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 parameters *, @, and argv are arrays containing all the positional parameters; thus argv[n], etc. is equivalent to simply n.

The following parameters are automatically set by the shell:

!

The process id of the last background command invoked.

#

The number of positional parameters in decimal.

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 parameters.

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. Also (assuming sufficient privileges), you may start a single command with a different effective user id by:

(EUID=euid ; command)

ERRNO

The value of errno as set by the most recently 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 exported 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 processed by the getopts command.

OPTIND

The index of the last option argument processed by the getopts command.

OSTYPE

The operating system, as determined at compile 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 generated 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 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.

SHLVL

Incremented by one each time a new shell is started.

signals

An array containing the names of the signals.

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 user 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 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.

cdpath (CDPATH)

An array (colon-separated list) of directories specifying the search path for the cd command.

COLUMNS

The number of columns for this terminal session. 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 automatically. 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 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

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 character signals the start of a quick history substitution (default `^'). The third character is the comment character (default `#').

HISTCHARS

Same as histcharsbP.

HISTFILE

The file to save the history in when an interactive 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 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.

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 starting with LC_.

LC_ALL

This variable overrides the value of the LANG variable and the value of any of the other variables starting with LC_.

LC_COLLATE

This variable determines the locale category for character collation information within ranges in glob brackets 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 session. 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 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 (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 parameter 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 element 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, however, 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 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

This string is output whenever the line editor exits. It usually contains termcap strings to reset the terminal.

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 sequences 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 integer 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 format.

%*

Current time of day in 24-hour format, 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 constructs 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. Truncation 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 displays 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, respectively. 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 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.

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 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.

watch (WATCH)

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

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.

%(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 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 considered part of a word by the line editor.

ZDOTDIR

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