France

ftp://ftp.cenatls.cena.dgac.fr/shells/zsh/

Israel

ftp://ftp.math.technion.ac.il/pub/zsh/

Italy

ftp://ftp.unina.it/pub/Unix/pkgs/shell/zsh/

Japan

ftp://ftp.nisiq.net/pub/shells/zsh/ (H)

Norway

ftp://ftp.uit.no/pub/unix/shells/zsh/

Poland

ftp://sunsite.icm.edu.pl/pub/unix/shells/zsh/

Sweden

ftp://ftp.lysator.liu.se/pub/unix/zsh/

UK

ftp://ftp.net.lut.ac.uk/zsh/

USA

ftp://uiarchive.uiuc.edu/pub/packages/shells/zsh/

−c

Take the first argument as a command to execute, rather than reading commands from a script or standard input. If any further arguments are given, the first one is assigned to $0, rather than being used as a positional parameter.

−i

Force shell to be interactive.

−s

Force shell to read commands from the standard input. If the −s flag is not present and an argument is given, the first argument is taken to be the pathname of a script to execute.

•

changing directories with the cd builtin

•

changing or unsetting the PATH, path, MODULE_PATH, module_path, SHELL, HISTFILE, HISTSIZE, GID, EGID, UID, EUID, USERNAME, LD_LIBRARY_PATH, LD_AOUT_LIBRARY_PATH, LD_PRELOAD and LD_AOUT_PRELOAD parameters

•

specifying command names containing /

•

specifying command pathnames using hash

•

redirecting output to files

•

using the exec builtin command to replace the shell with another command

•

using jobs −Z to overwrite the shell process’ argument and environment space

•

using the ARGV0 parameter to override argv[0] for external commands

•

turning off restricted mode with set +r or unsetopt RESTRICTED

−

The command is executed with a ’−’ prepended to its argv[0] string.

noglob

Filename generation (globbing) is not performed on any of the words.

exec

The command is executed in the parent shell without forking.

< word

Open file word for reading as standard input.

> word

Open file word for writing as standard output. If the file does not exist then it is created. If the file exists, and the CLOBBER option is unset, this causes an error; otherwise, it is truncated to zero length.

<& −

>& −

Close the standard input/output.

<& p

>& p

The input/output from/to the coprocess is moved to the standard input/output.

chpwd

Executed whenever the current working directory is changed.

precmd

Executed before each prompt.

%%

Current job.

%+

Equivalent to ’%%’.

%−

Previous job.

<< >>

bitwise shift left, right

&

bitwise AND

^

bitwise XOR

|

bitwise OR

**

exponentiation

* / %

multiplication, division, modulus (remainder)

+ −

addition, subtraction

== !=

equality and inequality

&&

logical AND

|| ^^

logical OR, XOR

? :

ternary operator

,

comma operator

−t fd

true if file descriptor number fd is open and associated with a terminal device. (note: fd is not optional)

! exp

true if exp is false.

%%

A ’%’.

%)

A ’)’.

%d

%/

Present working directory ($PWD). If an integer follows the ’%’, it specifies a number of trailing components of $PWD to show; zero means the whole path. A negative integer specifies leading components, i.e. %−1d specifies the first component.

%~

As %d and %/, but if $PWD 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 ’~’.

%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. With a negative integer, trailing components of the hostname are shown.

%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.

%N

The name of the script, sourced file, or shell function that zsh is currently executing, whichever was started most recently. If there is none, this is equivalent to the parameter $0. An integer may follow the ’%’ to specify a number of trailing path components to show; zero means the full path. A negative integer specifies leading components.

%i

The line number currently being executed in the script, sourced file, or shell function given by %N. This is most useful for debugging as part of $PS4.

%w

The date in day−dd format.

%W

The date in mm/dd/yy format.

%D

The date in yy−mm−dd format.

%l

The line (tty) the user is logged in on without /dev/ prefix. If name starts with /dev/tty this is stripped.

%y

The line (tty) the user is logged in on without /dev/ prefix. It does not treat /dev/tty* specially.

%?

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 negative or no integer means print as many as there are. This is most useful in prompts PS2 for continuation lines and PS4 for debugging with the XTRACE option; in the latter case it will also work non−interactively.

%E

Clears to end of line.

%#

A ’#’ if the shell is running with privileges, a ’%’ if not. Equivalent to ’%(!.#.%%)’. The definition of ’privileged’, for these purposes, is that either the effective user ID is zero, or, if POSIX.1e capabilities are supported, that at least one capability is raised in either the Effective or Inheritable capability vectors.

%v

The value of the first element of the psvar array parameter. Following the ’%’ with an integer gives that element of the array. Negative integers count from the end of the array.

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 at least n characters have already been printed on the current line.

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.

!

True if the shell is running with privileges.

%c

%.

%C

Trailing component of $PWD. An integer may follow the ’%’ to get more than one component. Unless ’%C’ is used, tilde contraction is performed first. These are deprecated as %c and %C are equivalent to %1~ and %1/, respectively, while explicit positive integers have the same effect as for the latter two sequences.

NAME

zshexpn − zsh expansion and substitution

DESCRIPTION

The following types of expansions are performed in the indicated order in five steps:
History Expansion

This is performed only in interactive shells.

Alias Expansion

Aliases are expanded immediately before the command line is parsed as explained under Aliasing in zshmisc(1).

Process Substitution
Parameter Expansion
Command Substitution
Arithmetic Expansion
Brace Expansion

These five are performed in one step in left−to−right fashion. After these expansions, all unquoted occurrences of the characters ’\’, ’’’ and ’"’ are removed.

Filename Expansion

If the SH_FILE_EXPANSION option is set, the order of expansion is modified for compatibility with sh and ksh. In that case filename expansion is performed immediately after alias expansion, preceding the set of five expansions mentioned above.

Filename Generation

This expansion, commonly referred to as globbing, is always done last.

The following sections explain the types of expansion in detail.

HISTORY EXPANSION

History expansion allows you to use words from previous command lines in the command line you are typing. This simplifies spelling corrections and the repetition of complicated commands or arguments. Immediately before execution, each command is saved in the history list, the size of which is controlled by the HISTSIZE parameter. The one most recent command is always retained in any case. Each saved command in the history list is called a history event and is assigned a number, beginning with 1 (one) when the shell starts up. The history number that you may see in your prompt (see Prompt Expansion in zshmisc(1)) is the number that is to be assigned to the next command.

Overview
A history expansion begins with the first character of the histchars parameter, which is ’!’ by default, and may occur anywhere on the command line; history expansions do not nest. The ’!’ can be escaped with ’\’ or can be enclosed between a pair of single quotes (’’) to suppress its special meaning. Double quotes will not work for this. Following this history character is an optional event designator (see the section ’Event Designators’) and then an optional word designator (the section ’Word Designators’); if neither of these designators is present, no history expansion occurs.

Input lines containing history expansions are echoed after being expanded, but before any other expansions take place and before the command is executed. It is this expanded form that is recorded as the history event for later references.

By default, a history reference with no event designator refers to the same event as any preceding history reference on that command line; if it is the only history reference in a command, it refers to the previous command. However, if the option CSH_JUNKIE_HISTORY is set, then every history reference with no event specification always refers to the previous command.

For example, ’!’ is the event designator for the previous command, so ’!!:1’ always refers to the first word of the previous command, and ’!!$’ always refers to the last word of the previous command. With CSH_JUNKIE_HISTORY set, then ’!:1’ and ’!$’ function in the same manner as ’!!:1’ and ’!!$’, respectively. Conversely, if CSH_JUNKIE_HISTORY is unset, then ’!:1’ and ’!$’ refer to the first and last words, respectively, of the same event referenced by the nearest other history reference preceding them on the current command line, or to the previous command if there is no preceding reference.

The character sequence ’^foo^bar’ (where ’^’ is actually the second character of the histchars parameter) repeats the last command, replacing the string foo with bar. More precisely, the sequence ’^foo^bar^’ is synonymous with ’!!:s^foo^bar^’, hence other modifiers (see the section ’Modifiers’) may follow the final ’^’.

If the shell encounters the character sequence ’!"’ in the input, the history mechanism is temporarily disabled until the current list (see zshmisc(1)) is fully parsed. The ’!"’ is removed from the input, and any subsequent ’!’ characters have no special significance.

A less convenient but more comprehensible form of command history support is provided by the fc builtin.

Event Designators
An event designator is a reference to a command−line entry in the history list. In the list below, remember that the initial ’!’ in each item may be changed to another character by setting the histchars parameter.

!?str[?]

Refer to the most recent command containing str. The trailing ’?’ is necessary if this reference is to be followed by a modifier or followed by any text that is not to be considered part of str.

Word Designators
A word designator indicates which word or words of a given command line are to be included in a history reference. A ’:’ usually separates the event specification from the word designator. It may be omitted only if the word designator begins with a ’^’, ’$’, ’*’, ’−’ or ’%’. Word designators include:

Note that a ’%’ word designator works only when used in one of ’!%’, ’!:%’ or ’!?str?:%’, and only when used after a !? expansion (possibly in an earlier command). Anything else results in an error, although the error may not be the most obvious one.

Modifiers
After the optional word designator, you can add a sequence of one or more of the following modifiers, each preceded by a ’:’. These modifiers also work on the result of filename generation and parameter expansion, except where noted.

s/l/r[/]

Substitute r for l as described below. Unless preceded immediately by a g, with no colon between, the substitution is done only for the first string that matches l. For arrays and for filename generation, this applies to each word of the expanded text.

The s/l/r/ substitution works as follows. The left−hand side of substitutions are not regular expressions, but character strings. Any character can be used as the delimiter in place of ’/’. A backslash quotes the delimiter character. The character ’&’, in the right−hand−side r, is replaced by the text from the left−hand−side l. The ’&’ can be quoted with a backslash. A null l uses the previous string either from the previous l or from the contextual scan string s from ’!?s’. You can omit the rightmost delimiter if a newline immediately follows r; the rightmost ’?’ in a context scan can similarly be omitted. Note the same record of the last l and r is maintained across all forms of expansion.

The following f, F, w and W modifiers work only with parameter expansion and filename generation. They are listed here to provide a single point of reference for all modifiers.

F:expr:

Like f, but repeats only n times if the expression expr evaluates to n. Any character can be used instead of the ’:’; if ’(’, ’[’, or ’{’ is used as the opening delimiter, the closing delimiter should be ’)’, ’]’, or ’}’, respectively.

PROCESS SUBSTITUTION

Each command argument of the form ’<(list)’, ’>(list)’ or ’=(list)’ is subject to process substitution. In the case of the < or > forms, the shell runs process list asynchronously. If the system supports the /dev/fd mechanism, the command argument is the name of the device file corresponding to a file descriptor; otherwise, if the system supports named pipes (FIFOs), the command argument will be a named pipe. If the form with > is selected then writing on this special file will provide input for list. If < is used, then the file passed as an argument will be connected to the output of the list process. For example,

paste <(cut −f1 file1) <(cut −f3 file2) |
tee >(process1) >(process2) >/dev/null

cuts fields 1 and 3 from the files file1 and file2 respectively, pastes the results together, and sends it to the processes process1 and process2.

Both the /dev/fd and the named pipe implementation have drawbacks. In the former case, some programmes may automatically close the file descriptor in question before examining the file on the command line, particularly if this is necessary for security reasons such as when the programme is running setuid. In the second case, if the programme does not actually open the file, the subshell attempting to read from or write to the pipe will (in a typical implementation, different operating systems may have different behaviour) block for ever and have to be killed explicitly. In both cases, the shell actually supplies the information using a pipe, so that programmes that expect to lseek (see lseek(2)) on the file will not work.

Also note that the previous example can be more compactly and efficiently written (provided the MULTIOS option is set) as:

paste <(cut −f1 file1) <(cut −f3 file2) \
> >(process1) > >(process2)

The shell uses pipes instead of FIFOs to implement the latter two process substitutions in the above example.

If = is used, then the file passed as an argument will be the name of a temporary file containing the output of the list process. This may be used instead of the < form for a program that expects to lseek (see lseek(2)) on the input file.

PARAMETER EXPANSION

The character ’$’ is used to introduce parameter expansions. See zshparam(1) for a description of parameters, including arrays, associative arrays, and subscript notation to access individual array elements.

In the expansions discussed below that require a pattern, the form of the pattern is the same as that used for filename generation; see the section ’Filename Generation’. Note that these patterns, along with the replacement text of any substitutions, are themselves subject to parameter expansion, command substitution, and arithmetic expansion. In addition to the following operations, the colon modifiers described in the section ’Modifiers’ in the section ’History Expansion’ can be applied: for example, ${i:s/foo/bar/} performs string substitution on the expansion of parameter $i.
${name}

The value, if any, of the parameter name is substituted. The braces are required if the expansion is to be followed by a letter, digit, or underscore that is not to be interpreted as part of name. In addition, more complicated forms of substitution usually require the braces to be present; exceptions, which only apply if the option KSH_ARRAYS is not set, are a single subscript or any colon modifiers appearing after the name, or any of the characters ’^’, ’=’, ’~’, ’#’ or ’+’ appearing before the name, all of which work with or without braces.

If name is an array parameter, and the KSH_ARRAYS option is not set, then the value of each element of name is substituted, one element per word. Otherwise, the expansion results in one word only; with KSH_ARRAYS, this is the first element of an array. No field splitting is done on the result unless the SH_WORD_SPLIT option is set.

${+name}

If name is the name of a set parameter ’1’ is substituted, otherwise ’0’ is substituted.

${name:−word}

If name is set and is non−null then substitute its value; otherwise substitute word. If name is missing, substitute word.

${name:=word}
${name::=word}

In the first form, if name is unset or is null then set it to word; in the second form, unconditionally set name to word. In both forms, the value of the parameter is then substituted.

${name:?word}

If name is set and is non−null then substitute its value; otherwise, print word and exit from the shell. Interactive shells instead return to the prompt. If word is omitted, then a standard message is printed.

${name:+word}

If name is set and is non−null then substitute word; otherwise substitute nothing.

If the colon is omitted from one of the above expressions containing a colon, then the shell only checks whether name is set, not whether its value is null.

In the following expressions, when name is an array and the substitution is not quoted, or if the ’(@)’ flag or the name[@] syntax is used, matching and replacement is performed on each array element separately.
${name#pattern}
${name##pattern}

If the pattern matches the beginning of the value of name, then substitute the value of name with the matched portion deleted; otherwise, just substitute the value of name. In the first form, the smallest matching pattern is preferred; in the second form, the largest matching pattern is preferred.

${name%pattern}
${name%%pattern}

If the pattern matches the end of the value of name, then substitute the value of name with the matched portion deleted; otherwise, just substitute the value of name. In the first form, the smallest matching pattern is preferred; in the second form, the largest matching pattern is preferred.

${name:#pattern}

If the pattern matches the value of name, then substitute the empty string; otherwise, just substitute the value of name. If name is an array the matching array elements are removed (use the ’(M)’ flag to remove the non−matched elements).

${name/pattern/repl}
${name//pattern/repl}

Replace the longest possible match of pattern in the expansion of parameter name by string repl. The first form replaces just the first occurrence, the second form all occurrences. Both pattern and repl are subject to double−quoted substitution, so that expressions like ${name/$opat/$npat} will work, but note the usual rule that pattern characters in $opat are not treated specially unless either the option GLOB_SUBST is set, or $opat is instead substituted as ${~opat}.

The pattern may begin with a ’#’, in which case the pattern must match at the start of the string, or ’%’, in which case it must match at the end of the string. The repl may be an empty string, in which case the final ’/’ may also be omitted. To quote the final ’/’ in other cases it should be preceded by a single backslash; this is not necessary if the ’/’ occurs inside a substituted parameter. Note also that the ’#’ and ’%’ are not active if they occur inside a substituted parameter, even at the start.

The first ’/’ may be preceded by a ’:’, in which case the match will only succeed if it matches the entire word. Note also the effect of the I and S parameter expansion flags below; however, the flags M, R, B, E and N are not useful.

For example,

foo="twinkle twinkle little star" sub="t*e" rep="spy"
print ${foo//${~sub}/$rep}
print ${(S)foo//${~sub}/$rep}

Here, the ’~’ ensures that the text of $sub is treated as a pattern rather than a plain string. In the first case, the longest match for t*e is substituted and the result is ’spy star’, while in the second case, the shortest matches are taken and the result is ’spy spy lispy star’.

${#spec}

If spec is one of the above substitutions, substitute the length in characters of the result instead of the result itself. If spec is an array expression, substitute the number of elements of the result. Note that ’^’, ’=’, and ’~’, below, must appear to the left of ’#’ when these forms are combined.

${^spec}

Turn on the RC_EXPAND_PARAM option for the evaluation of spec; if the ’^’ is doubled, turn it off. When this option is set, array expansions of the form foo${xx}bar, where the parameter xx is set to (a b c), are substituted with ’fooabar foobbar foocbar’ instead of the default ’fooa b cbar’.

Internally, each such expansion is converted into the equivalent list for brace expansion. E.g., ${^var} becomes {$var[1],$var[2],...}, and is processed as described in the section ’Brace Expansion’ below. If word splitting is also in effect the $var[N] may themselves be split into different list elements.

${=spec}

Perform word splitting using the rules for SH_WORD_SPLIT during the evaluation of spec, but regardless of whether the parameter appears in double quotes; if the ’=’ is doubled, turn it off. This forces parameter expansions to be split into separate words before substitution, using IFS as a delimiter. This is done by default in most other shells.

Note that splitting is applied to word in the assignment forms of spec before the assignment to name is performed. This affects the result of array assignments with the A flag.

${~spec}

Turn on the GLOB_SUBST option for the evaluation of spec; if the ’~’ is doubled, turn it off. When this option is set, the string resulting from the expansion will be interpreted as a pattern anywhere that is possible, such as in filename expansion and filename generation and pattern−matching contexts like the right hand side of the ’=’ and ’!=’ operators in conditions.

If a ${...} type parameter expression or a $(...) type command substitution is used in place of name above, it is expanded first and the result is used as if it were the value of name. Thus it is possible to perform nested operations: ${${foo#head}%tail} substitutes the value of $foo with both ’head’ and ’tail’ deleted. The form with $(...) is often useful in combination with the flags described next; see the examples below. Each name or nested ${...} in a parameter expansion may also be followed by a subscript expression as described in Array Parameters in zshparam(1).

Note that double quotes may appear around nested expressions, in which case only the part inside is treated as quoted; for example, ${(f)"$(foo)"} quotes the result of $(foo), but the flag ’(f)’ (see below) is applied using the rules for unquoted expansions. Note further that quotes are themselves nested in this context; for example, in "${(@f)"$(foo)"}", there are two sets of quotes, one surrounding the whole expression, the other (redundant) surrounding the $(foo) as before.

Parameter Expansion Flags
If the opening brace is directly followed by an opening parenthesis, the string up to the matching closing parenthesis will be taken as a list of flags. In cases where repeating a flag is meaningful, the repetitions need not be consecutive; for example, ’(q%q%q)’ means the same thing as the more readable ’(%%qqq)’. The following flags are supported:

local

right_blanks

for right justified parameters with leading blanks

right_zeros

for right justified parameters with leading zeros

readonly

for readonly parameters

special

for special parameters defined by the shell

Note that this is done very late, as for the ’(s)’ flag. So to access single words in the result, one has to use nested expansions as in ’${${(z)foo}[2]}’. Likewise, to remove the quotes in the resulting words one would do: ’${(Q)${(z)foo}}’.

The following flags (except p) are followed by one or more arguments as shown. Any character, or the matching pairs ’(...)’, ’{...}’, ’[...]’, or ’<...>’, may be used in place of a colon as delimiters, but note that when a flag takes more than one argument, a matched pair of delimiters must surround each argument.

j:string:

Join the words of arrays together using string as a separator. Note that this occurs before field splitting by the SH_WORD_SPLIT option.

l:expr::string1::string2:

Pad the resulting words on the left. Each word will be truncated if required and placed in a field expr characters wide. The space to the left will be filled with string1 (concatenated as often as needed) or spaces if string1 is not given. If both string1 and string2 are given, this string is inserted once directly to the left of each word, before padding.

r:expr::string1::string2:

As l, but pad the words on the right and insert string2 on the right.

s:string:

Force field splitting (see the option SH_WORD_SPLIT) at the separator string. Note that a string of two or more characters means all must all match in sequence; this differs from the treatment of two or more characters in the IFS parameter.

The following flags are meaningful with the ${...#...} or ${...%...} forms. The S and I flags may also be used with the ${.../...} forms.

I:expr:

Search the exprth match (where expr evaluates to a number). This only applies when searching for substrings, either with the S flag, or with ${.../...} (only the exprth match is substituted) or ${...//...} (all matches from the exprth on are substituted). The default is to take the first match.

The exprth match is counted such that there is either one or zero matches from each starting position in the string, although for global substitution matches overlapping previous replacements are ignored. With the ${...%...} and ${...%%...} forms, the starting position for the match moves backwards from the end as the index increases, while with the other forms it moves forward from the start.

Hence with the string

which switch is the right switch for Ipswich?

substitutions of the form ${(SI:N:)string#w*ch} as N increases from 1 will match and remove ’which’, ’witch’, ’witch’ and ’wich’; the form using ’##’ will match and remove ’which switch is the right switch for Ipswich’, ’witch is the right switch for Ipswich’, ’witch for Ipswich’ and ’wich’. The form using ’%’ will remove the same matches as for ’#’, but in reverse order, and the form using ’%%’ will remove the same matches as for ’##’ in reverse order.

Rules
Here is a summary of the rules for substitution; this assumes that braces are present around the substitution, i.e. ${...}. Some particular examples are given below. Note that the Zsh Development Group accepts no responsibility for any brain damage which may occur during the reading of the following rules.
1. Nested Substitution

If multiple nested ${...} forms are present, substitution is performed from the inside outwards. At each level, the substitution takes account of whether the current value is a scalar or an array, whether the whole substitution is in double quotes, and what flags are supplied to the current level of substitution, just as if the nested substitution were the outermost. The flags are not propagated up to enclosing substitutions; the nested substitution will return either a scalar or an array as determined by the flags, possibly adjusted for quoting. All the following steps take place where applicable at all levels of substitution. Note that, unless the ’(P)’ flag is present, the flags and any subscripts apply directly to the value of the nested substitution; for example, the expansion ${${foo}} behaves exactly the same as ${foo}.

2. Parameter Subscripting

If the value is a raw parameter reference with a subscript, such as ${var[3]}, the effect of subscripting is applied directly to the parameter. Subscripts are evaluated left to right; subsequent subscripts apply to the scalar or array value yielded by the previous subscript. Thus if var is an array, ${var[1][2]} is the second character of the first word, but ${var[2,4][2]} is the entire third word (the second word of the range of words two through four of the original array). Any number of subscripts may appear.

3. Parameter Name Replacement

The effect of any (P) flag, which treats the value so far as a parameter name and replaces it with the corresponding value, is applied.

4. Double−Quoted Joining

If the value after this process is an array, and the substitution appears in double quotes, and no (@) flag is present at the current level, the words of the value are joined with the first character of the parameter $IFS, by default a space, between each word (single word arrays are not modified). If the (j) flag is present, that is used for joining instead of $IFS.

5. Nested Subscripting

Any remaining subscripts (i.e. of a nested substitution) are evaluated at this point, based on whether the value is an array or a scalar. As with 2., multiple subscripts can appear. Note that ${foo[2,4][2]} is thus equivalent to ${${foo[2,4]}[2]} and also to "${${(@)foo[2,4]}[2]}" (the nested substitution returns an array in both cases), but not to "${${foo[2,4]}[2]}" (the nested substitution returns a scalar because of the quotes).

6. Modifiers

Any modifiers, as specified by a trailing ’#’, ’%’, ’/’ (possibly doubled) or by a set of modifiers of the form :... (see the section ’Modifiers’ in the section ’History Expansion’), are applied to the words of the value at this level.

7. Forced Joining

If the ’(j)’ flag is present, or no ’(j)’ flag is present but the string is to be split as given by rules 8. or 9., and joining did not take place at step 4., any words in the value are joined together using the given string or the first character of $IFS if none. Note that the ’(F)’ flag implicitly supplies a string for joining in this manner.

8. Forced Splitting

If one of the ’(s)’, ’(f)’ or ’(z)’ flags are present, or the ’=’ specifier was present (e.g. ${=var}), the word is split on occurrences of the specified string, or (for = with neither of the two flags present) any of the characters in $IFS.

9. Shell Word Splitting

If no ’(s)’, ’(f)’ or ’=’ was given, but the word is not quoted and the option SH_WORD_SPLIT is set, the word is split on occurrences of any of the characters in $IFS. Note this step, too, takes place at all levels of a nested substitution.

10. Re−Evaluation

Any ’(e)’ flag is applied to the value, forcing it to be re−examined for new parameter substitutions, but also for command and arithmetic substitutions.

11. Padding

Any padding of the value by the ’(l.fill.)’ or ’(r.fill.)’ flags is applied.

12. Semantic Joining

In contexts where expansion semantics requires a single word to result, all words are rejoined with the first character of IFS between. So in ’${(P)${(f)lines}}’ the value of ${lines} is split at newlines, but then must be joined again before the P flag can be applied.

If a single word is not required, this rule is skipped.

Examples
The flag f is useful to split a double−quoted substitution line by line. For example, ${(f)"$(<file)"} substitutes the contents of file divided so that each line is an element of the resulting array. Compare this with the effect of $(<file) alone, which divides the file up by words, or the same inside double quotes, which makes the entire content of the file a single string.

The following illustrates the rules for nested parameter expansions. Suppose that $foo contains the array (bar baz):
"${(@)${foo}[1]}"

This produces the result b. First, the inner substitution "${foo}", which has no array (@) flag, produces a single word result "bar baz". The outer substitution "${(@)...[1]}" detects that this is a scalar, so that (despite the ’(@)’ flag) the subscript picks the first character.

"${${(@)foo}[1]}"

This produces the result ’bar’. In this case, the inner substitution "${(@)foo}" produces the array ’(bar baz)’. The outer substitution "${...[1]}" detects that this is an array and picks the first word. This is similar to the simple case "${foo[1]}".

As an example of the rules for word splitting and joining, suppose $foo contains the array ’(ax1 bx1)’. Then
${(s/x/)foo}

produces the words ’a’, ’1 b’ and ’1’.

${(j/x/s/x/)foo}

produces ’a’, ’1’, ’b’ and ’1’.

${(s/x/)foo%%1*}

produces ’a’ and ’ b’ (note the extra space). As substitution occurs before either joining or splitting, the operation first generates the modified array (ax bx), which is joined to give "ax bx", and then split to give ’a’, ’ b’ and ’’. The final empty string will then be elided, as it is not in double quotes.

COMMAND SUBSTITUTION

A command enclosed in parentheses preceded by a dollar sign, like ’$(...)’, or quoted with grave accents, like ’’...’’, is replaced with its standard output, with any trailing newlines deleted. If the substitution is not enclosed in double quotes, the output is broken into words using the IFS parameter. The substitution ’$(cat foo)’ may be replaced by the equivalent but faster ’$(<foo)’. In either case, if the option GLOB_SUBST is set, the output is eligible for filename generation.

ARITHMETIC EXPANSION

A string of the form ’$[exp]’ or ’$((exp))’ is substituted with the value of the arithmetic expression exp. exp is subjected to parameter expansion, command substitution and arithmetic expansion before it is evaluated. See the section ’Arithmetic Evaluation’.

BRACE EXPANSION

A string of the form ’foo{xx,yy,zz}bar’ is expanded to the individual words ’fooxxbar’, ’fooyybar’ and ’foozzbar’. Left−to−right order is preserved. This construct may be nested. Commas may be quoted in order to include them literally in a word.

An expression of the form ’{n1..n2}’, where n1 and n2 are integers, is expanded to every number between n1 and n2 inclusive. If either number begins with a zero, all the resulting numbers will be padded with leading zeroes to that minimum width. If the numbers are in decreasing order the resulting sequence will also be in decreasing order.

If a brace expression matches none of the above forms, it is left unchanged, unless the BRACE_CCL option is set. In that case, it is expanded to a sorted list of the individual characters between the braces, in the manner of a search set. ’−’ is treated specially as in a search set, but ’^’ or ’!’ as the first character is treated normally.

Note that brace expansion is not part of filename generation (globbing); an expression such as */{foo,bar} is split into two separate words */foo and */bar before filename generation takes place. In particular, note that this is liable to produce a ’no match’ error if either of the two expressions does not match; this is to be contrasted with */(foo|bar), which is treated as a single pattern but otherwise has similar effects.

FILENAME EXPANSION

Each word is checked to see if it begins with an unquoted ’~’. If it does, then the word up to a ’/’, or the end of the word if there is no ’/’, is checked to see if it can be substituted in one of the ways described here. If so, then the ’~’ and the checked portion are replaced with the appropriate substitute value.

A ’~’ by itself is replaced by the value of $HOME. A ’~’ followed by a ’+’ or a ’−’ is replaced by the value of $PWD or $OLDPWD, respectively.

A ’~’ followed by a number is replaced by the directory at that position in the directory stack. ’~0’ is equivalent to ’~+’, and ’~1’ is the top of the stack. ’~+’ followed by a number is replaced by the directory at that position in the directory stack. ’~+0’ is equivalent to ’~+’, and ’~+1’ is the top of the stack. ’~−’ followed by a number is replaced by the directory that many positions from the bottom of the stack. ’~−0’ is the bottom of the stack. The PUSHD_MINUS option exchanges the effects of ’~+’ and ’~−’ where they are followed by a number.

A ’~’ followed by anything not already covered is looked up as a named directory, and replaced by the value of that named directory if found. Named directories are typically home directories for users on the system. They may also be defined if the text after the ’~’ is the name of a string shell parameter whose value begins with a ’/’. It is also possible to define directory names using the −d option to the hash builtin.

In certain circumstances (in prompts, for instance), when the shell prints a path, the path is checked to see if it has a named directory as its prefix. If so, then the prefix portion is replaced with a ’~’ followed by the name of the directory. The shortest way of referring to the directory is used, with ties broken in favour of using a named directory, except when the directory is / itself. The parameters $PWD and $OLDPWD are never abbreviated in this fashion.

If a word begins with an unquoted ’=’ and the EQUALS option is set, the remainder of the word is taken as the name of a command or alias. If a command exists by that name, the word is replaced by the full pathname of the command. If an alias exists by that name, the word is replaced with the text of the alias.

Filename expansion is performed on the right hand side of a parameter assignment, including those appearing after commands of the typeset family. In this case, the right hand side will be treated as a colon−separated list in the manner of the PATH parameter, so that a ’~’ or an ’=’ following a ’:’ is eligible for expansion. All such behaviour can be disabled by quoting the ’~’, the ’=’, or the whole expression (but not simply the colon); the EQUALS option is also respected.

If the option MAGIC_EQUAL_SUBST is set, any unquoted shell argument in the form ’identifier=expression’ becomes eligible for file expansion as described in the previous paragraph. Quoting the first ’=’ also inhibits this.

FILENAME GENERATION

If a word contains an unquoted instance of one of the characters ’*’, ’(’, ’|’, ’<’, ’[’, or ’?’, it is regarded as a pattern for filename generation, unless the GLOB option is unset. If the EXTENDED_GLOB option is set, the ’^’ and ’#’ characters also denote a pattern; otherwise they are not treated specially by the shell.

The word is replaced with a list of sorted filenames that match the pattern. If no matching pattern is found, the shell gives an error message, unless the NULL_GLOB option is set, in which case the word is deleted; or unless the NOMATCH option is unset, in which case the word is left unchanged.

In filename generation, the character ’/’ must be matched explicitly; also, a ’.’ must be matched explicitly at the beginning of a pattern or after a ’/’, unless the GLOB_DOTS option is set. No filename generation pattern matches the files ’.’ or ’..’. In other instances of pattern matching, the ’/’ and ’.’ are not treated specially.

Glob Operators

<[x]−[y]>

Matches any number in the range x to y, inclusive. Either of the numbers may be omitted to make the range open−ended; hence ’<−>’ matches any number. To match individual digits, the [...] form is more efficient.

Be careful when using other wildcards adjacent to patterns of this form; for example, <0−9>* will actually match any number whatsoever at the start of the string, since the ’<0−9>’ will match the first digit, and the ’*’ will match any others. This is a trap for the unwary, but is in fact an inevitable consequence of the rule that the longest possible match always succeeds. Expressions such as ’<0−9>[^[:digit:]]*’ can be used instead.

Note that grouping cannot extend over multiple directories: it is an error to have a ’/’ within a group (this only applies for patterns used in filename generation). There is one exception: a group of the form (pat/)# appearing as a complete path segment can match a sequence of directories. For example, foo/(a*/)#bar matches foo/bar, foo/any/bar, foo/any/anyother/bar, and so on.

ksh−like Glob Operators
If the KSH_GLOB option is set, the effects of parentheses can be modified by a preceding ’@’, ’*’, ’+’, ’?’ or ’!’. This character need not be unquoted to have special effects, but the ’(’ must be.

Precedence
The precedence of the operators given above is (highest) ’^’, ’/’, ’~’, ’|’ (lowest); the remaining operators are simply treated from left to right as part of a string, with ’#’ and ’##’ applying to the shortest possible preceding unit (i.e. a character, ’?’, ’[...]’, ’<...>’, or a parenthesised expression). As mentioned above, a ’/’ used as a directory separator may not appear inside parentheses, while a ’|’ must do so; in patterns used in other contexts than filename generation (for example, in case statements and tests within ’[[...]]’), a ’/’ is not special; and ’/’ is also not special after a ’~’ appearing outside parentheses in a filename pattern.

Globbing Flags
There are various flags which affect any text to their right up to the end of the enclosing group or to the end of the pattern; they require the EXTENDED_GLOB option. All take the form (#X) where X may have one of the following forms:

For example,

foo="a string with a message"
if [[ $foo = (a|an)’ ’(#b)(*)’ ’* ]]; then
print ${foo[$mbegin[1],$mend[1]]}
fi

prints ’string with a’. Note that the first parenthesis is before the (#b) and does not create a backreference.

Backreferences work with all forms of pattern matching other than filename generation, but note that when performing matches on an entire array, such as ${array#pattern}, or a global substitution, such as ${param//pat/repl}, only the data for the last match remains available. In the case of global replacements this may still be useful. See the example for the m flag below.

The numbering of backreferences strictly follows the order of the opening parentheses from left to right in the pattern string, although sets of parentheses may be nested. There are special rules for parentheses followed by ’#’ or ’##’. Only the last match of the parenthesis is remembered: for example, in ’[[ abab = (#b)([ab])# ]]’, only the final ’b’ is stored in match[1]. Thus extra parentheses may be necessary to match the complete segment: for example, use ’X((ab|cd)#)Y’ to match a whole string of either ’ab’ or ’cd’ between ’X’ and ’Y’, using the value of $match[1] rather than $match[2].

If the match fails none of the parameters is altered, so in some cases it may be necessary to initialise them beforehand. If some of the backreferences fail to match −−− which happens if they are in an alternate branch which fails to match, or if they are followed by # and matched zero times −−− then the matched string is set to the empty string, and the start and end indices are set to −1.

Pattern matching with backreferences is slightly slower than without.

For example,

arr=(veldt jynx grimps waqf zho buck)
print ${arr//(#m)[aeiou]/${(U)MATCH}}

forces all the matches (i.e. all vowels) into uppercase, printing ’vEldt jynx grImps wAqf zhO bUck’.

Unlike backreferences, there is no speed penalty for using match references, other than the extra substitutions required for the replacement strings in cases such as the example shown.

Another use is in parameter substitution; for example ’${array/(#s)A*Z(#e)}’ will remove only elements of an array which match the complete pattern ’A*Z’. There are other ways of performing many operations of this type, however the combination of the substitution operations ’/’ and ’//’ with the ’(#s)’ and ’(#e)’ flags provides a single simple and memorable method.

Note that assertions of the form ’(^(#s))’ also work, i.e. match anywhere except at the start of the string, although this actually means ’anything except a zero−length portion at the start of the string’; you need to use ’(""~(#s))’ to match a zero−length portion of the string not at the start.

For example, the test string fooxx can be matched by the pattern (#i)FOOXX, but not by (#l)FOOXX, (#i)FOO(#I)XX or ((#i)FOOX)X. The string (#ia2)readme specifies case−insensitive matching of readme with up to two errors.

When using the ksh syntax for grouping both KSH_GLOB and EXTENDED_GLOB must be set and the left parenthesis should be preceded by @. Note also that the flags do not affect letters inside [...] groups, in other words (#i)[a−z] still matches only lowercase letters. Finally, note that when examining whole paths case−insensitively every directory must be searched for all files which match, so that a pattern of the form (#i)/foo/bar/... is potentially slow.

Approximate Matching
When matching approximately, the shell keeps a count of the errors found, which cannot exceed the number specified in the (#anum) flags. Four types of error are recognised:

Thus, the pattern (#a3)abcd matches dcba, with the errors occurring by using the first rule twice and the second once, grouping the string as [d][cb][a] and [a][bc][d].

Non−literal parts of the pattern must match exactly, including characters in character ranges: hence (#a1)??? matches strings of length four, by applying rule 4 to an empty part of the pattern, but not strings of length two, since all the ? must match. Other characters which must match exactly are initial dots in filenames (unless the GLOB_DOTS option is set), and all slashes in filenames, so that a/bc is two errors from ab/c (the slash cannot be transposed with another character). Similarly, errors are counted separately for non−contiguous strings in the pattern, so that (ab|cd)ef is two errors from aebf.

When using exclusion via the ~ operator, approximate matching is treated entirely separately for the excluded part and must be activated separately. Thus, (#a1)README~READ_ME matches READ.ME but not READ_ME, as the trailing READ_ME is matched without approximation. However, (#a1)README~(#a1)READ_ME does not match any pattern of the form READ?ME as all such forms are now excluded.

Apart from exclusions, there is only one overall error count; however, the maximum errors allowed may be altered locally, and this can be delimited by grouping. For example, (#a1)cat((#a0)dog)fox allows one error in total, which may not occur in the dog section, and the pattern (#a1)cat(#a0)dog(#a1)fox is equivalent. Note that the point at which an error is first found is the crucial one for establishing whether to use approximation; for example, (#a1)abc(#a0)xyz will not match abcdxyz, because the error occurs at the ’x’, where approximation is turned off.

Entire path segments may be matched approximately, so that ’(#a1)/foo/d/is/available/at/the/bar’ allows one error in any path segment. This is much less efficient than without the (#a1), however, since every directory in the path must be scanned for a possible approximate match. It is best to place the (#a1) after any path segments which are known to be correct.

Recursive Globbing
A pathname component of the form ’(foo/)#’ matches a path consisting of zero or more directories matching the pattern foo.

As a shorthand, ’**/’ is equivalent to ’(*/)#’; note that this therefore matches files in the current directory as well as subdirectories. Thus:

ls (*/)#bar

or

ls **/bar

does a recursive directory search for files named ’bar’ (potentially including the file ’bar’ in the current directory). This form does not follow symbolic links; the alternative form ’***/’ does, but is otherwise identical. Neither of these can be combined with other forms of globbing within the same path segment; in that case, the ’*’ operators revert to their usual effect.

Glob Qualifiers
Patterns used for filename generation may end in a list of qualifiers enclosed in parentheses. The qualifiers specify which filenames that otherwise match the given pattern will be inserted in the argument list.

If the option BARE_GLOB_QUAL is set, then a trailing set of parentheses containing no ’|’ or ’(’ characters (or ’~’ if it is special) is taken as a set of glob qualifiers. A glob subexpression that would normally be taken as glob qualifiers, for example ’(^x)’, can be forced to be treated as part of the glob pattern by doubling the parentheses, in this case producing ’((^x))’.

A qualifier may be any one of the following:

If the qualifier ’f’ is followed by any other character anything up to the next matching character (’[’, ’{’, and ’<’ match ’]’, ’}’, and ’>’ respectively, any other character matches itself) is taken as a list of comma−separated sub−specs. Each sub−spec may be either an octal number as described above or a list of any of the characters ’u’, ’g’, ’o’, and ’a’, followed by a ’=’, a ’+’, or a ’−’, followed by a list of any of the characters ’r’, ’w’, ’x’, ’s’, and ’t’, or an octal digit. The first list of characters specify which access rights are to be checked. If a ’u’ is given, those for the owner of the file are used, if a ’g’ is given, those of the group are checked, a ’o’ means to test those of other users, and the ’a’ says to test all three groups. The ’=’, ’+’, and ’−’ again says how the modes are to be checked and have the same meaning as described for the first form above. The second list of characters finally says which access rights are to be expected: ’r’ for read access, ’w’ for write access, ’x’ for the right to execute the file (or to search a directory), ’s’ for the setuid and setgid bits, and ’t’ for the sticky bit.

Thus, ’*(f70?)’ gives the files for which the owner has read, write, and execute permission, and for which other group members have no rights, independent of the permissions for other users. The pattern ’*(f−100)’ gives all files for which the owner does not have execute permission, and ’*(f:gu+w,o−rx:)’ gives the files for which the owner and the other members of the group have at least write permission, and for which other users don’t have read or execute permission.

estring

The string will be executed as shell code. The filename will be included in the list if and only if the code returns a zero status (usually the status of the last command). The first character after the ’e’ will be used as a separator and anything up to the next matching separator will be taken as the string; ’[’, ’{’, and ’<’ match ’]’, ’}’, and ’>’, respectively, while any other character matches itself. Note that expansions must be quoted in the string to prevent them from being expanded before globbing is done.

During the execution of string the filename currently being tested is available in the parameter REPLY; the parameter may be altered to a string to be inserted into the list instead of the original filename. In addition, the parameter reply may be set to an array or a string, which overrides the value of REPLY. If set to an array, the latter is inserted into the command line word by word.

For example, suppose a directory contains a single file ’lonely’. Then the expression ’*(e:’reply=(${REPLY}{1,2})’:)’ will cause the words ’lonely1 lonely2’ to be inserted into the command line. Note the quotation marks.

l[−|+]ct

files having a link count less than ct (−), greater than ct (+), or equal to ct

a[Mwhms][−|+]n

files accessed exactly n days ago. Files accessed within the last n days are selected using a negative value for n (−n). Files accessed more than n days ago are selected by a positive n value (+n). Optional unit specifiers ’M’, ’w’, ’h’, ’m’ or ’s’ (e.g. ’ah5’) cause the check to be performed with months (of 30 days), weeks, hours, minutes or seconds instead of days, respectively. For instance, ’echo *(ah−5)’ would echo files accessed within the last five hours.

m[Mwhms][−|+]n

like the file access qualifier, except that it uses the file modification time.

c[Mwhms][−|+]n

like the file access qualifier, except that it uses the file inode change time.

L[+|−]n

files less than n bytes (−), more than n bytes (+), or exactly n bytes in length. If this flag is directly followed by a ’k’ (’K’), ’m’ (’M’), or ’p’ (’P’) (e.g. ’Lk−50’) the check is performed with kilobytes, megabytes, or blocks (of 512 bytes) instead.

[beg[,end]]

specifies which of the matched filenames should be included in the returned list. The syntax is the same as for array subscripts. beg and the optional end may be mathematical expressions. As in parameter subscripting they may be negative to make them count from the last match backward. E.g.: ’*(−OL[1,3])’ gives a list of the names of the three largest files.

More than one of these lists can be combined, separated by commas. The whole list matches if at least one of the sublists matches (they are ’or’ed, the qualifiers in the sublists are ’and’ed). Some qualifiers, however, affect all matches generated, independent of the sublist in which they are given. These are the qualifiers ’M’, ’T’, ’N’, ’D’, ’n’, ’o’, ’O’ and the subscripts given in brackets (’[...]’).

If a ’:’ appears in a qualifier list, the remainder of the expression in parenthesis is interpreted as a modifier (see the section ’Modifiers’ in the section ’History Expansion’). Note that each modifier must be introduced by a separate ’:’. Note also that the result after modification does not have to be an existing file. The name of any existing file can be followed by a modifier of the form ’(:..)’ even if no actual filename generation is performed. Thus:

ls *(−/)

lists all directories and symbolic links that point to directories, and

ls *(%W)

lists all world−writable device files in the current directory, and

ls *(W,X)

lists all files in the current directory that are world−writable or world−executable, and

echo /tmp/foo*(u0^@:t)

outputs the basename of all root−owned files beginning with the string ’foo’ in /tmp, ignoring symlinks, and

ls *.*~(lex|parse).[ch](^D^l1)

lists all files having a link count of one whose names contain a dot (but not those starting with a dot, since GLOB_DOTS is explicitly switched off) except for lex.c, lex.h, parse.c and parse.h.

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. See the section ’Array Parameters’ 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, and they stay special even if unset. ’<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 (not the keys, but see Subscript Flags below), in no particular order. When an array parameter is referenced as ’$name’ (with no subscript) it evaluates to ’$name[*]’, unless the KSH_ARRAYS option is set in which case it evaluates to ’${name[0]}’ (for an associative array, this means the value of the key ’0’, which may not exist even if there are values for other keys).

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

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

Array Element Assignment
A subscript may be used on the left side of an assignment like so:

name[exp]=value

In this form of assignment the element or range specified by exp is replaced by the expression on the right side. An array (but not an associative array) may be created by assignment to a range or element. Arrays do not nest, so assigning a parenthesized list of values to an element or range changes the number of elements in the array, shifting the other elements to accommodate the new values. (This is not supported for associative arrays.)

This syntax also works as an argument to the typeset command:

typeset "name[exp]"=value

The value may not be a parenthesized list in this case; only single−element assignments may be made with typeset. Note that quotes are necessary in this case to prevent the brackets from being interpreted as filename generation operators. The noglob precommand modifier could be used instead.

To delete an element of an ordinary array, assign ’()’ to that element. To delete an element of an associative array, use the unset command:

unset "name[exp]"

Subscript Flags
If the opening bracket, or the comma in a range, in any subscript expression is directly followed by an opening parenthesis, the string up to the matching closing one is considered to be a list of flags, as in ’name[(flags)exp]’. The flags currently understood are:

s:string:

This gives the string that separates words (for use with the w flag).

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.

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.

The basic rule to remember when writing a subscript expression is that all text between the opening ’[’ and the closing ’]’ is interpreted as if it were in double quotes (see zshmisc(1)). However, unlike double quotes which normally cannot nest, subscript expressions may appear inside double−quoted strings or inside other subscript expressions (or both!), so the rules have two important differences.

The first difference is that brackets (’[’ and ’]’) must appear as balanced pairs in a subscript expression unless they are preceded by a backslash (’\’). Therefore, within a subscript expression (and unlike true double−quoting) the sequence ’\[’ becomes ’[’, and similarly ’\]’ becomes ’]’. This applies even in cases where a backslash is not normally required; for example, the pattern ’[^[]’ (to match any character other than an open bracket) should be written ’[^\[]’ in a reverse−subscript pattern. However, note that ’\[^\[\]’ and even ’\[^[]’ mean the same thing, because backslashes are always stripped when they appear before brackets!

The same rule applies to parentheses (’(’ and ’)’) and braces (’{’ and ’}’): they must appear either in balanced pairs or preceded by a backslash, and backslashes that protect parentheses or braces are removed during parsing. This is because parameter expansions may be surrounded balanced braces, and subscript flags are introduced by balanced 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 contains an odd number of double−quote characters, but the reason for this difference is so that when a subscript expression appears inside true double−quotes, one can still write ’\"’ (rather than ’\\\"’) for ’"’.

To use an odd number of double quotes as a key in an assignment, use the typeset builtin and an enclosing pair of double quotes; to refer to the value of that key, again use double quotes:

typeset −A aa
typeset "aa[one\"two\"three\"quotes]"=QQQ
print "$aa[one\"two\"three\"quotes]"

It is important to note that the quoting rules do not change when a parameter expansion with a subscript is nested inside another subscript expression. That is, it is not necessary to use additional backslashes within the inner subscript expression; they are removed only once, from the innermost subscript outwards. Parameters are also expanded from the innermost subscript first, as each expansion is encountered left to right in the outer expression.

A further complication arises from a way in which subscript parsing is not different from double quote parsing. As in true double−quoting, the sequences ’\*’, and ’\@’ remain as two characters when they appear in a subscript expression. To use a literal ’*’ or ’@’ as an associative array key, the ’e’ flag must be used:

typeset −A aa
aa[(e)*]=star
print $aa[(e)*]

A last detail must be considered when reverse subscripting is performed. Parameters appearing in the subscript expression are first expanded and then the complete expression is interpreted as a pattern. This has two effects: first, parameters behave as if GLOB_SUBST were on (and it cannot be turned off); second, backslashes are interpreted twice, once when parsing the array subscript and again when parsing the pattern. In a reverse subscript, it’s necessary to use four backslashes to cause a single backslash to match literally in the pattern. For complex patterns, it is often easiest to assign the desired pattern to a parameter and then refer to that parameter in the subscript, because then the backslashes, brackets, parentheses, etc., are seen only when the complete expression is converted to a pattern. To match the value of a parameter literally in a reverse subscript, rather than as a pattern, use ’${(q)name}’ (see zshexpn(1)) to quote the expanded value.

Note that the ’k’ and ’K’ flags are reverse subscripting for an ordinary array, but are not reverse subscripting for an associative array! (For an associative array, the keys in the array itself are interpreted as patterns by those flags; the subscript is a plain string in that case.)

One final note, not directly related to subscripting: the numeric names of positional parameters (described below) are parsed specially, so for example ’$2foo’ is equivalent to ’${2}foo’. Therefore, to use subscript syntax to extract a substring from a positional parameter, the expansion must be surrounded by braces; for example, ’${2[3,5]}’ evaluates to the third through fifth characters of the second positional parameter, but ’$2[3,5]’ is the entire second parameter concatenated with the filename generation pattern ’[3,5]’.

POSITIONAL PARAMETERS

The positional parameters provide access to the command−line arguments of a shell function, shell script, or the shell itself; see the section ’Invocation’, and also the section ’Functions’. The parameter n, where n is a number, is the nth positional parameter. The 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 values. Note that, because the positional parameters form an array, an array assignment of the form ’n=(value ...)’ is allowed, and has the effect of shifting all the values at positions greater than n by as many positions as necessary to accommodate the new values.

LOCAL PARAMETERS

Shell function executions delimit scopes for shell parameters. (Parameters are dynamically scoped.) The typeset builtin, and its alternative forms declare, integer, local and readonly (but not export), can be used to declare a parameter as being local to the innermost scope.

When a parameter is read or assigned to, the innermost existing parameter of that name is used. (That is, the local parameter hides any less−local parameter.) However, assigning to a non−existent parameter, or declaring a new parameter with export, causes it to be created in the outermost scope.

Local parameters disappear when their scope ends. unset can be used to delete a parameter while it is still in scope; any outer parameter of the same name remains hidden.

Special parameters may also be made local; they retain their special attributes unless either the existing or the newly−created parameter has the −h (hide) attribute. This may have unexpected effects: there is no default value, so if there is no assignment at the point the variable is made local, it will be set to an empty value (or zero in the case of integers). The following:

typeset PATH=/new/directory:$PATH

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

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

PARAMETERS SET BY THE SHELL

The following parameters are automatically set by the shell:

ARGC <S> <Z>

Same as #.

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).

status <S> <Z>

Same as ?.

pipestatus <S> <Z>

An array containing the exit values returned by all commands in the last pipeline.

CPUTYPE

The machine type (microprocessor class or machine model), as determined at run time.

EGID <S>

The effective group ID of the shell process. If you have sufficient privileges, you may change the effective group ID of the shell process by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command with a different effective group ID by ’(EGID=gid; command)’

EUID <S>

The effective user ID of the shell process. If you have sufficient privileges, you may change the effective user ID of the shell process by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command with a different effective user ID by ’(EUID=uid; command)’

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.

GID <S>

The real group ID of the shell process. If you have sufficient privileges, you may change the group ID of the shell process by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command under a different group ID by ’(GID=gid; command)’

LINENO <S>

The line number of the current line within the current script, sourced file, or shell function being executed, whichever was started most recently. Note that in the case of shell functions the line number refers to the function as it appeared in the original definition, not necessarily as displayed by the functions builtin.

LOGNAME

If the corresponding variable is not set in the environment of the shell, it is initialized to the login name corresponding to the current login session. This parameter is exported by default but this can be disabled using the typeset builtin.

MACHTYPE

The machine type (microprocessor class or machine model), as determined at compile time.

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.

PPID <S>

The process ID of the parent of the shell.

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 RANDOM.

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.

SHLVL <S>

Incremented by one each time a new shell is started.

signals

An array containing the names of the signals.

TTYIDLE <S>

The idle time of the tty associated with the shell in seconds or −1 if there is no such tty.

UID <S>

The real user ID of the shell process. If you have sufficient privileges, you may change the user ID of the shell by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command under a different user ID by ’(UID=uid; command)’

USERNAME <S>

The username corresponding to the real user ID of the shell process. If you have sufficient privileges, you may change the username (and also the user ID and group ID) of the shell by assigning to this parameter. Also (assuming sufficient privileges), you may start a single command under a different username (and user ID and group ID) by ’(USERNAME=username; command)’

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 recreated, and recreating one of the pair will recreate the other.

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.

fignore <S> <Z> (FIGNORE <S>)

An array (colon separated list) containing the suffixes of files to be ignored during filename completion. However, if completion only generates files with suffixes in this list, then these files are completed anyway.

fpath <S> <Z> (FPATH <S>)

An array (colon separated list) of directories specifying the search path for function definitions. This path is searched when a function with the −u attribute is referenced. If an executable file is found, then it is read and executed in the current environment.

histchars <S>

Three characters used by the shell’s history and lexical analysis mechanism. The first character signals the start of a history expansion (default ’!’). The second character signals the start of a quick history substitution (default ’^’). The third character is the comment character (default ’#’).

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 difference 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 collation information within ranges in glob brackets and for sorting.

LC_CTYPE <S>

This variable determines the locale category for character handling 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 printing select lists and for the line editor.

LISTMAX

In the line editor, the number of matches to list without asking first. If the value is negative, the list will be shown if it spans at most as many lines as given by the absolute value. If set to zero, the shell asks only if the top of the listing would scroll off the screen.

LOGCHECK

The interval in seconds between checks for login/logout activity using the watch parameter.

MAILCHECK

The interval in seconds between checks for new mail.

mailpath <S> <Z> (MAILPATH <S>)

An array (colon−separated list) of filenames to check for new mail. Each filename can be followed by a ’?’ and a message that will be printed. The message will undergo parameter expansion, command substitution and arithmetic expansion with the variable $_ defined as the name of the file that has changed. The default message is ’You have new mail’. If an element is a directory instead of a file the shell will recursively check every file in every subdirectory of the element.

manpath <S> <Z> (MANPATH <S> <Z>)

An array (colon−separated list) whose value is not used by the shell. The manpath array can be useful, however, since setting it also sets MANPATH, and vice versa.

module_path <S> <Z> (MODULE_PATH <S>)

An array (colon−separated list) of directories that zmodload searches for dynamically loadable modules. This is initialized to a standard pathname, usually ’/usr/local/lib/zsh/$ZSH_VERSION’. (The ’/usr/local/lib’ part varies from installation to installation.) For security reasons, any value set in the environment when the shell is started will be ignored.

These parameters only exist if the installation supports dynamic module loading.

NULLCMD <S>

The command name to assume if a redirection is specified with no command. Defaults to cat. For sh/ksh behavior, change this to :. For csh−like behavior, unset this parameter; the shell will print an error message if null commands are entered.

path <S> <Z> (PATH <S>)

An array (colon−separated list) of directories to search for commands. When this parameter is set, each directory is scanned and all files found are put in a hash table.

POSTEDIT <S>

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

PROMPT <S> <Z>
PROMPT2 <S> <Z>
PROMPT3 <S> <Z>
PROMPT4 <S> <Z>

Same as PS1, PS2, PS3 and PS4, respectively.

prompt <S> <Z>

Same as PS1.

PS1 <S>

The primary prompt string, printed before a command is read. the default is ’%m%# ’. It undergoes a special form of expansion before being displayed; see the section ’Prompt Expansion’.

PS2 <S>

The secondary prompt, printed when the shell needs more information to complete a command. It is expanded in the same way as PS1. The default is ’%_> ’, which displays any shell constructs or quotation marks which are currently being processed.

PS3 <S>

Selection prompt used within a select loop. It is expanded in the same way as PS1. The default is ’?# ’.

PS4 <S>

The execution trace prompt. Default is ’+%N:%i> ’, which displays the name of the current shell structure and the line number within it. In sh or ksh emulation, the default is ’+ ’.

psvar <S> <Z> (PSVAR <S>)

An array (colon−separated list) whose 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 execution times (measured in seconds) are greater than this value have timing statistics printed for them.

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.

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

TERM <S>

The type of terminal in use. This is used when looking up termcap sequences. An assignment to TERM causes zsh to re−initialize the terminal, even if the value does not change (e.g., ’TERM=$TERM’). It is necessary to make such an assignment upon any change to the terminal definition database or terminal type in order for the new settings to take effect.

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 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).

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 following escape sequences:

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.

%(x:true−text:false−text)

Specifies a ternary expression. The character following the x is arbitrary; the same character is used to separate the text for the "true" result from that for the "false" result. Both the separator and the right parenthesis may be escaped with a backslash. Ternary expressions may be nested.

The test character x may be any one of ’l’, ’n’, ’m’ or ’M’, which indicate a ’true’ result if the corresponding escape sequence would return a non−empty value; or it may be ’a’, which indicates a ’true’ result if the watched user has logged in, or ’false’ if he has logged out. Other characters evaluate to neither true nor false; the entire expression is omitted in this case.

If the result is ’true’, then the true−text is formatted according to the rules above and printed, and the false−text is skipped. If ’false’, the true−text is skipped and the false−text is formatted and printed. Either or both of the branches may be empty, but both separators must be present in any case.

WORDCHARS <S>

A list of non−alphanumeric characters considered part of a word by the line editor.

ZDOTDIR

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

NAME

zshoptions − zsh options

SPECIFYING OPTIONS

Options are primarily referred to by name. These names are case insensitive and underscores are ignored. For example, ’allexport’ is equivalent to ’A__lleXP_ort’.

The sense of an option name may be inverted by preceding it with ’no’, so ’setopt No_Beep’ is equivalent to ’unsetopt beep’. This inversion can only be done once, so ’nonobeep’ is not a synonym for ’beep’. Similarly, ’tify’ is not a synonym for ’nonotify’ (the inversion of ’notify’).

Some options also have one or more single letter names. There are two sets of single letter options: one used by default, and another used to emulate sh/ksh (used when the SH_OPTION_LETTERS option is set). The single letter options can be used on the shell command line, or with the set, setopt and unsetopt builtins, as normal Unix options preceded by ’−’.

The sense of the single letter options may be inverted by using ’+’ instead of ’−’. Some of the single letter option names refer to an option being off, in which case the inversion of that name refers to the option being on. For example, ’+n’ is the short name of ’exec’, and ’−n’ is the short name of its inversion, ’noexec’.

In strings of single letter options supplied to the shell at startup, trailing whitespace will be ignored; for example the string ’−f ’ will be treated just as ’−f’, but the string ’−f i’ is an error. This is because many systems which implement the ’#!’ mechanism for calling scripts do not strip trailing whitespace.

DESCRIPTION OF OPTIONS

In the following list, options set by default in all emulations are marked <D>; those set by default only in csh, ksh, sh, or zsh emulations are marked <C>, <K>, <S>, <Z> as appropriate. When listing options (by ’setopt’, ’unsetopt’, ’set −o’ or ’set +o’), those turned on by default appear in the list prefixed with ’no’. Hence (unless KSH_OPTION_PRINT is set), ’setopt’ shows all options whose settings are changed from the default.
ALIASES <D>

Expand aliases.

ALL_EXPORT (−a, ksh: −a)

All parameters subsequently defined are automatically exported.

ALWAYS_LAST_PROMPT <D>

If unset, key functions that list completions try to return to the last prompt if given a numeric argument. If set these functions try to return to the last prompt if given no numeric argument.

ALWAYS_TO_END

If a completion is performed with the cursor within a word, and a full completion is inserted, the cursor is moved to the end of the word. That is, the cursor is moved to the end of the word if either a single match is inserted or menu completion is performed.

APPEND_HISTORY <D>

If this is set, zsh sessions will append their history list to the history file, rather than overwrite it. Thus, multiple parallel zsh sessions will all have their history lists added to the history file, in the order they are killed.

AUTO_CD (−J)

If a command is issued that can’t be executed as a normal command, and the command is the name of a directory, perform the cd command to that directory.

AUTO_LIST (−9) <D>

Automatically list choices on an ambiguous completion.

AUTO_MENU <D>

Automatically use menu completion after the second consecutive request for completion, for example by pressing the tab key repeatedly. This option is overridden by MENU_COMPLETE.

AUTO_NAME_DIRS

Any parameter that is set to the absolute name of a directory immediately becomes a name for that directory, that will be used by the ’%~’ and related prompt sequences, and will be available when completion is performed on a word starting with ’~’. (Otherwise, the parameter must be used in the form ’~param’ first.)

AUTO_PARAM_KEYS <D>

If a parameter name was completed and a following character (normally a space) automatically inserted, and the next character typed is one of those that have to come directly after the name (like ’}’, ’:’, etc.), the automatically added character is deleted, so that the character typed comes immediately after the parameter name. Completion in a brace expansion is affected similarly: the added character is a ’,’, which will be removed if ’}’ is typed next.

AUTO_PARAM_SLASH <D>

If a parameter is completed whose content is the name of a directory, then add a trailing slash instead of a space.

AUTO_PUSHD (−N)

Make cd push the old directory onto the directory stack.

AUTO_REMOVE_SLASH <D>

When the last character resulting from a completion is a slash and the next character typed is a word delimiter, a slash, or a character that ends a command (such as a semicolon or an ampersand), remove the slash.

AUTO_RESUME (−W)

Treat single word simple commands without redirection as candidates for resumption of an existing job.

BAD_PATTERN (+2) <C> <Z>

If a pattern for filename generation is badly formed, print an error message. (If this option is unset, the pattern will be left unchanged.)

BANG_HIST (+K) <C> <Z>

Perform textual history expansion, csh−style, treating the character ’!’ specially.

BARE_GLOB_QUAL <Z>

In a glob pattern, treat a trailing set of parentheses as a qualifier list, if it contains no ’|’, ’(’ or (if special) ’~’ characters. See the section ’Filename Generation’.

BASH_AUTO_LIST

On an ambiguous completion, automatically list choices when the completion function is called twice in succession. This takes precedence over AUTO_LIST. The setting of LIST_AMBIGUOUS is respected. If AUTO_MENU is set, the menu behaviour will then start with the third press. Note that this will not work with MENU_COMPLETE, since repeated completion calls immediately cycle through the list in that case.

BEEP (+B) <D>

Beep on error in ZLE.

BG_NICE (−6) <C> <Z>

Run all background jobs at a lower priority. This option is set by default.

BRACE_CCL

Expand expressions in braces which would not otherwise undergo brace expansion to a lexically ordered list of all the characters. See the section ’Brace Expansion’.

BSD_ECHO <S>

Make the echo builtin compatible with the BSD echo(1) command. This disables backslashed escape sequences in echo strings unless the −e option is specified.

C_BASES

Output hexadecimal numbers in the standard C format, for example ’0xFF’ instead of the usual ’16#FF’. If the option OCTAL_ZEROES is also set (it is not by default), octal numbers will be treated similarly and hence appear as ’077’ instead of ’8#77’. This option has no effect on the choice of the output base, nor on the output of bases other than hexadecimal and octal. Note that these formats will be understood on input irrespective of the setting of C_BASES.

CDABLE_VARS (−T)

If the argument to a cd command (or an implied cd with the AUTO_CD option set) is not a directory, and does not begin with a slash, try to expand the expression as if it were preceded by a ’~’ (see the section ’Filename Expansion’).

CHASE_DOTS

When changing to a directory containing a path segment ’..’ which would otherwise be treated as canceling the previous segment in the path (in other words, ’foo/..’ would be removed from the path, or if ’..’ is the first part of the path, the last part of $PWD would be deleted), instead resolve the path to the physical directory. This option is overridden by CHASE_LINKS.

For example, suppose /foo/bar is a link to the directory /alt/rod. Without this option set, ’cd /foo/bar/..’ changes to /foo; with it set, it changes to /alt. The same applies if the current directory is /foo/bar and ’cd ..’ is used. Note that all other symbolic links in the path will also be resolved.

CHASE_LINKS (−w)

Resolve symbolic links to their true values when changing directory. This also has the effect of CHASE_DOTS, i.e. a ’..’ path segment will be treated as referring to the physical parent, even if the preceding path segment is a symbolic link.

CHECK_JOBS <Z>

Report the status of background and suspended jobs before exiting a shell with job control; a second attempt to exit the shell will succeed. NO_CHECK_JOBS is best used only in combination with NO_HUP, else such jobs will be killed automatically.

The check is omitted if the commands run from the previous command line included a ’jobs’ command, since it is assumed the user is aware that there are background or suspended jobs. A ’jobs’ command run from the precmd function is not counted for this purpose.

CLOBBER (+C, ksh: +C) <D>

Allows ’>’ redirection to truncate existing files, and ’>>’ to create files. Otherwise ’>!’ or ’>|’ must be used to truncate a file, and ’>>!’ or ’>>|’ to create a file.

COMPLETE_ALIASES

Prevents aliases on the command line from being internally substituted before completion is attempted. The effect is to make the alias a distinct command for completion purposes.

COMPLETE_IN_WORD

If unset, the cursor is set to the end of the word if completion is started. Otherwise it stays there and completion is done from both ends.

CORRECT (−0)

Try to correct the spelling of commands.

CORRECT_ALL (−O)

Try to correct the spelling of all arguments in a line.

CSH_JUNKIE_HISTORY <C>

A history reference without an event specifier will always refer to the previous command. Without this option, such a history reference refers to the same event as the previous history reference, defaulting to the previous command.

CSH_JUNKIE_LOOPS <C>

Allow loop bodies to take the form ’list; end’ instead of ’do list; done’.

CSH_JUNKIE_QUOTES <C>

Changes the rules for single− and double−quoted text to match that of csh. These require that embedded newlines be preceded by a backslash; unescaped newlines will cause an error message. In double−quoted strings, it is made impossible to escape ’$’, ’’’ or ’"’ (and ’\’ itself no longer needs escaping). Command substitutions are only expanded once, and cannot be nested.

CSH_NULLCMD <C>

Do not use the values of NULLCMD and READNULLCMD when running redirections with no command. This make such redirections fail (see the section ’Redirection’).

CSH_NULL_GLOB <C>

If a pattern for filename generation has no matches, delete the pattern from the argument list; do not report an error unless all the patterns in a command have no matches. Overrides NOMATCH.

EQUALS <Z>

Perform = filename expansion. (See the section ’Filename Expansion’.)

ERR_EXIT (−e, ksh: −e)

If a command has a non−zero exit status, execute the ZERR trap, if set, and exit. This is disabled while running initialization scripts.

EXEC (+n, ksh: +n) <D>

Do execute commands. Without this option, commands are read and checked for syntax errors, but not executed. This option cannot be turned off in an interactive shell, except when ’−n’ is supplied to the shell at startup.

EXTENDED_GLOB

Treat the ’#’, ’~’ and ’^’ characters as part of patterns for filename generation, etc. (An initial unquoted ’~’ always produces named directory expansion.)

EXTENDED_HISTORY <C>

Save each command’s beginning timestamp (in seconds since the epoch) and the duration (in seconds) to the history file. The format of this prefixed data is:

’:<beginning time>:<elapsed seconds>:<command>’.

FLOW_CONTROL <D>

If this option is unset, output flow control via start/stop characters (usually assigned to ^S/^Q) is disabled in the shell’s editor.

FUNCTION_ARGZERO <C> <Z>

When executing a shell function or sourcing a script, set $0 temporarily to the name of the function/script.

GLOB (+F, ksh: +f) <D>

Perform filename generation (globbing). (See the section ’Filename Generation’.)

GLOBAL_EXPORT (<Z>)

If this option is set, passing the −x flag to the builtins declare, float, integer, readonly and typeset (but not local) will also set the −g flag; hence parameters exported to the environment will not be made local to the enclosing function, unless they were already or the flag +g is given explicitly. If the option is unset, exported parameters will be made local in just the same way as any other parameter.

This option is set by default for backward compatibility; it is not recommended that its behaviour be relied upon. Note that the builtin export always sets both the −x and −g flags, and hence its effect extends beyond the scope of the enclosing function; this is the most portable way to achieve this behaviour.

GLOBAL_RCS (−d) <D>

If this option is unset, the startup files /etc/zprofile, /etc/zshrc, /etc/zlogin and /etc/zlogout will not be run. It can be disabled and re−enabled at any time, including inside local startup files (.zshrc, etc.).

GLOB_ASSIGN <C>

If this option is set, filename generation (globbing) is performed on the right hand side of scalar parameter assignments of the form ’name=pattern (e.g. ’foo=*’). If the result has more than one word the parameter will become an array with those words as arguments. This option is provided for backwards compatibility only: globbing is always performed on the right hand side of array assignments of the form ’name=(value)’ (e.g. ’foo=(*)’) and this form is recommended for clarity; with this option set, it is not possible to predict whether the result will be an array or a scalar.

GLOB_COMPLETE

When the current word has a glob pattern, do not insert all the words resulting from the expansion but generate matches as for completion and cycle through them like MENU_COMPLETE. The matches are generated as if a ’*’ was added to the end of the word, or inserted at the cursor when COMPLETE_IN_WORD is set. This actually uses pattern matching, not globbing, so it works not only for files but for any completion, such as options, user names, etc.

GLOB_DOTS (−4)

Do not require a leading ’.’ in a filename to be matched explicitly.

GLOB_SUBST <C> <K> <S>

Treat any characters resulting from parameter expansion as being eligible for file expansion and filename generation, and any characters resulting from command substitution as being eligible for filename generation. Braces (and commas in between) do not become eligible for expansion.

HASH_CMDS <D>

Note the location of each command the first time it is executed. Subsequent invocations of the same command will use the saved location, avoiding a path search. If this option is unset, no path hashing is done at all. However, when CORRECT is set, commands whose names do not appear in the functions or aliases hash tables are hashed in order to avoid reporting them as spelling errors.

HASH_DIRS <D>

Whenever a command name is hashed, hash the directory containing it, as well as all directories that occur earlier in the path. Has no effect if neither HASH_CMDS nor CORRECT is set.

HASH_LIST_ALL <D>

Whenever a command completion is attempted, make sure the entire command path is hashed first. This makes the first completion slower.

HIST_ALLOW_CLOBBER

Add ’|’ to output redirections in the history. This allows history references to clobber files even when CLOBBER is unset.

HIST_BEEP <D>

Beep when an attempt is made to access a history entry which isn’t there.

HIST_EXPIRE_DUPS_FIRST

If the internal history needs to be trimmed to add the current command line, setting this option will cause the oldest history event that has a duplicate to be lost before losing a unique event from the list. You should be sure to set the value of HISTSIZE to a larger number than SAVEHIST in order to give you some room for the duplicated events, otherwise this option will behave just like HIST_IGNORE_ALL_DUPS once the history fills up with unique events.

HIST_FIND_NO_DUPS

When searching for history entries in the line editor, do not display duplicates of a line previously found, even if the duplicates are not contiguous.

HIST_IGNORE_ALL_DUPS

If a new command line being added to the history list duplicates an older one, the older command is removed from the list (even if it is not the previous event).

HIST_IGNORE_DUPS (−h)

Do not enter command lines into the history list if they are duplicates of the previous event.

HIST_IGNORE_SPACE (−g)

Remove command lines from the history list when the first character on the line is a space, or when one of the expanded aliases contains a leading space. Note that the command lingers in the internal history until the next command is entered before it vanishes, allowing you to briefly reuse or edit the line. If you want to make it vanish right away without entering another command, type a space and press return.

HIST_NO_FUNCTIONS

Remove function definitions from the history list. Note that the function lingers in the internal history until the next command is entered before it vanishes, allowing you to briefly reuse or edit the definition.

HIST_NO_STORE

Remove the history (fc −l) command from the history list when invoked. Note that the command lingers in the internal history until the next command is entered before it vanishes, allowing you to briefly reuse or edit the line.

HIST_REDUCE_BLANKS

Remove superfluous blanks from each command line being added to the history list.

HIST_SAVE_NO_DUPS

When writing out the history file, older commands that duplicate newer ones are omitted.

HIST_VERIFY

Whenever the user enters a line with history expansion, don’t execute the line directly; instead, perform history expansion and reload the line into the editing buffer.

HUP <Z>

Send the HUP signal to running jobs when the shell exits.

IGNORE_BRACES (−I) <S>

Do not perform brace expansion.

IGNORE_EOF (−7)

Do not exit on end−of−file. Require the use of exit or logout instead. However, ten consecutive EOFs will cause the shell to exit anyway, to avoid the shell hanging if its tty goes away.

Also, if this option is set and the Zsh Line Editor is used, widgets implemented by shell functions can be bound to EOF (normally Control−D) without printing the normal warning message. This works only for normal widgets, not for completion widgets.

INC_APPEND_HISTORY

This options works like APPEND_HISTORY except that new history lines are added to the $HISTFILE incrementally (as soon as they are entered), rather than waiting until the shell is killed. The file is periodically trimmed to the number of lines specified by $SAVEHIST, but can exceed this value between trimmings.

INTERACTIVE (−i, ksh: −i)

This is an interactive shell. This option is set upon initialisation if the standard input is a tty and commands are being read from standard input. (See the discussion of SHIN_STDIN.) This heuristic may be overridden by specifying a state for this option on the command line. The value of this option cannot be changed anywhere other than the command line.

INTERACTIVE_COMMENTS (−k) <K> <S>

Allow comments even in interactive shells.

KSH_ARRAYS <K> <S>

Emulate ksh array handling as closely as possible. If this option is set, array elements are numbered from zero, an array parameter without subscript refers to the first element instead of the whole array, and braces are required to delimit a subscript (’${path[2]}’ rather than just ’$path[2]’).

KSH_AUTOLOAD <K> <S>

Emulate ksh function autoloading. This means that when a function is autoloaded, the corresponding file is merely executed, and must define the function itself. (By default, the function is defined to the contents of the file. However, the most common ksh−style case − of the file containing only a simple definition of the function − is always handled in the ksh−compatible manner.)

KSH_GLOB <K>

In pattern matching, the interpretation of parentheses is affected by a preceding ’@’, ’*’, ’+’, ’?’ or ’!’. See the section ’Filename Generation’.

KSH_OPTION_PRINT <K>

Alters the way options settings are printed: instead of separate lists of set and unset options, all options are shown, marked ’on’ if they are in the non−default state, ’off’ otherwise.

KSH_TYPESET <K>

Alters the way arguments to the typeset family of commands, including declare, export, float, integer, local and readonly, are processed. Without this option, zsh will perform normal word splitting after command and parameter expansion in arguments of an assignment; with it, word splitting does not take place in those cases.

LIST_AMBIGUOUS <D>

This option works when AUTO_LIST or BASH_AUTO_LIST is also set. If there is an unambiguous prefix to insert on the command line, that is done without a completion list being displayed; in other words, auto−listing behaviour only takes place when nothing would be inserted. In the case of BASH_AUTO_LIST, this means that the list will be delayed to the third call of the function.

LIST_BEEP <D>

Beep on an ambiguous completion. More accurately, this forces the completion widgets to return status 1 on an ambiguous completion, which causes the shell to beep if the option BEEP is also set; this may be modified if completion is called from a user−defined widget.

LIST_PACKED

Try to make the completion list smaller (occupying less lines) by printing the matches in columns with different widths.

LIST_ROWS_FIRST

Lay out the matches in completion lists sorted horizontally, that is, the second match is to the right of the first one, not under it as usual.

LIST_TYPES (−X) <D>

When listing files that are possible completions, show the type of each file with a trailing identifying mark.

LOCAL_OPTIONS <K>

If this option is set at the point of return from a shell function, all the options (including this one) which were in force upon entry to the function are restored. Otherwise, only this option and the XTRACE and PRINT_EXIT_VALUE options are restored. Hence if this is explicitly unset by a shell function the other options in force at the point of return will remain so. A shell function can also guarantee itself a known shell configuration with a formulation like ’emulate −L zsh’; the −L activates LOCAL_OPTIONS.

LOCAL_TRAPS <K>

If this option is set when a signal trap is set inside a function, then the previous status of the trap for that signal will be restored when the function exits. Note that this option must be set prior to altering the trap behaviour in a function; unlike LOCAL_OPTIONS, the value on exit from the function is irrelevant. However, it does not need to be set before any global trap for that to be correctly restored by a function. For example,

unsetopt localtraps
trap − INT
fn() { setopt localtraps; trap ’’ INT; sleep 3; }

will restore normally handling of SIGINT after the function exits.

LOGIN (−l, ksh: −l)

This is a login shell. If this option is not explicitly set, the shell is a login shell if the first character of the argv[0] passed to the shell is a ’−’.

LONG_LIST_JOBS (−R)

List jobs in the long format by default.

MAGIC_EQUAL_SUBST

All unquoted arguments of the form ’anything=expression’ appearing after the command name have filename expansion (that is, where expression has a leading ’~’ or ’=’) performed on expression as if it were a parameter assignment. The argument is not otherwise treated specially; it is passed to the command as a single argument, and not used as an actual parameter assignment. For example, in echo foo=~/bar:~/rod, both occurrences of ~ would be replaced. Note that this happens anyway with typeset and similar statements.

This option respects the setting of the KSH_TYPESET option. In other words, if both options are in effect, arguments looking like assignments will not undergo wordsplitting.

MAIL_WARNING (−U)

Print a warning message if a mail file has been accessed since the shell last checked.

MARK_DIRS (−8, ksh: −X)

Append a trailing ’/’ to all directory names resulting from filename generation (globbing).

MENU_COMPLETE (−Y)

On an ambiguous completion, instead of listing possibilities or beeping, insert the first match immediately. Then when completion is requested again, remove the first match and insert the second match, etc. When there are no more matches, go back to the first one again. reverse−menu−complete may be used to loop through the list in the other direction. This option overrides AUTO_MENU.

MONITOR (−m, ksh: −m)

Allow job control. Set by default in interactive shells.

MULTIOS <Z>

Perform implicit tees or cats when multiple redirections are attempted (see the section ’Redirection’).

NOMATCH (+3) <C> <Z>

If a pattern for filename generation has no matches, print an error, instead of leaving it unchanged in the argument list. This also applies to file expansion of an initial ’~’ or ’=’.

NOTIFY (−5, ksh: −b) <Z>

Report the status of background jobs immediately, rather than waiting until just before printing a prompt.

NULL_GLOB (−G)

If a pattern for filename generation has no matches, delete the pattern from the argument list instead of reporting an error. Overrides NOMATCH.

NUMERIC_GLOB_SORT

If numeric filenames are matched by a filename generation pattern, sort the filenames numerically rather than lexicographically.

OCTAL_ZEROES <S>

Interpret any integer constant beginning with a 0 as octal, per IEEE Std 1003.2−1992 (ISO 9945−2:1993). This is not enabled by default as it causes problems with parsing of, for example, date and time strings with leading zeroes.

OVERSTRIKE

Start up the line editor in overstrike mode.

PATH_DIRS (−Q)

Perform a path search even on command names with slashes in them. Thus if ’/usr/local/bin’ is in the user’s path, and he or she types ’X11/xinit’, the command ’/usr/local/bin/X11/xinit’ will be executed (assuming it exists). Commands explicitly beginning with ’/’, ’./’ or ’../’ are not subject to the path search. This also applies to the . builtin.

Note that subdirectories of the current directory are always searched for executables specified in this form. This takes place before any search indicated by this option, and regardless of whether ’.’ or the current directory appear in the command search path.

POSIX_BUILTINS <K> <S>

When this option is set the command builtin can be used to execute shell builtin commands. Parameter assignments specified before shell functions and special builtins are kept after the command completes unless the special builtin is prefixed with the command builtin. Special builtins are ., :, break, continue, declare, eval, exit, export, integer, local, readonly, return, set, shift, source, times, trap and unset.

PRINT_EIGHT_BIT

Print eight bit characters literally in completion lists, etc. This option is not necessary if your system correctly returns the printability of eight bit characters (see ctype(3)).

PRINT_EXIT_VALUE (−1)

Print the exit value of programs with non−zero exit status.

PRIVILEGED (−p, ksh: −p)

Turn on privileged mode. This is enabled automatically on startup if the effective user (group) ID is not equal to the real user (group) ID. Turning this option off causes the effective user and group IDs to be set to the real user and group IDs. This option disables sourcing user startup files. If zsh is invoked as ’sh’ or ’ksh’ with this option set, /etc/suid_profile is sourced (after /etc/profile on interactive shells). Sourcing ~/.profile is disabled and the contents of the ENV variable is ignored. This option cannot be changed using the −m option of setopt and unsetopt, and changing it inside a function always changes it globally regardless of the LOCAL_OPTIONS option.

PROMPT_BANG <K>

If set, ’!’ is treated specially in prompt expansion. See the section ’Prompt Expansion’.

PROMPT_CR (+V) <D>

Print a carriage return just before printing a prompt in the line editor. This is on by default as multi−line editing is only possible if the editor knows where the start of the line appears.

PROMPT_PERCENT <C> <Z>

If set, ’%’ is treated specially in prompt expansion. See the section ’Prompt Expansion’.

PROMPT_SUBST <K>

If set, parameter expansion, command substitution and arithmetic expansion are performed in prompts.

PUSHD_IGNORE_DUPS

Don’t push multiple copies of the same directory onto the directory stack.

PUSHD_MINUS

Exchanges the meanings of ’+’ and ’−’ when used with a number to specify a directory in the stack.

PUSHD_SILENT (−E)

Do not print the directory stack after pushd or popd.

PUSHD_TO_HOME (−D)

Have pushd with no arguments act like ’pushd $HOME’.

RC_EXPAND_PARAM (−P)

Array expansions of the form ’foo${xx}bar’, where the parameter xx is set to (a b c), are substituted with ’fooabar foobbar foocbar’ instead of the default ’fooa b cbar’.

RC_QUOTES

Allow the character sequence ’’’’ to signify a single quote within singly quoted strings. Note this does not apply in quoted strings using the format $’...’, where a backslashed single quote can be used.

RCS (+f) <D>

After /etc/zshenv is sourced on startup, source the .zshenv, /etc/zprofile, .zprofile, /etc/zshrc, .zshrc, /etc/zlogin, .zlogin, and .zlogout files, as described in the section ’Files’. If this option is unset, the /etc/zshenv file is still sourced, but any of the others will not be; it can be set at any time to prevent the remaining startup files after the currently executing one from being sourced.

REC_EXACT (−S)

In completion, recognize exact matches even if they are ambiguous.

RESTRICTED (−r)

Enables restricted mode. This option cannot be changed using unsetopt, and setting it inside a function always changes it globally regardless of the LOCAL_OPTIONS option. See the section ’Restricted Shell’.

RM_STAR_SILENT (−H) <K> <S>

Do not query the user before executing ’rm *’ or ’rm path/*’.

RM_STAR_WAIT

If querying the user before executing ’rm *’ or ’rm path/*’, first wait ten seconds and ignore anything typed in that time. This avoids the problem of reflexively answering ’yes’ to the query when one didn’t really mean it. The wait and query can always be avoided by expanding the ’*’ in ZLE (with tab).

SHARE_HISTORY <K>

This option both imports new commands from the history file, and also causes your typed commands to be appended to the history file (the latter is like specifying INC_APPEND_HISTORY). The history lines are also output with timestamps ala EXTENDED_HISTORY (which makes it easier to find the spot where we left off reading the file after it gets re−written).

By default, history movement commands visit the imported lines as well as the local lines, but you can toggle this on and off with the set−local−history zle binding. It is also possible to create a zle widget that will make some commands ignore imported commands, and some include them.

If you find that you want more control over when commands get imported, you may wish to turn SHARE_HISTORY off, INC_APPEND_HISTORY on, and then manually import commands whenever you need them using ’fc −RI’.

SH_FILE_EXPANSION <K> <S>

Perform filename expansion (e.g., ~ expansion) before parameter expansion, command substitution, arithmetic expansion and brace expansion. If this option is unset, it is performed after brace expansion, so things like ’~$USERNAME’ and ’~{pfalstad,rc}’ will work.

SH_GLOB <K> <S>

Disables the special meaning of ’(’, ’|’, ’)’ and ’<’ for globbing the result of parameter and command substitutions, and in some other places where the shell accepts patterns. This option is set by default if zsh is invoked as sh or ksh.

SHIN_STDIN (−s, ksh: −s)

Commands are being read from the standard input. Commands are read from standard input if no command is specified with −c and no file of commands is specified. If SHIN_STDIN is set explicitly on the command line, any argument that would otherwise have been taken as a file to run will instead be treated as a normal positional parameter. Note that setting or unsetting this option on the command line does not necessarily affect the state the option will have while the shell is running − that is purely an indicator of whether on not commands are actually being read from standard input. The value of this option cannot be changed anywhere other than the command line.

SH_NULLCMD <K> <S>

Do not use the values of NULLCMD and READNULLCMD when doing redirections, use ’:’ instead (see the section ’Redirection’).

SH_OPTION_LETTERS <K> <S>

If this option is set the shell tries to interpret single letter options (which are used with set and setopt) like ksh does. This also affects the value of the − special parameter.

SHORT_LOOPS <C> <Z>

Allow the short forms of for, select, if, and function constructs.

SH_WORD_SPLIT (−y) <K> <S>

Causes field splitting to be performed on unquoted parameter expansions. Note that this option has nothing to do with word splitting. (See the section ’Parameter Expansion’.)

SINGLE_COMMAND (−t, ksh: −t)

If the shell is reading from standard input, it exits after a single command has been executed. This also makes the shell non−interactive, unless the INTERACTIVE option is explicitly set on the command line. The value of this option cannot be changed anywhere other than the command line.

SINGLE_LINE_ZLE (−M) <K>

Use single−line command line editing instead of multi−line.

SUN_KEYBOARD_HACK (−L)

If a line ends with a backquote, and there are an odd number of backquotes on the line, ignore the trailing backquote. This is useful on some keyboards where the return key is too small, and the backquote key lies annoyingly close to it.

UNSET (+u, ksh: +u) <K> <S> <Z>

Treat unset parameters as if they were empty when substituting. Otherwise they are treated as an error.

VERBOSE (−v, ksh: −v)

Print shell input lines as they are read.

XTRACE (−x, ksh: −x)

Print commands and their arguments as they are executed.

ZLE (−Z)

Use the zsh line editor. Set by default in interactive shells connected to a terminal.

OPTION ALIASES

Some options have alternative names. These aliases are never used for output, but can be used just like normal option names when specifying options to the shell.
BRACE_EXPAND

NO_IGNORE_BRACES (ksh and bash compatibility)

DOT_GLOB

GLOB_DOTS (bash compatibility)

HASH_ALL

HASH_CMDS (bash compatibility)

HIST_APPEND

APPEND_HISTORY (bash compatibility)

HIST_EXPAND

BANG_HIST (bash compatibility)

MAIL_WARN

MAIL_WARNING (bash compatibility)

ONE_CMD

SINGLE_COMMAND (bash compatibility)

PHYSICAL

CHASE_LINKS (ksh and bash compatibility)

PROMPT_VARS

PROMPT_SUBST (bash compatibility)

TRACK_ALL

HASH_CMDS (ksh compatibility)

SINGLE LETTER OPTIONS

Default set