dwww Home | Manual pages | Find package

ZSHPARAM(1)                 General Commands Manual                ZSHPARAM(1)

NAME
       zshparam - zsh parameters

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

       The  attributes  of  a parameter determine the type of its value, often
       referred to as the parameter type or variable type,  and  also  control
       other  processing  that  may  be applied to the value when it is refer-
       enced.  The value type may be a scalar (a  string,  an  integer,  or  a
       floating  point number), an array (indexed numerically), or an associa-
       tive 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.  Exported parameters are called
       environment variables. The shell also imports environment variables  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 interfere with the correct operation of
       other shell features.

       Parameters may also be special, that  is,  they  have  a  predetermined
       meaning  to  the  shell.   Special  parameters  cannot  have their type
       changed or their readonly attribute turned off, and if a special param-
       eter 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 parameter, 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 parameter can be incremented
       or appended to.  See the  section  `Array  Parameters'  and  Arithmetic
       Evaluation (in zshmisc(1)) for additional forms of assignment.

       Note  that assignment may implicitly change the attributes of a parame-
       ter.  For example, assigning a number to a variable in arithmetic eval-
       uation  may  change  its type to integer or float, and with GLOB_ASSIGN
       assigning a pattern to a variable may change its type to an array.

       To reference the value of a parameter, write `$name' or `${name}'.  See
       Parameter  Expansion  in zshexpn(1) for complete details.  That section
       also explains the effect of the difference between scalar and array as-
       signment 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 ele-
       ments 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  sub-
       script  expression  that may be used when directly subscripting a vari-
       able name, described in the section `Array Subscripts' below,  are  not
       available.

       The  syntaxes  with  and without the explicit key may be mixed.  An im-
       plicit key is deduced by incrementing the index from the previously as-
       signed  element.  Note that it is not treated as an error if latter as-
       signments 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 expan-
       sion  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 differs from ksh which allows the values themselves
       to be arrays.  A future version of zsh may support that.  To cause  the
       brackets  to  be  interpreted as a character class for filename genera-
       tion, 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  in-
       dex  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  ex-
       isting value at that index.

       Within the parentheses on the right hand side of either form of the as-
       signment, newlines and semicolons are treated the same as white  space,
       separating individual values.  Any consecutive sequence of such charac-
       ters 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 alternating 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 nu-
       merically indexed arrays.

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

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

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

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

              set -A name
              name=()

   Array Subscripts
       Individual  elements  of an array may be selected using a subscript.  A
       subscript of the form `[exp]' selects the single element exp, where exp
       is  an arithmetic expression which will be subject to arithmetic expan-
       sion 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 numbered from zero.

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

       If the KSH_ARRAYS option is not set, then by default accesses to an ar-
       ray element with a subscript that evaluates to  zero  return  an  empty
       string,  while an attempt to write such an element is treated as an er-
       ror.  For backward compatibility the KSH_ZERO_SUBSCRIPT option  can  be
       set  to  cause  subscript  values 0 and 1 to be equivalent; see the de-
       scription of the option in zshoptions(1).

       The same subscripting syntax is used  for  associative  arrays,  except
       that  no  arithmetic expansion 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.   `"$foo[*]"'  evaluates  to  `"$foo[1]  $foo[2]
       ..."', whereas `"$foo[@]"' evaluates to `"$foo[1]" "$foo[2]" ...'.  For
       associative arrays, `[*]' or `[@]' evaluate to all the  values,  in  no
       particular order.  Note that this does not substitute the keys; see the
       documentation for the `k' flag under Parameter Expansion Flags in  zsh-
       expn(1) for complete details.  When an array parameter is referenced as
       `$name' (with no subscript) it  evaluates  to  `$name[*]',  unless  the
       KSH_ARRAYS  option  is  set  in which case it evaluates to `${name[0]}'
       (for an 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, inclusive. (Associative arrays are unordered, and  so  do
       not  support  ranges.) If one of the subscripts evaluates to a negative
       number, say -n, then the nth element from the end of the array is used.
       Thus `$foo[-3]' is the third element from the end of the array foo, and
       `$foo[1,-1]' is the same as `$foo[*]'.

       Subscripting may also be performed on non-array values, in  which  case
       the  subscripts  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 matching,
       and in that case the substring extends from the start of the  match  of
       the  first  subscript  to the end of the match of the second subscript.
       For example,

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

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

       Note that in substring operations the second subscript is handled  dif-
       ferently  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 re-
       placed by the expression on the right side.  An array (but not an asso-
       ciative array) may be created by assignment to a range or element.  Ar-
       rays do not nest, so assigning a parenthesized list of values to an el-
       ement or range changes the number of elements in  the  array,  shifting
       the  other  elements  to accommodate the new values.  (This is not sup-
       ported 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-el-
       ement  assignments may be made with typeset.  Note that quotes are nec-
       essary 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 ex-
       pression is directly followed 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  character,  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 parame-
       ter substitution enclosed in braces as otherwise the expression is  in-
       terpreted 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 ele-
              ments separated by newlines.  This is a shorthand for `pws:\n:'.

       r      Reverse subscripting: if this flag is given, the exp is taken as
              a  pattern  and  the result is the first matching array element,
              substring or word (if the parameter is an  array,  if  it  is  a
              scalar,  or if it is a scalar and the `w' flag is given, respec-
              tively).  The subscript used is the number of the matching  ele-
              ment,  so  that  pairs of subscripts such as `$foo[(r)??,3]' and
              `$foo[(r)??,(r)f*]' are possible if the parameter is not an  as-
              sociative 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  ${ar-
              ray[(r)pattern]}  will  substitute  the  empty string.  Thus the
              success of a search can be tested by using the (i) flag, for ex-
              ample (assuming the option KSH_ARRAYS is not in effect):

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

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

       R      Like  `r',  but  gives  the last match.  For associative arrays,
              gives all possible matches. May be used for assigning  to  ordi-
              nary  array  elements,  but not for assigning to associative ar-
              rays.  On failure, for normal arrays this has the effect of  re-
              turning  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  (re-
              gardless  of  the setting of GLOB_SUBST which controls this fea-
              ture in normal pattern matching).  The flag `e' can be added  to
              inhibit  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  as-
              signment,  behaves  like  `r'.   For associative 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.

              Note:  Although  `i'  may be applied to a scalar substitution to
              find the offset of a substring, the results  are  likely  to  be
              misleading  when  searching  within  substitutions that yield an
              empty string, or when searching for the empty substring.

       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.

              Note:  If  the  option  KSH_ARRAYS  is in effect and no match is
              found, the result is indistinguishable from the  case  when  the
              first element of the array matches.

       k      If used in a subscript on an associative array, this flag causes
              the keys to be interpreted 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 as-
              signment 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  ig-
              nored  when the array is associative.  The delimiter character :
              is arbitrary; see above.

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

       e      This flag causes any pattern matching that would be performed on
              the subscript to  use  plain  string  matching  instead.   Hence
              `${array[(re)*]}'  matches only the array element whose value is
              *.  Note that other forms of substitution such as parameter sub-
              stitution 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 ma-
       nipulate the results of array subscripting.

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

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

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

       The basic rule to remember when writing a subscript expression is  that
       all  text between the opening `[' and the closing `]' is interpreted as
       if it were in double quotes (see zshmisc(1)).  However,  unlike  double
       quotes which normally cannot nest, subscript expressions may appear in-
       side 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 bal-
       anced pairs in a subscript expression unless they  are  preceded  by  a
       backslash  (`\').  Therefore, within a subscript expression (and unlike
       true double-quoting) the sequence `\[' becomes `[', and similarly  `\]'
       becomes  `]'.  This applies even in cases where a backslash is not nor-
       mally required; for example, the pattern `[^[]' (to match any character
       other than an open bracket) should be written `[^\[]' in a reverse-sub-
       script 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 back-
       slash, 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 expression without being preceded by  a  backslash,  and
       therefore  that the two characters `\"' remain as two characters in the
       subscript (in true double-quoting, `\"' becomes `"').  However, because
       of the standard shell quoting rules, any double-quotes that appear must
       occur in balanced pairs unless preceded by a backslash.  This makes  it
       more  difficult  to  write  a subscript expression that contains an odd
       number of double-quote characters, but the reason for  this  difference
       is  so  that  when  a  subscript  expression  appears  inside true dou-
       ble-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 pa-
       rameter  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 subscript 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 associa-
       tive 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  per-
       formed.  Parameters appearing in the subscript expression are first ex-
       panded and then the complete expression is interpreted  as  a  pattern.
       This has two effects: first, parameters behave as if GLOB_SUBST were on
       (and it cannot be turned  off);  second,  backslashes  are  interpreted
       twice, once when parsing the array subscript and again when parsing the
       pattern.  In a reverse subscript, it's  necessary  to  use  four  back-
       slashes  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, be-
       cause then the backslashes, brackets, parentheses, etc., are seen  only
       when  the  complete expression is converted to a pattern.  To match the
       value of a parameter literally in a reverse 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 ordi-
       nary 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 parameters (described below) are parsed specially, so for
       example  `$2foo'  is  equivalent  to `${2}foo'.  Therefore, to use sub-
       script syntax to extract a substring from a positional  parameter,  the
       expansion must be surrounded by braces; for example, `${2[3,5]}' evalu-
       ates to the third through fifth characters of the second positional pa-
       rameter, 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 `Functions'.  The parameter n, where
       n  is a number, is the nth positional parameter.  The parameter `$0' is
       a special case, see the section `Parameters Set By The Shell'.

       The parameters *, @ and argv are arrays containing all  the  positional
       parameters;  thus `$argv[n]', etc., is equivalent to simply `$n'.  Note
       that the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT apply to these arrays
       as  well,  so with either of those options set, `${argv[0]}' is equiva-
       lent 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  posi-
       tional  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 assign-
       ment of the form `n=(value ...)' is allowed,  and  has  the  effect  of
       shifting  all  the  values at positions greater than n by as many posi-
       tions as necessary to accommodate the new values.

LOCAL PARAMETERS
       Shell function executions delimit scopes for shell parameters.  (Param-
       eters  are  dynamically scoped.)  The typeset builtin, and its alterna-
       tive 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 parame-
       ter 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 unexpected effects: there
       is no default value, so if there is no  assignment  at  the  point  the
       variable  is  made  local, it will be set to an empty value (or zero in
       the case of integers).  The following:

              typeset PATH=/new/directory:$PATH

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

       Note  that  the restriction in older versions of zsh that local parame-
       ters 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 ex-
       ist when the shell initializes in sh or ksh emulation mode.

       The parameters `!', `#', `*', `-', `?', `@',  `$',  `ARGC',  `HISTCMD',
       `LINENO',     `PPID',    `status',    `TTYIDLE',    `zsh_eval_context',
       `ZSH_EVAL_CONTEXT', and `ZSH_SUBSHELL' are read-only and thus cannot be
       restored  by  the  user,  so they are not output by `typeset -p'.  This
       also applies to many read-only parameters loaded from modules.

       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 ${#} to resolve ambiguities.  In  par-
              ticular,  the  sequence  `$#-...' in an arithmetic expression is
              interpreted as the length of the parameter -, q.v.

       ARGC <S> <Z>
              Same as #.

       $ <S>  The process ID of this shell, set when  the  shell  initializes.
              Processes forked from the shell without executing a new program,
              such as command substitutions and commands grouped  with  (...),
              are subshells that duplicate the current shell, and thus substi-
              tute the same value for $$ as their parent shell.

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

       * <S>  An array containing the positional parameters.

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

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

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

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

       status <S> <Z>
              Same as ?.

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

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

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

       EGID <S>
              The effective group ID of the shell process.  If you have suffi-
              cient  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 locally.

       EUID <S>
              The  effective user ID of the shell process.  If you have suffi-
              cient 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 locally.

       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 in-
              tended for debugging purposes.   It  is  also  useful  with  the
              zsh/system  module  which  allows the number to be turned into a
              name or message.

              To use this parameter, it must first be assigned a value  (typi-
              cally  0  (zero)).  It is initially unset for scripting compati-
              bility.

       FUNCNEST <S>
              Integer.  If greater than or equal to zero, the maximum  nesting
              depth  of  shell  functions.   When  it is exceeded, an error is
              raised at the point where a function  is  called.   The  default
              value  is  determined when the shell is configured, but is typi-
              cally 500.  Increasing the value increases the danger of a  run-
              away  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 (assuming  sufficient  privi-
              leges),  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 locally.

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

       HOST   The current hostname.

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

       LOGNAME
              If the corresponding variable is not set in the  environment  of
              the  shell, it is initialized to the login name corresponding to
              the current login session. This 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 de-
              termined at compile time.

       OLDPWD The previous working directory.  This is set when the shell ini-
              tializes 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, set when the shell
              initializes.  As with $$, the value does not change in subshells
              created as a duplicate of the current shell.

       PWD    The  present working directory.  This is set when the shell ini-
              tializes 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; subshells that reference RANDOM will re-
              sult in identical pseudo-random values unless the value of  RAN-
              DOM  is referenced or seeded in the parent shell in between sub-
              shell invocations.

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

              Unlike other special parameters, the type of the SECONDS parame-
              ter can be changed using the typeset command.  The type  may  be
              changed only to one of the floating point types or back to inte-
              ger.  For example, `typeset -F SECONDS' causes the value  to  be
              reported  as a floating point number.  The value is available to
              microsecond accuracy, although the shell may show more or  fewer
              digits  depending  on the use of typeset.  See the documentation
              for the builtin typeset in zshbuiltins(1) for more details.

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

       signals
              An array containing the names of the signals.   Note  that  with
              the standard zsh numbering of array indices, where the first el-
              ement 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 ar-
              ray, which is used internally by zsh but is not known to the op-
              erating 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  other-
              wise.   It may be reset, clearing the error condition.  See Com-
              plex Commands in zshmisc(1)

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

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

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

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

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

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

       USERNAME <S>
              The username corresponding to the real  user  ID  of  the  shell
              process.   If you have sufficient privileges, you may change the
              username (and also the user ID and group ID) of the shell by as-
              signing  to  this  parameter.   Also (assuming sufficient privi-
              leges), you may start a single command under a  different  user-
              name  (and  user  ID  and group ID) by `(USERNAME=username; com-
              mand)'

       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  ap-
              pended  to  the  array to indicate the type of operation that is
              being performed.  Read in order the array gives an indication of
              the  stack of operations being performed with the most immediate
              context last.

              Note that the variable does not give  information  on  syntactic
              context  such  as  pipelines 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 exam-
                     ple by the source builtin.

              filecode
                     Lines of code being read from a .zwc file instead of  di-
                     rectly 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  prac-
                     tice.

              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 functions have the context  shfunc.   As
                     traps  are asynchronous they may have a different hierar-
                     chy from other code.

              zpty   Code executed by the zpty builtin from the zsh/zpty  mod-
                     ule.

              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 module.

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

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

       ZSH_NAME
              Expands  to  the basename of the command used to invoke this in-
              stance of zsh.

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

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

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

       ZSH_SUBSHELL
              Readonly  integer.   Initially  zero,  incremented each time the
              shell forks to create a  subshell  for  executing  code.   Hence
              `(print  $ZSH_SUBSHELL)' and `print $(print $ZSH_SUBSHELL)' out-
              put 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 cre-
       ated via `typeset -T'.  The normal use for the colon-separated form  is
       for exporting to the environment, while the array form is easier to ma-
       nipulate 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  com-
              mands.  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 neces-
              sary.  If the parameter is unset or the value is zero  the  com-
              pensation  mechanism is turned off.  The parameter is not set by
              default.

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

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

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

       CORRECT_IGNORE
              If set, is treated as a pattern during spelling correction.  Any
              potential correction that matches the pattern is  ignored.   For
              example,  if the value is `_*' then completion functions (which,
              by convention, have names beginning with `_') will never be  of-
              fered  as  spelling  corrections.  The pattern does not apply to
              the correction of file names, as applied by the CORRECT_ALL  op-
              tion (so with the example just given files beginning 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 of-
              fered 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 expansion,  command  substitution,
              and arithmetic expansion before being interpreted as a pathname.
              Note that ENV is not used unless the shell  is  interactive  and
              zsh is emulating sh or ksh.

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

       fignore <S> <Z> (FIGNORE <S>)
              An array (colon separated list) containing the suffixes of files
              to be ignored during filename completion.  However,  if  comple-
              tion 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 referenced.  If an exe-
              cutable  file is found, then it is read and executed in the cur-
              rent environment.

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

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

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

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

       HISTORY_IGNORE
              If  set,  is  treated as a pattern at the time history files are
              written.  Any 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,  ei-
              ther  of  which  would prevent such commands from being added to
              the interactive history at all.  If you wish to use  HISTORY_IG-
              NORE to stop history being added in the first place, you can de-
              fine 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  dif-
              ference 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 locally.

       HOME <S>
              The default argument for the cd command.  This is not set  auto-
              matically  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  before  interpreting  it  (interactive  shells
              only). It is intended to fix the problem with keys placed annoy-
              ingly close to return and replaces  the  SUNKEYBOARDHACK  option
              which did this for backquotes only.  Should the chosen character
              be one of singlequote, doublequote or backquote, there must also
              be an odd number of them on the command line for the last one to
              be removed.

              For backward compatibility, if the SUNKEYBOARDHACK option is ex-
              plicitly  set,  the value of KEYBOARD_HACK reverts to backquote.
              If the option is explicitly  unset,  this  variable  is  set  to
              empty.

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

       LANG <S>
              This variable determines the locale category  for  any  category
              not specifically selected 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  col-
              lation  information within ranges in glob brackets and for sort-
              ing.

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

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

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

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

       LINES <S>
              The number of lines for this terminal session.  Used for  print-
              ing 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.

       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 parameter  expansion,
              command  substitution and arithmetic expansion with the variable
              $_ defined as the name of the file that has  changed.   The  de-
              fault message is `You have new mail'.  If an element is a direc-
              tory instead of a file the shell will  recursively  check  every
              file in every subdirectory of the element.

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

       match
       mbegin
       mend   Arrays set by the shell when the b globbing flag is used in pat-
              tern matches.  See the subsection Globbing flags in the documen-
              tation 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 subsection 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/local/lib/zsh/$ZSH_VER-
              SION'.  (The `/usr/local/lib' part varies from  installation  to
              installation.)  For security reasons, any value set in the envi-
              ronment when the shell is started will be ignored.

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

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

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

       POSTEDIT <S>
              This string is output whenever the line editor exits.   It  usu-
              ally 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 ex-
              pansion, with the PROMPT_PERCENT option set.  If  not  set,  the
              default behavior is equivalent to the value `%B%S%#%s%b'.

       PS1 <S>
              The primary prompt string, printed before a command is read.  It
              undergoes a 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 informa-
              tion  to  complete a command.  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  dis-
              plays  the name of the current shell structure and the line num-
              ber 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  memory 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  trig-
              gers.   This  feature requires the getrusage() system call, com-
              monly supported by modern Unix-like systems.

       REPORTTIME
              If nonnegative, commands whose combined user and  system  execu-
              tion  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 comple-
              tion; commands explicitly marked with  the  time  keyword  still
              cause the summary to be printed in this case.

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

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

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

       RPROMPT2 <S>
       RPS2 <S>
              This prompt is displayed on the right-hand side  of  the  screen
              when  the secondary prompt is being displayed on the left.  This
              does not work if the SINGLE_LINE_ZLE option is set.  It  is  ex-
              panded 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 locally.

       SPROMPT <S>
              The  prompt used for spelling correction.  The sequence `%R' ex-
              pands to the string which presumably needs spelling  correction,
              and  `%r'  expands to the proposed correction.  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 argu-
              ments in order to set up the terminal before executing the  com-
              mand. The modes apply only to the command, and are reset when it
              finishes or is suspended. If the command is suspended  and  con-
              tinued  later with the fg or wait builtins it will see the modes
              specified by STTY, as if it were not  suspended.   This  (inten-
              tionally)  does  not apply if the command is continued via `kill
              -CONT'.  STTY is ignored if the command  is  run  in  the  back-
              ground,  or if it is in the environment of the shell but not ex-
              plicitly assigned to in the input line. This avoids running stty
              at  every  external  command  by accidentally exporting it. Also
              note that STTY should not be used  for  window  size  specifica-
              tions; these will not be local to the command.

              If  the parameter is set and empty, all of the above applies ex-
              cept that stty is not run. This can be useful as a way to freeze
              the  tty  around  a  single command, blocking its changes to tty
              settings, similar to the ttyctl builtin.

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

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

       TERMINFO_DIRS <S>
              A colon-seprarated list of terminfo databases, used by the `ter-
              minfo'  library  when  the  system has it; see terminfo(5). This
              variable is only used by certain terminal libraries, in particu-
              lar  ncurses;  see  terminfo(5) to check support on your system.
              If set, this causes the shell to reinitialise the terminal, mak-
              ing  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  avail-
              able on all systems, and some that are available may not be use-
              ful:

              %%     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  kilo-
                     bytes.
              %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 print-
              ing  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  mi-
              croseconds, 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.  Other-
              wise a new alarm is scheduled to TMOUT seconds  after  the  last
              keypress.

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

       TMPSUFFIX
              A filename suffix which the shell will use for  temporary  files
              created  by  process substitutions (e.g., `=(list)').  Note that
              the value should include a leading dot `.' if intended to be in-
              terpreted 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.

       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 termi-
              nal  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 charac-
              ters such as tabs and newlines can be inserted instead of invok-
              ing  editor  commands.   Furthermore, pasted text forms a single
              undo event and if the region is active, pasted text will replace
              the region.

              This  two-element  array  contains the terminal escape sequences
              for enabling and disabling the feature. These  escape  sequences
              are  used  to enable bracketed paste when ZLE is active and dis-
              able 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 cir-
              cumstances suffixes (typically space or slash) added by the com-
              pletion 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_RE-
              MOVE_SLASH is in effect and the directory DIR has just been com-
              pleted,  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 include `&' the result is `DIR &'.

              Note that certain completions may provide their own  suffix  re-
              moval  or  replacement  behaviour which overrides the values de-
              scribed here.  See the completion system documentation  in  zsh-
              compsys(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 5.9                          May 14, 2022                      ZSHPARAM(1)

Generated by dwww version 1.15 on Tue Jun 18 07:20:32 CEST 2024.