Provided by: zsh_4.3.17-1ubuntu1_amd64 bug

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  `!'.   The value may be a scalar (a string), an integer, an array (indexed
       numerically), or an associative array (an unordered set of name-value  pairs,  indexed  by
       name).   To  declare  the type of a parameter, or to assign a scalar or integer value to a
       parameter, use the typeset builtin.

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

              name=value

       If the integer attribute, -i, is  set  for  name,  the  value  is  subject  to  arithmetic
       evaluation.  Furthermore, by replacing `=' with `+=', a parameter can be added or appended
       to.  See the section `Array Parameters' for additional forms of assignment.

       To refer to the value of a parameter, write `$name' or `${name}'.  See Parameter Expansion
       in zshexpn(1) for complete details.

       In  the  parameter  lists  that  follow,  the  mark  `<S>' indicates that the parameter is
       special.  Special parameters cannot have their type changed or  their  readonly  attribute
       turned  off,  and  if  a  special  parameter  is  unset, then later recreated, the special
       properties will be retained.  `<Z>' indicates that the parameter does not exist  when  the
       shell initializes in sh or ksh emulation mode.

ARRAY PARAMETERS

       To assign an array value, write one of:

              set -A name value ...
              name=(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.  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 ...)

       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.

       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 numbered from zero.

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

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

       The  same  subscripting  syntax  is used for associative arrays, except that no arithmetic
       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 zshexpn(1) for complete details.  When an
       array parameter is referenced as `$name' (with no subscript) it evaluates  to  `$name[*]',
       unless  the  KSH_ARRAYS  option  is set in which case it evaluates to `${name[0]}' (for an
       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'.

   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
       expression 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
       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.

       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.  This  flag
              may not be used with the i or I flag.

       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
              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,
              respectively).  The subscript used is the number of the matching element,  so  that
              pairs of subscripts such as `$foo[(r)??,3]' and `$foo[(r)??,(r)f*]' are possible if
              the parameter is not an associative array.  If  the  parameter  is  an  associative
              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 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  assignment,  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.

       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
              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 assignment to an
              associative array element.  If used on another type of parameter, this behaves like
              `r'.

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

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

       b:expr:
              If  combined  with  `r',  `R',  `i' or `I', makes them begin at the nth or nth last
              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
              substitution are not inhibited.

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

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

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

       It is possible to avoid the use of subscripts in assignments to associative array elements
       by using the syntax:

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

       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.

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

       The same rule applies to parentheses (`(' and `)') and braces (`{'  and  `}'):  they  must
       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
       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
       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 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 associative array key, the `e' flag must be used:

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

       A  last  detail  must  be  considered  when reverse subscripting is performed.  Parameters
       appearing in the subscript expression are first expanded and then the complete  expression
       is  interpreted  as  a  pattern.   This  has  two  effects: first, parameters behave as if
       GLOB_SUBST were on (and it cannot be turned  off);  second,  backslashes  are  interpreted
       twice,  once  when  parsing  the array subscript and again when parsing the pattern.  In a
       reverse subscript, it's necessary 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,  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 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
       parameters (described below) are parsed specially, so for example `$2foo' is equivalent to
       `${2}foo'.   Therefore,  to  use subscript syntax to extract a substring from a positional
       parameter, the expansion must be surrounded by braces; for example, `${2[3,5]}'  evaluates
       to the third through fifth characters of the second positional parameter, but `$2[3,5]' is
       the entire second parameter concatenated with the filename generation pattern `[3,5]'.

POSITIONAL PARAMETERS

       The positional parameters  provide  access  to  the  command-line  arguments  of  a  shell
       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  parameters  *,  @  and  argv  are  arrays  containing all the positional
       parameters; thus `$argv[n]', etc., is equivalent to simply `$n'.

       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  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  parameters  were  never
       exported has been removed.

PARAMETERS SET BY THE SHELL

       The following parameters are automatically set by the shell:

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

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

       ARGC <S> <Z>
              Same as #.

       $ <S>  The  process ID of this shell.  Note that this indicates the original shell started
              by invoking zsh; all processes forked from  the  shells  without  executing  a  new
              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
              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.  If the FUNCTION_ARGZERO option is  set,
              this  is  set  temporarily within a shell function to the name of the function, and
              within a sourced script to the name of the script.

       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  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)'

       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)'

       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.

       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 privileges), you may start a single command under a  different
              group ID by `(GID=gid; command)'

       HISTCMD
              The  current  history  line number in an interactive shell, in other words the line
              number for the command that caused $HISTCMD to be read.

       HOST   The current hostname.

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

       LOGNAME
              If  the  corresponding  variable  is not set in the environment of the shell, it is
              initialized to the login name corresponding to  the  current  login  session.  This
              parameter  is  exported  by  default  but  this  can  be disabled using the typeset
              builtin.

       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;
              subshells  that  reference  RANDOM  will  result  in identical pseudo-random values
              unless the value of RANDOM is referenced or seeded in the parent shell  in  between
              subshell invocations.

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

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

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

       signals
              An array containing the names of the signals.

       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)

       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)'

       USERNAME <S>
              The username corresponding to the real user ID of the shell process.  If  you  have
              sufficient  privileges, you may change the username (and also the user ID and group
              ID) of the shell  by  assigning  to  this  parameter.   Also  (assuming  sufficient
              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
              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  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
                     functions have the context shfunc.  As traps are asynchronous they may  have
                     a different hierarchy from other code.

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

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

              zregexparse-action
                     Code executed as an action by the zregexparse  command  from  the  zsh/zutil
                     module.

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

       ZSH_PATCHLEVEL
              The  revision  string  for  the  version  number  of  the ChangeLog file in the zsh
              distribution.  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_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.

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

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

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

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

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

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

       CORRECT_IGNORE
              If set, is  treated  as  a  pattern  during  spelling  correction.   Any  potential
              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 offered 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  beginning  with  `_'  in  the  current directory would still be
              completed).

       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 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  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 referenced.  If an executable file is found, then it is read and executed in the
              current environment.

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

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

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

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

       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.

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

       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  collation  information
              within ranges in glob brackets and for sorting.

       LC_CTYPE <S>
              This  variable determines the locale category for character handling functions.  If
              the MULTIBYTE option is in effect this variable or LANG should contain a value that
              reflects  the  character  set  in  use,  even if it is a single-byte character set,
              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
              parameter.

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

       MAILCHECK
              The interval in seconds between checks for new mail.

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

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

       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_VERSION'.   (The   `/usr/local/lib'   part   varies   from
              installation  to  installation.)   For  security  reasons,  any  value  set  in the
              environment when the shell is started will be ignored.

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

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

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

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

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

       prompt <S> <Z>
              Same as PS1.

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

       PS1 <S>
              The primary prompt string, printed before  a  command  is  read.   It  undergoes  a
              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
              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 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 first nine  values  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.

       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.

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

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

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

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

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

       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
              correction.  All other prompt escapes are also allowed.

       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 finishes or is suspended. If the command is suspended  and  continued
              later  with  the fg or wait builtins it will see the modes specified by STTY, as if
              it were not suspended.  This (intentionally) does  not  apply  if  the  command  is
              continued  via  `kill  -CONT'.   STTY  is  ignored  if  the  command  is run in the
              background, or if it is in the environment of the shell but not explicitly assigned
              to  in  the  input  line.  This  avoids  running  stty at every external command by
              accidentally exporting it. Also note that STTY should not be used for  window  size
              specifications; these will not be local to the command.

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

       TERMINFO <S>
              A  reference  to  a  compiled  description  of the terminal, 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.

       TIMEFMT
              The  format of process time reports with the time keyword.  The default is `%E real
              %U user  %S system  %P %J'.  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 Kbytes.
              %D     The average amount in (unshared) data/stack space used in Kbytes.
              %K     The total space used (%X+%D) in Kbytes.
              %M     The  maximum memory the process had in use at any time in Kbytes.
              %F     The number of major page faults (page needed to be brought from disk).
              %R     The number of minor page faults.
              %I     The number of input operations.
              %O     The number of output operations.
              %r     The number of socket messages received.
              %s     The number of socket messages sent.
              %k     The number of signals received.
              %w     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.   This
              cause  the  time to be printed in `hh:mm:ss.ttt' format (hours and minutes are only
              printed if they are not zero).

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

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

       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  or  all  of  these
              components may be present in an entry; if a login/logout event matches all of them,
              it is reported.

       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.

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

       ZLE_REMOVE_SUFFIX_CHARS
       ZLE_SPACE_SUFFIX_CHARS
              These parameters are used by the line editor.  In  certain  circumstances  suffixes
              (typically  space  or  slash)  added  by  the  completion  system  will  be removed
              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 include `&' the result is `DIR &'.

              Note  that  certain completions may provide their own suffix removal or replacement
              behaviour which overrides the values described here.   See  the  completion  system
              documentation in zshcompsys(1).