Provided by: zsh_4.3.17-1ubuntu1_i386 bug


       zshparam - zsh parameters


       A  parameter  has  a name, a value, and a number of attributes.  A name
       may be any sequence of alphanumeric characters and underscores, or  the
       single  characters `*', `@', `#', `?', `-', `$', or `!'.  The value may
       be a scalar (a string), an integer, an array (indexed numerically),  or
       an  associative array (an unordered set of name-value pairs, indexed by
       name).  To declare the type of a parameter, or to assign  a  scalar  or
       integer value to a parameter, use the typeset builtin.

       The  value  of  a  scalar  or integer parameter may also be assigned by


       If the integer attribute, -i, is set for name, the value is subject  to
       arithmetic  evaluation.   Furthermore,  by  replacing  `=' with `+=', a
       parameter can  be  added  or  appended  to.   See  the  section  `Array
       Parameters' for additional forms of assignment.

       To  refer to the value of a parameter, write `$name' or `${name}'.  See
       Parameter Expansion in zshexpn(1) for complete details.

       In the parameter lists that follow, the mark `<S>' indicates  that  the
       parameter  is  special.   Special  parameters  cannot  have  their type
       changed or their readonly  attribute  turned  off,  and  if  a  special
       parameter  is  unset, then later recreated, the special properties will
       be retained.  `<Z>' indicates that the parameter does  not  exist  when
       the shell initializes in sh or ksh emulation mode.


       To assign an array value, write one of:

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

       If  no  parameter  name exists, an ordinary array parameter is created.
       If the parameter name exists and is a scalar, it is replaced by  a  new
       array.  Ordinary array parameters may also be explicitly declared with:

              typeset -a name

       Associative arrays must be declared before assignment, by using:

              typeset -A name

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

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

       Every key must have a value in this case.  Note that  this  assigns  to
       the entire array, deleting any elements that do not appear in the list.

       To create an empty array (including associative arrays), use one of:

              set -A name

   Array Subscripts
       Individual  elements  of an array may be selected using a subscript.  A
       subscript of the form `[exp]' selects the single element exp, where exp
       is  an  arithmetic  expression  which  will  be  subject  to arithmetic
       expansion 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
       zshexpn(1) for complete details.  When an array parameter is referenced
       as `$name' (with no subscript) it evaluates to `$name[*]',  unless  the
       KSH_ARRAYS  option  is  set  in which case it evaluates to `${name[0]}'
       (for an associative array, this means the value of the key  `0',  which
       may not exist even if there are values for other keys).

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

       Subscripting may also be performed on non-array values, in  which  case
       the  subscripts  specify  a substring to be extracted.  For example, if
       FOO is set to `foobar', then `echo $FOO[2,5]' prints `ooba'.

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


       In this form of assignment the element or range  specified  by  exp  is
       replaced  by  the  expression  on the right side.  An array (but not an
       associative array) may be created by assignment to a range or  element.
       Arrays  do  not nest, so assigning a parenthesized list of values to an
       element or range changes the number of elements in the array,  shifting
       the  other  elements  to  accommodate  the  new  values.   (This is not
       supported 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-element  assignments may be made with typeset.  Note that quotes
       are  necessary  in  this  case  to  prevent  the  brackets  from  being
       interpreted  as  filename  generation operators.  The noglob precommand
       modifier could be used instead.

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

              unset "name[exp]"

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

       The flags s, n and b take an argument; the delimiter is shown below  as
       `:',  but  any  character,  or  the  matching  pairs  `(...)', `{...}',
       `[...]', or `<...>', may be used.

       The flags currently understood are:

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

              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
              elements  separated  by  newlines.   This  is  a  shorthand  for

       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,
              respectively).  The subscript used is the number of the matching
              element, 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  ordinary  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

                     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'.

              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.

              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
              substitution 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.

       It is possible to  avoid  the  use  of  subscripts  in  assignments  to
       associative array elements by using the syntax:

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

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

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

       The  first  difference  is  that  brackets (`[' and `]') must appear as
       balanced 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
       normally required; for  example,  the  pattern  `[^[]'  (to  match  any
       character  other  than  an open bracket) should be written `[^\[]' in a
       reverse-subscript 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
       backslash, 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
       double-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
       associative array key, the `e' flag must be used:

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

       A  last  detail  must  be  considered  when  reverse  subscripting   is
       performed.   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
       backslashes  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
       ordinary  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
       subscript  syntax  to  extract a substring from a positional parameter,
       the expansion must be surrounded by braces;  for  example,  `${2[3,5]}'
       evaluates   to  the  third  through  fifth  characters  of  the  second
       positional parameter, but `$2[3,5]'  is  the  entire  second  parameter
       concatenated with the filename generation pattern `[3,5]'.


       The  positional parameters provide access to the command-line arguments
       of a shell function, shell script, or the shell itself; see the section
       `Invocation', and also the section `Functions'.  The parameter n, where
       n is a number, is the nth positional parameter.  The  parameters  *,  @
       and  argv  are  arrays  containing  all the positional parameters; thus
       `$argv[n]', etc., is equivalent to simply `$n'.

       Positional parameters may be changed after the shell or function starts
       by  using the set builtin, by assigning to the argv array, or by direct
       assignment of  the  form  `n=value'  where  n  is  the  number  of  the
       positional  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 assignment of the form `n=(value ...)' is allowed,  and  has  the
       effect  of  shifting  all  the values at positions greater than n by as
       many positions as necessary to accommodate the new values.


       Shell  function  executions  delimit  scopes  for   shell   parameters.
       (Parameters  are  dynamically  scoped.)   The  typeset builtin, and its
       alternative  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
       parameter  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
       parameters were never exported has been removed.


       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  ${#}  to  resolve  ambiguities.   In
              particular, the sequence `$#-...' 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
              subshells started by (...), substitute the same value.

       - <S>  Flags  supplied  to  the  shell  on  invocation or by the set or
              setopt commands.

       * <S>  An array containing the positional parameters.

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

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

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

       0 <S>  The  name  used  to  invoke   the   current   shell.    If   the
              FUNCTION_ARGZERO option is set, this is set temporarily within a
              shell function to the name of the function, and within a sourced
              script to the name of the script.

       status <S> <Z>
              Same as ?.

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

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

              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
              sufficient privileges, you may change the effective group ID  of
              the   shell  process  by  assigning  to  this  parameter.   Also
              (assuming sufficient privileges), you may start a single command
              with a different effective group ID by `(EGID=gid; command)'

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

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

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

              The  current  history  line  number  in an interactive shell, in
              other words the line number for the command that caused $HISTCMD
              to be read.

       HOST   The current hostname.

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

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

              The  machine  type  (microprocessor  class or machine model), as
              determined at compile time.

       OLDPWD The previous working directory.  This  is  set  when  the  shell
              initializes and whenever the directory changes.

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

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

       OSTYPE The operating system, as determined at compile time.

       PPID <S>
              The process ID of the parent of the shell.  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
              initializes 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
              parameter 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  floating point number.  The value is available to microsecond
              accuracy, 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.

              An array containing the names of the signals.

              In an always block, indicates whether the preceding list of code
              caused  an  error.   The  value  is  1  to  indicate an error, 0
              otherwise.  It may be reset, clearing the error condition.   See
              Complex Commands in zshmisc(1)

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

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

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

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

       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.

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

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

              eval   Code executed by the eval builtin.

                     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
                     example by the source builtin.

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

                     Code executed by the e or + glob qualifier.

                     Code executed to order files by the o glob qualifier.

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

                     Code  read  directly  from a file to define an autoloaded

                     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

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

                     The highest execution level of a  script  or  interactive

              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
                     hierarchy from other code.

              zpty   Code executed by  the  zpty  builtin  from  the  zsh/zpty

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

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

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

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

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

              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)'
              output 1, while `( (print $ZSH_SUBSHELL) )' outputs 2.

              The version number of the release of zsh.


       The following parameters are used by the shell.

       In  cases  where  there are two parameters with an upper- and lowercase
       form of the same name, such as path and PATH, the lowercase form is  an
       array and the uppercase form is a scalar with the elements of the array
       joined together by  colons.   These  are  similar  to  tied  parameters
       created  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
       recreated, and recreating one of the pair will recreate the other.

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

       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
              necessary.  If the parameter is unset or the value is  zero  the
              compensation  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.

              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).

              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 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
              completion 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
              executable file is found, then it is read and  executed  in  the
              current environment.

       histchars <S>
              Three  characters  used  by  the  shell's  history  and  lexical
              analysis mechanism.  The first character signals the start of  a
              history  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.)

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

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

       HOME <S>
              The  default  argument  for  the  cd  command.   This is not set
              automatically 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.

              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
              annoyingly  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.

              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
              collation  information  within  ranges  in glob brackets and for

       LC_CTYPE <S>
              This variable  determines  the  locale  category  for  character
              handling  functions.   If the MULTIBYTE option is in effect this
              variable or LANG  should  contain  a  value  that  reflects  the
              character 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

       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
              printing select lists and for the line editor.

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

              The interval in seconds between checks for login/logout activity
              using the watch parameter.

       MAIL   If this parameter is set and mailpath  is  not  set,  the  shell
              looks for mail in the specified file.

              The interval in seconds between checks for new mail.

       mailpath <S> <Z> (MAILPATH <S>)
              An  array  (colon-separated  list) of filenames to check for new
              mail.  Each filename can be followed by a `?' and a message that
              will  be printed.  The message will undergo parameter expansion,
              command substitution and arithmetic expansion with the  variable
              $_  defined  as  the  name  of  the  file that has changed.  The
              default message is `You have new mail'.   If  an  element  is  a
              directory  instead  of  a  file the shell will recursively check
              every file in every subdirectory of the element.

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

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

              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
              information  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

       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
              displays the name of the current shell structure  and  the  line
              number within it.  In sh or ksh emulation, the default is `+ '.

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

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

              If  nonnegative,  commands  whose  combined  user   and   system
              execution  times  (measured  in  seconds)  are greater than this
              value have timing statistics printed for them.

       REPLY  This parameter is reserved by convention to pass  string  values
              between  shell  scripts and shell builtins in situations where a
              function call or redirection are impossible or undesirable.  The
              read  builtin  and the select complex command may set REPLY, and
              filename generation  both  sets  and  examines  its  value  when
              evaluating  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.

              The maximum number of history events  to  save  in  the  history

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

       STTY   If this parameter is set in a command's environment,  the  shell
              runs  the  stty  command  with  the  value  of this parameter as
              arguments in order to set up the terminal before  executing  the
              command. The modes apply only to the command, and are reset when
              it finishes or is suspended. If the  command  is  suspended  and
              continued  later  with  the  fg or wait builtins it will see the
              modes specified by STTY, as if  it  were  not  suspended.   This
              (intentionally)  does  not apply if the command is continued via
              `kill -CONT'.  STTY is ignored if the  command  is  run  in  the
              background,  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
              specifications; these will not be local to the command.

       TERM <S>
              The  type  of  terminal  in  use.   This is used when looking up
              termcap  sequences.   An  assignment  to  TERM  causes  zsh   to
              re-initialize  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 a compiled description of the terminal,  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 workaround `TERM=$TERM' unnecessary.

              The  format  of process time reports with the time keyword.  The
              default is `%E real  %U user  %S system  %P %J'.  Recognizes the
              following escape sequences, although not all may be available on
              all systems, and some that are available may not be useful:

              %%     A `%'.
              %U     CPU seconds spent in user mode.
              %S     CPU seconds spent in kernel mode.
              %E     Elapsed time in seconds.
              %P     The CPU percentage, computed as (100*%U+%S)/%E.
              %W     Number of times the process was swapped.
              %X     The average amount in (shared) text space used in Kbytes.
              %D     The average amount in (unshared) data/stack space used in
              %K     The total space used (%X+%D) in Kbytes.
              %M     The  maximum memory the process had in use at any time in
              %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
              printing  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.
              Otherwise  a  new  alarm is scheduled to TMOUT seconds after the
              last keypress.

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

       watch <S> <Z> (WATCH <S>)
              An  array  (colon-separated  list)  of  login/logout  events  to
              report.   If  it  contains  the  single  word  `all',  then  all
              login/logout  events  are  reported.   If it contains the single
              word `notme', then all events are reported as with `all'  except
              $USERNAME.   An entry in this list may consist of a username, an
              `@' followed by a remote hostname, and a `%' followed by a  line
              (tty).   Any  or  all  of  these components may be present in an
              entry; if a login/logout  event  matches  all  of  them,  it  is

              The  format  of  login/logout  reports if the watch parameter is
              set.  Default is  `%n  has  %a  %l  from  %m'.   Recognizes  the
              following 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.
                     Otherwise they are treated as ordinary strings.

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

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

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

              %@     The time, in 12-hour, am/pm format.

              %T     The time, in 24-hour format.

              %w     The date in `day-dd' format.

              %W     The date in `mm/dd/yy' format.

              %D     The date in `yy-mm-dd' format.

                     Specifies  a ternary expression.  The character following
                     the x  is  arbitrary;  the  same  character  is  used  to
                     separate the text for the "true" result from that for the
                     "false"  result.   Both  the  separator  and  the   right
                     parenthesis  may  be  escaped  with a backslash.  Ternary
                     expressions may be nested.

                     The test character x may be any one of `l', `n',  `m'  or
                     `M',  which indicate a `true' result if the corresponding
                     escape sequence would return a non-empty value; or it may
                     be  `a',  which  indicates a `true' result if the watched
                     user has logged in, or `false'  if  he  has  logged  out.
                     Other  characters evaluate to neither true nor false; the
                     entire expression is omitted in this case.

                     If the result is `true', then the true-text is  formatted
                     according  to  the  rules  above  and  printed,  and  the
                     false-text is skipped.   If  `false',  the  true-text  is
                     skipped  and  the  false-text  is  formatted and printed.
                     Either or both of the branches may  be  empty,  but  both
                     separators must be present in any case.

       WORDCHARS <S>
              A  list of non-alphanumeric characters considered part of a word
              by the line editor.

       ZBEEP  If set, this gives a string of characters, which can use all the
              same  codes  as  the bindkey command as described in the zsh/zle
              module entry in  zshmodules(1),  that  will  be  output  to  the
              terminal instead of beeping.  This may have a visible instead of
              an audible effect; for example, the string `\e[?5h\e[?5l'  on  a
              vt100 or xterm will have the effect of flashing reverse video on
              and off (if you usually use reverse video, you  should  use  the
              string  `\e[?5l\e[?5h' instead).  This takes precedence over the
              NOBEEP option.

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

              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.

              These parameters are  used  by  the  line  editor.   In  certain
              circumstances  suffixes  (typically space or slash) added by the
              completion 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

              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:


              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_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
              removal or replacement  behaviour  which  overrides  the  values
              described  here.   See  the  completion  system documentation in