ZSHPARAM(1)                                                        ZSHPARAM(1)


       zshparam - zsh parameters


       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


       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  Parame-
       ters’ 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 param-
       eter  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.


       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

   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
       expressions otherwise are not treated as subscripts.

       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’.

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


       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  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 sin-
       gle-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 currently understood are:

       w      If  the  parameter  subscripted is a scalar than this flag makes
              subscripting work on words instead of characters.   The  default
              word separator is whitespace.

              This  gives  the string that separates words (for use with the w

       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 than 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
              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.

       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

       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.

       I      Like ‘i’, but gives the index of the last match, or all possible
              matching keys in an associative array.

       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.  This
              flag does not work on the left side of an assignment to an asso-
              ciative  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’.

              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.

              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.

       e      This flag has no effect and for ordinary arrays is retained  for
              backward  compatibility only.  For associative arrays, this flag
              can be used to force * or @ to be interpreted as  a  single  key
              rather than as a reference to all values.  This flag may be used
              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  asso-
       ciative 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 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
       balanced braces, and subscript flags are introduced by balanced  paren-

       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
       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 associa-
       tive array key, the ‘e’ flag must be used:

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

       A last detail must be considered  when  reverse  subscripting  is  per-
       formed.   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  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,
       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

       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

       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
       parameter, but ‘$2[3,5]’ is the entire  second  parameter  concatenated
       with the filename generation pattern ‘[3,5]’.


       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  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.


       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.


       The following parameters are automatically set by the shell:

       ! <S>  The process ID of the last background command invoked.

       # <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.

       - <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 value returned by the last command.

       0 <S>  The  name  used  to  invoke  the  current  shell.   If the FUNC-
              TION_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 values 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.

              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 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)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)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  privi-
              leges),  you  may start a single command under a different group
              ID by ‘(GID=gid; command)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.

              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 machine type (microprocessor class  or  machine  model),  as
              determined 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

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

       OSTYPE The operating system, as determined at compile time.

       PPID <S>
              The process ID of the parent of the 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
              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 parame-
              ter  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 float-
              ing point number.  The precision is six decimal places, although
              not all places may be useful.

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

              An array containing the names of the signals.

              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)

       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 pro-
              cess.  If you have sufficient privileges,  you  may  change  the
              username  (and  also  the  user ID and group ID) of the shell by
              assigning to this parameter.  Also (assuming  sufficient  privi-
              leges),  you  may start a single command under a different user-
              name (and user ID and group  ID)  by  ‘(USERNAME=username;  com-
              mand)VENDOR The vendor, as determined at compile time.

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

              The version number of this zsh.


       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 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
       manipulate within the shell.  Note that unsetting either  of  the  pair
       will  unset the other; they retain their special properties when recre-
       ated, 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  baud rate of the current connection.  Used by the line edi-
              tor update mechanism to compensate for a slow terminal by delay-
              ing  updates  until  necessary.  This may be profitably set to a
              lower value in some circumstances, e.g.  for slow modems dialing
              into  a communications server which is connected to a host via a
              fast link; in this case, this variable would be set  by  default
              to  the speed of the fast link, and not the modem.  This parame-
              ter should be set to the baud rate of the slowest  part  of  the
              link  for  best  performance.  The compensation mechanism can be
              turned off by setting the variable to zero.

       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.

              The maximum size of the directory  stack.   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.

       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 ‘#’).

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

              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  dif-
              ference as a cushion for saving duplicated history events.

       HOME <S>
              The default argument for the cd command.

       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.

              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-

       LC_CTYPE <S>
              This variable determines the locale category for character  han-
              dling functions.

       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.

              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.

              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.

              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_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.

       PS1 <S>
              The primary prompt string, printed before  a  command  is  read.
              the  default  is ‘%m%# ’.  It undergoes a special form of expan-
              sion before being displayed; see the section ‘Prompt Expansion’.

       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 first nine values can be
              used in PROMPT strings.  Setting psvar also sets PSVAR, and vice

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

              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.

       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  SINGLELINEZLE  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  SINGLELINEZLE  option  is  set.  It is
              expanded in the same way as PS2.

              The maximum number of history events  to  save  in  the  history

       SPROMPT <S>
              The  prompt  used  for  spelling  correction.  The sequence ‘%R’
              expands to the string which presumably  needs  spelling  correc-
              tion,  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 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
              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  specifi-
              cations; these will not be local to the command.

       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.

              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:

              %%     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 (%U+%S)/%E.
              %J     The name of this job.

              A star may be inserted between the percent sign and flags print-
              ing  time.   This cause the time to be printed in ‘hh:mm:ss.ttt’
              format (hours and minutes are  only  printed  if  they  are  not

       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

              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

       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

              The format of login/logout reports if  the  watch  parameter  is
              set.  Default is ‘%n has %a %l from %m’.  Recognizes the follow-
              ing 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.  Other-
                     wise they are treated as ordinary strings.

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

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

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

              %@     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.

                     Specifies a ternary expression.  The character  following
                     the  x  is arbitrary; the same character is used to sepa-
                     rate the text for the "true" result  from  that  for  the
                     "false"  result.  Both the separator and the right paren-
                     thesis may be escaped with a backslash.  Ternary  expres-
                     sions 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.

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

zsh 4.2.1                       August 13, 2004                    ZSHPARAM(1)

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