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zshparam (1)

Name

zshparam - zsh parameters

Synopsis

Please see following description for synopsis

Description

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 ...)
              name=([key]=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.

       In  the  third  form,  key  is  an expression that will be evaluated in
       arithmetic context (in its simplest form, an integer)  that  gives  the
       index  of the element to be assigned with value.  In this form any ele-
       ments not explicitly mentioned that come before the  largest  index  to
       which  a  value  is assigned are assigned an empty string.  The indices
       may be in any order.  Note that this syntax is strict: [  and  ]=  must
       not  be  quoted, and key may not consist of the unquoted string ]=, but
       is otherwise treated as a simple string.  The enhanced  forms  of  sub-
       script  expression  that may be used when directly subscripting a vari-
       able name, described in the section Array  Subscripts  below,  are  not
       available.

       The  syntaxes  with  and  without  the  explicit  key may be mixed.  An
       implicit key is deduced by incrementing the index from  the  previously
       assigned  element.   Note  that it is not treated as an error if latter
       assignments in this form overwrite earlier assignments.

       For example, assuming the option KSH_ARRAYS is not set, the following:

              array=(one [3]=three four)

       causes the array variable array to contain four elements one, an  empty
       string, three and four, in that order.

       In the forms where only value is specified, full command line expansion
       is performed.

       In the [key]=value form, both key and value undergo all forms of expan-
       sion  allowed  for  single word shell expansions (this does not include
       filename generation); these are as performed by the parameter expansion
       flag  (e)  as described in zshexpn(1).  Nested parentheses may surround
       value and are included as part of the value, which  is  joined  into  a
       plain  string; this differs from ksh which allows the values themselves
       to be arrays.  A future version of zsh may support that.  To cause  the
       brackets  to  be  interpreted as a character class for filename genera-
       tion, and therefore to treat the resulting list of files as  a  set  of
       values, quote the equal sign using any form of quoting.  Example:

              name=([a-z]'='*)

       To  append to an array without changing the existing values, use one of
       the following:

              name+=(value ...)
              name+=([key]=value ...)

       In the second form key may specify an existing  index  as  well  as  an
       index  off  the end of the old array; any existing value is overwritten
       by value.  Also, it is possible to use [key]+=value to  append  to  the
       existing value at that index.

       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 ...)
              name=([key]=value ...)

       Note  that  only one of the two syntaxes above may be used in any given
       assignment; the forms may not be mixed.  This is  unlike  the  case  of
       numerically indexed arrays.

       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 ...)
              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.  In the  second  form
       it is also possible to use [key]+=value to append to the existing value
       at that key.  Expansion is performed identically to  the  corresponding
       forms for normal arrays, as described above.

       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.   When combined with the i or I
              flag, the effect is to produce the index of the first  character
              of  the  first/last  word  which matches the given pattern; note
              that a failed match in this case always yields 0.

       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  &, put into the background with the bg builtin, or spawned
              with coproc.

       # <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.

       FUNCNEST <S>
              Integer.   If greater than or equal to zero, the maximum nesting
              depth of shell functions.  When it  is  exceeded,  an  error  is
              raised  at  the  point  where a function is called.  The default
              value is determined when the shell is configured, but  is  typi-
              cally  500.  Increasing the value increases the danger of a run-
              away function recursion causing the shell to crash.   Setting  a
              negative value turns off the check.

       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  output  of `git describe --tags --long' for the zsh reposi-
              tory used to build the shell.  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 kilobytes 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
                     kilobytes.
              %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 (e.g., `%*E'); this causes the time to  be  printed  in
              `hh:mm:ss.ttt'  format  (hours  and  minutes are only printed if
              they are not zero).  Alternatively,  `m'  or  `u'  may  be  used
              (e.g.,   `%mE')  to  produce  time  output  in  milliseconds  or
              microseconds, respectively.

       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 associated 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 5.8                        February 14, 2020                   ZSHPARAM(1)