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.TH ZSHEXPN 1 "June 26, 1996" "zsh version 3.0"
.SH NAME
zshexpn \- zsh command and parameter expansion
.SH DESCRIPTION
The types of expansions performed are
\fIhistory expansion\fP,
\fIalias expansion\fP,
\fIprocess substitution\fP,
\fIparameter expansion\fP,
\fIcommand substitution\fP,
\fIarithmetic expansion\fP,
\fIbrace expansion\fP,
\fIfilename expansion\fP,
and \fIfilename generation\fP.
.PP
Exansion is done in the above specified order in five steps. The
first is \fIHistory\fP expansion which is only performed in
interactive shells. The next step is \fIalias\fP expansion which is
done right before the command line is parsed. They are followed by
\fIprocess substitution\fP, \fIparameter expansion\fP, \fIcommand
substitution\fP, \fIarithmetic expansion\fP and \fIbrace expansion\fP
which are preformed in one step in left\-to\-right fashion. After
these expansions, all unquoted occurrences of the characters \fB\e\fP,
.BR ' ,
and \fB"\fP are removed and the result is subjected to
\fIfilename expansion\fP followed by \fIfilename generation\fP.
.PP
If the
.B SH_FILE_EXPANSION
option is set, the order of expansion is modified
for compatibility with sh and ksh.
.I Filename expansion
is performed immediately after
.IR "alias substitution" ,
preceding the set of five substitutions mentioned above.
.SH FILENAME EXPANSION
Each word is checked to see if it begins with an unquoted
.BR ~ .
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.
.PP
A ~ by itself is replaced by the value of the \fBHOME\fP parameter.
A ~ followed by a + or a \- is replaced by the value of
\fBPWD\fP or \fBOLDPWD\fP, respectively.
.PP
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
.B PUSHD_MINUS
option exchanges the effects of ~+ and ~- where they are
followed by a number.
.PP
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
.B hash
builtin.
.PP
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 /.
.PP
If a word begins with an unquoted \fB=\fP and the
\fBEQUALS\fP 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.
.PP
Filename expansion is performed on the right hand side of a parameter
assignment, including those appearing after commands of the
\fBtypeset\fR family. In this case, the right hand side will be treated
as a colon-separated list in the manner of \fBPATH\fR so that a ~ or an
= following a : is eligible for expansion. All such behavior can be
disabled by quoting the ~, the =, or the whole expression (but not
simply the colon); the \fBEQUALS\fP option is also respected.
.PP
If the option \fBMAGIC_EQUAL_SUBST\fP is set, any unquoted shell
argument in the form \fIidentifier\fP=\fIexpression\fP becomes eligible
for file expansion as described in the previous paragraph. Quoting the
first = also inhibits this.
.SH PROCESS SUBSTITUTION
Each command argument of the form
\fB<(\fIlist\^\fB)\fR
or
\fB>(\fIlist\^\fB)\fR
or
\fB=(\fIlist\^\fB)\fR
is subject to process substitution.
In the case of the
.B <
or
.B >
forms, the shell will run process
.I list
asynchronously connected to a named pipe (FIFO).
The name of this pipe will become the argument to the command.
If the form with
.B >
is selected then writing on this file will provide input for
.IR list .
If
.B <
is used,
then the file passed as an argument will
be a named pipe connected to the output of the
.I list
process.
For example,
.RS
.PP
\fBpaste <(cut \-f1\fP \fIfile1\fB) <(cut \-f3\fP \fIfile2\fB) | tee >(\fIprocess1\fB) >(\fIprocess2\fB)\fR >/dev/null
.RE
.PP
.BR cut s
fields 1 and 3 from
the files
.I file1
and
.I file2
respectively,
.BR paste s
the results together, and sends it to the processes
.I process1
and
.IR process2 .
Note that the file, which is passed as an argument to the command,
is a system
pipe
so programs that expect to
.BR lseek (2)
on the file will not work.
Also note that the previous example can be more compactly and
efficiently written as:
.RS
.PP
\fBpaste <(cut \-f1\fP \fIfile1\fB) <(cut \-f3\fP \fIfile2\fB) > >(\fIprocess1\fB) > >(\fIprocess2\fB)\fR
.RE
.PP
The shell uses pipes instead of FIFOs to implement the latter
two process substitutions in the above example.
.PP
If
.B =
is used,
then the file passed as an argument will be the name
of a temporary file containing
the output of the
.I list
process. This may be used instead of the
.B <
form for a program that expects to \fBlseek\fP(2) on the input file.
.SH PARAMETER EXPANSION
The character \fB$\fP is used to introduce parameter expansions.
See \fBPARAMETERS\fP below for a description of parameters.
In the expansions discussed below that require a pattern, the form of
the pattern is the same as that used for filename generation;
see \fIFilename Generation\fP.
.PD
.RS
.TP
\fB${\fIname\fB}\fR
The value, if any, of the parameter \fIname\fP is substituted.
The braces are required if \fIname\fP is followed by
a letter, digit, or underscore that is not to be interpreted
as part of its name.
If \fIname\fP is an array parameter, then the values of each
element of \fIname\fP is substituted, one element per word.
Otherwise, the expansion results in one word only; no
word splitting is done on the result.
.TP
\fB${+\fIname\fB}\fR
If \fIname\fP is the name of a set parameter `1' is substituted,
otherwise `0' is substituted.
.TP
\fB${\fIname\fB:\-\fIword\fB}\fR
If \fIname\fP is set and is non-null then substitute its
value; otherwise substitute \fIword\fP. If \fIname\fP is
missing, substitute \fIword\fP.
.TP
\fB${\fIname\fB:=\fIword\fB}\fR
If \fIname\fP is unset or is null then
set it to \fIword\fP; the value of the parameter is then
substituted.
.TP
\fB${\fIname\fB::=\fIword\fB}\fR
Set \fIname\fP to \fIword\fP; the value of the parameter is then
substituted.
.TP
\fB${\fIname\fB:?\fIword\fB}\fR
If \fIname\fP is set and is non-null, then substitute
its value; otherwise, print \fIword\fP and exit from the shell.
If \fIword\fP is omitted, then a standard message is printed.
.TP
\fB${\fIname\fB:+\fIword\fB}\fR
If \fIname\fP is set and is non-null then substitute
\fIword\fP; otherwise substitute nothing.
.PD 0
.TP
\fB${\fIname\fB#\fIpattern\fB}\fR
.TP
\fB${\fIname\fB##\fIpattern\fB}\fR
.PD
If the \fIpattern\fP matches the beginning of the value of
\fIname\fP, then substitute the value of \fIname\fP with
the matched portion deleted; otherwise, just
substitute the value of \fIname\fP. In the first
form, the smallest matching pattern is preferred;
in the second form, the largest matching pattern is
preferred. If \fIname\fP is an array and the substitution
is not quoted or the \fB@\fP flag or the \fIname\fB[@]\fR syntax
is used, matching is performed on each array elements separately.
.PD 0
.TP
\fB${\fIname\fB%\fIpattern\fB}\fR
.TP
\fB${\fIname\fB%%\fIpattern\fB}\fR
.PD
If the \fIpattern\fP matches the end of the value of
\fIname\fP, then substitute the value of \fIname\fP with
the matched portion deleted; otherwise, just
substitute the value of \fIname\fP. In the first
form, the smallest matching pattern is preferred;
in the second form, the largest matching pattern is
preferred. If \fIname\fP is an array and the substitution
is not quoted or the \fB@\fP flag or the \fIname\fB[@]\fR syntax
is used, matching is performed on each array elements separately.
.TP
\fB${\fIname\fB:#\fIpattern\fB}\fR
If the \fIpattern\fP matches the value of \fIname\fP, then substitute
the empty string; otherwise, just substitute the value of \fIname\fP.
If \fIname\fP is an array and the substitution
is not quoted or the \fB@\fP flag or the \fIname\fB[@]\fR syntax
is used, matching is performed on each array elements separately, and
the matched array elements are removed (use the \fBM\fP flag to
remove the non-matched elements).
.TP
\fB${#\fIspec\fB}\fR
If \fIspec\fP is one of the above substitutions, substitute
the length in characters of the result instead of
the result itself. If \fIspec\fP is an array expression,
substitute the number of elements of the result.
.TP
\fB${^\fIspec\fB}\fR
Turn on the \fBRC_EXPAND_PARAM\fP option for the
evaluation of \fIspec\fP; if the ^ is doubled, turn it off.
When this option is set, array expansions of the form
\fIfoo\fB${\fIxx\fB}\fIbar\fR, where the parameter
\fIxx\fP is set to (\fIa b c\fP), are substituted with
\fIfooabar foobbar foocbar\fP instead of the default
\fIfooa b cbar\fP.
.TP
\fB${=\fIspec\fB}\fR
Turn on the \fBSH_WORD_SPLIT\fP option for the
evaluation of \fIspec\fP; if the = is doubled, turn it off.
When this option is set, parameter values are split into
separate words using \fBIFS\fP as a delimiter
before substitution.
This is done by default in most other shells.
.TP
\fB${~\fIspec\fB}\fR
Turn on the \fBGLOB_SUBST\fP option for the evaluation of
\fIspec\fP; if the ~ is doubled, turn it off. When this option is
set, any pattern characters resulting
from the substitution become eligible for file expansion and filename
generation.
.PD
.RE
.PP
If the colon is omitted from one of the above expressions
containing a colon, then the shell only checks whether
\fIname\fP is set or not, not whether it is null.
.PP
If a \fB${...}\fP type parameter expression or a \fB$(...)\fP type command
substitution is used in place of \fIname\fP above, it is substituted first
and the result is used as it were the value of \fIname\fP.
.PP
If the opening brace is directly followed by an opening parentheses
the string up to the matching closing parentheses will be taken as a
list of flags. Where arguments are valid, any character, or the
matching pairs `(...)', `{...}', `[...]', or `<...>', may be used
in place of the colon as delimiters. The following flags are supported:
.PD
.RS
.TP
.B A
Create an array parameter with \fB${...:=...}\fP or \fB${...::=...}\fP.
Assignment is made before sorting or padding.
.TP
.B @
In double quotes, array elements are put into separate words.
Eg. \fB"${(@)foo}"\fP is equivalent to \fB"${foo[@]}"\fP and
\fB"${(@)foo[1,2]}"\fP is the same as \fB"$foo[1]" "$foo[2]"\fP.
.TP
.B e
Perform \fIparameter expansion\fP, \fIcommand substitution\fP and
\fIarithmetic expansion\fP on the result. Such expansions can be
nested but too deep recursion may have unpredictable effects.
.TP
.B o
Sort the resulting words in ascending order.
.TP
.B O
Sort the resulting words in descending order.
.TP
.B i
With \fBo\fP or \fBO\fP, sort case-independently.
.TP
.B L
Convert all letters in the result to lower case.
.TP
.B U
Convert all letters in the result to upper case.
.TP
.B C
Capitalize the resulting words.
.TP
.B c
With \fB${#\fIname\fB}\fR, count the total number of characters in an array,
as if the elements were concatenated with spaces between them.
.TP
.B w
With \fB${#\fIname\fB}\fR, count words in arrays or strings; the \fIs\fP
flag may be used to set a word delimiter.
.TP
.B W
Similar to \fBw\fP with the difference that empty words between
repeated delimiters are also counted.
.TP
.B p
Recognize the same escape sequences as the \fBprint\fP builtin
in string arguments to subsequent flags.
.TP
.B l:\fIexpr\fB::\fIstring1\fB::\fIstring2\fB:
Pad the resulting words on the left. Each word will be truncated if
required and placed in a field \fIexpr\fP characters wide. The space
to the left will be filled with \fIstring1\fP (concatenated as often
as needed) or spaces if \fIstring1\fP is not given. If both
\fIstring1\fP and \fIstring2\fP are given, this string will be placed
exactly once directly to the left of the resulting word.
.TP
.B r:\fIexpr\fB::\fIstring1\fB::\fIstring2\fB:
As \fBl...\fP, but pad the words on the right.
.TP
.B j:\fIstring\fB:
Join the words of arrays together using \fIstring\fP as a separator.
Note that this occurs before word splitting by the \fBSH_WORD_SPLIT\fP
option.
.TP
.B F
Join the words of arrays together using newline as a separator.
This is a shorthand for \fBpj:\\n:\fP.
.TP
.B s:\fIstring\fB:
Force word splitting (see the option \fBSH_WORD_SPLIT\fP) at the
separator \fIstring\fP. Splitting only occurs in places where an
array value is valid.
.TP
.B f
Split the result of the expansion to lines. This is a shorthand
for \fBps:\\n:\fP.
.TP
.B S
(This and all remaining flags are used with the \fB${...#...}\fP or
\fB${...%...}\fP forms):
search substrings as well as beginnings or ends.
.TP
.B I:\fIexpr\fB:
Search the \fIexpr\fP'th match (where \fIexpr\fP evaluates to a number).
.TP
.B M
Include the matched portion in the result.
.TP
.B R
Include the unmatched portion in the result (the \fIR\fPest).
.TP
.B B
Include the index of the beginning of the match in the result.
.TP
.B E
Include the index of the end of the match in the result.
.TP
.B N
Include the length of the match in the result.
.PD
.RE
.PP
.SH COMMAND SUBSTITUTION
A command enclosed in parentheses
preceded by a dollar sign, like so: $(...) or quoted with grave
accents: `...` is replaced with its standard output, with any
trailing newlines deleted.
If the substitution is not enclosed in double quotes, the
output is broken into words using the \fBIFS\fP parameter.
The substitution \fB$(cat foo)\fP may be replaced
by the equivalent but faster \fB$(<foo)\fP. In either case, if the
option \fBGLOB_SUBST\fP is set the output is eligible for filename
generation.
.SH ARITHMETIC EXPANSION
A string of the form \fB$[\fIexp\fB]\fR or \fB$((\fIexp\fB))\fR is substituted
with the value of the arithmetic expression \fIexp\fP. \fIexp\fP is
subjected to \fIparameter expansion\fP, \fIcommand substitution\fP
and \fIarithmetic expansion\fP before it is evaluated.
See \fBARITHMETIC EVALUATION\fP below.
.SH BRACE EXPANSION
A string of the form
\fIfoo\fB{\fIxx\fB,\fIyy\fB,\fIzz\fB}\fIbar\fR
is expanded to the individual words
\fIfooxxbar\fP, \fIfooyybar\fP, and \fIfoozzbar\fP.
Left-to-right order is preserved. This construct
may be nested. Commas may be quoted in order to
include them literally in a word.
.PP
An expression of the form
\fB{\fIn1\fB..\fIn2\fB}\fR,
where \fIn1\fP and \fIn2\fP are integers,
is expanded to every number between
\fIn1\fP and \fIn2\fP, 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.
.PP
If a brace expression matches none of the above forms, it is left
unchanged, unless the \fBBRACE_CCL\fP 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.
.SH FILENAME GENERATION (GLOBBING)
If a word contains an unquoted instance of one of the characters
*, |, <, [, or ?, it is regarded
as a pattern for filename generation, unless the \fBGLOB\fP option is unset.
If the \fBEXTENDED_GLOB\fP option is set, the
^, ~ and # characters also denote a pattern; otherwise
(except for an initial ~, see \fBFilename Expansion\fP above)
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 \fBNULL_GLOB\fP option is set,
in which case the word is deleted; or unless the \fBNOMATCH\fP
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
\fBGLOB_DOTS\fP option is set. No filename generation pattern
matches the files "." or "..". In other instances of pattern
matching, the / and . are not treated specially.
.PP
.RS
.PD 0
.TP
.B *
matches any string, including the null string.
.TP
.B ?
matches any character.
.TP
\fB[...]\fP
matches any of the enclosed characters. Ranges of characters
can be specified by separating two characters by a \fB\-\fP.
A \fB\-\fP or \fB]\fP may be matched by including it as the
first character in the list.
.TP
.PD 0
\fB[^...]\fP
.TP
\fB[!...]\fP
.PD
like \fB[...]\fP, except that it matches any character which is
not in the given set.
.TP
\fB<x\-y>\fP
matches any number in the range x to y, inclusive.
If x is omitted, the number must be less than or equal to y.
If y is omitted, the number must be greater than or equal to x.
A pattern of the form \fB<\->\fP matches any number.
.TP
\fB^x\fP
matches anything except the pattern x.
.TP
\fBx|y\fP
matches either x or y.
.TP
\fBx#\fP
matches zero or more occurrences of the pattern x.
.TP
\fBx##\fP
matches one or more occurrences of the pattern x.
.RE
.PD
.PP
Parentheses may be used for grouping. Note that the \fB|\fP character
must be within parentheses, so that the lexical analyzer does
not think it is a pipe character. Also note that "/" has a
higher precedence than "^"; that is:
.RS
.PP
ls
.BI ^ foo / bar
.RE
.PP
will search directories in "." except "./foo" for a file named bar.
.PP
A pathname component of the form
.BI ( foo /)#
matches a path consisting of zero or more directories
matching the pattern foo.
As a shorthand,
.B **/
is equivalent to
.BR (*/)# .
Thus:
.RS
.PP
ls
.BI (*/)# bar
.RE
.PP
or
.RS
.PP
ls
.BI **/ bar
.RE
.PP
does a recursive directory search for files named bar, not following
symbolic links. For this you can use the form
.BR ***/ .
.PP
If used for filename generation, a pattern may contain an exclusion
specifier. Such patterns are of the form \fIpat1\fB~\fIpat2\fR.
This pattern will generate all files matching \fIpat1\fP, but which
do not match \fIpat2\fP. For example, \fB*.c~lex.c\fP will match
all files ending in .c, except the file \fBlex.c\fP. This may appear
inside parentheses. Note that "~" has a higher precedence than "|",
so that \fIpat1\fB|\fIpat2\fB~\fIpat3\fR matches any time that
\fIpat1\fR matches, or if \fIpat2\fR matches while \fIpat3\fR does
not. Note also that "/" characters are not treated specially in the
exclusion specifier so that a "*" will match multiple path segments if
they appear in the pattern to the left of the "~".
.PP
Patterns used for filename generation may also 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.
A qualifier may be any one of the following:
.PD 0
.RS
.TP
.B /
directories
.TP
.B .
plain files
.TP
.B @
symbolic links
.TP
.B =
sockets
.TP
.B p
named pipes (FIFOs)
.TP
.B *
executable plain files (0100)
.TP
.B %
device files (character or block special)
.TP
.B %b
block special files
.TP
.B %c
character special files
.TP
.B r
owner-readable files (0400)
.TP
.B w
owner-writable files (0200)
.TP
.B x
owner-executable files (0100)
.TP
.B A
group-readable files (0040)
.TP
.B I
group-writable files (0020)
.TP
.B E
group-executable files (0010)
.TP
.B R
world-readable files (0004)
.TP
.B W
world-writable files (0002)
.TP
.B X
world-executable files (0001)
.TP
.B s
setuid files (04000)
.TP
.B S
setgid files (02000)
.TP
.B t
files with the sticky bit (01000)
.TP
\fBd\fIdev\fR
files on the device \fIdev\fP
.TP
\fBl\fI[-|+]ct\fR
files having a link count less than \fIct\fP (-), greater than
\fIct\fP (+), or is equal to \fIct\fP
.TP
\fBU\fP
files owned by the effective user id
.TP
\fBG\fP
files owned by the effective group id
.TP
\fBu\fIid\fR
files owned by user id \fIid\fP if it is a number, if not, than the
character after the \fBu\fP will be used as a separator and the string
between it and the next matching separator (`(', `[', `{', and `<'
match `)', `]', `}', and `>' respectively, any other character matches
itself) will be taken as a user name and the user id of this user will
be taken (e.g. \fBu:foo:\fP or \fBu[foo]\fP for user \fBfoo\fP)
.TP
\fBg\fIid\fR
like \fBu\fIid\fR but with group ids or names
.TP
\fBa[Mwhm]\fI[-|+]n\fR
files accessed exactly \fIn\fP days ago. Files accessed within the
last \fIn\fP days are selected using a negative value for \fIn\fP
(\fI-n\fP). Files accessed more than \fIn\fP days ago are selected by a
positive \fIn\fP value (\fI+n\fP). Optional unit specifiers \fBM\fP,
\fBw\fP, \fBh\fP, or \fBm\fP (e.g. \fBah5\fP) cause the check to be
performed with months (of 30 days), weeks, hours, or minutes instead of
days, respectively. For instance, \fBecho *(ah-5)\fP would echo files
accessed within the last five hours.
.TP
\fBm[Mwhm]\fI[-|+]n\fR
like the file access qualifier, except that it uses the file modification
time.
.TP
\fBc[Mwhm]\fI[-|+]n\fR
like the file access qualifier, except that it uses the file inode change
time.
.TP
\fBL\fI[+|-]n\fR
files less than n bytes (-), more than n bytes (+), or
exactly n bytes in length. If this flag is directly followed by a \fBk\fP
(\fBK\fP), \fBm\fP (\fBM\fP), or \fBp\fP (\fBP\fP) (e.g. \fBLk+50\fP)
the check is performed with kilobytes, megabytes, or blocks (of 512 bytes)
instead.
.TP
\fB^\fP
negates all qualifiers following it
.TP
\fB\-\fP
toggles between making the qualifiers work on symbolic links (the
default) and the files they point to
.TP
\fBM\fP
sets the \fBMARK_DIRS\fP option for the current pattern
.TP
\fBT\fP
appends a traling qualifier mark to the file names, analogous to the
\fBLIST_TYPES\fP option, for the current pattern (overrides \fBM\fP)
.TP
\fBN\fP
sets the \fBNULL_GLOB\fP option for the current pattern
.TP
\fBD\fP
sets the \fBGLOB_DOTS\fP option for the current pattern
.PD
.RE
.PP
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').
.PP
If a : appears in a qualifier list, the remainder of the expression in
parenthesis is interpreted as a modifier (see the subsection
\fBModifiers\fR of the section \fBHISTORY EXPANSION\fR). 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 filename generation is performed.
.PP
Thus:
.RS
.PP
ls
.B *(\-/)
.RE
.PP
lists all directories and symbolic links that point to directories,
and
.RS
.PP
ls
.B *(%W)
.RE
.PP
lists all world-writable device files in the current directory,
and
.RS
.PP
ls
.B *(W,X)
.RE
.PP
lists all files in the current directory that are
world-writable or world-executable, and
.RS
.PP
echo
.B /tmp/foo*(u0^@:t)
.RE
.PP
outputs the basename of all root-owned files beginning with the string
"foo" in /tmp, ignoring symlinks, and
.RS
.PP
ls
.B *.*~(lex|parse).[ch](^D^l1)
.RE
.PP
lists all files having a link count of one whose names contain a dot
(but not those starting with a dot, since \fBGLOB_DOTS\fP is explicitly
switched off) except for lex.c, lex.h, parse.c, and parse.h.
.SH HISTORY EXPANSION
History substitution 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.
Command lines are saved in the history list, the size of which
is controlled by the
.B HISTSIZE
variable. The most recent command is retained in any case.
A history substitution begins with the fist character of the
\fBhistchars\fP parameter which is
.B !
by default and may occur anywhere on the command line; history
substitutions do not nest. The
.B !
can be escaped with
.B \e
or can be enclosed between a pair of single quotes ('') to suppress
its special meaning. Double quotes will \fInot\fP work for this.
.PP
Input lines containing history substitutions are echoed on the
terminal after being expanded, but before any other
substitutions take place or the command gets executed.
.SS Event Designators
.PP
An event designator is a reference to a command-line entry in
the history list.
.RS
.PD 0
.TP
.B !
Start a history substitution, except when followed by a blank, newline,
.BR = ,
or
.BR ( .
.TP
.B !!
Refer to the previous command.
By itself, this substitution
repeats the previous command.
.TP
.BI ! n
Refer to command-line
.IR n .
.TP
.BI ! \-n
Refer to the current command-line minus
.IR n .
.TP
.BI ! str
Refer to the most recent command starting with
.IR str .
.TP
.BI !? str\fR[\fP ? \fR]\fP
Refer to the most recent command containing
.IR str .
.TP
.B !#
Refer to the current command line typed in so far. The line is
treated as if it were complete up to and including the word before the
one with the !# reference.
.TP
.BR !{ .\|.\|. }
Insulate a history reference from adjacent characters (if necessary).
.PD
.RE
.SS Word Designators
.PP
A word designator indicates which word or words of a given command line will
be included in a history reference. A
.RB ` : '
separates the event specification from the word designator.
It can be omitted if the word designator begins with a
.BR ^ ,
.BR $ ,
.BR * ,
.B \-
or
.BR % .
Word designators include:
.RS
.PD 0
.TP
.B 0
The first input word (command).
.TP
.I n
The
.IR n 'th
argument.
.TP
.B ^
The first argument, that is,
.BR 1 .
.TP
.B $
The last argument.
.TP
.B %
The word matched by (the most recent)
.BI ? str
search.
.TP
.IB x \- y
A range of words;
.BI \- y
abbreviates
.BI 0\- y\fR.
.TP
.B *
All the arguments, or a null value if there is just
one word in the event.
.TP
.IB x *
Abbreviates
.IB x \-$ .
.TP
.IB x \-
Like
.I x*
but omitting word
.BR $ .
.PD
.RE
Note that a
.RB ` % '
word designator will only work when used as
.B !%,
.B !:%,
.BI !? str ?:%
and only when used after a !? substitution. Anything else will result
in an error, although the error may not be the most obvious one.
.PP
.SS Modifiers
.PP
After the optional word designator, you can add
a sequence of one or more of the following modifiers,
each preceded by a
.BR : .
These modifiers also work on the result
of \fIfilename\fP and \fIparameter expansion\fP.
.RS
.TP
.B h
Remove a trailing pathname component, leaving the head.
.PD 0
.TP
.B r
Remove a trailing suffix of the form
.RB ` "\&.\fIxxx" ',
leaving the basename.
.TP
.B e
Remove all but the suffix.
.TP
.B t
Remove all leading pathname components, leaving the tail.
.TP
.B &
Repeat the previous substitution.
.TP
.B g
Apply the change to the first occurrence of a match in each word,
by prefixing the above (for example,
.BR g& ).
.TP
.B p
Print the new command but do not execute it.
.TP
.B q
Quote the substituted words, escaping further substitutions.
.TP
.B x
Like
.BR q ,
but break into words at each blank.
.TP
.B l
Convert the words to all lowercase.
.TP
.B u
Convert the words to all uppercase.
.TP
.B f
Repeats the immediately (without a colon) following modifier until the
resulting word doesn't change any more. This and the following
\fBF\fP, \fBw\fP and \fBW\fP modifier only work with parameter and
filename expansion.
.TP
.B F:\fIexpr\fB:
Like \fBf\fP, but repeats only \fIn\fP times if the expression
\fIexpr\fP evaluates to \fIn\fP. Any character can be used instead of
the `:', if any of `(', `[', or `{' is used as the opening delimiter
the second one has to be ')', `]', or `}' respectively.
.TP
.B w
Makes the immediately following modifier work on each word in the
string.
.TP
.B W:\fIsep\fB:
Like \fBw\fP but words are considered to be the parts of the string
that are separated by \fIsep\fP. Any character can be used instead of
the `:', opening parentheses are handled specially, see above.
.TP
.BI s/ l / r\fR[\fP / \fR]\fP
Substitute
.I r
for
.IR l .
.PD
.RE
.PP
Unless preceded by a
.BR g ,
the substitution is done only for the
first string that matches
.IR l .
.PP
The left-hand side of substitutions are not regular expressions,
but character strings.
Any character can be used as the delimiter in place of
.BR / .
A backslash quotes the delimiter character.
The character
.BR & ,
in the right hand side, is replaced by the text
from the left-hand-side.
The
.B &
can be quoted with a backslash.
A null
.I l
uses the previous string either from a
.I l
or from a contextual scan string
.I s
from
.BI !? s\fR.
You can omit the rightmost delimiter if a newline
immediately follows
.IR r ;
the rightmost
.B ?
in a context scan can similarly be omitted.
.PP
By default, a history reference with no event specification refers to the same
line as the last history reference on that command line, unless it is the
first history reference in a command. In that case, a history reference
with no event specification always refers to the previous command. However,
if the option \fBCSH_JUNKIE_HISTORY\fP is set, then history reference with no
event specification will \fIalways\fP refer to the previous command.
For example,
.B !!:1
will always refer to the first word of the previous command and
.B !!$
will always refer to the last word of the previous command. And with
\fBCSH_JUNKIE_HISTORY\fP set, then
.B !:1
and
.B !$
will function in the same manner as
.B !!:1
and
.B !!$,
respectively. However, if \fBCSH_JUNKIE_HISTORY\fP is unset, then
.B !:1
and
.B !$
will refer to the first and last words respectively, of the last command
referenced on the current command line. However, if they are the first history
reference on the command line, then they refer to the previous command.
.PP
The character sequence
.BI ^ foo ^ bar
repeats the last command, replacing the string "foo" with the
string "bar".
.PP
If the shell encounters the character sequence
\fB!"\fP
in the input, the history mechanism is temporarily disabled until
the current list is fully parsed. The
\fB!"\fP
is removed from the input, and any subsequent
.B !
characters have no special significance.
.PP
A less convenient but more comprehensible
form of command history support
is provided by the
.B fc
builtin (see the entry in the \fBzshbuiltins\fP manual).
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.