path: root/Doc/Zsh/params.yo

texinode(Parameters)(Options)(Expansion)(Top)
chapter(Parameters)
cindex(parameters)
sect(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
`tt(*)', `tt(@)', `tt(#)', `tt(?)', `tt(-)', `tt($)', or `tt(!)'.
The value may be a em(scalar) (a string),
an integer, an array (indexed numerically), or an em(associative)
array (an unordered set of name-value pairs, indexed by name).
To assign a scalar or integer value to a parameter,
use the tt(typeset) builtin.
findex(typeset, use of)
To assign an array value, use `tt(set -A) var(name) var(value) ...'.
findex(set, use of)
The value of a parameter may also be assigned by writing:

indent(var(name)tt(=)var(value))

If the integer attribute, tt(-i), is set for var(name), the var(value)
is subject to arithmetic evaluation.  See noderef(Array Parameters)
for additional forms of assignment.

In the parameter lists that follow, the mark `<S>' indicates that the
parameter is special.
Special parameters cannot have their type changed, and they stay special even
if unset.  `<Z>' indicates that the parameter does not exist when the shell
initializes in tt(sh) or tt(ksh) emulation mode.
startmenu()
menu(Array Parameters)
menu(Positional Parameters)
menu(Local Parameters)
menu(Parameters Set By The Shell)
menu(Parameters Used By The Shell)
endmenu()
texinode(Array Parameters)(Positional Parameters)()(Parameters)
sect(Array Parameters)
The value of an array parameter may be assigned by writing:

indent(var(name)tt(=LPAR())var(value) ...tt(RPAR()))

If no parameter var(name) exists, an ordinary array parameter is created.
Associative arrays must be declared first, by `tt(typeset -A) var(name)'.
When var(name) refers to an associative array, the parenthesized list is
interpreted as alternating keys and values:

indent(var(name)tt(=LPAR())var(key) var(value) ...tt(RPAR()))

Every var(key) must have a var(value) in this case.  To create an empty
array or associative array, use:

indent(var(name)tt(=LPAR()RPAR()))

Individual elements of an array may be selected using a
subscript.  A subscript of the form `tt([)var(exp)tt(])'
selects the single element var(exp), where var(exp) is
an arithmetic expression which will be subject to arithmetic
expansion as if it were surrounded by `tt($LPAR()LPAR())...tt(RPAR()RPAR())'.
The elements are numbered beginning with 1 unless the
tt(KSH_ARRAYS) option is set when they are numbered from zero.
cindex(subscripts)
pindex(KSH_ARRAYS, use of)

The same subscripting syntax is used for associative arrays,
except that no arithmetic expansion is applied to var(exp).

A subscript of the form `tt([*])' or `tt([@])' evaluates to all
elements of an array; there is no difference between the two
except when they appear within double quotes.
`tt("$foo[*]")' evaluates to `tt("$foo[1] $foo[2] )...tt(")', while
`tt("$foo[@]")' evaluates to `tt("$foo[1]" "$foo[2]")', etc.

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

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

Subscripts may be used inside braces used to delimit a parameter name, thus
`tt(${foo[2]})' is equivalent to `tt($foo[2])'.  If the tt(KSH_ARRAYS)
option is set, the braced form is the only one that will
work, the subscript otherwise not being treated specially.

If a subscript is used on the left side of an assignment the selected
element or range 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.)

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

If the opening bracket or the comma is directly followed by an opening
parentheses the string up to the matching closing one is considered to
be a list of flags. The flags currently understood are:

startitem()
item(tt(w))(
If the parameter subscripted is a scalar than this flag makes
subscripting work on words instead of characters.  The default word
separator is whitespace.
)
item(tt(s:)var(string)tt(:))(
This gives the var(string) that separates words (for use with the
tt(w) flag).
)
item(tt(p))(
Recognize the same escape sequences as the tt(print) builtin in
the string argument of a subsequent `tt(s)' flag.
)
item(tt(f))(
If the parameter subscripted is a scalar than this flag makes
subscripting work on lines instead of characters, i.e. with elements
separated by newlines.  This is a shorthand for `tt(pws:\n:)'.
)
item(tt(r))(
Reverse subscripting:  if this flag is given, the var(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 `tt(w)' flag is given, respectively).  The subscript used is the
number of the matching element, so that pairs of subscripts such as
`tt($foo[(r))var(??)tt(,3])' and `tt($foo[(r))var(??)tt(,(r)f*])'
are possible.  If the parameter is an associative array, only the value part
of each pair is compared to the pattern.
)
item(tt(R))(
Like `tt(r)', but gives the last match.  For associative arrays, gives
all possible matches.
)
item(tt(k))(
If used in a subscript on a parameter that is not an associative
array, this behaves like `tt(r)', but if used on an association, it
makes the keys be interpreted as patterns and returns the first value
whose key matches the var(exp).
)
item(tt(K))(
On an association this is like `tt(k)' but returns all values whose
keys match the var(exp). On other types of parameters this has the
same effect as `tt(R)'.
)
item(tt(i))(
like `tt(r)', but gives the index of the match instead; this may not
be combined with a second argument.  For associative arrays, the key
part of each pair is compared to the pattern, and the first matching
key found is used.
)
item(tt(I))(
like `tt(i)', but gives the index of the last match, or all possible
matching keys in an associative array.
)
item(tt(n:)var(expr)tt(:))(
if combined with `tt(r)', `tt(R)', `tt(i)' or `tt(I)', makes them give
the var(n)th or var(n)th last match (if var(expr) evaluates to
var(n)).  This flag is ignored when the array is associative.
)
item(tt(b:)var(expr)tt(:))(
if combined with `tt(r)', `tt(R)', `tt(i)' or `tt(I)', makes them begin
at the var(n)th or var(n)th last element, word, or character (if var(expr)
evaluates to var(n)).  This flag is ignored when the array is associative.
)
item(tt(e))(
This option has no effect and retained for backward compatibility only.
)
enditem()
texinode(Positional Parameters)(Local Parameters)(Array Parameters)(Parameters)
sect(Positional Parameters)
The positional parameters provide access to the command-line arguments
of a shell function, shell script, or the shell itself; see
noderef(Invocation), and also noderef(Functions).
The parameter var(n), where var(n) is a number,
is the var(n)th positional parameter.
The parameters tt(*), tt(@) and tt(argv) are
arrays containing all the positional parameters;
thus `tt($argv[)var(n)tt(])', etc., is equivalent to simply `tt($)var(n)'.

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

texinode(Local Parameters)(Parameters Set By The Shell)(Positional Parameters)(Parameters)
sect(Local Parameters)
Shell function executions delimit scopes for shell parameters.
(Parameters are dynamically scoped.)  The tt(typeset) builtin, and its
alternative forms tt(declare), tt(integer), tt(local) and tt(readonly)
(but not tt(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 tt(export),
causes it to be created in the em(outer)most scope.

Local parameters disappear when their scope ends.
tt(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 tt(-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:

example(typeset PATH=/new/directory:$PATH)

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

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

texinode(Parameters Set By The Shell)(Parameters Used By The Shell)(Local Parameters)(Parameters)
sect(Parameters Set By The Shell)
The following parameters are automatically set by the shell:

startitem()
vindex(!)
item(tt(!) <S>)(
The process ID of the last background command invoked.
)
vindex(#)
item(tt(#) <S>)(
The number of positional parameters in decimal.
)
vindex(ARGC)
item(tt(ARGC) <S> <Z>)(
Same as tt(#).
)
vindex($)
item(tt($) <S>)(
The process ID of this shell.
)
vindex(-)
item(tt(-) <S>)(
Flags supplied to the shell on invocation or by the tt(set)
or tt(setopt) commands.
)
vindex(*)
item(tt(*) <S>)(
An array containing the positional parameters.
)
vindex(argv)
item(tt(argv) <S> <Z>)(
Same as tt(*).  Assigning to tt(argv) changes the local positional
parameters, but tt(argv) is em(not) itself a local parameter.
Deleting tt(argv) with tt(unset) in any function deletes it everywhere,
although only the innermost positional parameter array is deleted (so
tt(*) and tt(@) in other scopes are not affected).
)
vindex(@)
item(tt(@) <S>)(
Same as tt(argv[@]), even when tt(argv) is not set.
)
vindex(?)
item(tt(?) <S>)(
The exit value returned by the last command.
)
vindex(0)
item(tt(0) <S>)(
The name used to invoke the current shell.  If the tt(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.
)
vindex(status)
item(tt(status) <S> <Z>)(
Same as tt(?).
)
vindex(pipestatus)
item(tt(pipestatus) <S> <Z>)(
An array containing the exit values returned by all commands in the
last pipeline.
)
vindex(_)
item(tt(_) <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.
)
vindex(CPUTYPE)
item(tt(CPUTYPE))(
The machine type (microprocessor class or machine model),
as determined at run time.
)
vindex(EGID)
item(tt(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 `tt(LPAR()EGID=)var(gid)tt(; command+RPAR())'
)
vindex(EUID)
item(tt(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 `tt(LPAR()EUID=)var(uid)tt(; command+RPAR())'
)
vindex(ERRNO)
item(tt(ERRNO) <S>)(
The value of errno (see manref(errno)(3))
as set by the most recently failed system call.
This value is system dependent and is intended for debugging
purposes.
)
vindex(GID)
item(tt(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 `tt(LPAR()GID=)var(gid)tt(; command+RPAR())'
)
vindex(HOST)
item(tt(HOST))(
The current hostname.
)
vindex(LINENO)
item(tt(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 tt(functions) builtin.
)
vindex(LOGNAME)
item(tt(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 tt(typeset) builtin.
)
vindex(MACHTYPE)
item(tt(MACHTYPE))(
The machine type (microprocessor class or machine model),
as determined at compile time.
)
vindex(OLDPWD)
item(tt(OLDPWD))(
The previous working directory.  This is set when the shell initializes
and whenever the directory changes.
)
vindex(OPTARG)
item(tt(OPTARG) <S>)(
The value of the last option argument processed by the tt(getopts)
command.
)
vindex(OPTIND)
item(tt(OPTIND) <S>)(
The index of the last option argument processed by the tt(getopts)
command.
)
vindex(OSTYPE)
item(tt(OSTYPE))(
The operating system, as determined at compile time.
)
vindex(PPID)
item(tt(PPID) <S>)(
The process ID of the parent of the shell.
)
vindex(PWD)
item(tt(PWD))(
The present working directory.  This is set when the shell initializes
and whenever the directory changes.
)
vindex(RANDOM)
item(tt(RANDOM) <S>)(
A 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 tt(RANDOM).
)
vindex(SECONDS)
item(tt(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.
)
vindex(SHLVL)
item(tt(SHLVL) <S>)(
Incremented by one each time a new shell is started.
)
vindex(signals)
item(tt(signals))(
An array containing the names of the signals.
)
vindex(TTY)
item(tt(TTY))(
The name of the tty associated with the shell, if any.
)
vindex(TTYIDLE)
item(tt(TTYIDLE) <S>)(
The idle time of the tty associated with the shell in seconds or -1 if there
is no such tty.
)
vindex(UID)
item(tt(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 `tt(LPAR()UID=)var(uid)tt(; command+RPAR())'
)
vindex(USERNAME)
item(tt(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 `tt(LPAR()USERNAME=)var(username)tt(; command+RPAR())'
)
vindex(VENDOR)
item(tt(VENDOR))(
The vendor, as determined at compile time.
)
vindex(ZSH_NAME)
item(tt(ZSH_NAME))(
Expands to the basename of the command used to invoke this instance
of zsh.
)
vindex(ZSH_VERSION)
item(tt(ZSH_VERSION))(
The version number of this zsh.
)
enditem()
texinode(Parameters Used By The Shell)()(Parameters Set By The Shell)(Parameters)
sect(Parameters Used By The Shell)
The following parameters are used by the shell:

startitem()
vindex(ARGV0)
item(tt(ARGV0))(
If exported, its value is used as the tt(argv[0]) of external commands.
Usually used in constructs like `tt(ARGV0=emacs nethack)'.
)
vindex(BAUD)
item(tt(BAUD))(
The baud rate of the current connection.  Used by the line editor
update mechanism to compensate for a slow terminal by delaying
updates until necessary.  This may be profitably set to a lower value
in some circumstances, e.g.
for slow modems dialing into a communications server which is connected
to a host via a fast link; in this case, this variable
would be set by default to the speed of the fast link, and not
the modem.
This parameter should be set to the baud
rate of the slowest part of the link for best performance. The compensation
mechanism can be turned off by setting the variable to zero.
)
vindex(cdpath)
vindex(CDPATH)
item(tt(cdpath) <S> <Z> (tt(CDPATH) <S>))(
An array (colon-separated list)
of directories specifying the search path for the tt(cd) command.
)
vindex(COLUMNS)
item(tt(COLUMNS) <S>)(
The number of columns for this terminal session.
Used for printing select lists and for the line editor.
)
vindex(DIRSTACKSIZE)
item(tt(DIRSTACKSIZE))(
The maximum size of the directory stack.  If the
stack gets larger than this, it will be truncated automatically.
This is useful with the tt(AUTO_PUSHD) option.
pindex(AUTO_PUSHD, use of)
)
vindex(FCEDIT)
item(tt(FCEDIT))(
The default editor for the tt(fc) builtin.
)
vindex(fignore)
vindex(FIGNORE)
item(tt(fignore) <S> <Z> (tt(FIGNORE) <S>))(
An array (colon separated list)
containing the suffixes of files to be ignored
during filename completion.  However, if the completion generates only files
which would match if this variable would be ignored, than these files are
completed anyway.
)
vindex(fpath)
vindex(FPATH)
item(tt(fpath) <S> <Z> (tt(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 tt(-u) attribute is referenced.  If an executable
file is found, then it is read and executed in the current environment.
)
vindex(histchars)
item(tt(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 `tt(!)').  The second character signals the
start of a quick history substitution (default `tt(^)').  The third
character is the comment character (default `tt(#)').
)
vindex(HISTCHARS)
item(tt(HISTCHARS) <S> <Z>)(
Same as tt(histchars).  (Deprecated.)
)
vindex(HISTFILE)
item(tt(HISTFILE))(
The file to save the history in when an interactive shell exits.
If unset, the history is not saved.
)
vindex(HISTSIZE)
item(tt(HISTSIZE) <S>)(
The maximum number of events stored in the internal history list.
If you use the tt(HIST_EXPIRE_DUPS_FIRST) option, setting this value
larger than the tt(SAVEHIST) size will give you the difference as a
cushion for saving duplicated history events.
)
vindex(HOME)
item(tt(HOME) <S>)(
The default argument for the tt(cd) command.
)
vindex(IFS)
item(tt(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 tt(read) builtin.  Any characters from the set space, tab and
newline that appear in the IFS are called em(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.
)
vindex(KEYTIMEOUT)
item(tt(KEYTIMEOUT))(
The time the shell waits, in hundredths of seconds, for another key to
be pressed when reading bound multi-character sequences.
)
vindex(LANG)
item(tt(LANG) <S>)(
This variable determines the locale category for any category not
specifically selected via a variable starting with `tt(LC_)'.
)
vindex(LC_ALL)
item(tt(LC_ALL) <S>)(
This variable overrides the value of the `tt(LANG)' variable and the value
of any of the other variables starting with `tt(LC_)'.
)
vindex(LC_COLLATE)
item(tt(LC_COLLATE) <S>)(
This variable determines the locale category for character collation
information within ranges in glob brackets and for sorting.
)
vindex(LC_CTYPE)
item(tt(LC_CTYPE) <S>)(
This variable determines the locale category for character handling
functions.
)
vindex(LC_MESSAGES)
item(tt(LC_MESSAGES) <S>)(
This variable determines the language in which messages should be
written.  Note that zsh does not use message catalogs.
)
vindex(LC_NUMERIC)
item(tt(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.
)
vindex(LC_TIME)
item(tt(LC_TIME) <S>)(
This variable determines the locale category for date and time
formatting in prompt escape sequences.
)
vindex(LINES)
item(tt(LINES) <S>)(
The number of lines for this terminal session.
Used for printing select lists and for the line editor.
)
vindex(LISTMAX)
item(tt(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.
)
vindex(LOGCHECK)
item(tt(LOGCHECK))(
The interval in seconds between checks for login/logout activity
using the tt(watch) parameter.
)
vindex(MAIL)
item(tt(MAIL))(
If this parameter is set and tt(mailpath) is not set,
the shell looks for mail in the specified file.
)
vindex(MAILCHECK)
item(tt(MAILCHECK))(
The interval in seconds between checks for new mail.
)
vindex(mailpath)
vindex(MAILPATH)
item(tt(mailpath) <S> <Z> (tt(MAILPATH) <S>))(
An array (colon-separated list) of filenames to check for
new mail.  Each filename can be followed by a `tt(?)' and a
message that will be printed.  The message will undergo
parameter expansion, command substitution and arithmetic
expansion with the variable tt($_) defined as the name
of the file that has changed.  The default message is
`tt(You have new mail)'.  If an element is a directory
instead of a file the shell will recursively check every
file in every subdirectory of the element.
)
vindex(manpath)
vindex(MANPATH)
item(tt(manpath) <S> <Z> (tt(MANPATH) <S> <Z>))(
An array (colon-separated list)
whose value is not used by the shell.  The tt(manpath)
array can be useful, however, since setting it also sets
tt(MANPATH), and vice versa.
)
vindex(module_path)
vindex(MODULE_PATH)
item(tt(module_path) <S> <Z> (tt(MODULE_PATH) <S>))(
An array (colon-separated list)
of directories that tt(zmodload)
searches for dynamically loadable modules.
This is initialized to a standard pathname,
usually `tt(/usr/local/lib/zsh/$ZSH_VERSION)'.
(The `tt(/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.
)
vindex(NULLCMD)
cindex(null command style)
cindex(csh, null command style)
cindex(ksh, null command style)
item(tt(NULLCMD) <S>)(
The command name to assume if a redirection is specified
with no command.  Defaults to tt(cat).  For bf(sh)/bf(ksh)
behavior, change this to tt(:).  For bf(csh)-like
behavior, unset this parameter; the shell will print an
error message if null commands are entered.
)
vindex(path)
vindex(PATH)
item(tt(path) <S> <Z> (tt(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.
)
vindex(POSTEDIT)
item(tt(POSTEDIT) <S>)(
This string is output whenever the line editor exits.
It usually contains termcap strings to reset the terminal.
)
vindex(PROMPT)
xitem(tt(PROMPT) <S> <Z>)
vindex(PROMPT2)
xitem(tt(PROMPT2) <S> <Z>)
vindex(PROMPT3)
xitem(tt(PROMPT3) <S> <Z>)
vindex(PROMPT4)
item(tt(PROMPT4) <S> <Z>)(
Same as tt(PS1), tt(PS2), tt(PS3) and tt(PS4),
respectively.
)
vindex(prompt)
item(tt(prompt) <S> <Z>)(
Same as tt(PS1).
)
vindex(PS1)
item(tt(PS1) <S>)(
The primary prompt string, printed before a command is read.
the default is `tt(%m%# )'.  It undergoes a special form of expansion
before being displayed; see noderef(Prompt Expansion).
)
vindex(PS2)
item(tt(PS2) <S>)(
The secondary prompt, printed when the shell needs more information
to complete a command.
It is expanded in the same way as tt(PS1).
The default is `tt(%_> )', which displays any shell constructs or quotation
marks which are currently being processed.
)
vindex(PS3)
item(tt(PS3) <S>)(
Selection prompt used within a tt(select) loop.
It is expanded in the same way as tt(PS1).
The default is `tt(?# )'.
)
vindex(PS4)
item(tt(PS4) <S>)(
The execution trace prompt.  Default is `tt(PLUS()%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 `tt(PLUS() )'.
)
vindex(psvar)
vindex(PSVAR)
item(tt(psvar) <S> <Z> (tt(PSVAR) <S>))(
An array (colon-separated list) whose first nine values can be used in
tt(PROMPT) strings.  Setting tt(psvar) also sets tt(PSVAR), and
vice versa.
)
vindex(READNULLCMD)
item(tt(READNULLCMD) <S>)(
The command name to assume if a single input redirection
is specified with no command.  Defaults to tt(more).
)
vindex(REPORTTIME)
item(tt(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.
)
vindex(REPLY)
item(tt(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 tt(read) builtin and the
tt(select) complex command may set tt(REPLY), and filename generation both
sets and examines its value when evaluating certain expressions.  Some
modules also employ tt(REPLY) for similar purposes.
)
vindex(reply)
item(tt(reply))(
As tt(REPLY), but for array values rather than strings.
)
vindex(RPROMPT)
xitem(tt(RPROMPT) <S>)
vindex(RPS1)
item(tt(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 tt(SINGLELINEZLE) option is set.
It is expanded in the same way as tt(PS1).
)
vindex(SAVEHIST)
item(tt(SAVEHIST))(
The maximum number of history events to save in the history file.
)
vindex(SPROMPT)
item(tt(SPROMPT) <S>)(
The prompt used for spelling correction.  The sequence
`tt(%R)' expands to the string which presumably needs spelling
correction, and `tt(%r)' expands to the proposed correction.
All other prompt escapes are also allowed.
)
vindex(STTY)
item(tt(STTY))(
If this parameter is set in a command's environment, the shell runs the
tt(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 tt(fg) or tt(wait) builtins it will
see the modes specified by tt(STTY), as if it were not suspended.  This
(intentionally) does not apply if the command is continued via `tt(kill
-CONT)'.  tt(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 tt(STTY) should not be used for
window size specifications; these will not be local to the command.
)
vindex(TERM)
item(tt(TERM) <S>)(
The type of terminal in use.  This is used when looking up termcap sequences.
)
vindex(TIMEFMT)
item(tt(TIMEFMT))(
The format of process time reports with the tt(time) keyword.
The default is `tt(%E real  %U user  %S system  %P %J)'.
Recognizes the following escape sequences:

startsitem()
sitem(tt(%%))(A `tt(%)'.)
sitem(tt(%U))(CPU seconds spent in user mode.)
sitem(tt(%S))(CPU seconds spent in kernel mode.)
sitem(tt(%E))(Elapsed time in seconds.)
sitem(tt(%P))(The CPU percentage, computed as (tt(%U)PLUS()tt(%S))/tt(%E).)
sitem(tt(%J))(The name of this job.)
endsitem()

A star may be inserted between the percent sign and flags printing time.
This cause the time to be printed in
`var(hh)tt(:)var(mm)tt(:)var(ss)tt(.)var(ttt)'
format (hours and minutes are only printed if they are not zero).
)
vindex(TMOUT)
item(tt(TMOUT))(
If this parameter is nonzero, the shell will receive an tt(ALRM)
signal if a command is not entered within the specified number of
seconds after issuing a prompt. If there is a trap on tt(SIGALRM), it
will be executed and a new alarm is scheduled using the value of the
tt(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
tt(TMOUT) parameter, zsh terminates.  Otherwise a new alarm is
scheduled to tt(TMOUT) seconds after the last keypress.
)
vindex(TMPPREFIX)
item(tt(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 `tt(/tmp/zsh)'.
)
vindex(watch)
vindex(WATCH)
item(tt(watch) <S> <Z> (tt(WATCH) <S>))(
An array (colon-separated list) of login/logout events to report.
If it contains the single word `tt(all)', then all login/logout events
are reported.  If it contains the single word `tt(notme)', then all
events are reported as with `tt(all)' except tt($USERNAME).
An entry in this list may consist of a username,
an `tt(@)' followed by a remote hostname,
and a `tt(%)' 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 reported.
)
vindex(WATCHFMT)
item(tt(WATCHFMT))(
The format of login/logout reports if the tt(watch) parameter is set.
Default is `tt(%n has %a %l from %m)'.
Recognizes the following escape sequences:

startitem()
item(tt(%n))(
The name of the user that logged in/out.
)
item(tt(%a))(
The observed action, i.e. "logged on" or "logged off".
)
item(tt(%l))(
The line (tty) the user is logged in on.
)
item(tt(%M))(
The full hostname of the remote host.
)
item(tt(%m))(
The hostname up to the first `tt(.)'.  If only the
IP address is available or the utmp field contains
the name of an X-windows display, the whole name is printed.

em(NOTE:)
The `tt(%m)' and `tt(%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.
)
item(tt(%S) LPAR()tt(%s)RPAR())(
Start (stop) standout mode.
)
item(tt(%U) LPAR()tt(%u)RPAR())(
Start (stop) underline mode.
)
item(tt(%B) LPAR()tt(%b)RPAR())(
Start (stop) boldface mode.
)
xitem(tt(%t))
item(tt(%@))(
The time, in 12-hour, am/pm format.
)
item(tt(%T))(
The time, in 24-hour format.
)
item(tt(%w))(
The date in `var(day)tt(-)var(dd)' format.
)
item(tt(%W))(
The date in `var(mm)tt(/)var(dd)tt(/)var(yy)' format.
)
item(tt(%D))(
The date in `var(yy)tt(-)var(mm)tt(-)var(dd)' format.
)
item(tt(%LPAR())var(x)tt(:)var(true-text)tt(:)var(false-text)tt(RPAR()))(
Specifies a ternary expression.
The character following the var(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 var(x) may be any one of `tt(l)', `tt(n)', `tt(m)'
or `tt(M)', which indicate a `true' result if the corresponding
escape sequence would return a non-empty value; or it may be `tt(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 var(true-text)
is formatted according to the rules above and printed,
and the var(false-text) is skipped.
If `false', the var(true-text) is skipped and the var(false-text)
is formatted and printed.
Either or both of the branches may be empty, but
both separators must be present in any case.
)
enditem()
)
vindex(WORDCHARS)
item(tt(WORDCHARS) <S>)(
A list of non-alphanumeric characters considered part of a word
by the line editor.
)
vindex(ZBEEP)
item(tt(ZBEEP))(
If set, this gives a string of characters, which can use all the same codes
as the tt(bindkey) command as described in
ifzman(the zsh/zle module entry in zmanref(zshmodules))\
ifnzman(noderef(The zsh/zle Module))\
, that will be output to the terminal
instead of beeping.  This may have a visible instead of an audible effect;
for example, the string `tt(\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 `tt(\e[?5l\e[?5h)' instead).  This takes
precedence over the tt(NOBEEP) option.
)
vindex(ZDOTDIR)
item(tt(ZDOTDIR))(
The directory to search for shell startup files (.zshrc, etc),
if not tt($HOME).
)
enditem()