zshparam

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
       referenced.  The value type may be a scalar (a string, an integer, or a
       floating point number), an array (indexed numerically), or an
       associative 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
       parameter 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
       parameter.  For example, assigning a number to a variable in arithmetic
       evaluation 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
       elements 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
       subscript expression that may be used when directly subscripting a
       variable 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
       expansion 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
       generation, 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
       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'.  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
       character is referenced (not the range of characters covered by the
       match).

       Note that in substring operations the second subscript is handled
       differently 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
       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, but note that `<...>' can only be
       used if the subscript is inside a double quoted expression or a
       parameter 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
              elements 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,
              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 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
              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.

       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
       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
              aa[(e)*]=star
              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]'.

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
       equivalent 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
       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.

LOCAL PARAMETERS
       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.

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 ${#} to resolve ambiguities.  In
              particular, the sequence `$#-...' 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, 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
              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)'

              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
              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)'

              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
              typically 500.  Increasing the value increases the danger of a
              runaway 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
              privileges), 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
              number.

       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.

       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
              initializes 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
              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.

       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
              otherwise.  It may be reset, clearing the error condition.  See
              Complex 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
              propagated.

       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
              privileges), you may start a single command under a different
              username (and user ID and group ID) by `(USERNAME=username;
              command)'

       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
                     example 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
                     practice.

              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
                     hierarchy from other code.

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

              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
              repository 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)'
              output 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
       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
              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
              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.

       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
              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.)

       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
              HISTORY_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
              difference 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
              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.

       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
              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.

              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
              collation information within ranges in glob brackets and for
              sorting.

       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
              (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
              printing 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
              pattern matches.  See the subsection Globbing flags in the
              documentation 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_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.

       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
              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
              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
              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 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
              triggers.  This feature requires the getrusage() system call,
              commonly supported by modern Unix-like systems.

       REPORTTIME
              If nonnegative, commands whose combined user and system
              execution 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 completion; 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
              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.

       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
              correction, and `%r' expands to the proposed correction.  All
              other prompt escapes are also allowed.

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

       STTY   If this parameter is set in a command's environment, the shell
              runs the stty command with the value of this parameter as
              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 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
              workaround `TERM=$TERM' unnecessary.

       TERMINFO_DIRS <S>
              A colon-seprarated list of terminfo databases, used by the
              `terminfo' library when the system has it; see terminfo(5). This
              variable is only used by certain terminal libraries, in
              particular ncurses; see terminfo(5) to check support on your
              system.  If set, this causes the shell to reinitialise the
              terminal, making 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
              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
                     kilobytes.
              %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
              printing 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.
              Otherwise 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
              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.

              %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
                     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.

       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
              characters such as tabs and newlines can be inserted instead of
              invoking 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
              disable 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
              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
              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_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
              zshcompsys(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)