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ZSHPARAM(1)		    General Commands Manual		   ZSHPARAM(1)

NAME
       zshparam	- zsh parameters

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

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

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

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

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

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

	      name=value

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

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

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

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

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.  To append to an array without changing the existing values, use
       the syntax:

	      name+=(value ...)

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

       Ordinary	array parameters may also be explicitly	declared with:

	      typeset -a name

       Associative arrays must be declared before assignment, by using:

	      typeset -A name

       When  name refers to an associative array, the list in an assignment is
       interpreted as 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.
       The append syntax may also be used with an associative array:

	      name+=(key value ...)

       This adds a new key/value pair if the key is not	already	 present,  and
       replaces	the value for the existing key if it is.

       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.

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

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

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

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

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

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

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

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

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

	      name[exp]=value

       In this form of assignment the element or range	specified  by  exp  is
       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, but note that	`<...>'	 can  only  be
       used if the subscript is	inside a double	quoted expression or a parame-
       ter substitution	enclosed in braces  as	otherwise  the	expression  is
       interpreted as a	redirection.

       The flags currently understood are:

       w      If  the  parameter  subscripted is a scalar then this flag makes
	      subscripting work	on words instead of characters.	  The  default
	      word  separator  is  whitespace.	This flag may not be used with
	      the i or I flag.

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

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

       f      If the parameter subscripted is a	scalar then  this  flag	 makes
	      subscripting work	on lines instead of characters,	i.e. with 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.

       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.  On failure, for normal arrays this has  the  effect  of
	      returning	 the  element  corresponding  to  subscript 0; this is
	      empty unless one of the options KSH_ARRAYS or KSH_ZERO_SUBSCRIPT
	      is in effect.

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

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

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

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

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

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

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

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

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

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

       See Parameter Expansion	Flags  (zshexpn(1))  for  additional  ways  to
       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.

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

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

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

       The first difference is that brackets (`[' and `]') must	appear as bal-
       anced  pairs  in	 a  subscript expression unless	they are preceded by a
       backslash (`\').	 Therefore, within a subscript expression (and	unlike
       true  double-quoting) the sequence `\[' becomes `[', and	similarly `\]'
       becomes `]'.  This applies even in cases	where a	backslash is not  nor-
       mally required; for example, the	pattern	`[^[]' (to match any character
       other than an open bracket) should be written `[^\[]' in	a reverse-sub-
       script pattern.	However, note that `\[^\[\]' and even `\[^[]' mean the
       same thing, because backslashes are always stripped  when  they	appear
       before brackets!

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

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

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

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

       It  is  important  to  note that	the quoting rules do not change	when a
       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 parameter `$0' is
       a special case, see the section `Parameters Set By The Shell'.

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

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

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

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

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

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

	      typeset PATH=/new/directory:$PATH

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

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

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

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

       status <S> <Z>
	      Same as ?.

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

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

       CPUTYPE
	      The  machine  type  (microprocessor  class or machine model), as
	      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)'

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

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

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

       ERRNO <S>
	      The value	of errno (see errno(3))	as set by  the	most  recently
	      failed  system  call.   This  value  is  system dependent	and is
	      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)'

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

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

       HOST   The current hostname.

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

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

       MACHTYPE
	      The  machine  type  (microprocessor  class or machine model), as
	      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 value is	available to microsecond accu-
	      racy, although the shell may show	more or	fewer digits depending
	      on  the  use  of typeset.	 See the documentation for the builtin
	      typeset in zshbuiltins(1)	for more details.

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

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

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

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

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

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

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

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

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

       USERNAME	<S>
	      The username corresponding to the	real  user  ID	of  the	 shell
	      process.	 If you	have sufficient	privileges, you	may change the
	      username (and also the user ID and group ID)  of	the  shell  by
	      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_eval_context	<S> <Z>	(ZSH_EVAL_CONTEXT <S>)
	      An array (colon-separated	list) indicating the context of	 shell
	      code that	is being run.  Each time a piece of shell code that is
	      stored within the	shell is  executed  a  string  is  temporarily
	      appended	to the array to	indicate the type of operation that is
	      being performed.	Read in	order the array	gives an indication of
	      the  stack of operations being performed with the	most immediate
	      context last.

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

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

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

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

	      eval   Code executed by the eval builtin.

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

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

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

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

	      globqual
		     Code executed by the e or + glob qualifier.

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

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

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

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

	      sched  Code executed by the sched	builtin.

	      shfunc A shell function.

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

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

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

	      trap   Code  executed  as	 a  trap  defined by the trap builtin.
		     Traps defined as functions	have the context  shfunc.   As
		     traps  are	asynchronous they may have a different hierar-
		     chy from other code.

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

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

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

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

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

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

       ZSH_PATCHLEVEL
	      The revision string for the version number of the	ChangeLog file
	      in  the  zsh distribution.  This is most useful in order to keep
	      track of	versions  of  the  shell  during  development  between
	      releases;	 hence most users should not use it and	should instead
	      rely on $ZSH_VERSION.

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

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

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

       ZSH_VERSION
	      The version number of the	release	of zsh.

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

       In cases	where there are	two parameters with an	upper-	and  lowercase
       form  of	the same name, such as path and	PATH, the lowercase form is an
       array and the uppercase form is a scalar	with the elements of the array
       joined  together	 by colons.  These are similar to tied parameters cre-
       ated via	`typeset -T'.  The normal use for the colon-separated form  is
       for  exporting  to  the	environment, while the array form is easier to
       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.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       prompt <S> <Z>
	      Same as PS1.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       STTY   If  this	parameter is set in a command's	environment, the shell
	      runs the stty command with the value of this parameter as	 argu-
	      ments  in	order to set up	the terminal before executing the com-
	      mand. The	modes apply only to the	command, and are reset when it
	      finishes	or  is suspended. If the command is suspended and con-
	      tinued later with	the fg or wait builtins	it will	see the	 modes
	      specified	 by  STTY,  as if it were not suspended.  This (inten-
	      tionally)	does not apply if the command is continued  via	 `kill
	      -CONT'.	STTY  is  ignored  if  the command is run in the back-
	      ground, or if it is in the environment  of  the  shell  but  not
	      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.

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

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

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

	      %%     A `%'.
	      %U     CPU seconds spent in user mode.
	      %S     CPU seconds spent in kernel mode.
	      %E     Elapsed time in seconds.
	      %P     The CPU percentage, computed as 100*(%U+%S)/%E.
	      %W     Number of times the process was swapped.
	      %X     The average amount	in (shared) text space used  in	 kilo-
		     bytes.
	      %D     The average amount	in (unshared) data/stack space used in
		     kilobytes.
	      %K     The total space used (%X+%D) in kilobytes.
	      %M     The  maximum memory the process had in use	at any time in
		     megabytes.
	      %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'.

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

       watch _S_ _Z_ (WATCH _S_)
	      An  array	 (colon-separated  list)  of  login/logout  events  to
	      report.

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

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

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

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

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

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

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

	      %(x:true-text:false-text)
		     Specifies a ternary expression.  The character  following
		     the  x  is	arbitrary; the same character is used to 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.

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

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

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

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

       ZLE_REMOVE_SUFFIX_CHARS
       ZLE_SPACE_SUFFIX_CHARS
	      These parameters are used	by the line editor.  In	 certain  cir-
	      cumstances suffixes (typically space or slash) added by the com-
	      pletion system will be removed automatically, either because the
	      next editing command was not an insertable character, or because
	      the character was	marked as requiring the	suffix to be removed.

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

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

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

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

		     ZLE_SPACE_SUFFIX_CHARS=$'&|'

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

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

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

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

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

zsh 5.3.1		       December	21, 2016		   ZSHPARAM(1)

NAME | DESCRIPTION | ARRAY PARAMETERS | POSITIONAL PARAMETERS | LOCAL PARAMETERS | PARAMETERS SET BY THE SHELL | PARAMETERS USED BY THE SHELL

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