
               built by tilde expansion.

       repeat count command
               The specified command, which is subject to the same restrictions as the command in
               the one line if statement above, is executed count times.  I/O redirections  occur
               exactly once, even if count is 0.

       rootnode //nodename (+)
               Changes  the  rootnode  to //nodename, so that `/' will be interpreted as `//node-
               name'.  (Domain/OS only)

       sched (+)
       sched [+]hh:mm command (+)
       sched -n (+)
               The first form prints the scheduled-event list.  The sched shell variable  may  be
               set to define the format in which the scheduled-event list is printed.  The second
               form adds command to the scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes the shell to echo `It's eleven o'clock.' at 11 AM.   The  time  may  be  in
               12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A  relative  time  specification may not use AM/PM format.  The third form removes
               item n from the event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                        2  Wed Apr  4 17:00  set prompt=[%h] It's after 5; go home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

               A command in the scheduled-event list is executed just before the first prompt  is
               printed  after the time when the command is scheduled.  It is possible to miss the
               exact time when the command is to be run, but an overdue command will  execute  at
               the  next  prompt.   A command which comes due while the shell is waiting for user
               input is executed immediately.  However, normal operation  of  an  already-running
               command will not be interrupted so that a scheduled-event list element may be run.

               This  mechanism is similar to, but not the same as, the at(1) command on some Unix
               systems.  Its major disadvantage is that it may not run a command at  exactly  the
               specified  time.  Its major advantage is that because sched runs directly from the
               shell, it has access to shell variables and other  structures.   This  provides  a
               mechanism for changing one's working environment based on the time of day.

       set
       set name ...
       set name=word ...
       set [-r] [-f|-l] name=(wordlist) ... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word ... (+)
               The  first form of the command prints the value of all shell variables.  Variables
               which contain more than a single word print as a  parenthesized  word  list.   The
               second  form sets name to the null string.  The third form sets name to the single
               word.  The fourth form sets name to the list of words in wordlist.  In  all  cases
               the  value is command and filename expanded.  If -r is specified, the value is set
               read-only.  If -f or -l are specified, set only unique words keeping their  order.
               -f  prefers  the first occurrence of a word, and -l the last.  The fifth form sets
               the index'th component of name to word; this component must  already  exist.   The
               sixth  form  lists  only the names of all shell variables that are read-only.  The
               seventh form makes name read-only, whether or not it has a value.  The eighth form
               is the same as the third form, but make name read-only at the same time.

               These arguments can be repeated to set and/or make read-only multiple variables in
               a single set command.  Note, however, that variable expansion happens for all  ar-
               guments  before  any  setting  occurs.  Note also that `=' can be adjacent to both
               name and word or separated from both by whitespace, but cannot be adjacent to only
               one or the other.  See also the unset builtin command.

       setenv [name [value]]
               Without  arguments,  prints  the  names  and  values of all environment variables.
               Given name, sets the environment variable name to value or, without value, to  the
               null string.

       setpath path (+)
               Equivalent to setpath(1).  (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path.  (TCF only)

       settc cap value (+)
               Tells  the  shell to believe that the terminal capability cap (as defined in term-
               cap(5)) has the value value.  No sanity checking is done.  Concept terminal  users
               may have to `settc xn no' to get proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls  which  tty  modes  (see Terminal management) the shell does not allow to
               change.  -d, -q or -x tells setty to act on the `edit', `quote' or  `execute'  set
               of tty modes respectively; without -d, -q or -x, `execute' is used.

               Without  other  arguments, setty lists the modes in the chosen set which are fixed
               on (`+mode') or off (`-mode').  The available modes, and thus  the  display,  vary
               from  system to system.  With -a, lists all tty modes in the chosen set whether or
               not they are fixed.  With +mode, -mode or mode, fixes mode on or  off  or  removes
               control  from  mode  in  the  chosen set.  For example, `setty +echok echoe' fixes
               `echok' mode on and allows commands to turn `echoe' mode on or off, both when  the
               shell is executing commands.

       setxvers [string] (+)
               Set the experimental version prefix to string, or removes it if string is omitted.
               (TCF only)

       shift [variable]
               Without arguments, discards argv[1] and shifts the members of argv  to  the  left.
               It  is  an  error  for  argv not to be set or to have less than one word as value.
               With variable, performs the same function on variable.

       source [-h] name [args ...]
               The shell reads and executes commands from name.  The commands are not  placed  on
               the  history  list.   If  any args are given, they are placed in argv.  (+) source
               commands may be nested; if they are nested too deeply the shell  may  run  out  of
               file  descriptors.  An error in a source at any level terminates all nested source
               commands.  With -h, commands are placed on the history list instead of being  exe-
               cuted, much like `history -L'.

       stop %job|pid ...
               Stops  the specified jobs or processes which are executing in the background.  job
               may be a number, a string, `', `%', `+' or `-' as described under Jobs.  There  is
               no default job; saying just `stop' does not stop the current job.

       suspend Causes  the shell to stop in its tracks, much as if it had been sent a stop signal
               with ^Z.  This is most often used to stop shells started by su(1).

       switch (string)
       case str1:
           ...
           breaksw
       ...
       default:
           ...
           breaksw
       endsw   Each case label is successively matched, against the  specified  string  which  is
               first command and filename expanded.  The file metacharacters `*', `?' and `[...]'
               may be used in the case labels, which are variable expanded.  If none of  the  la-
               bels  match before a `default' label is found, then the execution begins after the
               default label.  Each case label and the default label must appear at the beginning
               of  a  line.   The  command  breaksw causes execution to continue after the endsw.
               Otherwise control may fall through case labels and default labels as in C.  If  no
               label matches and there is no default, execution continues after the endsw.

       telltc (+)
               Lists the values of all terminal capabilities (see termcap(5)).

       termname [terminal type] (+)
               Tests if terminal type (or the current value of TERM if no terminal type is given)
               has an entry in the hosts termcap(5) or terminfo(5) database. Prints the  terminal
               type to stdout and returns 0 if an entry is present otherwise returns 1.

       time [command]
               Executes command (which must be a simple command, not an alias, a pipeline, a com-
               mand list or a parenthesized command list) and prints a time summary as  described
               under  the  time  variable.   If necessary, an extra shell is created to print the
               time statistic when the command completes.  Without command, prints a time summary
               for the current shell and its children.

       umask [value]
               Sets  the file creation mask to value, which is given in octal.  Common values for
               the mask are 002, giving all access to the group and read and  execute  access  to
               others,  and 022, giving read and execute access to the group and others.  Without
               value, prints the current file creation mask.

       unalias pattern
               Removes all aliases whose names match  pattern.   `unalias  *'  thus  removes  all
               aliases.  It is not an error for nothing to be unaliased.

       uncomplete pattern (+)
               Removes  all  completions  whose names match pattern.  `uncomplete *' thus removes
               all completions.  It is not an error for nothing to be uncompleted.

       unhash  Disables use of the internal hash table to speed location of executed programs.

       universe universe (+)
               Sets the universe to universe.  (Masscomp/RTU only)

       unlimit [-hf] [resource]
               Removes the limitation on resource or, if no resource is specified,  all  resource
               limitations.  With -h, the corresponding hard limits are removed.  Only the super-
               user may do this.  Note that unlimit may not exit successful, since  most  systems
               do not allow descriptors to be unlimited.  With -f errors are ignored.

       unset pattern
               Removes  all variables whose names match pattern, unless they are read-only.  `un-
               set *' thus removes all variables unless they are read-only; this is a  bad  idea.
               It is not an error for nothing to be unset.

       unsetenv pattern
               Removes  all  environment  variables whose names match pattern.  `unsetenv *' thus
               removes all environment variables; this is a bad idea.  It is  not  an  error  for
               nothing to be unsetenved.

       ver [systype [command]] (+)
               Without  arguments,  prints SYSTYPE.  With systype, sets SYSTYPE to systype.  With
               systype and command, executes command under systype.  systype may be  `bsd4.3'  or
               `sys5.3'.  (Domain/OS only)

       wait    The  shell  waits for all background jobs.  If the shell is interactive, an inter-
               rupt will disrupt the wait and cause the shell to print the names and job  numbers
               of all outstanding jobs.

       warp universe (+)
               Sets the universe to universe.  (Convex/OS only)

       watchlog (+)
               An alternate name for the log builtin command (q.v.).  Available only if the shell
               was so compiled; see the version shell variable.

       where command (+)
               Reports all known instances of command, including aliases, builtins  and  executa-
               bles in path.

       which command (+)
               Displays  the command that will be executed by the shell after substitutions, path
               searching, etc.  The builtin command is just like which(1), but it  correctly  re-
               ports  tcsh  aliases  and  builtins  and  is 10 to 100 times faster.  See also the
               which-command editor command.

       while (expr)
       ...
       end     Executes the commands between the while and the matching end while  expr  (an  ex-
               pression,  as described under Expressions) evaluates non-zero.  while and end must
               appear alone on their input lines.  break and continue may be used to terminate or
               continue  the  loop prematurely.  If the input is a terminal, the user is prompted
               the first time through the loop as with foreach.

   Special aliases (+)
       If set, each of these aliases executes automatically at the indicated time.  They are  all
       initially undefined.

       beepcmd Runs when the shell wants to ring the terminal bell.

       cwdcmd  Runs after every change of working directory.  For example, if the user is working
               on an X window system using xterm(1) and a re-parenting window manager  that  sup-
               ports title bars such as twm(1) and does

                   > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

               then the shell will change the title of the running xterm(1) to be the name of the
               host, a colon, and the full current working directory.  A fancier way to  do  that
               is

                   > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

               This  will  put  the  hostname and working directory on the title bar but only the
               hostname in the icon manager menu.

               Note that putting a cd, pushd or popd in cwdcmd may cause an infinite loop.  It is
               the author's opinion that anyone doing so will get what they deserve.

       jobcmd  Runs  before  each command gets executed, or when the command changes state.  This
               is similar to postcmd, but it does not print builtins.

                   > alias jobcmd  'echo -n "^[]2\;\!#:q^G"'

               then executing vi foo.c will put the command string in the xterm title bar.

       helpcommand
               Invoked by the run-help editor command.  The command name for which help is sought
               is passed as sole argument.  For example, if one does

                   > alias helpcommand '\!:1 --help'

               then  the  help  display of the command itself will be invoked, using the GNU help
               calling convention.  Currently there is no easy way to account for various calling
               conventions  (e.g., the customary Unix `-h'), except by using a table of many com-
               mands.

       periodic
               Runs every tperiod minutes.  This provides a convenient means for checking on com-
               mon but infrequent changes such as new mail.  For example, if one does

                   > set tperiod = 30
                   > alias periodic checknews

               then  the checknews(1) program runs every 30 minutes.  If periodic is set but tpe-
               riod is unset or set to 0, periodic behaves like precmd.

       precmd  Runs just before each prompt is printed.  For example, if one does

                   > alias precmd date

               then date(1) runs just before the shell prompts for each command.   There  are  no
               limits on what precmd can be set to do, but discretion should be used.

       postcmd Runs before each command gets executed.

                   > alias postcmd  'echo -n "^[]2\;\!#:q^G"'

               then executing vi foo.c will put the command string in the xterm title bar.

       shell   Specifies  the  interpreter for executable scripts which do not themselves specify
               an interpreter.  The first word should be a full path name to the  desired  inter-
               preter (e.g., `/bin/csh' or `/usr/local/bin/tcsh').

   Special shell variables
       The variables described in this section have special meaning to the shell.

       The  shell  sets  addsuffix, argv, autologout, csubstnonl, command, echo_style, edit, gid,
       group, home, loginsh, oid, path, prompt, prompt2, prompt3, shell, shlvl, tcsh, term,  tty,
       uid,  user  and  version  at  startup; they do not change thereafter unless changed by the
       user.  The shell updates cwd, dirstack, owd and status when necessary, and sets logout  on
       logout.

       The  shell synchronizes group, home, path, shlvl, term and user with the environment vari-
       ables of the same names: whenever the environment variable changes the shell  changes  the
       corresponding  shell  variable  to match (unless the shell variable is read-only) and vice
       versa.  Note that although cwd and PWD have identical meanings, they are not  synchronized
       in this manner, and that the shell automatically converts between the different formats of
       path and PATH.

       addsuffix (+)
               If set, filename completion adds `/' to the end of directories and a space to  the
               end of normal files when they are matched exactly.  Set by default.

       afsuser (+)
               If set, autologout's autolock feature uses its value instead of the local username
               for kerberos authentication.

       ampm (+)
               If set, all times are shown in 12-hour AM/PM format.

       anyerror (+)
               This variable selects what is propagated to the value of the status variable.  For
               more information see the description of the status variable below.

       argv    The arguments to the shell.  Positional parameters are taken from argv, i.e., `$1'
               is replaced by `$argv[1]', etc.  Set by default, but usually empty in  interactive
               shells.

       autocorrect (+)
               If set, the spell-word editor command is invoked automatically before each comple-
               tion attempt.

       autoexpand (+)
               If set, the expand-history editor command is  invoked  automatically  before  each
               completion  attempt.  If this is set to onlyhistory, then only history will be ex-
               panded and a second completion will expand filenames.

       autolist (+)
               If set, possibilities are listed after an ambiguous completion.  If  set  to  `am-
               biguous',  possibilities  are listed only when no new characters are added by com-
               pletion.

       autologout (+)
               The first word is the number of minutes of  inactivity  before  automatic  logout.
               The  optional  second word is the number of minutes of inactivity before automatic
               locking.  When the shell automatically logs out, it prints `auto-logout', sets the
               variable logout to `automatic' and exits.  When the shell automatically locks, the
               user is required to enter his password to continue working.   Five  incorrect  at-
               tempts  result  in  automatic logout.  Set to `60' (automatic logout after 60 min-
               utes, and no locking) by default in login and superuser shells,  but  not  if  the
               shell  thinks  it  is running under a window system (i.e., the DISPLAY environment
               variable is set), the tty is a pseudo-tty (pty) or the shell was not  so  compiled
               (see  the  version  shell  variable).  See also the afsuser and logout shell vari-
               ables.

       autorehash (+)
               If set, the internal hash table of the contents of the  directories  in  the  path
               variable will be recomputed if a command is not found in the hash table.  In addi-
               tion, the list of available commands will be rebuilt for each  command  completion
               or  spelling correction attempt if set to `complete' or `correct' respectively; if
               set to `always', this will be done for both cases.

       backslash_quote (+)
               If set, backslashes (`\') always quote `\', `'', and `"'.  This may  make  complex
               quoting tasks easier, but it can cause syntax errors in csh(1) scripts.

       catalog The  file  name  of  the message catalog.  If set, tcsh use `tcsh.${catalog}' as a
               message catalog instead of default `tcsh'.

       cdpath  A list of directories in which cd should search for subdirectories if they  aren't
               found in the current directory.

       cdtohome (+)
               If not set, cd requires a directory name, and will not go to the home directory if
               it's omitted.  This is set by default.

       color   If set, it enables color display for the builtin ls-F and it  passes  --color=auto
               to  ls.   Alternatively,  it can be set to only ls-F or only ls to enable color to
               only one command.  Setting it to nothing is equivalent to setting it to (ls-F ls).

       colorcat
               If set, it enables color escape sequence for NLS message files.  And display  col-
               orful NLS messages.

       command (+)
               If set, the command which was passed to the shell with the -c flag (q.v.).

       compat_expr (+)
               If set, the shell will evaluate expressions right to left, like the original csh.

       complete (+)
               If  set  to  `igncase',  the  completion becomes case insensitive.  If set to `en-
               hance', completion ignores case and considers hyphens and underscores to be equiv-
               alent;  it  will also treat periods, hyphens and underscores (`.', `-' and `_') as
               word separators.  If set to `Enhance', completion matches uppercase and underscore
               characters explicitly and matches lowercase and hyphens in a case-insensitive man-
               ner; it will treat periods, hyphens and underscores as word separators.

       continue (+)
               If set to a list of commands, the shell will continue the listed commands, instead
               of starting a new one.

       continue_args (+)
               Same as continue, but the shell will execute:

                   echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

       correct (+)
               If  set  to `cmd', commands are automatically spelling-corrected.  If set to `com-
               plete', commands are automatically completed.  If set to `all', the entire command
               line is corrected.

       csubstnonl (+)
               If set, newlines and carriage returns in command substitution are replaced by spa-
               ces.  Set by default.

       cwd     The full pathname of the current directory.  See also the dirstack and  owd  shell
               variables.

       dextract (+)
               If set, `pushd +n' extracts the nth directory from the directory stack rather than
               rotating it to the top.

       dirsfile (+)
               The default location in which `dirs -S' and `dirs -L' look for a history file.  If
               unset,  ~/.cshdirs  is  used.   Because  only ~/.tcshrc is normally sourced before
               ~/.cshdirs, dirsfile should be set in ~/.tcshrc rather than ~/.login.

       dirstack (+)
               An array of all the directories on the directory  stack.   `$dirstack[1]'  is  the
               current  working  directory, `$dirstack[2]' the first directory on the stack, etc.
               Note that the current working directory is `$dirstack[1]' but  `=0'  in  directory
               stack  substitutions,  etc.   One  can  change  the  stack  arbitrarily by setting
               dirstack, but the first element (the current working directory) is always correct.
               See also the cwd and owd shell variables.

       dspmbyte (+)
               Has  an effect iff 'dspm' is listed as part of the version shell variable.  If set
               to `euc', it enables display and editing  EUC-kanji(Japanese)  code.   If  set  to
               `sjis',  it  enables  display  and  editing  Shift-JIS(Japanese)  code.  If set to
               `big5', it enables display and editing Big5(Chinese) code.  If set to  `utf8',  it
               enables  display  and editing Utf8(Unicode) code.  If set to the following format,
               it enables display and editing of original multi-byte code format:

                   > set dspmbyte = 0000....(256 bytes)....0000

               The table requires just 256 bytes.  Each character of 256  characters  corresponds
               (from  left  to right) to the ASCII codes 0x00, 0x01, ... 0xff.  Each character is
               set to number 0,1,2 and 3.  Each number has the following meaning:
                 0 ... not used for multi-byte characters.
                 1 ... used for the first byte of a multi-byte character.
                 2 ... used for the second byte of a multi-byte character.
                 3 ... used for both the first byte and second byte of a multi-byte character.

                 Example:
               If set to `001322', the first character (means 0x00 of the ASCII code) and  second
               character  (means  0x01  of  ASCII code) are set to `0'.  Then, it is not used for
               multi-byte characters.  The 3rd character (0x02) is set to '1', indicating that it
               is  used for the first byte of a multi-byte character.  The 4th character(0x03) is
               set '3'.  It is used for both the first byte and the second byte of  a  multi-byte
               character.  The 5th and 6th characters (0x04,0x05) are set to '2', indicating that
               they are used for the second byte of a multi-byte character.

               The GNU fileutils version of ls cannot display multi-byte filenames without the -N
               (  --literal  )  option.    If  you are using this version, set the second word of
               dspmbyte to "ls".  If not, for example, "ls-F -l" cannot display multi-byte  file-
               names.

                 Note:
               This  variable  can only be used if KANJI and DSPMBYTE has been defined at compile
               time.

       dunique (+)
               If set, pushd removes any instances of name from the stack before pushing it  onto
               the stack.

       echo    If set, each command with its arguments is echoed just before it is executed.  For
               non-builtin commands all expansions occur before echoing.   Builtin  commands  are
               echoed  before  command and filename substitution, because these substitutions are
               then done selectively.  Set by the -x command line option.

       echo_style (+)
               The style of the echo builtin.  May be set to

               bsd     Don't echo a newline if the first argument is `-n'; the default for csh.
               sysv    Recognize backslashed escape sequences in echo strings.
               both    Recognize both the `-n' flag and backslashed escape sequences; the default
                       for tcsh.
               none    Recognize neither.

               Set  by default to the local system default.  The BSD and System V options are de-
               scribed in the echo(1) man pages on the appropriate systems.

       edit (+)
               If set, the command-line editor is used.  Set by default in interactive shells.

       editors (+)
               A list of command names for the run-fg-editor editor command  to  match.   If  not
               set,  the  EDITOR (`ed' if unset) and VISUAL (`vi' if unset) environment variables
               will be used instead.

       ellipsis (+)
               If set, the `%c'/`%.' and `%C' prompt sequences (see the  prompt  shell  variable)
               indicate skipped directories with an ellipsis (`...')  instead of `/<skipped>'.

       euid (+)
               The user's effective user ID.

       euser (+)
               The first matching passwd entry name corresponding to the effective user ID.

       fignore (+)
               Lists file name suffixes to be ignored by completion.

       filec   In  tcsh,  completion  is  always used and this variable is ignored by default. If
               edit is unset, then the traditional csh completion is used.  If set in csh,  file-
               name completion is used.

       gid (+) The user's real group ID.

       globdot (+)
               If  set,  wild-card  glob patterns will match files and directories beginning with
               `.' except for `.' and `..'

       globstar (+)
               If set, the `**' and `***' file glob patterns will match any string of  characters
               including `/' traversing any existing sub-directories.  (e.g.  `ls **.c' will list
               all the .c files in the current directory tree).  If used by itself, it will match
               zero  or more sub-directories (e.g. `ls /usr/include/**/time.h' will list any file
               named  `time.h'  in  the  /usr/include  directory  tree;  whereas   `ls   /usr/in-
               clude/**time.h'  will  match any file in the /usr/include directory tree ending in
               `time.h').  To prevent problems with recursion, the `**' glob-pattern will not de-
               scend into a symbolic link containing a directory.  To override this, use `***'

       group (+)
               The user's group name.

       highlight
               If  set,  the incremental search match (in i-search-back and i-search-fwd) and the
               region between the mark and the cursor are highlighted in reverse video.

               Highlighting requires more frequent terminal writes, which introduces extra  over-
               head. If you care about terminal performance, you may want to leave this unset.

       histchars
               A  string  value  determining  the characters used in History substitution (q.v.).
               The first character of its value is used as the  history  substitution  character,
               replacing  the  default character `!'.  The second character of its value replaces
               the character `^' in quick substitutions.

       histdup (+)
               Controls handling of duplicate entries in the history list.  If set to `all'  only
               unique  history  events are entered in the history list.  If set to `prev' and the
               last history event is the same as the current command, then the current command is
               not  entered in the history.  If set to `erase' and the same event is found in the
               history list, that old event gets erased and the current one gets inserted.   Note
               that the `prev' and `all' options renumber history events so there are no gaps.

       histfile (+)
               The  default  location  in  which `history -S' and `history -L' look for a history
               file.  If unset, ~/.history is used.  histfile is useful  when  sharing  the  same
               home  directory  between  different machines, or when saving separate histories on
               different terminals.  Because only ~/.tcshrc is normally  sourced  before  ~/.his-
               tory, histfile should be set in ~/.tcshrc rather than ~/.login.

       histlit (+)
               If  set,  builtin  and  editor commands and the savehist mechanism use the literal
               (unexpanded) form of lines in the history list.  See also the  toggle-literal-his-
               tory editor command.

       history The  first word indicates the number of history events to save.  The optional sec-
               ond word (+) indicates the format in which  history  is  printed;  if  not  given,
               `%h\t%T\t%R\n'  is  used.   The format sequences are described below under prompt;
               note the variable meaning of `%R'.  Set to `100' by default.

       home    Initialized to the home directory of the invoker.  The filename expansion  of  `~'
               refers to this variable.

       ignoreeof
               If  set to the empty string or `0' and the input device is a terminal, the end-of-
               file command (usually generated by the user by  typing  `^D'  on  an  empty  line)
               causes  the  shell  to print `Use "exit" to leave tcsh.' instead of exiting.  This
               prevents the shell from accidentally being killed.  Historically this setting  ex-
               ited after 26 successive EOF's to avoid infinite loops.  If set to a number n, the
               shell ignores n - 1 consecutive end-of-files and exits on the nth.  (+) If  unset,
               `1' is used, i.e., the shell exits on a single `^D'.

       implicitcd (+)
               If  set,  the shell treats a directory name typed as a command as though it were a
               request to change to that directory.  If set to verbose, the change  of  directory
               is  echoed  to the standard output.  This behavior is inhibited in non-interactive
               shell scripts, or for command strings with more than one word.  Changing directory
               takes  precedence  over executing a like-named command, but it is done after alias
               substitutions.  Tilde and variable expansions work as expected.

       inputmode (+)
               If set to `insert' or `overwrite', puts the editor into that input mode at the be-
               ginning of each line.

       killdup (+)
               Controls  handling  of  duplicate  entries in the kill ring.  If set to `all' only
               unique strings are entered in the kill ring.  If set to `prev' and the last killed
               string  is  the  same as the current killed string, then the current string is not
               entered in the ring.  If set to `erase' and the same string is found in  the  kill
               ring, the old string is erased and the current one is inserted.

       killring (+)
               Indicates the number of killed strings to keep in memory.  Set to `30' by default.
               If unset or set to less than `2', the shell  will  only  keep  the  most  recently
               killed string.  Strings are put in the killring by the editor commands that delete
               (kill) strings of text, e.g. backward-delete-word, kill-line, etc, as well as  the
               copy-region-as-kill  command.  The yank editor command will yank the most recently
               killed string into the command-line, while yank-pop (see Editor commands)  can  be
               used to yank earlier killed strings.

       listflags (+)
               If  set to `x', `a' or `A', or any combination thereof (e.g., `xA'), they are used
               as flags to ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a combination
               (e.g.,  `ls -FxA'): `a' shows all files (even if they start with a `.'), `A' shows
               all files but `.' and `..', and `x' sorts across instead of down.  If  the  second
               word of listflags is set, it is used as the path to `ls(1)'.

       listjobs (+)
               If  set, all jobs are listed when a job is suspended.  If set to `long', the list-
               ing is in long format.

       listlinks (+)
               If set, the ls-F builtin command shows the type of file  to  which  each  symbolic
               link points.

       listmax (+)
               The  maximum number of items which the list-choices editor command will list with-
               out asking first.

       listmaxrows (+)
               The maximum number of rows of items which the  list-choices  editor  command  will
               list without asking first.

       loginsh (+)
               Set  by  the shell if it is a login shell.  Setting or unsetting it within a shell
               has no effect.  See also shlvl.

       logout (+)
               Set by the shell to `normal' before a normal logout, `automatic' before  an  auto-
               matic  logout, and `hangup' if the shell was killed by a hangup signal (see Signal
               handling).  See also the autologout shell variable.

       mail    A list of files and directories to check for incoming mail, optionally preceded by
               a  numeric  word.   Before  each  prompt, if 10 minutes have passed since the last
               check, the shell checks each file and says `You have new mail.' (or, if mail  con-
               tains  multiple  files,  `You  have new mail in name.') if the filesize is greater
               than zero in size and has a modification time greater than its access time.

               If you are in a login shell, then no mail file is reported unless it has been mod-
               ified after the time the shell has started up, to prevent redundant notifications.
               Most login programs will tell you whether or not you have mail when you log in.

               If a file specified in mail is a directory, the shell will count each file  within
               that  directory as a separate message, and will report `You have n mails.' or `You
               have n mails in name.' as appropriate.  This functionality is  provided  primarily
               for those systems which store mail in this manner, such as the Andrew Mail System.

               If  the first word of mail is numeric it is taken as a different mail checking in-
               terval, in seconds.

               Under very rare circumstances, the shell may report `You have  mail.'  instead  of
               `You have new mail.'

       matchbeep (+)
               If  set  to  `never',  completion never beeps.  If set to `nomatch', it beeps only
               when there is no match.  If set to `ambiguous', it beeps when there  are  multiple
               matches.  If set to `notunique', it beeps when there is one exact and other longer
               matches.  If unset, `ambiguous' is used.

       nobeep (+)
               If set, beeping is completely disabled.  See also visiblebell.

       noclobber
               If set, restrictions are placed on output redirection to insure that files are not
               accidentally  destroyed and that `>>' redirections refer to existing files, as de-
               scribed in the Input/output section.

       noding  If set, disable the printing of `DING!' in  the  prompt  time  specifiers  at  the
               change of hour.

       noglob  If  set,  Filename substitution and Directory stack substitution (q.v.) are inhib-
               ited.  This is most useful in shell scripts which do not deal with  filenames,  or
               after  a list of filenames has been obtained and further expansions are not desir-
               able.

       nokanji (+)
               If set and the shell supports Kanji (see the version shell variable), it  is  dis-
               abled so that the meta key can be used.

       nonomatch
               If  set, a Filename substitution or Directory stack substitution (q.v.) which does
               not match any existing files is left untouched rather than causing an  error.   It
               is still an error for the substitution to be malformed, e.g., `echo [' still gives
               an error.

       nostat (+)
               A list of directories (or glob-patterns which match directories; see Filename sub-
               stitution)  that  should  not be stat(2)ed during a completion operation.  This is
               usually used to exclude directories which take too much time to stat(2), for exam-
               ple /afs.

       notify  If  set,  the  shell  announces job completions asynchronously.  The default is to
               present job completions just before printing a prompt.

       oid (+) The user's real organization ID.  (Domain/OS only)

       owd (+) The old working directory, equivalent to the `-' used by cd and pushd.   See  also
               the cwd and dirstack shell variables.

       padhour If  set,  enable the printing of padding '0' for hours, in 24 and 12 hour formats.
               E.G.: 07:45:42 vs. 7:45:42.

       parseoctal
               To retain compatibily with older versions numeric variables starting  with  0  are
               not interpreted as octal. Setting this variable enables proper octal parsing.

       path    A list of directories in which to look for executable commands.  A null word spec-
               ifies the current directory.  If there is no path variable  then  only  full  path
               names will execute.  path is set by the shell at startup from the PATH environment
               variable or, if PATH does not exist, to a system-dependent default something  like
               `(/usr/local/bin  /usr/bsd /bin /usr/bin .)'.  The shell may put `.' first or last
               in path or omit it entirely depending on how it  was  compiled;  see  the  version
               shell  variable.   A  shell which is given neither the -c nor the -t option hashes
               the contents of the directories in path after reading ~/.tcshrc and each time path
               is reset.  If one adds a new command to a directory in path while the shell is ac-
               tive, one may need to do a rehash for the shell to find it.

       printexitvalue (+)
               If set and an interactive program exits with a non-zero status, the  shell  prints
               `Exit status'.

       prompt  The string which is printed before reading each command from the terminal.  prompt
               may include any of the following formatting sequences (+), which are  replaced  by
               the given information:

               %/  The current working directory.
               %~  The  current  working  directory, but with one's home directory represented by
                   `~' and other users' home directories represented by `~user' as  per  Filename
                   substitution.  `~user' substitution happens only if the shell has already used
                   `~user' in a pathname in the current session.
               %c[[0]n], %.[[0]n]
                   The trailing component of the current working directory, or n trailing  compo-
                   nents if a digit n is given.  If n begins with `0', the number of skipped com-
                   ponents precede the trailing component(s) in the format  `/<skipped>trailing'.
                   If  the  ellipsis shell variable is set, skipped components are represented by
                   an ellipsis so the whole becomes `...trailing'.  `~' substitution is  done  as
                   in  `%~' above, but the `~' component is ignored when counting trailing compo-
                   nents.
               %C  Like %c, but without `~' substitution.
               %h, %!, !
                   The current history event number.
               %M  The full hostname.
               %m  The hostname up to the first `.'.
               %S (%s)
                   Start (stop) standout mode.
               %B (%b)
                   Start (stop) boldfacing mode.
               %U (%u)
                   Start (stop) underline mode.
               %t, %@
                   The time of day in 12-hour AM/PM format.
               %T  Like `%t', but in 24-hour format (but see the ampm shell variable).
               %p  The `precise' time of day in 12-hour AM/PM format, with seconds.
               %P  Like `%p', but in 24-hour format (but see the ampm shell variable).
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %N  The effective user name.
               %j  The number of jobs.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears from the end of the prompt to end of the display  or  the  end  of  the
                   line.
               %$  Expands the shell or environment variable name immediately after the `$'.
               %#  `>'  (or  the  first  character  of the promptchars shell variable) for normal
                   users, `#' (or the second character of promptchars) for the superuser.
               %{string%}
                   Includes string as a literal escape sequence.   It  should  be  used  only  to
                   change terminal attributes and should not move the cursor location.  This can-
                   not be the last sequence in prompt.
               %?  The return code of the command executed just before the prompt.
               %R  In prompt2, the status of the parser.  In prompt3, the corrected  string.   In
                   history, the history string.

               `%B',  `%S',  `%U'  and `%{string%}' are available in only eight-bit-clean shells;
               see the version shell variable.

               The bold, standout and underline sequences are often used to distinguish  a  supe-
               ruser shell.  For example,

                   > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               If  `%t',  `%@',  `%T',  `%p',  or `%P' is used, and noding is not set, then print
               `DING!' on the change of hour (i.e, `:00' minutes) instead of the actual time.

               Set by default to `%# ' in interactive shells.

       prompt2 (+)
               The string with which to prompt in while and foreach loops and after lines  ending
               in `\'.  The same format sequences may be used as in prompt (q.v.); note the vari-
               able meaning of `%R'.  Set by default to `%R? ' in interactive shells.

       prompt3 (+)
               The string with which to prompt when  confirming  automatic  spelling  correction.
               The same format sequences may be used as in prompt (q.v.); note the variable mean-
               ing of `%R'.  Set by default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

       promptchars (+)
               If set (to a two-character string), the `%#' formatting  sequence  in  the  prompt
               shell  variable is replaced with the first character for normal users and the sec-
               ond character for the superuser.

       pushdtohome (+)
               If set, pushd without arguments does `pushd ~', like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the directory stack.

       recexact (+)
               If set, completion completes on an exact match even if a longer match is possible.

       recognize_only_executables (+)
               If set, command listing displays only files  in  the  path  that  are  executable.
               Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is executed.

       rprompt (+)
               The string to print on the right-hand side of the screen (after the command input)
               when the prompt is being displayed on the left.  It recognizes the same formatting
               characters  as prompt.  It will automatically disappear and reappear as necessary,
               to ensure that command input isn't obscured, and will appear only if  the  prompt,
               command input, and itself will fit together on the first line.  If edit isn't set,
               then rprompt will be printed after the prompt and before the command input.

       savedirs (+)
               If set, the shell does `dirs -S' before exiting.  If the first word is  set  to  a
               number, at most that many directory stack entries are saved.

       savehist
               If set, the shell does `history -S' before exiting.  If the first word is set to a
               number, at most that many lines are saved.  (The number should  be  less  than  or
               equal  to  the  number history entries; if it is set to greater than the number of
               history settings, only history entries will be saved) If the second word is set to
               `merge',  the history list is merged with the existing history file instead of re-
               placing it (if there is one) and sorted by time stamp and the most  recent  events
               are retained.  If the second word of savehist is `merge' and the third word is set
               to `lock', the history file update will be serialized with  other  shell  sessions
               that would possibly like to merge history at exactly the same time. (+)

       sched (+)
               The  format  in  which  the  sched builtin command prints scheduled events; if not
               given, `%h\t%T\t%R\n' is used.  The format sequences  are  described  above  under
               prompt; note the variable meaning of `%R'.

       shell   The  file in which the shell resides.  This is used in forking shells to interpret
               files which have execute bits set, but which are not  executable  by  the  system.
               (See  the  description of Builtin and non-builtin command execution.)  Initialized
               to the (system-dependent) home of the shell.

       shlvl (+)
               The number of nested shells.  Reset to 1 in login shells.  See also loginsh.

       status  The exit status from the last command or backquote expansion, or any command in  a
               pipeline  is propagated to status.  (This is also the default csh behavior.)  This
               default does not match what POSIX mandates (to return the status of the last  com-
               mand only). To match the POSIX behavior, you need to unset anyerror.

               If  the  anyerror  variable  is unset, the exit status of a pipeline is determined
               only from the last command in the pipeline, and the exit status of a backquote ex-
               pansion is not propagated to status.

               If  a  command  terminated  abnormally, then 0200 is added to the status.  Builtin
               commands which fail return exit status `1', all other builtin commands return sta-
               tus `0'.

       symlinks (+)
               Can  be set to several different values to control symbolic link (`symlink') reso-
               lution:

               If set to `chase', whenever the current directory changes to a directory  contain-
               ing a symbolic link, it is expanded to the real name of the directory to which the
               link points.  This does not work for the user's home directory; this is a bug.

               If set to `ignore', the shell tries to construct a current directory  relative  to
               the  current directory before the link was crossed.  This means that cding through
               a symbolic link and then `cd ..'ing returns one to the original  directory.   This
               affects only builtin commands and filename completion.

               If  set  to  `expand', the shell tries to fix symbolic links by actually expanding
               arguments which look  like  path  names.   This  affects  any  command,  not  just
               builtins.  Unfortunately, this does not work for hard-to-recognize filenames, such
               as those embedded in command options.  Expansion  may  be  prevented  by  quoting.
               While  this setting is usually the most convenient, it is sometimes misleading and
               sometimes confusing when it fails to recognize an argument  which  should  be  ex-
               panded.  A compromise is to use `ignore' and use the editor command normalize-path
               (bound by default to ^X-n) when necessary.

               Some examples are in order.  First, let's set up some play directories:

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dst

               Here's the behavior with symlinks unset,

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `chase',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/from/src
                   > cd ..; echo $cwd
                   /tmp/from

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to

               and here's the behavior with symlinks set to `expand'.

                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ..; echo $cwd
                   /tmp/to
                   > cd /tmp/to/dst; echo $cwd
                   /tmp/to/dst
                   > cd ".."; echo $cwd
                   /tmp/from
                   > /bin/echo ..
                   /tmp/to
                   > /bin/echo ".."
                   ..

               Note that `expand' expansion 1) works just like `ignore' for builtins like cd,  2)
               is prevented by quoting, and 3) happens before filenames are passed to non-builtin
               commands.

       tcsh (+)
               The version number of the shell in the format `R.VV.PP', where `R'  is  the  major
               release number, `VV' the current version and `PP' the patchlevel.

       term    The  terminal  type.  Usually set in ~/.login as described under Startup and shut-
               down.

       time    If set to a number, then the time builtin (q.v.) executes automatically after each
               command  which  takes more than that many CPU seconds.  If there is a second word,
               it is used as a format string for the output of the time builtin.  (u) The follow-
               ing sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu seconds.
               %S  The time the process spent in kernel mode in cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used in Kbytes.
               %D  The average amount in (unshared) data/stack space used in Kbytes.
               %K  The total space used (%X + %D) in Kbytes.
               %M  The maximum memory the process had in use at any time in Kbytes.
               %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  The number of voluntary context switches (waits).
               %c  The number of involuntary context switches.

               Only  the first four sequences are supported on systems without BSD resource limit
               functions.  The default time format is `%Uu %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for
               systems that support resource usage reporting and `%Uu %Ss %E %P' for systems that
               do not.

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not available, but  the  fol-
               lowing additional sequences are:

               %Y  The number of system calls performed.
               %Z  The number of pages which are zero-filled on demand.
               %i  The number of times a process's resident set size was increased by the kernel.
               %d  The number of times a process's resident set size was decreased by the kernel.
               %l  The number of read system calls performed.
               %m  The number of write system calls performed.
               %p  The number of reads from raw disk devices.
               %q  The number of writes to raw disk devices.

               and  the  default  time format is `%Uu %Ss %E %P %I+%Oio %Fpf+%Ww'.  Note that the
               CPU percentage can be higher than 100% on multi-processors.

       tperiod (+)
               The period, in minutes, between executions of the periodic special alias.

       tty (+) The name of the tty, or empty if not attached to one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If set, causes the words of each command to be printed, after history substitution
               (if any).  Set by the -v command line option.

       version (+)
               The  version ID stamp.  It contains the shell's version number (see tcsh), origin,
               release date, vendor,  operating  system  and  machine  (see  VENDOR,  OSTYPE  and
               MACHTYPE)  and  a  comma-separated list of options which were set at compile time.
               Options which are set by default in the distribution are noted.

               8b    The shell is eight bit clean; default
               7b    The shell is not eight bit clean
               wide  The shell is multibyte encoding clean (like UTF-8)
               nls   The system's NLS is used; default for systems with NLS
               lf    Login shells execute /etc/csh.login before instead of  after  /etc/csh.cshrc
                     and ~/.login before instead of after ~/.tcshrc and ~/.history.
               dl    `.' is put last in path for security; default
               nd    `.' is omitted from path for security
               vi    vi(1)-style editing is the default rather than emacs(1)-style
               dtr   Login shells drop DTR when exiting
               bye   bye is a synonym for logout and log is an alternate name for watchlog
               al    autologout is enabled; default
               kan   Kanji  is  used  if  appropriate  according  to  locale settings, unless the
                     nokanji shell variable is set
               sm    The system's malloc(3) is used
               hb    The `#!<program> <args>' convention is emulated when executing shell scripts
               ng    The newgrp builtin is available
               rh    The shell attempts to set the REMOTEHOST environment variable
               afs   The shell verifies your password with the kerberos server if local authenti-
                     cation  fails.   The afsuser shell variable or the AFSUSER environment vari-
                     able override your local username if set.

               An administrator may enter additional strings to indicate differences in the local
               version.

       vimode (+)
               If  unset,  various  key  bindings change behavior to be more emacs(1)-style: word
               boundaries are determined by wordchars versus other characters.

               If set, various key bindings change behavior to be more vi(1)-style:  word  bound-
               aries  are determined by wordchars versus whitespace versus other characters; cur-
               sor behavior depends upon current vi mode (command, delete, insert, replace).

               This variable is unset by bindkey -e and set by bindkey -v.  vimode may be explic-
               itly set or unset by the user after those bindkey operations if required.

       visiblebell (+)
               If set, a screen flash is used rather than the audible bell.  See also nobeep.

       watch (+)
               A list of user/terminal pairs to watch for logins and logouts.  If either the user
               is `any' all terminals are watched for the given user  and  vice  versa.   Setting
               watch to `(any any)' watches all users and terminals.  For example,

                   set watch = (george ttyd1 any console $user any)

               reports  activity of the user `george' on ttyd1, any user on the console, and one-
               self (or a trespasser) on any terminal.

               Logins and logouts are checked every 10 minutes by default, but the first word  of
               watch can be set to a number to check every so many minutes.  For example,

                   set watch = (1 any any)

               reports  any  login/logout  once every minute.  For the impatient, the log builtin
               command triggers a watch report at any time.  All current logins are reported  (as
               with the log builtin) when watch is first set.

               The who shell variable controls the format of watch reports.

       who (+) The format string for watch messages.  The following sequences are replaced by the
               given information:

               %n  The name of the user who logged in/out.
               %a  The observed action, i.e., `logged on', `logged off' or `replaced olduser on'.
               %l  The terminal (tty) on which the user logged in/out.
               %M  The full hostname of the remote host, or `local' if the login/logout was  from
                   the local host.
               %m  The hostname of the remote host up to the first `.'.  The full name is printed
                   if it is an IP address or an X Window System display.

               %M and %m are available  on  only  systems  that  store  the  remote  hostname  in
               /etc/utmp.   If unset, `%n has %a %l from %m.' is used, or `%n has %a %l.' on sys-
               tems which don't store the remote hostname.

       wordchars (+)
               A list of non-alphanumeric characters to be considered part of a word by the  for-
               ward-word,  backward-word  etc.,  editor commands.  If unset, the default value is
               determined based on the state of vimode: if vimode is unset, `*?_-.[]~='  is  used
               as the default; if vimode is set, `_' is used as the default.

ENVIRONMENT
       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The number of columns in the terminal.  See Terminal management.

       DISPLAY Used  by  X  Window  System (see X(1)).  If set, the shell does not set autologout
               (q.v.).

       EDITOR  The pathname to a default editor.  Used by the run-fg-editor editor command if the
               the editors shell variable is unset.  See also the VISUAL environment variable.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HOST (+)
               Initialized  to  the  name of the machine on which the shell is running, as deter-
               mined by the gethostname(2) system call.

       HOSTTYPE (+)
               Initialized to the type of machine on which the shell is running, as determined at
               compile time.  This variable is obsolete and will be removed in a future version.

       HPATH (+)
               A  colon-separated  list of directories in which the run-help editor command looks
               for command documentation.

       LANG    Gives the preferred character environment.  See Native Language System support.

       LC_CTYPE
               If set, only ctype character handling is changed.  See Native Language System sup-
               port.

       LINES   The number of lines in the terminal.  See Terminal management.

       LS_COLORS
               The format of this variable is reminiscent of the termcap(5) file format; a colon-
               separated list of expressions of the form "xx=string", where "xx" is a two-charac-
               ter variable name.  The variables with their associated defaults are:

                   no   0      Normal (non-filename) text
                   fi   0      Regular file
                   di   01;34  Directory
                   ln   01;36  Symbolic link
                   pi   33     Named pipe (FIFO)
                   so   01;35  Socket
                   do   01;35  Door
                   bd   01;33  Block device
                   cd   01;32  Character device
                   ex   01;32  Executable file
                   mi   (none) Missing file (defaults to fi)
                   or   (none) Orphaned symbolic link (defaults to ln)
                   lc   ^[[    Left code
                   rc   m      Right code
                   ec   (none) End code (replaces lc+no+rc)

               You need to include only the variables you want to change from the default.

               File  names  can also be colorized based on filename extension.  This is specified
               in the LS_COLORS variable using the syntax "*ext=string".  For example, using  ISO
               6429  codes, to color all C-language source files blue you would specify "*.c=34".
               This would color all files ending in .c in blue (34) color.

               Control characters can be  written  either  in  C-style-escaped  notation,  or  in
               stty-like  ^-notation.   The  C-style  notation adds ^[ for Escape, _ for a normal
               space character, and ? for Delete.  In addition, the ^[ escape  character  can  be
               used to override the default interpretation of ^[, ^, : and =.

               Each  file will be written as <lc> <color-code> <rc> <filename> <ec>.  If the <ec>
               code is undefined, the sequence <lc> <no> <rc> will be used instead.  This is gen-
               erally  more  convenient  to use, but less general.  The left, right and end codes
               are provided so you don't have to type common parts over and  over  again  and  to
               support  weird terminals; you will generally not need to change them at all unless
               your terminal does not use ISO 6429 color sequences but a different system.

               If your terminal does use ISO 6429 color codes, you can  compose  the  type  codes
               (i.e.,  all  except the lc, rc, and ec codes) from numerical commands separated by
               semicolons.  The most common commands are:

                       0   to restore default color
                       1   for brighter colors
                       4   for underlined text
                       5   for flashing text
                       30  for black foreground
                       31  for red foreground
                       32  for green foreground
                       33  for yellow (or brown) foreground
                       34  for blue foreground
                       35  for purple foreground
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background

               Not all commands will work on all systems or display devices.

               A few terminal programs do not recognize the default end code  properly.   If  all
               text  gets  colorized after you do a directory listing, try changing the no and fi
               codes from 0 to the numerical codes for your standard fore- and background colors.

       MACHTYPE (+)
               The machine type (microprocessor class or machine model), as determined at compile
               time.

       NOREBIND (+)
               If  set,  printable characters are not rebound to self-insert-command.  See Native
               Language System support.

       OSTYPE (+)
               The operating system, as determined at compile time.

       PATH    A colon-separated list of directories in which to look for  executables.   Equiva-
               lent to the path shell variable, but in a different format.

       PWD (+) Equivalent to the cwd shell variable, but not synchronized to it; updated only af-
               ter an actual directory change.

       REMOTEHOST (+)
               The host from which the user has logged in remotely, if this is the case  and  the
               shell  is  able  to  determine it.  Set only if the shell was so compiled; see the
               version shell variable.

       SHLVL (+)
               Equivalent to the shlvl shell variable.

       SYSTYPE (+)
               The current system type.  (Domain/OS only)

       TERM    Equivalent to the term shell variable.

       TERMCAP The terminal capability string.  See Terminal management.

       USER    Equivalent to the user shell variable.

       VENDOR (+)
               The vendor, as determined at compile time.

       VISUAL  The pathname to a default full-screen editor.  Used by  the  run-fg-editor  editor
               command  if the the editors shell variable is unset.  See also the EDITOR environ-
               ment variable.

FILES
       /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and Intel use /etc/cshrc and
                       NeXTs use /etc/cshrc.std.  A/UX, AMIX, Cray and IRIX have no equivalent in
                       csh(1), but read this file in tcsh anyway.  Solaris 2.x does not  have  it
                       either, but tcsh reads /etc/.cshrc.  (+)
       /etc/csh.login  Read  by  login  shells after /etc/csh.cshrc.  ConvexOS, Stellix and Intel
                       use /etc/login, NeXTs use /etc/login.std, Solaris 2.x uses /etc/.login and
                       A/UX, AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its equivalent.
       ~/.cshrc        Read  by  every shell, if ~/.tcshrc doesn't exist, after /etc/csh.cshrc or
                       its equivalent.  This manual uses `~/.tcshrc' to mean  `~/.tcshrc  or,  if
                       ~/.tcshrc is not found, ~/.cshrc'.
       ~/.history      Read  by  login  shells  after  ~/.tcshrc if savehist is set, but see also
                       histfile.
       ~/.login        Read by login shells after ~/.tcshrc or ~/.history.  The shell may be com-
                       piled  to  read ~/.login before instead of after ~/.tcshrc and ~/.history;
                       see the version shell variable.
       ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is set, but see also dirs-
                       file.
       /etc/csh.logout Read  by login shells at logout.  ConvexOS, Stellix and Intel use /etc/lo-
                       gout and NeXTs use /etc/logout.std.  A/UX, AMIX, Cray  and  IRIX  have  no
                       equivalent in csh(1), but read this file in tcsh anyway.  Solaris 2.x does
                       not have it either, but tcsh reads /etc/.logout.  (+)
       ~/.logout       Read by login shells at logout after /etc/csh.logout or its equivalent.
       /bin/sh         Used to interpret shell scripts not starting with a `#'.
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of home directories for `~name' substitutions.

       The order in which startup files are read may differ if the shell  was  so  compiled;  see
       Startup and shutdown and the version shell variable.

NEW FEATURES (+)
       This  manual  describes tcsh as a single entity, but experienced csh(1) users will want to
       pay special attention to tcsh's new features.

       A command-line editor, which supports emacs(1)-style or vi(1)-style key bindings.  See The
       command-line editor and Editor commands.

       Programmable, interactive word completion and listing.  See Completion and listing and the
       complete and uncomplete builtin commands.

       Spelling correction (q.v.) of filenames, commands and variables.

       Editor commands (q.v.) which perform other useful functions in the middle  of  typed  com-
       mands,  including documentation lookup (run-help), quick editor restarting (run-fg-editor)
       and command resolution (which-command).

       An enhanced history mechanism.  Events in the history list are time-stamped.  See also the
       history  command and its associated shell variables, the previously undocumented `#' event
       specifier and new modifiers under History substitution, the  *-history,  history-search-*,
       i-search-*,  vi-search-*  and toggle-literal-history editor commands and the histlit shell
       variable.

       Enhanced directory parsing and directory stack handling.  See the cd, pushd, popd and dirs
       commands  and their associated shell variables, the description of Directory stack substi-
       tution, the dirstack, owd and symlinks shell variables and the normalize-command and  nor-
       malize-path editor commands.

       Negation in glob-patterns.  See Filename substitution.

       New File inquiry operators (q.v.) and a filetest builtin which uses them.

       A  variety of Automatic, periodic and timed events (q.v.) including scheduled events, spe-
       cial aliases, automatic logout and terminal locking, command timing and watching  for  lo-
       gins and logouts.

       Support  for  the  Native Language System (see Native Language System support), OS variant
       features (see OS variant support and the echo_style shell variable)  and  system-dependent
       file locations (see FILES).

       Extensive terminal-management capabilities.  See Terminal management.

       New  builtin  commands  including  builtins,  hup, ls-F, newgrp, printenv, which and where
       (q.v.).

       New variables that make useful information easily available to the shell.   See  the  gid,
       loginsh,  oid, shlvl, tcsh, tty, uid and version shell variables and the HOST, REMOTEHOST,
       VENDOR, OSTYPE and MACHTYPE environment variables.

       A new syntax for including useful information in the prompt string (see prompt), and  spe-
       cial prompts for loops and spelling correction (see prompt2 and prompt3).

       Read-only variables.  See Variable substitution.

BUGS
       When  a  suspended  command  is restarted, the shell prints the directory it started in if
       this is different from the current directory.  This can be misleading (i.e., wrong) as the
       job may have changed directories internally.

       Shell builtin functions are not stoppable/restartable.  Command sequences of the form `a ;
       b ; c' are also not handled gracefully when stopping is attempted.  If  you  suspend  `b',
       the shell will then immediately execute `c'.  This is especially noticeable if this expan-
       sion results from an alias.  It suffices to place the sequence  of  commands  in  ()'s  to
       force it to a subshell, i.e., `( a ; b ; c )'.

       Control  over  tty  output after processes are started is primitive; perhaps this will in-
       spire someone to work on a good virtual terminal interface.  In a virtual terminal  inter-
       face much more interesting things could be done with output control.

       Alias  substitution is most often used to clumsily simulate shell procedures; shell proce-
       dures should be provided rather than aliases.

       Control structures should be parsed rather than being  recognized  as  built-in  commands.
       This  would  allow control commands to be placed anywhere, to be combined with `|', and to
       be used with `&' and `;' metasyntax.

       foreach doesn't ignore here documents when looking for its end.

       It should be possible to use the `:' modifiers on the output of command substitutions.

       The screen update for lines longer than the screen width is very poor if the terminal can-
       not move the cursor up (i.e., terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns  which  do not use `?', `*' or `[]' or which use `{}' or `~' are not negated
       correctly.

       The single-command form of if does output redirection even if the expression is false  and
       the command is not executed.

       ls-F  includes  file  identification characters when sorting filenames and does not handle
       control characters in filenames well.  It cannot be interrupted.

       Command substitution supports multiple commands and conditions, but not cycles or backward
       gotos.

       Report bugs at https://bugs.astron.com/, preferably with fixes.  If you want to help main-
       tain and test tcsh, add yourself to the mailing list in https://mailman.astron.com/.

THE T IN TCSH
       In 1964, DEC produced the PDP-6.  The PDP-10 was a later re-implementation.   It  was  re-
       christened the DECsystem-10 in 1970 or so when DEC brought out the second model, the KI10.

       TENEX  was  created  at  Bolt, Beranek & Newman (a Cambridge, Massachusetts think tank) in
       1972 as an experiment in demand-paged virtual memory operating systems.  They built a  new
       pager for the DEC PDP-10 and created the OS to go with it.  It was extremely successful in
       academia.

       In 1975, DEC brought out a new model of the PDP-10, the KL10; they intended to have only a
       version  of  TENEX,  which they had licensed from BBN, for the new box.  They called their
       version TOPS-20 (their capitalization is trademarked).  A lot of TOPS-10 users (`The OPer-
       ating  System for PDP-10') objected; thus DEC found themselves supporting two incompatible
       systems on the same hardware--but then there were 6 on the PDP-11!

       TENEX, and TOPS-20 to version 3, had command completion via a  user-code-level  subroutine
       library  called  ULTCMD.   With version 3, DEC moved all that capability and more into the
       monitor (`kernel' for you Unix types), accessed by the COMND% JSYS (`Jump to  SYStem'  in-
       struction, the supervisor call mechanism [are my IBM roots also showing?]).

       The creator of tcsh was impressed by this feature and several others of TENEX and TOPS-20,
       and created a version of csh which mimicked them.

LIMITATIONS
       The system limits argument lists to ARG_MAX characters.

       The number of arguments to a command which involves filename expansion is limited to 1/6th
       the number of characters allowed in an argument list.

       Command  substitutions  may  substitute no more characters than are allowed in an argument
       list.

       To detect looping, the shell restricts the number of alias substitutions on a single  line
       to 20.

SEE ALSO
       csh(1),  emacs(1),  ls(1),  newgrp(1),  sh(1), setpath(1), stty(1), su(1), tset(1), vi(1),
       x(1), access(2), execve(2), fork(2), killpg(2), pipe(2), setrlimit(2), sigvec(2), stat(2),
       umask(2),  vfork(2), wait(2), malloc(3), setlocale(3), tty(4), a.out(5), termcap(5), envi-
       ron(7), termio(7), Introduction to the C Shell

VERSION
       This manual documents tcsh 6.21.00 (Astron) 2019-05-08.

AUTHORS
       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Command line editor, prompt routines, new glob syntax and numerous fixes and speedups
       Karl Kleinpaste, CCI 1983-4
         Special aliases, directory stack extraction stuff, login/logout watch, scheduled events,
         and the idea of the new prompt format
       Rayan Zachariassen, University of Toronto, 1984
         ls-F and which builtins and numerous bug fixes, modifications and speedups
       Chris Kingsley, Caltech
         Fast storage allocator routines
       Chris Grevstad, TRW, 1987
         Incorporated 4.3BSD csh into tcsh
       Christos S. Zoulas, Cornell U. EE Dept., 1987-94
         Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c, SHORT_STRINGS support and a new
         version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
         wordchars
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
         ~/.tcshrc
       Ray Moody, Purdue Physics, 1989
         Magic space bar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
         Extended key support
       Eric Schnoebelen, Convex, 1990
         Convex support, lots of csh bug fixes, save and restore of directory stack
       Ron Flax, Apple, 1990
         A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
         NLS support and simulated NLS support for non NLS sites, fixes
       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi mode fixes, expand-line, window change fixes, Symmetry port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist beeping options, modified the history search to search  for  the  whole  string
         from the beginning of the line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
         Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
         ANSIfication fixes, new exec hashing code, imake fixes, where
       Bruce Sterling Woodcock, sterling AT netcom.com, 1991-1995
         ETA  and  Pyramid port, Makefile and lint fixes, ignoreeof=n addition, and various other
         portability changes and bug fixes
       Jeff Fink, 1992
         complete-word-fwd and complete-word-back
       Harry C. Pulley, 1992
         Coherent port
       Andy Phillips, Mullard Space Science Lab U.K., 1992
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking process group fixes, csh bug fixes, POSIX file tests, POSIX SIGHUP
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek, m88k, Titan and Masscomp ports and fixes.  Added autoconf support.
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber AT kruuna.FI, 1992
         Linux port
       Tim P. Starrin, NASA Langley Research Center Operations, 1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New man page and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced directory printing in prompt, added ellipsis and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing library  and  message
         catalog code to interface to Windows.
       Taga Nayuta, 1998
         Color ls additions.

THANKS TO
       Bryan  Dunlap,  Clayton  Elwell, Karl Kleinpaste, Bob Manson, Steve Romig, Diana Smetters,
       Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all the other people at Ohio State  for
       suggestions and encouragement

       All  the people on the net, for putting up with, reporting bugs in, and suggesting new ad-
       ditions to each and every version

       Richard M. Alderson III, for writing the `T in tcsh' section

Astron 6.21.00                              8 May 2019                                    TCSH(1)

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