zshparam(1)

NAME

zshparam - zsh parameters

DESCRIPTIONS

A parameter has a name, a value, and a number of at

tributes. A name may be any sequence of alphanumeric characters

and _'s, or the single characters *, @, #, ?, -, $, or !. The

value may be either a scalar (a string), an integer, or an array.

To assign a scalar or integer value to a parameter, use the

typeset builtin. To assign an array value, use set -A name value

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

name=value ...

If the integer attribute, -i, is set for name, the value

is subject to arithmetic evaluation.

The value of an array parameter may be assigned by writ

ing:

name=(value ...) ...

Individual elements of an array may be selected using a

subscript. A subscript of the form [exp] selects the single ele

ment 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 when they are numbered from zero.

A subscript of the form [*] or [@] evaluates to all ele

ments of an array; there is no difference between the two except

when they appear within double quotes. "$foo[*]" evaluates to

"$foo[1] $foo[2] ...", while "$foo[@]" evaluates to "$foo[1]"

"$foo[2]", etc.

A subscript of the form [exp1,exp2] selects all elements

in the range exp1 to exp2, inclusive. 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 ele

ment 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.

Subscripts may be used inside braces used to delimit a pa

rameter name, thus ${foo[2]} is equivalent to $foo[2]. If the

KSH_ARRAYS

will work, the subscript otherwise not being treated specially.
If a subscript is used on the left side of an assignment

the selected range is replaced by the expression on the right

side.

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 un

derstood are:

e this option has no effect and retained for

backward compatibility only

w if the parameter subscripted is a scalar

than this flag makes subscription work on a per-word basis in

stead of characters

s:string:

this gives the string that separates words

(for use with the w flag)

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

than this flag makes subscription work on a per-line basis in

stead of characters. This is a shorthand for pws:n:.

r if this flag is given the exp is taken as a

pattern and the result is the first matching array element, sub

string 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); note

that this is like giving a number: $foo[(r)??,3] and

$foo[(r)??,(r)f*] work

R like r, but gives the last match

i like r, but gives the index of the match in

stead; this may not be combined with a second argument

I like i, but gives the index of the last

match

n:expr:

if combined with r, R, , or I, makes them

give the n'th or n'th last match (if expr evaluates to n)

Positional Parameters

Positional parameters are set by the shell on invocation,

by the set builtin, or by direct assignment. The parameter n,

where n is a number, is the nth positional parameter. The param

eters *, @, and argv are arrays containing all the positional pa

rameters; thus argv[n], etc. is equivalent to simply n.

Special Parameters

The following parameters are automatically set by the

shell:

! The process id of the last background com

mand invoked.
# The number of positional parameters in deci

mal.
ARGC Same as #. It has no special meaning in

sh/ksh compatibility mode.
$ The process id of this shell.
- Flags supplied to the shell on invocation or

by the set or setopt commands.
* An array containing the positional parame

ters.
argv Same as *. It has no special meaning in

sh/ksh compatibility mode.
@ Same as argv[@] but it can be used in sh/ksh

compatibility mode.
? The exit value returned by the last command.
status Same as ?. It has no special meaning in

sh/ksh compatibility mode.
_ 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.
EGID 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=egid ; command)

EUID 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. Al

so (assuming sufficient privileges), you may start a single com

mand with a different effective user id by:

(EUID=euid ; command)

ERRNO The value of errno as set by the most re

cently failed system call. This value is system dependent and is

intended for debugging purposes.
GID The 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)

HOST The current hostname.
LINENO The line number of the current line within

the current script being executed.
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 ex

ported by default but this can be disabled using the typeset

builtin.

MACHTYPE

The machine type (microprocessor class or

machine model), as determined at compile time.

OLDPWD The previous working directory.
OPTARG The value of the last option argument pro

cessed by the getopts command.
OPTIND The index of the last option argument pro

cessed by the getopts command.
OSTYPE The operating system, as determined at com

pile time.
PPID The process id of the parent of the shell.
PWD The present working directory.
RANDOM A random integer from 0 to 32767, newly gen

erated each time this parameter is referenced. The random number

generator can be seeded by assigning a numeric value to RANDOM.
SECONDS

The number of seconds since shell invoca

tion. If this parameter is assigned a value, then the value re

turned upon reference will be the value that was assigned plus

the number of seconds since the assignment.

SHLVL Incremented by one each time a new shell is

started.
signals

An array containing the names of the sig

nals.

TTY The name of the tty associated with the

shell, if any.
TTYIDLE

The idle time of the tty associated with the

shell in seconds or -1 if there is no such tty.

UID The 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 us

er id by:

(UID=uid ; command)

USERNAME

The username corresponding to the 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.
ZSHNAME

Expands to the basename of the command used

to invoke this instance of zsh.

ZSH_NAME

Expands to the basename of the command used

to invoke this instance of zsh.

ZSH_VERSION

The version number of this zsh.

The following parameters are used by the shell:

ARGV0 If exported, it's value is used as argv[0]

of external commands. Usually used in constructs like

'ARGV0=emacs nethack'.
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 prof

itably 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.
cdpath (CDPATH)

An array (colon-separated list) of directo

ries specifying the search path for the cd command.

COLUMNS

The number of columns for this terminal ses

sion. Used for printing select lists and for the line editor.

DIRSTACKSIZE

The maximum size of the directory stack. If

the stack gets larger than this, it will be truncated automati

cally. This is useful with the AUTO_PUSHD option.

FCEDIT The default editor for the fc builtin.
fignore (FIGNORE)

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.

fpath (FPATH)

An array (colon separated list) of directo

ries specifying the search path for function definitions. This

path is searched when a function with the -u attribute is refer

enced. If an executable file is found, then it is read and exe

cuted in the current environment.

histchars

Three characters used by the shell's history

and lexical analysis mechanism. The first character signals the

start of a history substitution (default `!'). The second char

acter signals the start of a quick history substitution (default

`^'). The third character is the comment character (default

`#').

HISTCHARS

Same as histchars.

HISTFILE

The file to save the history in when an in

teractive shell exits. If unset, the history is not saved.

HISTSIZE

The maximum size of the history list.

HOME The default argument for the cd command.
IFS Internal field separators, normally space,

tab, and newline, that are used to separate words which result

from command or parameter substitution 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 to

gether with any adjacent IFS white space character delimit a

field. If an IFS white space character appears twice consecu

tively in the IFS, this character is treated as if it were not an

IFS white space character.
KEYTIMEOUT

The time the shell waits, in hundredths of

seconds, for another key to be pressed when reading bound multi

character sequences.

LANG This variable determines the locale category

for any category not specifically selected via a variable start

ing with LC_.
LC_ALL This variable overrides the value of the

LANG variable and the value of any of the other variables start

ing with LC_.
LC_COLLATE

This variable determines the locale category

for character collation information within ranges in glob brack

ets and for sorting.

LC_CTYPE

This variable determines the locale category

for character handling functions.

LC_MESSAGES

This variable determines the language in

which messages should be written. Note that zsh does not use

message catalogs.

LC_TIME

This variable determines the locale category

for date and time formatting in promt escape sequences.

LINES The number of lines for this terminal ses

sion. Used for printing select lists and for the line editor.
LISTMAX

In the line editor, the number of filenames

to list without asking first. If set to zero, the shell asks on

ly 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 (MAILPATH)

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 parame

ter expansion, command substitution and arithmetic substitution

with the variable $_ defined as the name of the file that has

changed. The default message is "You have new mail." If an ele

ment is a directory instead of a file the shell will recursively

check every file in every subdirectory of the element.

manpath (MANPATH)

An array (colon-separated list) whose value

is not used by the shell. The manpath array can be useful, how

ever, since setting it also sets MANPATH, and vice versa.

NULLCMD

The command name to assume if a redirection

is specified with no command. Defaults to cat. For sh/ksh-like

behavior, change this to :. For csh-like behavior, unset this

parameter; the shell will print an error message if null commands

are entered.

path (PATH)

An array (colon-separated list) of directo

ries to search for commands. When this parameter is set, each

directory is scanned and all files found are put in a hash table.

POSTEDIT

This string is output whenever the line edi

tor exits. It usually contains termcap strings to reset the ter

minal.

PS1 The primary prompt string, printed before a

command is read; the default is "%m%# ". If the escape sequence

takes an optional integer, it should appear between the '%' and

the next character of the sequence. The following escape se

quences are recognized:

%% A `%'.
%) A `)'.
%d
%/ Present working directory ($PWD).
%~ $PWD. If it has a named directory

as its prefix, that part is replaced by a ~ followed by the name

of the directory. If it starts with $HOME, that part is replaced

by a ~.
%c
%.
%C Trailing component of $PWD. An in

teger may follow the '%' to get more than one component. Unless

%C is used, tilde expansion is performed first.
%h
%! Current history event number
%L The current value of $SHLVL.
%M The full machine hostname.
%m The hostname up to the first '.'.

An integer may follow the '%' to specify how many components of

the hostname are desired.

%S (%s)

Start (stop) standout mode.

%U (%u)

Start (stop) underline mode.

%B (%b)

Start (stop) boldface mode.

%t
%@ Current time of day, in 12-hour,

am/pm format.
%T Current time of day, in 24-hour for

mat.
%* Current time of day in 24-hour for

mat, with seconds.
%n $USERNAME.
%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}

string is formatted using the

strftime function. See strftime(3) for more details, if your

system has it.

%l The line (tty) the user is logged in

on.
%? The return code of the last command

executed just before the prompt.
%_ The status of the parser, i.e. the

shell constructs (like `if' and `for') that have been started on

the command line. If given an integer number that many strings

will be printed; zero or no integer means print as many as there

are.
%E Clears to end of line.
%# A '#' if the shell is running as

root, a '%' if not. Equivalent to %(#.#.%%).
%v The value of the first element of

the $psvar array parameter. Following the '%' with an integer

gives that element of the array.

%{...%}

Include a string as a literal escape

sequence. The string within the braces should not change the

cursor position.

%(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. This separator may not appear in the true-text,

except as part of a % sequence. A `)' may appear in the

false-text as `%)'. True-text and false-text may both contain

arbitrarily-nested escape sequences, including further ternary

expressions. The left parenthesis may be preceded or followed by

a positive integer n, which defaults to zero. The test character

x may be any of the following:

c
.
~ True if the current path,

with prefix replacement, has at least n elements.
/
C True if the current absolute

path has at least n elements.
t True if the time in minutes

is equal to n.
T True if the time in hours is

equal to n.
d True if the day of the month

is equal to n.
D True if the month is equal to

n (January = 0).
w True if the day of the week

is equal to n (Sunday = 0).
? True if the exit status of

the last command was n.
# True if the effective uid of

the current process is n.
g True if the effective gid of

the current process is n.
L True if the SHLVL parameter

is at least n.
S True if the SECONDS parameter

is at least n.
v True if the array psvar has

at least n elements.
_ True if at least n shell con

structs were started.

%<string<
%>string>
%[xstring]

Specifies truncation behaviour. The

third form is equivalent to `%xstringx', i.e. x may be `<' or

`>'. The numeric argument, which in the third form may appear

immediately after the `[', specifies the maximum permitted length

of the various strings that can be displayed in the prompt. If

this integer is zero, or missing, truncation is disabled. Trun

cation is initially disabled. The forms with `<' truncate at the

left of the string, and the forms with `>' truncate at the right

of the string. For example, if the current directory is

`/home/pike', the prompt `%8<..<%/' will expand to `..e/pike'.

The string will be displayed in place of the truncated portion of

any string. In this string, the terminating character (`<', `>'

or `]'), or in fact any character, may be quoted by a preceding

`´. % sequences are not treated specially. If the string is

longer than the specified truncation length, it will appear in

full, completely replacing the truncated string.

PS2 The secondary prompt, printed when the shell

needs more information to complete a command. Recognizes the

same escape sequences as $PS1. The default is "%_> ", which dis

plays any shell constructs or quotation marks which are currently

being processed.
PS3 Selection prompt used within a select loop.

Recognizes the same escape sequences as $PS1. The default is "?#

".
PS4 The execution trace prompt. Default is "+

".
PROMPT
PROMPT2
PROMPT3
PROMPT4

Same as PS1, PS2, PS3, and PS4, respective

ly. These parameters do not have any special meaning in sh/ksh

compatibility mode.

psvar (PSVAR)

An array (colon-separated list) whose first

nine values can be used in PROMPT strings. Setting psvar also

sets PSVAR, and vice versa.

prompt Same as PS1. It has no special meaning in

sh/ksh compatibility mode.
READNULLCMD

The command name to assume if a single input

redirection is specified with no command. Defaults to more.

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.

RPROMPT
RPS1 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 SINGLELINEZLE option is set.

Recognizes the same escape sequences as PROMPT.
SAVEHIST

The maximum number of history events to save

in the history file.

SPROMPT

The prompt used for spelling correction.

The sequence %R expands to the string which presumably needs

spelling correction, and %r expands to the proposed correction.

All other PROMPT escapes are also allowed.

STTY If this parameter is set in a command's en

vironment, the shell runs the stty command with the value of this

parameter as arguments in order to set up the terminal before ex

ecuting the command. The modes apply only to the command, and are

reset when it finishes or is suspended. If the command is sus

pended 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. Al

so note that STTY should not be used for window size specifica

tions; these will not be local to the command.
TIMEFMT

The format of process time reports with the

time keyword. The default is "%E real %U user %S system %P

%J". Recognizes the following escape sequences:

%% 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

(%U+%S)/%E.
%J The name of this job.

A star may be inserted between the percent sign and

flags printing time. This cause the time to be printed in

hh:mm:ss.ttt format (hours and minutes are only printed if they

are not zero).
TMOUT If this parameter is nonzero, the shell will

receive an ALRM signal if a command is not entered within the

specified number of seconds after issuing a prompt. If there is a

trap on SIGALRM, it will be executed and a new alarm is scheduled

using the value of the TMOUT parametr after exececuting 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 key

press.
TMPPREFIX

A pathname prefix which the shell will use

for all temporary files. Note that this should include an ini

tial part for the file name as well as any directory names. The

default is /tmp/zsh.

watch (WATCH)

An array (colon-separated list) of login/lo

gout 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 user

name, an `@' followed by a remote hostname, and a `%' followed by

a line (tty). Any or all of these components may be present in

an entry; if a login/logout event matches all of them, it is re

ported.

WATCHFMT

The format of login/logout reports if the

watch parameter is set. Default is "%n has %a %l from %m." Rec

ognizes 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. Oth

erwise 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.

%(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 corre

sponding escape sequence would return a non-empty value; or 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

A list of nonalphanumeric characters consid

ered part of a word by the line editor.

ZDOTDIR

The directory to search for shell startup

files (.zshrc, etc), if not $HOME.

zsh version 3.0 June 26, 1996

ZSHPARAM(1)