zshparam
ZSHPARAM(1) 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 ‘*’, ‘@’, ‘#’, ‘?’, ‘-’, ‘$’, or ‘!’. The value may
be a scalar (a string), an integer, an array (indexed numerically), or
an associative array (an unordered set of name-value pairs, indexed by
name). To declare the type of a parameter, or to assign a scalar or
integer value to a parameter, use the typeset builtin.
The value of a scalar or integer parameter may also be assigned by
writing:
name=value
If the integer attribute, -i, is set for name, the value is subject to
arithmetic evaluation. Furthermore, by replacing ‘=’ with ‘+=’, a
parameter can be added or appended to. See the section ‘Array Parame-
ters’ for additional forms of assignment.
To refer to the value of a parameter, write ‘$name’ or ‘${name}’. See
Parameter Expansion in zshexpn(1) for complete details.
In the parameter lists that follow, the mark ‘<S>’ indicates that the
parameter is special. Special parameters cannot have their type
changed or their readonly attribute turned off, and if a special
parameter is unset, then later recreated, the special properties will
be retained. ‘<Z>’ indicates that the parameter does not exist when
the shell initializes in sh or ksh emulation mode.
ARRAY PARAMETERS
To assign an array value, write one of:
set -A name value ...
name=(value ...)
If no parameter name exists, an ordinary array parameter is created.
If the parameter name exists and is a scalar, it is replaced by a new
array. Ordinary array parameters may also be explicitly declared
with:
typeset -a name
Associative arrays must be declared before assignment, by using:
typeset -A name
When name refers to an associative array, the list in an assignment is
interpreted as alternating keys and values:
set -A name key value ...
name=(key value ...)
Every key must have a value in this case. Note that this assigns to
the entire array, deleting any elements that do not appear in the
list.
To create an empty array (including associative arrays), use one of:
set -A name
name=()
Array Subscripts
Individual elements of an array may be selected using a subscript. A
subscript of the form ‘[exp]’ selects the single element exp, where
exp is an arithmetic expression which will be subject to arithmetic
expansion as if it were surrounded by ‘$((...))’. 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.
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 refer-
enced as ‘$name’ (with no subscript) it evaluates to ‘$name[*]’,
unless the KSH_ARRAYS option is set in which case it evaluates to
‘${name[0]}’ (for an associative array, this means the value of the
key ‘0’, which may not exist even if there are values for other keys).
A subscript of the form ‘[exp1,exp2]’ selects all elements in the
range exp1 to exp2, inclusive. (Associative arrays are unordered, and
so do not support ranges.) If one of the subscripts evaluates to a
negative number, say -n, then the nth element from the end of the
array is used. Thus ‘$foo[-3]’ is the third element from the end of
the array foo, and ‘$foo[1,-1]’ is the same as ‘$foo[*]’.
Subscripting may also be performed on non-array values, in which case
the subscripts specify a substring to be extracted. For example, if
FOO is set to ‘foobar’, then ‘echo $FOO[2,5]’ prints ‘ooba’.
Array Element Assignment
A subscript may be used on the left side of an assignment like so:
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 sup-
ported 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 sin-
gle-element assignments may be made with typeset. Note that quotes
are necessary in this case to prevent the brackets from being inter-
preted as filename generation operators. The noglob precommand modi-
fier could be used instead.
To delete an element of an ordinary array, assign ‘()’ to that ele-
ment. 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 currently understood are:
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.
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
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 ele-
ment, 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 match-
ing element, so that pairs of subscripts such as
‘$foo[(r)??,3]’ and ‘$foo[(r)??,(r)f*]’ are possible. 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.
Reverse subscripts may be used for assigning to ordinary array
elements, but not for assigning to associative arrays.
R Like ‘r’, but gives the last match. For associative arrays,
gives all possible matches.
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.
I Like ‘i’, but gives the index of the last match, or all possi-
ble matching keys in an associative array.
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.
This flag does not work on the left side of an assignment to an
associative array element. If used on another type of parame-
ter, 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.
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.
e This flag has no effect and for ordinary arrays is retained for
backward compatibility only. For associative arrays, this flag
can be used to force * or @ to be interpreted as a single key
rather than as a reference to all values. This flag may be
used on the left side of an assignment.
See Parameter Expansion Flags (zshexpn(1)) for additional ways to
manipulate the results of array subscripting.
Subscript Parsing
This discussion applies mainly to associative array key strings and to
patterns used for reverse subscripting (the ‘r’, ‘R’, ‘i’, etc.
flags), but it may also affect parameter substitutions that appear as
part of an arithmetic expression in an ordinary subscript.
It is possible to avoid the use of subscripts in assignments to asso-
ciative array elements by using the syntax:
aa+=(’key with "*strange*" characters’ ’value string’)
This adds a new key/value pair if the key is not already present, and
replaces the value for the existing key if it is.
The basic rule to remember when writing a subscript expression is that
all text between the opening ‘[’ and the closing ‘]’ is interpreted as
if it were in double quotes (see zshmisc(1)). However, unlike double
quotes which normally cannot nest, subscript expressions may appear
inside double-quoted strings or inside other subscript expressions (or
both!), so the rules have two important differences.
The first difference is that brackets (‘[’ and ‘]’) must appear as
balanced pairs in a subscript expression unless they are preceded by a
backslash (‘\’). Therefore, within a subscript expression (and unlike
true double-quoting) the sequence ‘\[’ becomes ‘[’, and similarly ‘\]’
becomes ‘]’. This applies even in cases where a backslash is not nor-
mally required; for example, the pattern ‘[^[]’ (to match any charac-
ter 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 back-
slash, and backslashes that protect parentheses or braces are removed
during parsing. This is because parameter expansions may be sur-
rounded balanced braces, and subscript flags are introduced by bal-
anced parenthesis.
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 con-
tains 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 sub-
script 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 associa-
tive array key, the ‘e’ flag must be used:
typeset -A aa
aa[(e)*]=star
print $aa[(e)*]
A last detail must be considered when reverse subscripting is per-
formed. Parameters appearing in the subscript expression are first
expanded and then the complete expression is interpreted as a pattern.
This has two effects: first, parameters behave as if GLOB_SUBST were
on (and it cannot be turned off); second, backslashes are interpreted
twice, once when parsing the array subscript and again when parsing
the pattern. In a reverse subscript, it’s necessary to use four back-
slashes to cause a single backslash to match literally in the pattern.
For complex patterns, it is often easiest to assign the desired pat-
tern to a parameter and then refer to that parameter in the subscript,
because then the backslashes, brackets, parentheses, etc., are seen
only when the complete expression is converted to a pattern. To match
the value of a parameter literally in a reverse subscript, rather than
as a pattern, use ‘${(q)name}’ (see zshexpn(1)) to quote the expanded
value.
Note that the ‘k’ and ‘K’ flags are reverse subscripting for an ordi-
nary array, but are not reverse subscripting for an associative array!
(For an associative array, the keys in the array itself are inter-
preted 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 posi-
tional parameter, but ‘$2[3,5]’ is the entire second parameter con-
catenated with the filename generation pattern ‘[3,5]’.
POSITIONAL PARAMETERS
The positional parameters provide access to the command-line arguments
of a shell function, shell script, or the shell itself; see the sec-
tion ‘Invocation’, and also the section ‘Functions’. The parameter n,
where n is a number, is the nth positional parameter. The parameters
*, @ and argv are arrays containing all the positional parameters;
thus ‘$argv[n]’, etc., is equivalent to simply ‘$n’.
Positional parameters may be changed after the shell or function
starts by using the set builtin, by assigning to the argv array, or by
direct assignment of the form ‘n=value’ where n is the number of the
positional parameter to be changed. This also creates (with empty
values) any of the positions from 1 to n that do not already have val-
ues. Note that, because the positional parameters form an array, an
array assignment of the form ‘n=(value ...)’ is allowed, and has the
effect of shifting all the values at positions greater than n by as
many positions as necessary to accommodate the new values.
LOCAL PARAMETERS
Shell function executions delimit scopes for shell parameters.
(Parameters are dynamically scoped.) The typeset builtin, and its
alternative forms declare, integer, local and readonly (but not
export), can be used to declare a parameter as being local to the
innermost scope.
When a parameter is read or assigned to, the innermost existing param-
eter of that name is used. (That is, the local parameter hides any
less-local parameter.) However, assigning to a non-existent parame-
ter, or declaring a new parameter with export, causes it to be created
in the outermost scope.
Local parameters disappear when their scope ends. unset can be used
to delete a parameter while it is still in scope; any outer parameter
of the same name remains hidden.
Special parameters may also be made local; they retain their special
attributes unless either the existing or the newly-created parameter
has the -h (hide) attribute. This may have unexpected effects: there
is no default value, so if there is no assignment at the point the
variable is made local, it will be set to an empty value (or zero in
the case of integers). The following:
typeset PATH=/new/directory:$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 parame-
ters were never exported has been removed.
PARAMETERS SET BY THE SHELL
The following parameters are automatically set by the shell:
! <S> The process ID of the last background command invoked.
# <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 ${#} to resolve ambiguities. In par-
ticular, the sequence ‘$#-...’ 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.
- <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 value returned by the last command.
0 <S> The name used to invoke the current shell. If the FUNC-
TION_ARGZERO option is set, this is set temporarily within a
shell function to the name of the function, and within a
sourced script to the name of the script.
status <S> <Z>
Same as ?.
pipestatus <S> <Z>
An array containing the exit values returned by all commands in
the last pipeline.
_ <S> The last argument of the previous command. Also, this parame-
ter 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 suf-
ficient privileges, you may change the effective group ID of
the shell process by assigning to this parameter. Also (assum-
ing sufficient privileges), you may start a single command with
a different effective group ID by ‘(EGID=gid; command)’
EUID <S>
The effective user ID of the shell process. If you have suffi-
cient privileges, you may change the effective user ID of the
shell process by assigning to this parameter. Also (assuming
sufficient privileges), you may start a single command with a
different effective user ID by ‘(EUID=uid; command)’
ERRNO <S>
The value of errno (see errno(3)) as set by the most recently
failed system call. This value is system dependent and is
intended for debugging purposes. It is also useful with the
zsh/system module which allows the number to be turned into a
name or message.
GID <S>
The real group ID of the shell process. If you have sufficient
privileges, you may change the group ID of the shell process by
assigning to this parameter. Also (assuming sufficient privi-
leges), you may start a single command under a different group
ID by ‘(GID=gid; command)’
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 func-
tions 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.
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.
PWD The present working directory. This is set when the shell ini-
tializes 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 parame-
ter 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 param-
eter 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 precision is six decimal places,
although not all places may be useful.
SHLVL <S>
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 <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 assign-
ing to this parameter. Also (assuming sufficient privileges),
you may start a single command under a different user ID by
‘(UID=uid; command)’
USERNAME <S>
The username corresponding to the real user ID of the shell
process. If you have sufficient privileges, you may change the
username (and also the user ID and group ID) of the shell by
assigning to this parameter. Also (assuming sufficient privi-
leges), you may start a single command under a different user-
name (and user ID and group ID) by ‘(USERNAME=username; com-
mand)’
VENDOR The vendor, as determined at compile time.
ZSH_NAME
Expands to the basename of the command used to invoke this
instance of zsh.
ZSH_VERSION
The version number of this zsh.
PARAMETERS USED BY THE SHELL
The following parameters are used by the shell.
In cases where there are two parameters with an upper- and lowercase
form of the same name, such as path and PATH, the lowercase form is an
array and the uppercase form is a scalar with the elements of the
array joined together by colons. These are similar to tied parameters
created via ‘typeset -T’. The normal use for the colon-separated form
is for exporting to the environment, while the array form is easier to
manipulate within the shell. Note that unsetting either of the pair
will unset the other; they retain their special properties when recre-
ated, and recreating one of the pair will recreate the other.
ARGV0 If exported, its value is used as the argv[0] of external com-
mands. Usually used in constructs like ‘ARGV0=emacs nethack’.
BAUD The baud rate of the current connection. Used by the line edi-
tor 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 mecha-
nism can be turned off by setting the variable to zero.
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.
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.
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 sub-
stitution, and arithmetic expansion before being interpreted as
a pathname. Note that ENV is not used unless zsh is emulating
sh or ksh.
FCEDIT The default editor for the fc builtin.
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 analy-
sis mechanism. The first character signals the start of a his-
tory expansion (default ‘!’). The second character signals the
start of a quick history substitution (default ‘^’). The third
character is the comment character (default ‘#’).
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.
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 dif-
ference as a cushion for saving duplicated history events.
HOME <S>
The default argument for the cd command.
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.
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 col-
lation information within ranges in glob brackets and for sort-
ing.
LC_CTYPE <S>
This variable determines the locale category for character han-
dling functions.
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 print-
ing select lists and for the line editor.
LISTMAX
In the line editor, the number of matches to list without ask-
ing 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 activ-
ity 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 $_ defined as the name of the file that has
changed. The default message is ‘You have new mail’. If an
element is a directory instead of a file the shell will recur-
sively check every file in every subdirectory of the element.
manpath <S> <Z> (MANPATH <S> <Z>)
An array (colon-separated list) whose value is not used by the
shell. The manpath array can be useful, however, since setting
it also sets MANPATH, and vice versa.
module_path <S> <Z> (MODULE_PATH <S>)
An array (colon-separated list) of directories that zmodload
searches for dynamically loadable modules. This is initialized
to a standard pathname, usually ‘/usr/local/lib/zsh/$ZSH_VER-
SION’. (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 usu-
ally 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.
PS1 <S>
The primary prompt string, printed before a command is read.
the default is ‘%m%# ’. It undergoes a special form of expan-
sion before being displayed; see the section ‘Prompt Expan-
sion’.
PS2 <S>
The secondary prompt, printed when the shell needs more infor-
mation to complete a command. It is expanded in the same way
as PS1. The default is ‘%_> ’, which displays any shell con-
structs 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 dis-
plays the name of the current shell structure and the line num-
ber within it. In sh or ksh emulation, the default is ‘+ ’.
psvar <S> <Z> (PSVAR <S>)
An array (colon-separated list) whose first nine values can be
used in PROMPT strings. Setting psvar also sets PSVAR, and
vice versa.
READNULLCMD <S>
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 execu-
tion times (measured in seconds) are greater than this value
have timing statistics printed for them.
REPLY This parameter is reserved by convention to pass string values
between shell scripts and shell builtins in situations where a
function call or redirection are impossible or undesirable.
The read builtin and the select complex command may set REPLY,
and filename generation both sets and examines its value when
evaluating certain expressions. Some modules also employ REPLY
for similar purposes.
reply As REPLY, but for array values rather than strings.
RPROMPT <S>
RPS1 <S>
This prompt is displayed on the right-hand side of the screen
when the primary prompt is being displayed on the left. This
does not work if the SINGLELINEZLE 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 SINGLELINEZLE 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.
SPROMPT <S>
The prompt used for spelling correction. The sequence ‘%R’
expands to the string which presumably needs spelling correc-
tion, 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 argu-
ments in order to set up the terminal before executing the com-
mand. 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 specifi-
cations; 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-ini-
tialize 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.
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 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. Other-
wise 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 <S> <Z> (WATCH <S>)
An array (colon-separated list) of login/logout events to
report. If it contains the single word ‘all’, then all
login/logout events are reported. If it contains the single
word ‘notme’, then all events are reported as with ‘all’ except
$USERNAME. An entry in this list may consist of a username, an
‘@’ followed by a remote hostname, and a ‘%’ followed by a line
(tty). Any or all of these components may be present in an
entry; if a login/logout event matches all of them, it is
reported.
WATCHFMT
The format of login/logout reports if the watch parameter is
set. Default is ‘%n has %a %l from %m’. Recognizes the fol-
lowing 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 sepa-
rate the text for the "true" result from that for the
"false" result. Both the separator and the right paren-
thesis may be escaped with a backslash. Ternary expres-
sions 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.
zsh 4.2.0 March 19, 2004 ZSHPARAM(1)
