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ZSHPARAM(1)                            General Commands Manual                           ZSHPARAM(1)



NAME
       zshparam - zsh parameters

DESCRIPTION
       A  parameter  has a name, a value, and a number of attributes.  A name may be any sequence of
       alphanumeric characters and underscores, or the single characters `*', `@',  `#',  `?',  `-',
       `$',  or  `!'.   A parameter whose name begins with an alphanumeric or underscore is also re‐
       ferred to as a variable.

       The attributes of a parameter determine the type of its value, often referred to as  the  pa‐
       rameter  type  or variable type, and also control other processing that may be applied to the
       value when it is referenced.  The value type may be a scalar (a  string,  an  integer,  or  a
       floating point number), an array (indexed numerically), or an associative array (an unordered
       set of name-value pairs, indexed by name, also referred to as a hash).

       Named scalar parameters may have the exported, -x, attribute, to copy them into  the  process
       environment,  which  is  then passed from the shell to any new processes that it starts.  Ex‐
       ported parameters are called environment variables. The shell also imports environment  vari‐
       ables at startup time and automatically marks the corresponding parameters as exported.  Some
       environment variables are not imported for reasons of security or because they  would  inter‐
       fere with the correct operation of other shell features.

       Parameters  may  also  be  special,  that is, they have a predetermined meaning to the shell.
       Special parameters cannot have their type changed or their readonly attribute turned off, and
       if  a  special  parameter  is unset, then later recreated, the special properties will be re‐
       tained.

       To declare the type of a parameter, or to assign a string or numeric value to a scalar param‐
       eter, use the typeset builtin.

       The value of a scalar parameter may also be assigned by writing:

              name=value

       In  scalar  assignment, value is expanded as a single string, in which the elements of arrays
       are joined together; filename expansion is not performed unless  the  option  GLOB_ASSIGN  is
       set.

       When the integer attribute, -i, or a floating point attribute, -E or -F, is set for name, the
       value is subject to arithmetic evaluation.  Furthermore, by replacing `=' with `+=', a param‐
       eter  can  be  incremented or appended to.  See the section `Array Parameters' and Arithmetic
       Evaluation (in zshmisc(1)) for additional forms of assignment.

       Note that assignment may implicitly change the attributes of a parameter.  For  example,  as‐
       signing  a  number  to  a variable in arithmetic evaluation may change its type to integer or
       float, and with GLOB_ASSIGN assigning a pattern to a variable may change its type to  an  ar‐
       ray.

       To  reference  the value of a parameter, write `$name' or `${name}'.  See Parameter Expansion
       in zshexpn(1) for complete details.  That section also explains the effect of the  difference
       between scalar and array assignment on parameter expansion.

ARRAY PARAMETERS
       To assign an array value, write one of:

              set -A name value ...
              name=(value ...)
              name=([key]=value ...)

       If  no  parameter name exists, an ordinary array parameter is created.  If the parameter name
       exists and is a scalar, it is replaced by a new array.

       In the third form, key is an expression that will be evaluated in arithmetic context (in  its
       simplest form, an integer) that gives the index of the element to be assigned with value.  In
       this form any elements not explicitly mentioned that come before the largest index to which a
       value  is assigned are assigned an empty string.  The indices may be in any order.  Note that
       this syntax is strict: [ and ]= must not be quoted, and key may not consist of  the  unquoted
       string  ]=, but is otherwise treated as a simple string.  The enhanced forms of subscript ex‐
       pression that may be used when directly subscripting a variable name, described in  the  sec‐
       tion Array Subscripts below, are not available.

       The  syntaxes  with and without the explicit key may be mixed.  An implicit key is deduced by
       incrementing the index from the previously assigned element.  Note that it is not treated  as
       an error if latter assignments in this form overwrite earlier assignments.

       For example, assuming the option KSH_ARRAYS is not set, the following:

              array=(one [3]=three four)

       causes  the  array  variable  array  to contain four elements one, an empty string, three and
       four, in that order.

       In the forms where only value is specified, full command line expansion is performed.

       In the [key]=value form, both key and value undergo all forms of expansion allowed for single
       word  shell expansions (this does not include filename generation); these are as performed by
       the parameter expansion flag (e) as described in zshexpn(1).  Nested parentheses may surround
       value  and  are included as part of the value, which is joined into a plain string; this dif‐
       fers from ksh which allows the values themselves to be arrays.  A future version of  zsh  may
       support that.  To cause the brackets to be interpreted as a character class for filename gen‐
       eration, and therefore to treat the resulting list of files as a set  of  values,  quote  the
       equal sign using any form of quoting.  Example:

              name=([a-z]'='*)

       To append to an array without changing the existing values, use one of the following:

              name+=(value ...)
              name+=([key]=value ...)

       In  the  second form key may specify an existing index as well as an index off the end of the
       old array; any existing value  is  overwritten  by  value.   Also,  it  is  possible  to  use
       [key]+=value to append to the existing value at that index.

       Within  the parentheses on the right hand side of either form of the assignment, newlines and
       semicolons are treated the same as white space, separating individual values.   Any  consecu‐
       tive sequence of such characters has the same effect.

       Ordinary array parameters may also be explicitly declared with:

              typeset -a name

       Associative arrays must be declared before assignment, by using:

              typeset -A name

       When  name refers to an associative array, the list in an assignment is interpreted as alter‐
       nating keys and values:

              set -A name key value ...
              name=(key value ...)
              name=([key]=value ...)

       Note that only one of the two syntaxes above may be used in any given assignment;  the  forms
       may not be mixed.  This is unlike the case of numerically indexed arrays.

       Every key must have a value in this case.  Note that this assigns to the entire array, delet‐
       ing any elements that do not appear in the list.  The append syntax may also be used with  an
       associative array:

              name+=(key value ...)
              name+=([key]=value ...)

       This  adds a new key/value pair if the key is not already present, and replaces the value for
       the existing key if it is.  In the second form it is also possible to use [key]+=value to ap‐
       pend  to  the  existing  value at that key.  Expansion is performed identically to the corre‐
       sponding forms for normal arrays, as described above.

       To create an empty array (including associative arrays), use one of:

              set -A name
              name=()

   Array Subscripts
       Individual elements of an array may be selected using a subscript.  A subscript of  the  form
       `[exp]'  selects  the single element exp, where exp is an arithmetic expression which will be
       subject to arithmetic expansion as if it were surrounded by  `$((...))'.   The  elements  are
       numbered  beginning  with  1, unless the KSH_ARRAYS option is set in which case they are num‐
       bered from zero.

       Subscripts may be used inside braces used to delimit a parameter name,  thus  `${foo[2]}'  is
       equivalent  to  `$foo[2]'.   If the KSH_ARRAYS option is set, the braced form is the only one
       that works, as bracketed expressions otherwise are not treated as subscripts.

       If the KSH_ARRAYS option is not set, then by default accesses to an array element with a sub‐
       script  that evaluates to zero return an empty string, while an attempt to write such an ele‐
       ment is treated as an error.  For backward compatibility the KSH_ZERO_SUBSCRIPT option can be
       set  to cause subscript values 0 and 1 to be equivalent; see the description of the option in
       zshoptions(1).

       The same subscripting syntax is used for associative arrays, except that no arithmetic expan‐
       sion  is  applied to exp.  However, the parsing rules for arithmetic expressions still apply,
       which affects the way that certain special characters must be protected from  interpretation.
       See Subscript Parsing below for details.

       A  subscript  of  the  form `[*]' or `[@]' evaluates to all elements of an array; there is no
       difference between the two except when they appear within double quotes.  `"$foo[*]"'  evalu‐
       ates  to `"$foo[1] $foo[2] ..."', whereas `"$foo[@]"' evaluates to `"$foo[1]" "$foo[2]" ...'.
       For associative arrays, `[*]' or `[@]' evaluate to all the values, in  no  particular  order.
       Note that this does not substitute the keys; see the documentation for the `k' flag under Parameter Expansion Flags in zshexpn(1) for complete details.  When an array parameter is  ref‐
       erenced  as `$name' (with no subscript) it evaluates to `$name[*]', unless the KSH_ARRAYS op‐
       tion is set in which case it evaluates to `${name[0]}' (for an associative array, this  means
       the value of the key `0', which may not exist even if there are values for other keys).

       A  subscript of the form `[exp1,exp2]' selects all elements in the range exp1 to exp2, inclu‐
       sive. (Associative arrays are unordered, and so do not support ranges.) If one  of  the  sub‐
       scripts  evaluates to a negative number, say -n, then the nth element from the end of the ar‐
       ray is used.  Thus `$foo[-3]' is the third element  from  the  end  of  the  array  foo,  and
       `$foo[1,-1]' is the same as `$foo[*]'.

       Subscripting  may also be performed on non-array values, in which case the subscripts specify
       a substring to be extracted.  For example, if FOO is set to `foobar', then  `echo  $FOO[2,5]'
       prints  `ooba'.   Note that some forms of subscripting described below perform pattern match‐
       ing, and in that case the substring extends from the start of the match  of  the  first  sub‐
       script to the end of the match of the second subscript.  For example,

              string="abcdefghijklm"
              print ${string[(r)d?,(r)h?]}

       prints `defghi'.  This is an obvious generalisation of the rule for single-character matches.
       For a single subscript, only a single character is referenced (not the  range  of  characters
       covered by the match).

       Note  that in substring operations the second subscript is handled differently by the r and R
       subscript flags: the former takes the shortest match as the length and the latter the longest
       match.   Hence  in  the  former  case a * at the end is redundant while in the latter case it
       matches the whole remainder of the string.  This does not affect the  result  of  the  single
       subscript case as here the length of the match is irrelevant.

   Array Element Assignment
       A subscript may be used on the left side of an assignment like so:

              name[exp]=value

       In  this  form of assignment the element or range specified by exp is replaced by the expres‐
       sion on the right side.  An array (but not an associative array) may be created by assignment
       to a range or element.  Arrays do not nest, so assigning a parenthesized list of values to an
       element or range changes the number of elements in the array, shifting the other elements  to
       accommodate the new values.  (This is not supported for associative arrays.)

       This syntax also works as an argument to the typeset command:

              typeset "name[exp]"=value

       The  value  may not be a parenthesized list in this case; only single-element assignments may
       be made with typeset.  Note that quotes are necessary in this case to  prevent  the  brackets
       from  being  interpreted  as  filename  generation operators.  The noglob precommand modifier
       could be used instead.

       To delete an element of an ordinary array, assign `()' to that element.  To delete an element
       of an associative array, use the unset command:

              unset "name[exp]"

   Subscript Flags
       If the opening bracket, or the comma in a range, in any subscript expression is directly fol‐
       lowed by an opening parenthesis, the string up to the matching closing one is  considered  to
       be a list of flags, as in `name[(flags)exp]'.

       The  flags  s, n and b take an argument; the delimiter is shown below as `:', but any charac‐
       ter, or the matching pairs `(...)', `{...}', `[...]', or `<...>', may be used, but note  that
       `<...>' can only be used if the subscript is inside a double quoted expression or a parameter
       substitution enclosed in braces as otherwise the expression is interpreted as a redirection.

       The flags currently understood are:

       w      If the parameter subscripted is a scalar then this flag  makes  subscripting  work  on
              words instead of characters.  The default word separator is whitespace.  When combined
              with the i or I flag, the effect is to produce the index of the first character of the
              first/last word which matches the given pattern; note that a failed match in this case
              always yields 0.

       s:string:
              This gives the string that separates words (for use with the w flag).   The  delimiter
              character : is arbitrary; see above.

       p      Recognize  the  same escape sequences as the print builtin in the string argument of a
              subsequent `s' flag.

       f      If the parameter subscripted is a scalar then this flag  makes  subscripting  work  on
              lines  instead  of  characters,  i.e.  with elements separated by newlines.  This is a
              shorthand for `pws:\n:'.

       r      Reverse subscripting: if this flag is given, the exp is taken as a pattern and the re‐
              sult  is  the  first matching array element, substring or word (if the parameter is an
              array, if it is a scalar, or if it is a scalar and the  `w'  flag  is  given,  respec‐
              tively).   The  subscript used is the number of the matching element, so that pairs of
              subscripts such as `$foo[(r)??,3]' and `$foo[(r)??,(r)f*]' are possible if the parame‐
              ter  is  not an associative array.  If the parameter is an associative array, only the
              value part of each pair is compared to the pattern, and the result is that value.

              If a search through an ordinary array failed, the search sets  the  subscript  to  one
              past  the  end  of the array, and hence ${array[(r)pattern]} will substitute the empty
              string.  Thus the success of a search can be tested by using the (i) flag, for example
              (assuming the option KSH_ARRAYS is not in effect):

                     [[ ${array[(i)pattern]} -le ${#array} ]]

              If KSH_ARRAYS is in effect, the -le should be replaced by -lt.

       R      Like  `r',  but  gives  the  last  match.   For associative arrays, gives all possible
              matches. May be used for assigning to ordinary array elements, but not  for  assigning
              to associative arrays.  On failure, for normal arrays this has the effect of returning
              the element corresponding to subscript 0; this is empty  unless  one  of  the  options
              KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in effect.

              Note  that  in  subscripts with both `r' and `R' pattern characters are active even if
              they were substituted for a parameter (regardless of the setting of  GLOB_SUBST  which
              controls  this  feature in normal pattern matching).  The flag `e' can be added to in‐
              hibit pattern matching.  As this flag does not inhibit other  forms  of  substitution,
              care is still required; using a parameter to hold the key has the desired effect:

                     key2='original key'
                     print ${array[(Re)$key2]}

       i      Like  `r',  but  gives the index of the match instead; this may not be combined with a
              second argument.  On the left side of an assignment, behaves like `r'.   For  associa‐
              tive  arrays,  the  key  part  of  each pair is compared to the pattern, and the first
              matching key found is the result.  On failure substitutes the length of the array plus
              one, as discussed under the description of `r', or the empty string for an associative
              array.

       I      Like `i', but gives the index of the last match, or all possible matching keys  in  an
              associative  array.   On failure substitutes 0, or the empty string for an associative
              array.  This flag is best when testing for values or keys that do not exist.

       k      If used in a subscript on an associative array, this flag causes the keys to be inter‐
              preted as patterns, and returns the value for the first key found where exp is matched
              by the key.  Note this could be any such key as no ordering of associative  arrays  is
              defined.   This flag does not work on the left side of an assignment to an associative
              array element.  If used on another type of parameter, this behaves like `r'.

       K      On an associative array this is like `k' but returns all values where exp  is  matched
              by the keys.  On other types of parameters this has the same effect as `R'.

       n:expr:
              If  combined  with `r', `R', `i' or `I', makes them give the nth or nth last match (if
              expr evaluates to n).  This flag is ignored when the array is associative.  The delim‐
              iter character : is arbitrary; see above.

       b:expr:
              If  combined  with  `r', `R', `i' or `I', makes them begin at the nth or nth last ele‐
              ment, word, or character (if expr evaluates to n).  This flag is ignored when the  ar‐
              ray is associative.  The delimiter character : is arbitrary; see above.

       e      This  flag causes any pattern matching that would be performed on the subscript to use
              plain string matching instead.  Hence `${array[(re)*]}' matches only the array element
              whose  value  is *.  Note that other forms of substitution such as parameter substitu‐
              tion are not inhibited.

              This flag can also be used to force * or @ to be interpreted as a  single  key  rather
              than as a reference to all values.  It may be used for either purpose on the left side
              of an assignment.

       See Parameter Expansion Flags (zshexpn(1)) for additional ways to manipulate the  results  of
       array subscripting.

   Subscript Parsing
       This  discussion applies mainly to associative array key strings and to patterns used for re‐
       verse subscripting (the `r', `R', `i', etc. flags), but it may also affect parameter  substi‐
       tutions that appear as part of an arithmetic expression in an ordinary subscript.

       To  avoid subscript parsing limitations in assignments to associative array elements, use the
       append syntax:

              aa+=('key with "*strange*" characters' 'value string')

       The basic rule to remember when writing a subscript expression is that all text  between  the
       opening  `['  and  the  closing  `]'  is interpreted as if it were in double quotes (see zshmisc(1)).  However, unlike double quotes which normally cannot  nest,  subscript  expressions
       may  appear inside double-quoted strings or inside other subscript expressions (or both!), so
       the rules have two important differences.

       The first difference is that brackets (`[' and `]') must appear as balanced pairs in  a  sub‐
       script  expression  unless  they are preceded by a backslash (`\').  Therefore, within a sub‐
       script expression (and unlike true double-quoting) the sequence `\[' becomes `[',  and  simi‐
       larly  `\]'  becomes  `]'.   This applies even in cases where a backslash is not normally re‐
       quired; for example, the pattern `[^[]' (to match any character other than an  open  bracket)
       should  be  written `[^\[]' in a reverse-subscript pattern.  However, note that `\[^\[\]' and
       even `\[^[]' mean the same thing, because backslashes are always stripped  when  they  appear
       before brackets!

       The same rule applies to parentheses (`(' and `)') and braces (`{' and `}'): they must appear
       either in balanced pairs or preceded by a backslash, and backslashes that protect parentheses
       or braces are removed during parsing.  This is because parameter expansions may be surrounded
       by balanced braces, and subscript flags are introduced by balanced parentheses.

       The second difference is that a double-quote (`"') may appear as part of a subscript  expres‐
       sion without being preceded by a backslash, and therefore that the two characters `\"' remain
       as two characters in the subscript (in true double-quoting, `\"' becomes `"').  However,  be‐
       cause  of  the standard shell quoting rules, any double-quotes that appear must occur in bal‐
       anced pairs unless preceded by a backslash.  This makes it more difficult  to  write  a  sub‐
       script  expression that contains an odd number of double-quote characters, but the reason for
       this difference is so that when a subscript expression appears inside true double-quotes, one
       can still write `\"' (rather than `\\\"') for `"'.

       To  use an odd number of double quotes as a key in an assignment, use the typeset builtin and
       an enclosing pair of double quotes; to refer to the value  of  that  key,  again  use  double
       quotes:

              typeset -A aa
              typeset "aa[one\"two\"three\"quotes]"=QQQ
              print "$aa[one\"two\"three\"quotes]"

       It  is important to note that the quoting rules do not change when a parameter expansion with
       a subscript is nested inside another subscript expression.  That is, it is not  necessary  to
       use additional backslashes within the inner subscript expression; they are removed only once,
       from the innermost subscript outwards.  Parameters are also expanded from the innermost  sub‐
       script first, as each expansion is encountered left to right in the outer expression.

       A  further  complication  arises  from a way in which subscript parsing is not different from
       double quote parsing.  As in true double-quoting, the sequences `\*', and `\@' remain as  two
       characters when they appear in a subscript expression.  To use a literal `*' or `@' as an as‐
       sociative array key, the `e' flag must be used:

              typeset -A aa
              aa[(e)*]=star
              print $aa[(e)*]

       A last detail must be considered when reverse subscripting is performed.  Parameters  appear‐
       ing in the subscript expression are first expanded and then the complete expression is inter‐
       preted as a pattern.  This has two effects: first, parameters behave as if GLOB_SUBST were on
       (and  it  cannot be turned off); second, backslashes are interpreted twice, once when parsing
       the array subscript and again when parsing the pattern.  In a reverse subscript, it's  neces‐
       sary  to  use four backslashes to cause a single backslash to match literally in the pattern.
       For complex patterns, it is often easiest to assign the desired pattern to  a  parameter  and
       then refer to that parameter in the subscript, because then the backslashes, brackets, paren‐
       theses, etc., are seen only when the complete expression is converted to a pattern.  To match
       the  value  of  a  parameter  literally in a reverse subscript, rather than as a pattern, use
       `${(q)name}' (see zshexpn(1)) to quote the expanded value.

       Note that the `k' and `K' flags are reverse subscripting for an ordinary array, but  are  not
       reverse  subscripting  for  an associative array!  (For an associative array, the keys in the
       array itself are interpreted as patterns by those flags; the subscript is a plain  string  in
       that case.)

       One final note, not directly related to subscripting: the numeric names of positional parame‐
       ters (described below) are  parsed  specially,  so  for  example  `$2foo'  is  equivalent  to
       `${2}foo'.   Therefore,  to use subscript syntax to extract a substring from a positional pa‐
       rameter, the expansion must be surrounded by braces; for example,  `${2[3,5]}'  evaluates  to
       the  third  through fifth characters of the second positional parameter, but `$2[3,5]' is the
       entire second parameter concatenated with the filename generation pattern `[3,5]'.

POSITIONAL PARAMETERS
       The positional parameters provide access to the command-line arguments of a  shell  function,
       shell  script, or the shell itself; see the section `Invocation', and also the section `Func‐
       tions'.  The parameter n, where n is a number, is the nth positional parameter.  The  parame‐
       ter `$0' is a special case, see the section `Parameters Set By The Shell'.

       The  parameters  *,  @  and  argv  are  arrays containing all the positional parameters; thus
       `$argv[n]', etc., is equivalent  to  simply  `$n'.   Note  that  the  options  KSH_ARRAYS  or
       KSH_ZERO_SUBSCRIPT  apply  to  these  arrays  as  well,  so with either of those options set,
       `${argv[0]}' is equivalent to `$1' and so on.

       Positional parameters may be changed after the shell or function  starts  by  using  the  set
       builtin,  by assigning to the argv array, or by direct assignment of the form `n=value' where
       n is the number of the positional parameter to be changed.  This  also  creates  (with  empty
       values) any of the positions from 1 to n that do not already have values.  Note that, because
       the positional parameters form an array, an array assignment of the form `n=(value  ...)'  is
       allowed, and has the effect of shifting all the values at positions greater than n by as many
       positions as necessary to accommodate the new values.

LOCAL PARAMETERS
       Shell function executions delimit scopes for shell parameters.  (Parameters  are  dynamically
       scoped.)  The typeset builtin, and its alternative forms declare, integer, local and readonly
       (but not export), can be used to declare a parameter as being local to the innermost scope.

       When a parameter is read or assigned to, the innermost existing parameter  of  that  name  is
       used.   (That is, the local parameter hides any less-local parameter.)  However, assigning to
       a non-existent parameter, or declaring a new parameter with export, causes it to  be  created
       in the outermost scope.

       Local  parameters  disappear  when their scope ends.  unset can be used to delete a parameter
       while it is still in scope; any outer parameter of the same name remains hidden.

       Special parameters may also be made local; they retain their special attributes unless either
       the existing or the newly-created parameter has the -h (hide) attribute.  This may have unex‐
       pected effects: there is no default value, so if there is no  assignment  at  the  point  the
       variable  is  made local, it will be set to an empty value (or zero in the case of integers).
       The following:

              typeset PATH=/new/directory:$PATH

       is valid for temporarily allowing the shell or programmes called from it to find the programs
       in /new/directory inside a function.

       Note  that the restriction in older versions of zsh that local parameters were never exported
       has been removed.

PARAMETERS SET BY THE SHELL
       In the parameter lists that follow, the mark `<S>' indicates that the parameter  is  special.
       `<Z>' indicates that the parameter does not exist when the shell initializes in sh or ksh em‐
       ulation mode.

       The following parameters are automatically set by the shell:

       ! <S>  The process ID of the last command started in the background  with  &,  put  into  the
              background with the bg builtin, or spawned with coproc.

       # <S>  The  number  of  positional parameters in decimal.  Note that some confusion may occur
              with the syntax $#param which substitutes the length of param.  Use  ${#}  to  resolve
              ambiguities.   In particular, the sequence `$#-...' in an arithmetic expression is in‐
              terpreted as the length of the parameter -, q.v.

       ARGC <S> <Z>
              Same as #.

       $ <S>  The process ID of this shell.  Note that this indicates the original shell started  by
              invoking  zsh;  all  processes forked from the shells without executing a new program,
              such as subshells started by (...), substitute the same value.

       - <S>  Flags supplied to the shell on invocation or by the set or setopt commands.

       * <S>  An array containing the positional parameters.

       argv <S> <Z>
              Same as *.  Assigning to argv changes the local positional parameters, but argv is not
              itself  a local parameter.  Deleting argv with unset in any function deletes it every‐
              where, although only the innermost positional parameter array is deleted (so *  and  @
              in other scopes are not affected).

       @ <S>  Same as argv[@], even when argv is not set.

       ? <S>  The exit status returned by the last command.

       0 <S>  The  name  used  to  invoke the current shell, or as set by the -c command line option
              upon invocation.  If the FUNCTION_ARGZERO option is set, $0 is set  upon  entry  to  a
              shell  function to the name of the function, and upon entry to a sourced script to the
              name of the script, and reset to its previous value when the function  or  script  re‐
              turns.

       status <S> <Z>
              Same as ?.

       pipestatus <S> <Z>
              An array containing the exit statuses returned by all commands in the last pipeline.

       _ <S>  The  last  argument of the previous command.  Also, this parameter is set in the envi‐
              ronment of every command executed to the full pathname of the command.

       CPUTYPE
              The machine type (microprocessor class or machine model), as determined at run time.

       EGID <S>
              The effective group ID of the shell process.  If you have sufficient  privileges,  you
              may change the effective group ID of the shell process by assigning to this parameter.
              Also (assuming sufficient privileges), you may start a single command with a different
              effective group ID by `(EGID=gid; command)'

              If  this  is  made local, it is not implicitly set to 0, but may be explicitly set lo‐
              cally.

       EUID <S>
              The effective user ID of the shell process.  If you have  sufficient  privileges,  you
              may  change the effective user ID of the shell process by assigning to this parameter.
              Also (assuming sufficient privileges), you may start a single command with a different
              effective user ID by `(EUID=uid; command)'

              If  this  is  made local, it is not implicitly set to 0, but may be explicitly set lo‐
              cally.

       ERRNO <S>
              The value of errno (see errno(3)) as set by the  most  recently  failed  system  call.
              This  value  is  system  dependent and is intended for debugging purposes.  It is also
              useful with the zsh/system module which allows the number to be turned into a name  or
              message.

       FUNCNEST <S>
              Integer.   If  greater than or equal to zero, the maximum nesting depth of shell func‐
              tions.  When it is exceeded, an error is raised at  the  point  where  a  function  is
              called.   The  default  value is determined when the shell is configured, but is typi‐
              cally 500.  Increasing the value increases the danger of a runaway function  recursion
              causing the shell to crash.  Setting a negative value turns off the check.

       GID <S>
              The  real  group  ID of the shell process.  If you have sufficient privileges, you may
              change the group ID of the shell process by assigning to this parameter.  Also (assum‐
              ing  sufficient privileges), you may start a single command under a different group ID
              by `(GID=gid; command)'

              If this is made local, it is not implicitly set to 0, but may be  explicitly  set  lo‐
              cally.

       HISTCMD
              The  current  history  event  number in an interactive shell, in other words the event
              number for the command that caused $HISTCMD to be read.  If the current history  event
              modifies the history, HISTCMD changes to the new maximum history event number.

       HOST   The current hostname.

       LINENO <S>
              The  line number of the current line within the current script, sourced file, or shell
              function being executed, whichever was started most recently.  Note that in  the  case
              of shell functions the line number refers to the function as it appeared in the origi‐
              nal definition, not necessarily as displayed by the functions builtin.

       LOGNAME
              If the corresponding variable is not set in the environment of the shell, it  is  ini‐
              tialized  to the login name corresponding to the current login session. This parameter
              is exported by default but this can be disabled using the typeset builtin.  The  value
              is set to the string returned by the getlogin(3) system call if that is available.

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

       OLDPWD The previous working directory.  This is set when the shell initializes  and  whenever
              the directory changes.

       OPTARG <S>
              The value of the last option argument processed by the getopts command.

       OPTIND <S>
              The index of the last option argument processed by the getopts command.

       OSTYPE The operating system, as determined at compile time.

       PPID <S>
              The  process ID of the parent of the shell.  As for $$, the value indicates the parent
              of the original shell and does not change in subshells.

       PWD    The present working directory.  This is set when the shell  initializes  and  whenever
              the directory changes.

       RANDOM <S>
              A  pseudo-random  integer from 0 to 32767, newly generated each time this parameter is
              referenced.  The random number generator can be seeded by assigning a numeric value to
              RANDOM.

              The  values  of  RANDOM  form an intentionally-repeatable pseudo-random sequence; sub‐
              shells that reference RANDOM will result in identical pseudo-random values unless  the
              value  of RANDOM is referenced or seeded in the parent shell in between subshell invo‐
              cations.

       SECONDS <S>
              The number of seconds since shell invocation.  If this parameter is assigned a  value,
              then  the  value  returned upon reference will be the value that was assigned plus the
              number of seconds since the assignment.

              Unlike other special parameters, the type of the SECONDS parameter can be changed  us‐
              ing  the  typeset  command.   Only integer and one of the floating point types are al‐
              lowed.  For example, `typeset -F SECONDS' causes the value to be reported as a  float‐
              ing  point number.  The value is available to microsecond accuracy, although the shell
              may show more or fewer digits depending on the use of typeset.  See the  documentation
              for the builtin typeset in zshbuiltins(1) for more details.

       SHLVL <S>
              Incremented by one each time a new shell is started.

       signals
              An array containing the names of the signals.  Note that with the standard zsh number‐
              ing of array indices, where the first element has index 1, the signals are offset by 1
              from  the  signal  number  used  by  the  operating  system.   For example, on typical
              Unix-like systems HUP is signal number 1, but is referred to as $signals[2].  This  is
              because of EXIT at position 1 in the array, which is used internally by zsh but is not
              known to the operating system.

       TRY_BLOCK_ERROR <S>
              In an always block, indicates whether the preceding list of code caused an error.  The
              value  is  1  to  indicate an error, 0 otherwise.  It may be reset, clearing the error
              condition.  See Complex Commands in zshmisc(1)

       TRY_BLOCK_INTERRUPT <S>
              This variable works in a similar way to TRY_BLOCK_ERROR, but represents the status  of
              an  interrupt from the signal SIGINT, which typically comes from the keyboard when the
              user types ^C.  If set to 0, any such interrupt will be reset; otherwise,  the  inter‐
              rupt is propagated after the always block.

              Note  that it is possible that an interrupt arrives during the execution of the always
              block; this interrupt is also propagated.

       TTY    The name of the tty associated with the shell, if any.

       TTYIDLE <S>
              The idle time of the tty associated with the shell in seconds or -1  if  there  is  no
              such tty.

       UID <S>
              The  real  user  ID  of the shell process.  If you have sufficient privileges, you may
              change the user ID of the shell by assigning to this parameter.  Also (assuming suffi‐
              cient  privileges),  you  may  start  a  single  command  under a different user ID by
              `(UID=uid; command)'

              If this is made local, it is not implicitly set to 0, but may be  explicitly  set  lo‐
              cally.

       USERNAME <S>
              The username corresponding to the real user ID of the shell process.  If you have suf‐
              ficient privileges, you may change the username (and also the user ID and group ID) of
              the  shell by assigning to this parameter.  Also (assuming sufficient privileges), you
              may start a single command under a different username (and user ID and  group  ID)  by
              `(USERNAME=username; command)'

       VENDOR The vendor, as determined at compile time.

       zsh_eval_context <S> <Z> (ZSH_EVAL_CONTEXT <S>)
              An  array  (colon-separated  list)  indicating the context of shell code that is being
              run.  Each time a piece of shell code that is stored within the shell  is  executed  a
              string  is temporarily appended to the array to indicate the type of operation that is
              being performed.  Read in order the array gives an indication of the stack  of  opera‐
              tions being performed with the most immediate context last.

              Note  that  the  variable does not give information on syntactic context such as pipe‐
              lines or subshells.  Use $ZSH_SUBSHELL to detect subshells.

              The context is one of the following:
              cmdarg Code specified by the -c option to the command line that invoked the shell.

              cmdsubst
                     Command substitution using the `...` or $(...) construct.

              equalsubst
                     File substitution using the =(...) construct.

              eval   Code executed by the eval builtin.

              evalautofunc
                     Code executed with the KSH_AUTOLOAD mechanism in order to define an  autoloaded
                     function.

              fc     Code from the shell history executed by the -e option to the fc builtin.

              file   Lines  of  code  being  read  directly  from  a file, for example by the source
                     builtin.

              filecode
                     Lines of code being read from a .zwc file instead of directly from  the  source
                     file.

              globqual
                     Code executed by the e or + glob qualifier.

              globsort
                     Code executed to order files by the o glob qualifier.

              insubst
                     File substitution using the <(...) construct.

              loadautofunc
                     Code read directly from a file to define an autoloaded function.

              outsubst
                     File substitution using the >(...) construct.

              sched  Code executed by the sched builtin.

              shfunc A shell function.

              stty   Code  passed to stty by the STTY environment variable.  Normally this is passed
                     directly to the system's stty command, so this value is unlikely to be seen  in
                     practice.

              style  Code  executed  as  part  of  a  style retrieved by the zstyle builtin from the
                     zsh/zutil module.

              toplevel
                     The highest execution level of a script or interactive shell.

              trap   Code executed as a trap defined by the trap builtin.  Traps  defined  as  func‐
                     tions  have the context shfunc.  As traps are asynchronous they may have a dif‐
                     ferent hierarchy from other code.

              zpty   Code executed by the zpty builtin from the zsh/zpty module.

              zregexparse-guard
                     Code executed as a guard by the zregexparse command from the zsh/zutil module.

              zregexparse-action
                     Code executed as an action by the zregexparse command from the  zsh/zutil  mod‐
                     ule.

       ZSH_ARGZERO
              If  zsh was invoked to run a script, this is the name of the script.  Otherwise, it is
              the name used to invoke the current shell.  This is the same as the value of  $0  when
              the POSIX_ARGZERO option is set, but is always available.

       ZSH_EXECUTION_STRING
              If  the shell was started with the option -c, this contains the argument passed to the
              option.  Otherwise it is not set.

       ZSH_NAME
              Expands to the basename of the command used to invoke this instance of zsh.

       ZSH_PATCHLEVEL
              The output of `git describe --tags --long' for the zsh repository used  to  build  the
              shell.  This is most useful in order to keep track of versions of the shell during de‐
              velopment between releases; hence most users should not use it and should instead rely
              on $ZSH_VERSION.

       zsh_scheduled_events
              See the section `The zsh/sched Module' in zshmodules(1).

       ZSH_SCRIPT
              If  zsh  was  invoked to run a script, this is the name of the script, otherwise it is
              unset.

       ZSH_SUBSHELL
              Readonly integer.  Initially zero, incremented each time the shell forks to  create  a
              subshell  for  executing  code.   Hence  `(print  $ZSH_SUBSHELL)'  and  `print $(print
              $ZSH_SUBSHELL)' output 1, while `( (print $ZSH_SUBSHELL) )' outputs 2.

       ZSH_VERSION
              The version number of the release of zsh.

PARAMETERS USED BY THE SHELL
       The following parameters are used by the shell.  Again, `<S>' indicates that the parameter is
       special  and  `<Z>' indicates that the parameter does not exist when the shell initializes in
       sh or ksh emulation mode.

       In cases where there are two parameters with an upper- and lowercase form of the  same  name,
       such as path and PATH, the lowercase form is an array and the uppercase form is a scalar with
       the elements of the array joined together by colons.  These are similar  to  tied  parameters
       created  via  `typeset  -T'.  The normal use for the colon-separated form is for exporting to
       the environment, while the array form is easier to manipulate within the  shell.   Note  that
       unsetting  either of the pair will unset the other; they retain their special properties when
       recreated, and recreating one of the pair will recreate the other.

       ARGV0  If exported, its value is used as the argv[0] of external commands.  Usually  used  in
              constructs like `ARGV0=emacs nethack'.

       BAUD   The  rate in bits per second at which data reaches the terminal.  The line editor will
              use this value in order to compensate for a slow terminal by delaying updates  to  the
              display until necessary.  If the parameter is unset or the value is zero the compensa‐
              tion mechanism is turned off.  The parameter is not set by default.

              This parameter may be profitably set in some circumstances, e.g.  for slow modems  di‐
              aling  into a communications server, or on a slow wide area network.  It should be set
              to the baud rate of the slowest part of the link for best performance.

       cdpath <S> <Z> (CDPATH <S>)
              An array (colon-separated list) of directories specifying the search path for  the  cd
              command.

       COLUMNS <S>
              The  number  of columns for this terminal session.  Used for printing select lists and
              for the line editor.

       CORRECT_IGNORE
              If set, is treated as a pattern during spelling correction.  Any potential  correction
              that  matches  the pattern is ignored.  For example, if the value is `_*' then comple‐
              tion functions (which, by convention, have names beginning with `_') will never be of‐
              fered  as  spelling corrections.  The pattern does not apply to the correction of file
              names, as applied by the CORRECT_ALL option (so with the example just given files  be‐
              ginning with `_' in the current directory would still be completed).

       CORRECT_IGNORE_FILE
              If  set,  is  treated as a pattern during spelling correction of file names.  Any file
              name that matches the pattern is never offered as a correction.  For example,  if  the
              value is `.*' then dot file names will never be offered as spelling corrections.  This
              is useful with the CORRECT_ALL option.

       DIRSTACKSIZE
              The maximum size of the directory stack, by default there is no limit.  If  the  stack
              gets  larger  than  this, it will be truncated automatically.  This is useful with the
              AUTO_PUSHD option.

       ENV    If the ENV environment variable is set when zsh is invoked  as  sh  or  ksh,  $ENV  is
              sourced  after the profile scripts.  The value of ENV is subjected to parameter expan‐
              sion, command substitution, and arithmetic expansion before  being  interpreted  as  a
              pathname.   Note  that ENV is not used unless the shell is interactive and zsh is emu‐
              lating sh or ksh.

       FCEDIT The default editor for the fc builtin.  If FCEDIT is not set, the parameter EDITOR  is
              used; if that is not set either, a builtin default, usually vi, is used.

       fignore <S> <Z> (FIGNORE <S>)
              An  array (colon separated list) containing the suffixes of files to be ignored during
              filename completion.  However, if completion only generates  files  with  suffixes  in
              this list, then these files are completed anyway.

       fpath <S> <Z> (FPATH <S>)
              An array (colon separated list) of directories specifying the search path for function
              definitions.  This path is searched when a function with the -u  attribute  is  refer‐
              enced.   If  an  executable file is found, then it is read and executed in the current
              environment.

       histchars <S>
              Three characters used by the shell's history  and  lexical  analysis  mechanism.   The
              first  character  signals  the start of a history expansion (default `!').  The second
              character signals the start of a quick history substitution (default `^').  The  third
              character is the comment character (default `#').

              The  characters  must  be  in the ASCII character set; any attempt to set histchars to
              characters with a locale-dependent meaning will be rejected with an error message.

       HISTCHARS <S> <Z>
              Same as histchars.  (Deprecated.)

       HISTFILE
              The file to save the history in when an interactive shell exits.  If unset,  the  his‐
              tory is not saved.

       HISTORY_IGNORE
              If  set, is treated as a pattern at the time history files are written.  Any potential
              history entry that matches the pattern is skipped.  For example, if the value  is  `fc
              *'  then  commands that invoke the interactive history editor are never written to the
              history file.

              Note that HISTORY_IGNORE defines a single pattern: to  specify  alternatives  use  the
              `(first|second|...)' syntax.

              Compare the HIST_NO_STORE option or the zshaddhistory hook, either of which would pre‐
              vent such commands from being added to the interactive history at all.  If you wish to
              use  HISTORY_IGNORE to stop history being added in the first place, you can define the
              following hook:

                     zshaddhistory() {
                       emulate -L zsh
                       ## uncomment if HISTORY_IGNORE
                       ## should use EXTENDED_GLOB syntax
                       # setopt extendedglob
                       [[ $1 != ${~HISTORY_IGNORE} ]]
                     }

       HISTSIZE <S>
              The maximum number of events stored in the internal history  list.   If  you  use  the
              HIST_EXPIRE_DUPS_FIRST  option,  setting this value larger than the SAVEHIST size will
              give you the difference as a cushion for saving duplicated history events.

              If this is made local, it is not implicitly set to 0, but may be  explicitly  set  lo‐
              cally.

       HOME <S>
              The  default  argument for the cd command.  This is not set automatically by the shell
              in sh, ksh or csh emulation, but it is typically present in  the  environment  anyway,
              and if it becomes set it has its usual special behaviour.

       IFS <S>
              Internal  field  separators (by default space, tab, newline and NUL), that are used to
              separate words which result from command or parameter expansion and words read by  the
              read  builtin.   Any characters from the set space, tab and newline that appear in the
              IFS are called IFS white space.  One or more IFS white space characters or one non-IFS
              white  space  character together with any adjacent IFS white space character delimit a
              field.  If an IFS white space character appears twice consecutively in the  IFS,  this
              character is treated as if it were not an IFS white space character.

              If the parameter is unset, the default is used.  Note this has a different effect from
              setting the parameter to an empty string.

       KEYBOARD_HACK
              This variable defines a character to be removed from the end of the command  line  be‐
              fore interpreting it (interactive shells only). It is intended to fix the problem with
              keys placed annoyingly close to return and replaces the SUNKEYBOARDHACK  option  which
              did this for backquotes only.  Should the chosen character be one of singlequote, dou‐
              blequote or backquote, there must also be an odd number of them on  the  command  line
              for the last one to be removed.

              For backward compatibility, if the SUNKEYBOARDHACK option is explicitly set, the value
              of KEYBOARD_HACK reverts to backquote.  If the option is explicitly unset, this  vari‐
              able is set to empty.

       KEYTIMEOUT
              The time the shell waits, in hundredths of seconds, for another key to be pressed when
              reading bound multi-character sequences.

       LANG <S>
              This variable determines the locale category for any  category  not  specifically  se‐
              lected via a variable starting with `LC_'.

       LC_ALL <S>
              This  variable  overrides the value of the `LANG' variable and the value of any of the
              other variables starting with `LC_'.

       LC_COLLATE <S>
              This variable determines the  locale  category  for  character  collation  information
              within ranges in glob brackets and for sorting.

       LC_CTYPE <S>
              This variable determines the locale category for character handling functions.  If the
              MULTIBYTE option is in effect this variable or LANG should contain a  value  that  re‐
              flects  the  character  set  in use, even if it is a single-byte character set, unless
              only the 7-bit subset  (ASCII)  is  used.   For  example,  if  the  character  set  is
              ISO-8859-1,  a suitable value might be en_US.iso88591 (certain Linux distributions) or
              en_US.ISO8859-1 (MacOS).

       LC_MESSAGES <S>
              This variable determines the language in which messages should be written.  Note  that
              zsh does not use message catalogs.

       LC_NUMERIC <S>
              This  variable  affects  the decimal point character and thousands separator character
              for the formatted input/output functions and string conversion functions.   Note  that
              zsh ignores this setting when parsing floating point mathematical expressions.

       LC_TIME <S>
              This  variable  determines  the locale category for date and time formatting in prompt
              escape sequences.

       LINES <S>
              The number of lines for this terminal session.  Used for printing select lists and for
              the line editor.

       LISTMAX
              In  the  line editor, the number of matches to list without asking first. If the value
              is negative, the list will be shown if it spans at most as many lines as given by  the
              absolute  value.   If set to zero, the shell asks only if the top of the listing would
              scroll off the screen.

       LOGCHECK
              The interval in seconds between checks for login/logout activity using the  watch  pa‐
              rameter.

       MAIL   If  this  parameter  is  set  and mailpath is not set, the shell looks for mail in the
              specified file.

       MAILCHECK
              The interval in seconds between checks for new mail.

       mailpath <S> <Z> (MAILPATH <S>)
              An array (colon-separated list) of filenames to check for new mail.  Each filename can
              be followed by a `?' and a message that will be printed.  The message will undergo pa‐
              rameter expansion, command substitution and arithmetic expansion with the variable  $_
              defined  as  the  name of the file that has changed.  The default message is `You have
              new mail'.  If an element is a directory instead of a file the shell will  recursively
              check every file in every subdirectory of the element.

       manpath <S> <Z> (MANPATH <S> <Z>)
              An array (colon-separated list) whose value is not used by the shell.  The manpath ar‐
              ray can be useful, however, since setting it also sets MANPATH, and vice versa.

       match
       mbegin
       mend   Arrays set by the shell when the b globbing flag is used in pattern matches.  See  the
              subsection Globbing flags in the documentation for Filename Generation in zshexpn(1).

       MATCH
       MBEGIN
       MEND   Set by the shell when the m globbing flag is used in pattern matches.  See the subsec‐
              tion Globbing flags in the documentation for Filename Generation in zshexpn(1).

       module_path <S> <Z> (MODULE_PATH <S>)
              An array (colon-separated list) of directories that zmodload searches for  dynamically
              loadable  modules.   This  is  initialized  to  a standard pathname, usually `/usr/lo‐‐
              cal/lib/zsh/$ZSH_VERSION'.  (The `/usr/local/lib' part varies from installation to in‐
              stallation.)  For security reasons, any value set in the environment when the shell is
              started will be ignored.

              These parameters only exist if the installation supports dynamic module loading.

       NULLCMD <S>
              The command name to assume if a redirection is specified with no command.  Defaults to
              cat.  For sh/ksh behavior, change this to :.  For csh-like behavior, unset this param‐
              eter; the shell will print an error message if null commands are entered.

       path <S> <Z> (PATH <S>)
              An array (colon-separated list) of directories to search for commands.  When this  pa‐
              rameter is set, each directory is scanned and all files found are put in a hash table.

       POSTEDIT <S>
              This  string  is  output  whenever the line editor exits.  It usually contains termcap
              strings to reset the terminal.

       PROMPT <S> <Z>
       PROMPT2 <S> <Z>
       PROMPT3 <S> <Z>
       PROMPT4 <S> <Z>
              Same as PS1, PS2, PS3 and PS4, respectively.

       prompt <S> <Z>
              Same as PS1.

       PROMPT_EOL_MARK
              When the PROMPT_CR and PROMPT_SP options are set, the PROMPT_EOL_MARK parameter can be
              used  to  customize  how the end of partial lines are shown.  This parameter undergoes
              prompt expansion, with the PROMPT_PERCENT option set.  If not set, the default  behav‐
              ior is equivalent to the value `%B%S%#%s%b'.

       PS1 <S>
              The  primary  prompt string, printed before a command is read.  It undergoes a special
              form of expansion before being displayed; see EXPANSION OF PROMPT  SEQUENCES  in  zshmisc(1).  The default is `%m%# '.

       PS2 <S>
              The secondary prompt, printed when the shell needs more information to complete a com‐
              mand.  It is expanded in the same way as PS1.  The default is `%_> ',  which  displays
              any shell constructs or quotation marks which are currently being processed.

       PS3 <S>
              Selection  prompt  used  within a select loop.  It is expanded in the same way as PS1.
              The default is `?# '.

       PS4 <S>
              The execution trace prompt.  Default is `+%N:%i> ', which displays  the  name  of  the
              current  shell  structure  and the line number within it.  In sh or ksh emulation, the
              default is `+ '.

       psvar <S> <Z> (PSVAR <S>)
              An array (colon-separated list) whose elements can be used in PROMPT strings.  Setting
              psvar also sets PSVAR, and vice versa.

       READNULLCMD <S>
              The command name to assume if a single input redirection is specified with no command.
              Defaults to more.

       REPORTMEMORY
              If nonnegative, commands whose maximum resident set size (roughly speaking, main  mem‐
              ory  usage)  in  kilobytes is greater than this value have timing statistics reported.
              The format used to output statistics is the value of the TIMEFMT parameter,  which  is
              the  same  as  for  the REPORTTIME variable and the time builtin; note that by default
              this does not output memory usage.  Appending " max RSS %M" to the  value  of  TIMEFMT
              causes  it  to  output  the value that triggered the report.  If REPORTTIME is also in
              use, at most a single report is printed for both triggers.  This feature requires  the
              getrusage() system call, commonly supported by modern Unix-like systems.

       REPORTTIME
              If  nonnegative,  commands whose combined user and system execution times (measured in
              seconds) are greater than this value have timing statistics printed for them.   Output
              is suppressed for commands executed within the line editor, including completion; com‐
              mands explicitly marked with the time keyword still cause the summary to be printed in
              this case.

       REPLY  This  parameter  is reserved by convention to pass string values between shell scripts
              and shell builtins in situations where a function call or redirection  are  impossible
              or  undesirable.   The  read builtin and the select complex command may set REPLY, and
              filename generation both sets and examines its value when evaluating  certain  expres‐
              sions.  Some modules also employ REPLY for similar purposes.

       reply  As REPLY, but for array values rather than strings.

       RPROMPT <S>
       RPS1 <S>
              This  prompt is displayed on the right-hand side of the screen when the primary prompt
              is being displayed on the left.  This does not work if the SINGLE_LINE_ZLE  option  is
              set.  It is expanded in the same way as PS1.

       RPROMPT2 <S>
       RPS2 <S>
              This  prompt  is  displayed  on  the  right-hand side of the screen when the secondary
              prompt is being displayed on the left.  This does not work if the SINGLE_LINE_ZLE  op‐
              tion is set.  It is expanded in the same way as PS2.

       SAVEHIST
              The maximum number of history events to save in the history file.

              If  this  is  made local, it is not implicitly set to 0, but may be explicitly set lo‐
              cally.

       SPROMPT <S>
              The prompt used for spelling correction.  The sequence  `%R'  expands  to  the  string
              which  presumably  needs spelling correction, and `%r' expands to the proposed correc‐
              tion.  All other prompt escapes are also allowed.

              The actions available at the prompt are [nyae]:
              n (`no') (default)
                     Discard the correction and run the command.
              y (`yes')
                     Make the correction and run the command.
              a (`abort')
                     Discard the entire command line without running it.
              e (`edit')
                     Resume editing the command line.

       STTY   If this parameter is set in a command's environment, the shell runs the  stty  command
              with  the  value of this parameter as arguments in order to set up the terminal before
              executing the command. The modes apply only to the command, and are reset when it fin‐
              ishes  or is suspended. If the command is suspended and continued later with the fg or
              wait builtins it will see the modes specified by STTY, as if it  were  not  suspended.
              This  (intentionally)  does  not  apply  if the command is continued via `kill -CONT'.
              STTY is ignored if the command is run in the background, or if it is in  the  environ‐
              ment  of  the shell but not explicitly assigned to in the input line. This avoids run‐
              ning stty at every external command by accidentally exporting it. Also note that  STTY
              should not be used for window size specifications; these will not be local to the com‐
              mand.

       TERM <S>
              The type of terminal in use.  This is used when looking up termcap sequences.  An  as‐
              signment  to TERM causes zsh to re-initialize the terminal, even if the value does not
              change (e.g., `TERM=$TERM').  It is necessary to make  such  an  assignment  upon  any
              change  to the terminal definition database or terminal type in order for the new set‐
              tings to take effect.

       TERMINFO <S>
              A reference to your terminfo database, used by the `terminfo' library when the  system
              has  it; see terminfo(5).  If set, this causes the shell to reinitialise the terminal,
              making the workaround `TERM=$TERM' unnecessary.

       TERMINFO_DIRS <S>
              A colon-seprarated list of terminfo databases, used by the `terminfo' library when the
              system  has  it;  see  terminfo(5). This variable is only used by certain terminal li‐
              braries, in particular ncurses; see terminfo(5) to check support on your  system.   If
              set,  this  causes  the  shell  to  reinitialise  the  terminal, making the workaround
              `TERM=$TERM' unnecessary.  Note that unlike other colon-separated arrays this  is  not
              tied to a zsh array.

       TIMEFMT
              The format of process time reports with the time keyword.  The default is `%J  %U user
              %S system %P cpu %*E total'.  Recognizes the following escape sequences, although  not
              all may be available on all systems, and some that are available may not be useful:

              %%     A `%'.
              %U     CPU seconds spent in user mode.
              %S     CPU seconds spent in kernel mode.
              %E     Elapsed time in seconds.
              %P     The CPU percentage, computed as 100*(%U+%S)/%E.
              %W     Number of times the process was swapped.
              %X     The average amount in (shared) text space used in kilobytes.
              %D     The average amount in (unshared) data/stack space used in kilobytes.
              %K     The total space used (%X+%D) in kilobytes.
              %M     The  maximum memory the process had in use at any time in kilobytes.
              %F     The number of major page faults (page needed to be brought from disk).
              %R     The number of minor page faults.
              %I     The number of input operations.
              %O     The number of output operations.
              %r     The number of socket messages received.
              %s     The number of socket messages sent.
              %k     The number of signals received.
              %w     Number of voluntary context switches (waits).
              %c     Number of involuntary context switches.
              %J     The name of this job.

              A star may be inserted between the percent sign and flags printing time (e.g., `%*E');
              this causes the time to be printed in `hh:mm:ss.ttt' format  (hours  and  minutes  are
              only  printed  if  they  are  not zero).  Alternatively, `m' or `u' may be used (e.g.,
              `%mE') to produce time output in milliseconds or microseconds, respectively.

       TMOUT  If this parameter is nonzero, the shell will receive an ALRM signal if  a  command  is
              not entered within the specified number of seconds after issuing a prompt. If there is
              a trap on SIGALRM, it will be executed and a new alarm is scheduled using the value of
              the TMOUT parameter after executing the trap.  If no trap is set, and the idle time of
              the terminal is not less than the value of the TMOUT parameter, zsh terminates.   Oth‐
              erwise a new alarm is scheduled to TMOUT seconds after the last keypress.

       TMPPREFIX
              A  pathname  prefix  which the shell will use for all temporary files.  Note that this
              should include an initial part for the file name as well as any directory names.   The
              default is `/tmp/zsh'.

       TMPSUFFIX
              A filename suffix which the shell will use for temporary files created by process sub‐
              stitutions (e.g., `=(list)').  Note that the value should include a leading dot `.' if
              intended to be interpreted as a file extension.  The default is not to append any suffix, thus this parameter should be assigned only when needed and then unset again.

       watch <S> <Z> (WATCH <S>)
              An array (colon-separated list) of login/logout events to report.

              If it contains the single word `all', then all login/logout events are  reported.   If
              it contains the single word `notme', then all events are reported as with `all' except
              $USERNAME.

              An entry in this list may consist of a username, an `@' followed by a remote hostname,
              and  a  `%' followed by a line (tty).  Any of these may be a pattern (be sure to quote
              this during the assignment to watch so that it does not immediately perform file  gen‐
              eration);  the  setting of the EXTENDED_GLOB option is respected.  Any or all of these
              components may be present in an entry; if a login/logout event matches all of them, it
              is reported.

              For example, with the EXTENDED_GLOB option set, the following:

                     watch=('^(pws|barts)')

              causes reports for activity associated with any user other than pws or barts.

       WATCHFMT
              The  format of login/logout reports if the watch parameter is set.  Default is `%n has
              %a %l from %m'.  Recognizes the following escape sequences:

              %n     The name of the user that logged in/out.

              %a     The observed action, i.e. "logged on" or "logged off".

              %l     The line (tty) the user is logged in on.

              %M     The full hostname of the remote host.

              %m     The hostname up to the first `.'.  If only the IP address is available  or  the
                     utmp  field  contains  the  name  of  an  X-windows  display, the whole name is
                     printed.

                     NOTE: The `%m' and `%M' escapes will work only if there is a host name field in
                     the utmp on your machine.  Otherwise they are treated as ordinary strings.

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

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

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

              %t
              %@     The time, in 12-hour, am/pm format.

              %T     The time, in 24-hour format.

              %w     The date in `day-dd' format.

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

              %D     The date in `yy-mm-dd' format.

              %D{string}
                     The  date  formatted as string using the strftime function, with zsh extensions
                     as described by EXPANSION OF PROMPT SEQUENCES in zshmisc(1).

              %(x:true-text:false-text)
                     Specifies a ternary expression.  The character following the  x  is  arbitrary;
                     the same character is used to separate the text for the "true" result from that
                     for the "false" result.  Both the separator and the right  parenthesis  may  be
                     escaped with a backslash.  Ternary expressions may be nested.

                     The  test  character x may be any one of `l', `n', `m' or `M', which indicate a
                     `true' result if the corresponding escape sequence  would  return  a  non-empty
                     value;  or  it  may be `a', which indicates a `true' result if the watched user
                     has logged in, or `false' if he has logged out.  Other characters  evaluate  to
                     neither true nor false; the entire expression is omitted in this case.

                     If the result is `true', then the true-text is formatted according to the rules
                     above and printed, and the false-text is skipped.  If `false', the true-text is
                     skipped  and  the  false-text  is formatted and printed.  Either or both of the
                     branches may be empty, but both separators must be present in any case.

       WORDCHARS <S>
              A list of non-alphanumeric characters considered part of a word by the line editor.

       ZBEEP  If set, this gives a string of characters, which can use all the  same  codes  as  the
              bindkey  command  as described in the zsh/zle module entry in zshmodules(1), that will
              be output to the terminal instead of beeping.  This may have a visible instead  of  an
              audible  effect;  for example, the string `\e[?5h\e[?5l' on a vt100 or xterm will have
              the effect of flashing reverse video on and off (if you usually use reverse video, you
              should  use the string `\e[?5l\e[?5h' instead).  This takes precedence over the NOBEEP
              option.

       ZDOTDIR
              The directory to search for shell startup files (.zshrc, etc), if not $HOME.

       zle_bracketed_paste
              Many terminal emulators have a feature that allows applications to identify when  text
              is pasted into the terminal rather than being typed normally. For ZLE, this means that
              special characters such as tabs and newlines can be inserted instead of invoking  edi‐
              tor commands.  Furthermore, pasted text forms a single undo event and if the region is
              active, pasted text will replace the region.

              This two-element array contains the terminal escape sequences for  enabling  and  dis‐
              abling the feature. These escape sequences are used to enable bracketed paste when ZLE
              is active and disable it at other times.  Unsetting the parameter has  the  effect  of
              ensuring that bracketed paste remains disabled.

       zle_highlight
              An  array describing contexts in which ZLE should highlight the input text.  See Character Highlighting in zshzle(1).

       ZLE_LINE_ABORTED
              This parameter is set by the line editor when an error occurs.  It contains  the  line
              that was being edited at the point of the error.  `print -zr -- $ZLE_LINE_ABORTED' can
              be used to recover the line.  Only the most recent line of this kind is remembered.

       ZLE_REMOVE_SUFFIX_CHARS
       ZLE_SPACE_SUFFIX_CHARS
              These parameters are used by the line editor.  In certain circumstances suffixes (typ‐
              ically  space  or slash) added by the completion system will be removed automatically,
              either because the next editing command was not an insertable  character,  or  because
              the character was marked as requiring the suffix to be removed.

              These  variables  can  contain the sets of characters that will cause the suffix to be
              removed.  If ZLE_REMOVE_SUFFIX_CHARS is set, those characters will cause the suffix to
              be  removed;  if ZLE_SPACE_SUFFIX_CHARS is set, those characters will cause the suffix
              to be removed and replaced by a space.

              If ZLE_REMOVE_SUFFIX_CHARS is not set, the default behaviour is equivalent to:

                     ZLE_REMOVE_SUFFIX_CHARS=$' \t\n;&|'

              If ZLE_REMOVE_SUFFIX_CHARS is set but is empty, no  characters  have  this  behaviour.
              ZLE_SPACE_SUFFIX_CHARS takes precedence, so that the following:

                     ZLE_SPACE_SUFFIX_CHARS=$'&|'

              causes the characters `&' and `|' to remove the suffix but to replace it with a space.

              To  illustrate  the difference, suppose that the option AUTO_REMOVE_SLASH is in effect
              and the directory DIR has just been completed, with an appended /, following which the
              user  types  `&'.  The default result is `DIR&'.  With ZLE_REMOVE_SUFFIX_CHARS set but
              without including `&' the result is `DIR/&'.  With ZLE_SPACE_SUFFIX_CHARS set  to  in‐
              clude `&' the result is `DIR &'.

              Note  that certain completions may provide their own suffix removal or replacement be‐
              haviour which overrides the values described here.  See the completion system documen‐
              tation in zshcompsys(1).

       ZLE_RPROMPT_INDENT <S>
              If  set,  used to give the indentation between the right hand side of the right prompt
              in the line editor as given by RPS1 or RPROMPT and the right hand side of the  screen.
              If not set, the value 1 is used.

              Typically  this  will  be  used to set the value to 0 so that the prompt appears flush
              with the right hand side of the screen.  This is not the default as many terminals  do
              not handle this correctly, in particular when the prompt appears at the extreme bottom
              right of the screen.  Recent virtual terminals are more likely  to  handle  this  case
              correctly.  Some experimentation is necessary.



zsh 5.8.1                                 February 12, 2022                              ZSHPARAM(1)
zshparam(1)
NAME DESCRIPTION ARRAY PARAMETERS
Array Subscripts Array Element Assignment Subscript Flags Subscript Parsing
POSITIONAL PARAMETERS LOCAL PARAMETERS PARAMETERS SET BY THE SHELL
signals
PARAMETERS USED BY THE SHELL
match mbegin

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