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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 re-
       tained.

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

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

	      name=value

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

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

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

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

ARRAY PARAMETERS
       To assign an array value, write one of:

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

       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 as-
       signment,  newlines and semicolons are treated the same as white	space,
       separating individual values.  Any consecutive sequence of such charac-
       ters has	the same effect.

       Ordinary	array parameters may also be explicitly	declared with:

	      typeset -a name

       Associative arrays must be declared before assignment, by using:

	      typeset -A name

       When  name refers to an associative array, the list in an assignment is
       interpreted as alternating keys and values:

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

       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  ex-
       pressions otherwise are not treated as subscripts.

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

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

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

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

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

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

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

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

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

	      name[exp]=value

       In this form of assignment the element or range specified by exp	is re-
       placed by the expression	on the right side.  An array (but not an asso-
       ciative array) may be created by	assignment to a	range or element.  Ar-
       rays do not nest, so assigning a	parenthesized list of values to	an el-
       ement or	range changes the number of elements in	 the  array,  shifting
       the  other  elements  to	accommodate the	new values.  (This is not sup-
       ported for associative arrays.)

       This syntax also	works as an argument to	the typeset command:

	      typeset "name[exp]"=value

       The value may not be a parenthesized list in this case; only single-el-
       ement  assignments may be made with typeset.  Note that quotes are nec-
       essary in this case to prevent the brackets from	being  interpreted  as
       filename	generation operators.  The noglob precommand modifier could be
       used instead.

       To delete an element of an ordinary array, assign `()' to that element.
       To delete an element of an associative array, use the unset command:

	      unset "name[exp]"

   Subscript Flags
       If  the	opening	bracket, or the	comma in a range, in any subscript ex-
       pression	is directly followed by	an opening parenthesis,	the string  up
       to  the matching	closing	one is considered to be	a list of flags, as in
       `name[(flags)exp]'.

       The flags s, n and b take an argument; the delimiter is shown below  as
       `:',  but  any  character,  or  the  matching  pairs  `(...)', `{...}',
       `[...]',	or `<...>', may	be used, but note that	`<...>'	 can  only  be
       used if the subscript is	inside a double	quoted expression or a parame-
       ter substitution	enclosed in braces as otherwise	the expression is  in-
       terpreted as a redirection.

       The flags currently understood are:

       w      If  the  parameter  subscripted is a scalar then this flag makes
	      subscripting work	on words instead of characters.	  The  default
	      word  separator  is  whitespace.	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  as-
	      sociative	array.	If the parameter is an associative array, only
	      the value	part of	each pair is compared to the pattern, and  the
	      result is	that value.

	      If  a  search  through an	ordinary array failed, the search sets
	      the subscript to one past	the end	of the array, and hence	 ${ar-
	      ray[(r)pattern]}	will  substitute  the  empty string.  Thus the
	      success of a search can be tested	by using the (i) flag, for ex-
	      ample (assuming the option KSH_ARRAYS is not in effect):

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

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

       R      Like  `r',  but  gives  the last match.  For associative arrays,
	      gives all	possible matches. May be used for assigning  to	 ordi-
	      nary  array  elements,  but not for assigning to associative ar-
	      rays.  On	failure, for normal arrays this	has the	effect of  re-
	      turning  the element corresponding to subscript 0; this is empty
	      unless one of the	options	KSH_ARRAYS or KSH_ZERO_SUBSCRIPT is in
	      effect.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       It is important to note that the	quoting	rules do not change when a pa-
       rameter expansion with a	subscript is nested inside  another  subscript
       expression.  That is, it	is not necessary to use	additional backslashes
       within the inner	subscript expression; they are removed only once, from
       the  innermost  subscript  outwards.  Parameters	are also expanded from
       the innermost subscript first, as each expansion	is encountered left to
       right in	the outer expression.

       A  further complication arises from a way in which subscript parsing is
       not different from double quote parsing.	 As  in	 true  double-quoting,
       the  sequences `\*', and	`\@' remain as two characters when they	appear
       in a subscript expression.  To use a literal `*'	or `@' as an  associa-
       tive array key, the `e' flag must be used:

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

       A  last	detail	must  be  considered when reverse subscripting is per-
       formed.	Parameters appearing in	the subscript expression are first ex-
       panded  and  then  the complete expression is interpreted as a pattern.
       This has	two effects: first, parameters behave as if GLOB_SUBST were on
       (and  it	 cannot	 be  turned  off); second, backslashes are interpreted
       twice, once when	parsing	the array subscript and	again when parsing the
       pattern.	  In  a	 reverse  subscript,  it's necessary to	use four back-
       slashes to cause	a single backslash to match literally in the  pattern.
       For complex patterns, it	is often easiest to assign the desired pattern
       to a parameter and then refer to	that parameter in the  subscript,  be-
       cause  then the backslashes, brackets, parentheses, etc., are seen only
       when the	complete expression is converted to a pattern.	To  match  the
       value of	a parameter literally in a reverse subscript, rather than as a
       pattern,	use `${(q)name}' (see zshexpn(1)) to quote the expanded	value.

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

       One final note, not directly related to subscripting: the numeric names
       of positional parameters	(described below) are parsed specially,	so for
       example `$2foo' is equivalent to	`${2}foo'.   Therefore,	 to  use  sub-
       script  syntax  to extract a substring from a positional	parameter, the
       expansion must be surrounded by braces; for example, `${2[3,5]}'	evalu-
       ates to the third through fifth characters of the second	positional pa-
       rameter,	but `$2[3,5]' is the entire second parameter concatenated with
       the filename generation pattern `[3,5]'.

POSITIONAL PARAMETERS
       The  positional parameters provide access to the	command-line arguments
       of a shell function, shell script, or the shell itself; see the section
       `Invocation', and also the section `Functions'.	The parameter n, where
       n is a number, is the nth positional parameter.	The parameter `$0'  is
       a special case, see the section `Parameters Set By The Shell'.

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

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

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

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

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

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

	      typeset PATH=/new/directory:$PATH

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

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

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

       The 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 se-
	      topt commands.

       * <S>  An array containing the positional parameters.

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

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

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

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

       status <S> <Z>
	      Same as ?.

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

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

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

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

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

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

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

       ERRNO <S>
	      The  value  of  errno (see errno(3)) as set by the most recently
	      failed system call.  This	value is system	dependent and  is  in-
	      tended  for  debugging  purposes.	  It  is  also useful with the
	      zsh/system module	which allows the number	to be  turned  into  a
	      name or message.

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

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

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

       HOST   The current hostname.

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

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

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

       OLDPWD The previous working directory.  This is set when	the shell ini-
	      tializes and whenever the	directory changes.

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

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

       OSTYPE The operating system, as determined at compile time.

       PPID <S>
	      The process ID of	the parent of the shell.  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 re-
	      sult  in identical pseudo-random values unless the value of RAN-
	      DOM is referenced	or seeded in the parent	shell in between  sub-
	      shell invocations.

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

	      Unlike other special parameters, the type	of the SECONDS parame-
	      ter  can be changed using	the typeset command.  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 el-
	      ement  has  index	1, the signals are offset by 1 from the	signal
	      number used by the operating system.  For	 example,  on  typical
	      Unix-like	 systems HUP is	signal number 1, but is	referred to as
	      $signals[2].  This is because of EXIT at position	1 in  the  ar-
	      ray, which is used internally by zsh but is not known to the op-
	      erating system.

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

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

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

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

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

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

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

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

       VENDOR The vendor, as determined	at compile time.

       zsh_eval_context	<S> <Z>	(ZSH_EVAL_CONTEXT <S>)
	      An  array	(colon-separated list) indicating the context of shell
	      code that	is being run.  Each time a piece of shell code that is
	      stored  within the shell is executed a string is temporarily ap-
	      pended to	the array to indicate the type of  operation  that  is
	      being performed.	Read in	order the array	gives an indication of
	      the stack	of operations being performed with the most  immediate
	      context last.

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

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

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

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

	      eval   Code executed by the eval builtin.

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

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

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

	      filecode
		     Lines  of code being read from a .zwc file	instead	of di-
		     rectly from the source file.

	      globqual
		     Code executed by the e or + glob qualifier.

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

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

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

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

	      sched  Code executed by the sched	builtin.

	      shfunc A shell function.

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

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

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

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

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

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

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

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

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

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

       ZSH_PATCHLEVEL
	      The 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 re-
	      leases; hence most users should not use it  and  should  instead
	      rely on $ZSH_VERSION.

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

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

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

       ZSH_VERSION
	      The version number of the	release	of zsh.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	      Compare  the HIST_NO_STORE option	or the zshaddhistory hook, ei-
	      ther of which would prevent such commands	from  being  added  to
	      the  interactive history at all.	If you wish to use HISTORY_IG-
	      NORE to stop history being added in the first place, you can de-
	      fine the following hook:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

       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  de-
	      fault message is `You have new mail'.  If	an element is a	direc-
	      tory instead of a	file the shell will  recursively  check	 every
	      file in every subdirectory of the	element.

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

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

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

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

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

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

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

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

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

       prompt <S> <Z>
	      Same as PS1.

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

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

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

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

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

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

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

       REPORTMEMORY
	      If  nonnegative,	commands  whose	 maximum  resident  set	  size
	      (roughly	speaking,  main	 memory	usage) in 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 ex-
	      panded in	the same way as	PS1.

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

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

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

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

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

       STTY   If this parameter	is set in a command's environment,  the	 shell
	      runs  the	stty command with the value of this parameter as argu-
	      ments in order to	set up the terminal before executing the  com-
	      mand. The	modes apply only to the	command, and are reset when it
	      finishes or is suspended.	If the command is suspended  and  con-
	      tinued  later with the fg	or wait	builtins it will see the modes
	      specified	by STTY, as if it were not  suspended.	 This  (inten-
	      tionally)	 does  not apply if the	command	is continued via `kill
	      -CONT'.  STTY is ignored if the command  is  run	in  the	 back-
	      ground,  or if it	is in the environment of the shell but not ex-
	      plicitly assigned	to in the input	line. This avoids running stty
	      at  every	 external  command  by accidentally exporting it. Also
	      note that	STTY should not	be used	 for  window  size  specifica-
	      tions; these will	not be local to	the command.

       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 in-
	      terpreted	as a file extension.  The default is not to append any
	      suffix,  thus this parameter should be assigned only when	needed
	      and then unset again.

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

	      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 as-
	      signment to watch	so that	it does	not immediately	 perform  file
	      generation);  the	 setting  of  the  EXTENDED_GLOB option	is re-
	      spected.	Any or all of these components may be  present	in  an
	      entry;  if  a  login/logout event	matches	all of them, it	is re-
	      ported.

	      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.  Ei-
		     ther or both of the branches may be empty,	but both sepa-
		     rators 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_RE-
	      MOVE_SLASH is in effect and the directory	DIR has	just been com-
	      pleted,  with an appended	/, following which the user types `&'.
	      The default result is `DIR&'.  With ZLE_REMOVE_SUFFIX_CHARS  set
	      but   without   including	 `&'  the  result  is  `DIR/&'.	  With
	      ZLE_SPACE_SUFFIX_CHARS set to include `&'	the result is `DIR &'.

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

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

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

zsh 5.3.1		       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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