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ZSHPARAM(1)							   ZSHPARAM(1)

NAME
       zshparam - zsh parameters

DESCRIPTION
       A  parameter  has  a name, a value, and a number of attributes.	A name
       may be any sequence of alphanumeric characters and underscores, or  the
       single  characters `*', `@', `#', `?', `-', `$', or `!'.	 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  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.

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 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:

	      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  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 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.

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

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

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

       r      Reverse subscripting: if this flag is given, the exp is taken as
	      a	 pattern  and  the result is the first matching array element,
	      substring or word (if the parameter is an	 array,	 if  it	 is  a
	      scalar,  or if it is a scalar and the `w' flag is given, respec-
	      tively).	The subscript used is the number of the matching  ele-
	      ment,  so	 that  pairs of subscripts such as `$foo[(r)??,3]' and
	      `$foo[(r)??,(r)f*]' are possible if  the	parameter  is  not  an
	      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.

	      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).  It is therefore  necessary
	      to  quote pattern characters for an exact string match.  Given a
	      string in $key, and assuming the EXTENDED_GLOB  option  is  set,
	      the  following  is  sufficient  to  match an element of an array
	      $array containing exactly the value of $key:

		     key2=${key//(#m)[\][()\\*?#<>~^]/\\$MATCH}
		     print ${array[(R)$key2]}

       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
	      arrays.

	      Note  that  this	flag  can give odd results on failure.	For an
	      ordinary array the item substituted  is  that  corresponding  to
	      subscript 0.  If the option KSH_ARRAYS is not in effect, this is
	      the same as the element corresponding to subscript  1,  although
	      the  form	 ${array[(I)pattern]}  will evaluate to 0 for a failed
	      match.  If the option KSH_ARRAYS is in effect, the subscript  is
	      still  0 for a failed match; this cannot be distinguished from a
	      successful match without testing ${array[0]}  against  the  pat-
	      tern.

       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.

	      See `r' for discussion of subscripts of failed matches.

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

	      See `R' for discussion of subscripts of failed matches.

       k      If used in a subscript on an associative array, this flag causes
	      the  keys	 to  be interpreted as patterns, and returns the value
	      for the first key found where exp is matched by the  key.	  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'.

       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 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-
       thesis.

       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
	      aa[(e)*]=star
	      print $aa[(e)*]

       A  last	detail	must  be  considered when reverse subscripting is per-
       formed.	Parameters appearing in the  subscript	expression  are	 first
       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
       value.

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

       One final note, not directly related to subscripting: the numeric names
       of positional parameters (described below) are parsed specially, so for
       example	`$2foo'	 is  equivalent	 to `${2}foo'.	Therefore, to use sub-
       script syntax to extract a substring from a positional  parameter,  the
       expansion must be surrounded by braces; for example, `${2[3,5]}' evalu-
       ates to the third through fifth characters  of  the  second  positional
       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 posi-
       tional parameter to be changed.	This also creates (with empty  values)
       any of the positions from 1 to n that do not already have values.  Note
       that, because the positional parameters form an array, an array assign-
       ment  of	 the  form  `n=(value  ...)' is allowed, and has the effect of
       shifting all the values at positions greater than n by  as  many	 posi-
       tions as necessary to accommodate the new values.

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

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

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

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

	      typeset PATH=/new/directory:$PATH

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

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

PARAMETERS SET BY THE SHELL
       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 ${#} to resolve ambiguities.  In  par-
	      ticular,	the  sequence  `$#-...' 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.   Note  that  this	indicates  the
	      original	shell  started	by  invoking zsh; all processes forked
	      from the shells without executing a new program,	such  as  sub-
	      shells 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	 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 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 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)'

       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 func-
	      tions builtin.

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

       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 ini-
	      tializes and whenever the directory changes.

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

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

       OSTYPE The operating system, as determined at compile time.

       PPID <S>
	      The process ID of the parent of the shell.  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 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.

       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 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
	      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 privi-
	      leges), you may start a single command under a  different	 user-
	      name  (and  user	ID  and group ID) by `(USERNAME=username; com-
	      mand)'

       VENDOR The vendor, as determined at compile time.

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

       ZSH_VERSION
	      The version number of this 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  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 rate in bits per second at which data reaches the  terminal.
	      The line editor will use this value in order to compensate for a
	      slow terminal by delaying updates to the	display	 until	neces-
	      sary.   If  the parameter is unset or the value is zero the com-
	      pensation mechanism is turned off.  The parameter is not set  by
	      default.

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

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

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

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

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

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

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

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

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

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

       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.	 This is not set auto-
	      matically by the shell in sh, ksh or csh emulation,  but	it  is
	      typically	 present  in the environment anyway, and if it becomes
	      set it has its usual special behaviour.

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

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

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

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

       LC_COLLATE <S>
	      This  variable determines the locale category for character col-
	      lation information within ranges in glob brackets and for	 sort-
	      ing.

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

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

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

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

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

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

       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_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
	      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 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.

       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 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.

       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 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
	      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.	Other-
	      wise a new alarm is scheduled to TMOUT seconds  after  the  last
	      keypress.

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

       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 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.

	      %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 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 termi-
	      nal instead of beeping.  This may have a visible instead	of  an
	      audible  effect;	for  example,  the  string `\e[?5h\e[?5l' on a
	      vt100 or xterm will have the effect of flashing reverse video on
	      and  off	(if  you usually use reverse video, you should use the
	      string `\e[?5l\e[?5h' instead).  This takes precedence over  the
	      NOBEEP option.

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

zsh 4.3.4			April 19, 2006			   ZSHPARAM(1)
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