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21 Completion Using compctl
21.1 Types of completion
This version of zsh has two ways of performing completion of words on the command line. New users of the shell may prefer to use the newer and more powerful system based on shell functions; this is described in Completion System, and the basic shell mechanisms which support it are described in Completion Widgets. This chapter describes the older compctl command.
21.2 Description
compctl [ -CDT ] options
[ command
... ]
compctl [ -CDT ] options
[ -x pattern
options
- ... -- ]
[ + options
[ -x ... -- ] ... [+] ] [ command
... ]
compctl -M match-specs
...
compctl -L [ -CDTM ] [ command
... ]
compctl + command
...
Control the editor’s completion behavior according to the supplied set
of options
. Various editing commands, notably expand-or-complete-word,
usually bound to tab, will attempt to complete a word typed by the user,
while others, notably delete-char-or-list, usually bound to ^D in EMACS
editing mode, list the possibilities; compctl controls what those
possibilities are. They may for example be filenames (the most common
case, and hence the default), shell variables, or words from a
user-specified list.
21.3 Command Flags
Completion of the arguments of a command may be different for each
command or may use the default. The behavior when completing the command
word itself may also be separately specified. These correspond to the
following flags and arguments, all of which (except for -L) may be
combined with any combination of the options
described subsequently in
Option Flags:
command
...
controls completion for the named commands, which must be listed last on
the command line. If completion is attempted for a command with a
pathname containing slashes and no completion definition is found, the
search is retried with the last pathname component. If the command
starts with a =, completion is tried with the pathname of the command.
Any of the command
strings may be patterns of the form normally used
for filename generation. These should be quoted to protect them from
immediate expansion; for example the command string ’foo*’ arranges for
completion of the words of any command beginning with foo. When
completion is attempted, all pattern completions are tried in the
reverse order of their definition until one matches. By default,
completion then proceeds as normal, i.e. the shell will try to generate
more matches for the specific command on the command line; this can be
overridden by including -tn in the flags for the pattern completion.
Note that aliases are expanded before the command name is determined unless the COMPLETE_ALIASES option is set. Commands may not be combined with the -C, -D or -T flags.
-C
controls completion when the command word itself is being completed. If
no compctl -C command has been issued, the names of any as aliases or
functions) are completed.
-D
controls default completion behavior for the arguments of commands not
assigned any special behavior. If no compctl -D command has been issued,
filenames are completed.
-T
supplies completion flags to be used before any other processing is
done, even before processing for compctls defined for specific commands.
This is especially useful when combined with extended completion (the -x
flag, see Extended Completion below). Using this
flag you can define default behavior which will apply to all commands
without exception, or you can alter the standard behavior for all
commands. For example, if your access to the user database is too slow
and/or it contains too many users (so that completion after ‘~’ is too
slow to be usable), you can use
compctl -T -x 's[~] C[0,[^/]#]' -k friends -S/ -tn
to complete the strings in the array friends after a ‘~’. The
C[...
] argument is necessary so that this form of ~-completion is
not tried after the directory name is finished.
-L
no argument
If no argument is given, compctl lists all defined completions in an
abbreviated form; with a list of options
, all completions with those
flags set (not counting extended completion) are listed.
If the + flag is alone and followed immediately by the command
list,
the completion behavior for all the commands in the list is reset to the
default. In other words, completion will subsequently use the options
specified by the -D flag.
The form with -M as the first and only option defines global matching specifications (see Completion Matching Control). The match specifications given will be used for every completion attempt (only when using compctl, not with the new completion system) and are tried in the order in which they are defined until one generates at least one match. E.g.:
compctl -M '' 'm:{a-zA-Z}={A-Za-z}'
This will first try completion without any global match specifications (the empty string) and, if that generates no matches, will try case insensitive completion.
21.4 Option Flags
[ -fcFBdeaRGovNAIOPZEnbjrzu/12 ]
[ -k array
] [ -g globstring
] [ -s subststring
]
[ -K function
]
[ -Q ] [ -P prefix
] [ -S suffix
]
[ -W file-prefix
] [ -H num pattern
]
[ -q ] [ -X explanation
] [ -Y explanation
]
[ -y func-or-var
] [ -l cmd
] [ -h cmd
] [ -U ]
[ -t continue
] [ -J name
] [ -V name
]
[ -M match-spec
]
The remaining options
specify the type of command arguments to look
for during completion. Any combination of these flags may be specified;
the result is a sorted list of all the possibilities. The options are as
follows.
21.4.1 Simple Flags
These produce completion lists made up by the shell itself:
-f
Filenames and file system paths.
-/
Just file system paths.
-c
Command names, including aliases, shell functions, builtins and reserved
words.
-F
Function names.
-B
Names of builtin commands.
-m
Names of external commands.
-w
Reserved words.
-a
Alias names.
-R
Names of regular (non-global) aliases.
-G
Names of global aliases.
-d
This can be combined with -F, -B, -w, -a, -R and -G to get names of
disabled functions, builtins, reserved words or aliases.
-e
This option (to show enabled commands) is in effect by default, but may
be combined with -d; -de in combination with -F, -B, -w, -a, -R and -G
will complete names of functions, builtins, reserved words or aliases
whether or not they are disabled.
-o
Names of shell options (see Options).
-v
Names of any variable defined in the shell.
-N
Names of scalar (non-array) parameters.
-A
Array names.
-I
Names of integer variables.
-O
Names of read-only variables.
-p
Names of parameters used by the shell (including special parameters).
-Z
Names of shell special parameters.
-E
Names of environment variables.
-n
Named directories.
-b
Key binding names.
-j
Job names: the first word of the job leader’s command line. This is
useful with the kill builtin.
-r
Names of running jobs.
-z
Names of suspended jobs.
-u
User names.
21.4.2 Flags with Arguments
These have user supplied arguments to determine how the list of completions is to be made up:
-k array
Names taken from the elements of $array
(note that the ‘$’ does not
appear on the command line). Alternatively, the argument array
itself
may be a set of space- or comma-separated values in parentheses, in
which any delimiter may be escaped with a backslash; in this case the
argument should be quoted. For example,
compctl -k "(cputime filesize datasize stacksize
coredumpsize resident descriptors)" limit
-g globstring
The globstring
is expanded using filename globbing; it should be
quoted to protect it from immediate expansion. The resulting filenames
are taken as the possible completions. Use ‘*(/)’ instead of ‘*/’ for
directories. The fignore special parameter is not applied to the
resulting files. More than one pattern may be given separated by blanks.
(Note that brace expansion is not part of globbing. Use the syntax
‘(either|or)’ to match alternatives.)
-s subststring
The subststring
is split into words and these words are than expanded
using all shell expansion mechanisms (see
Expansion). The resulting words are taken as
possible completions. The fignore special parameter is not applied to
the resulting files. Note that -g is faster for filenames.
-K function
Call the given function to get the completions. Unless the name starts with an underscore, the function is passed two arguments: the prefix and the suffix of the word on which completion is to be attempted, in other words those characters before the cursor position, and those from the cursor position onwards. The whole command line can be accessed with the -c and -l flags of the read builtin. The function should set the variable reply to an array containing the completions (one completion per element); note that reply should not be made local to the function. From such a function the command line can be accessed with the -c and -l flags to the read builtin. For example,
function whoson { reply=(`users`); }
compctl -K whoson talk
completes only logged-on users after ‘talk’. Note that ‘whoson’ must return an array, so ‘reply=‘users‘’ would be incorrect.
-H num pattern
The possible completions are taken from the last num
history lines.
Only words matching pattern
are taken. If num
is zero or negative
the whole history is searched and if pattern
is the empty string all
words are taken (as with ‘*’). A typical use is
compctl -D -f + -H 0 ''
which forces completion to look back in the history list for a word if no filename matches.
21.4.3 Control Flags
These do not directly specify types of name to be completed, but manipulate the options that do:
-Q
This instructs the shell not to quote any metacharacters in the possible
completions. Normally the results of a completion are inserted into the
command line with any metacharacters quoted so that they are interpreted
as normal characters. This is appropriate for filenames and ordinary
strings. However, for special effects, such as inserting a backquoted
expression from a completion array (-k) so that the expression will not
be evaluated until the complete line is executed, this option must be
used.
-P prefix
The prefix
is inserted just before the completed string; any initial
part already typed will be completed and the whole prefix
ignored for
completion purposes. For example,
compctl -j -P "%" kill
inserts a ‘%’ after the kill command and then completes job names.
-S suffix
When a completion is found the suffix
is inserted after the completed
string. In the case of menu completion the suffix is inserted
immediately, but it is still possible to cycle through the list of
completions by repeatedly hitting the same key.
-W file-prefix
With directory file-prefix
: for command, file, directory and globbing
completion (options -c, -f, -/, -g), the file prefix is implicitly added
in front of the completion. For example,
compctl -/ -W ~/Mail maildirs
completes any subdirectories to any depth beneath the directory ~/Mail,
although that prefix does not appear on the command line. The
file-prefix
may also be of the form accepted by the -k flag, i.e. the
name of an array or a literal list in parenthesis. In this case all the
directories in the list will be searched for possible completions.
-q
If used with a suffix as specified by the -S option, this causes the
suffix to be removed if the next character typed is a blank or does not
insert anything or if the suffix consists of only one character and the
next character typed is the same character; this the same rule used for
the AUTO_REMOVE_SLASH option. The option is most useful for list
separators (comma, colon, etc.).
-l cmd
This option restricts the range of command line words that are
considered to be arguments. If combined with one of the extended
completion patterns ‘p[...]’, ‘r[...]’, or ‘R[...]’ (see Extended
Completion below) the range is restricted to the
range of arguments specified in the brackets. Completion is then
performed as if these had been given as arguments to the cmd
supplied
with the option. If the cmd
string is empty the first word in the
range is instead taken as the command name, and command name completion
performed on the first word in the range. For example,
compctl -x 'r[-exec,;]' -l '' -- find
completes arguments between ‘-exec’ and the following ‘;’ (or the end of the command line if there is no such string) as if they were a separate command line.
-h cmd
Normally zsh completes quoted strings as a whole. With this option,
completion can be done separately on different parts of such strings. It
works like the -l option but makes the completion code work on the parts
of the current word that are separated by spaces. These parts are
completed as if they were arguments to the given cmd
. If cmd
is the
empty string, the first part is completed as a command name, as with -l.
-U
Use the whole list of possible completions, whether or not they actually
match the word on the command line. The word typed so far will be
deleted. This is most useful with a function (given by the -K option)
which can examine the word components passed to it (or via the read
builtin’s -c and -l flags) and use its own criteria to decide what
matches. If there is no completion, the original word is retained. Since
the produced possible completions seldom have interesting common
prefixes and suffixes, menu completion is started immediately if
AUTO_MENU is set and this flag is used.
-y func-or-var
The list provided by func-or-var
is displayed instead of the list of
completions whenever a listing is required; the actual completions to be
inserted are not affected. It can be provided in two ways. Firstly, if
func-or-var
begins with a $ it defines a variable, or if it begins
with a left parenthesis a literal array, which contains the list. A
variable may have been set by a call to a function using the -K option.
Otherwise it contains the name of a function which will be executed to
create the list. The function will be passed as an argument list all
matching completions, including prefixes and suffixes expanded in full,
and should set the array reply to the result. In both cases, the display
list will only be retrieved after a complete list of matches has been
created.
Note that the returned list does not have to correspond, even in length, to the original set of matches, and may be passed as a scalar instead of an array. No special formatting of characters is performed on the output in this case; in particular, newlines are printed literally and if they appear output in columns is suppressed.
-X explanation
Print explanation
when trying completion on the current set of
options. A ‘%n’ in this string is replaced by the number of matches that
were added for this explanation string. The explanation only appears if
completion was tried and there was no unique match, or when listing
completions. Explanation strings will be listed together with the
matches of the group specified together with the -X option (using the -J
or -V option). If the same explanation string is given to multiple -X
options, the string appears only once (for each group) and the number of
matches shown for the ‘%n’ is the total number of all matches for each
of these uses. In any case, the explanation string will only be shown if
there was at least one match added for the explanation string.
The sequences %B, %b, %S, %s, %U, and %u specify output attributes
(bold, standout, and underline), %F, %f, %K, %k specify foreground and
background colours, and %{...
%} can be used to include literal escape
sequences as in prompts.
-Y explanation
Identical to -X, except that the explanation
first undergoes expansion
following the usual rules for strings in double quotes. The expansion
will be carried out after any functions are called for the -K or -y
options, allowing them to set variables.
-t continue
The continue
-string contains a character that specifies which set of
completion flags should be used next. It is useful:
(i) With -T, or when trying a list of pattern completions, when compctl would usually continue with ordinary processing after finding matches; this can be suppressed with ‘-tn’.
(ii) With a list of alternatives separated by +, when compctl would normally stop when one of the alternatives generates matches. It can be forced to consider the next set of completions by adding ‘-t+’ to the flags of the alternative before the ‘+’.
(iii) In an extended completion list (see below), when compctl would normally continue until a set of conditions succeeded, then use only the immediately following flags. With ‘-t-’, compctl will continue trying extended completions after the next ‘-’; with ‘-tx’ it will attempt completion with the default flags, in other words those before the ‘-x’.
-J name
This gives the name of the group the matches should be placed in. Groups
are listed and sorted separately; likewise, menu completion will offer
the matches in the groups in the order in which the groups were defined.
If no group name is explicitly given, the matches are stored in a group
named default. The first time a group name is encountered, a group with
that name is created. After that all matches with the same group name
are stored in that group.
This can be useful with non-exclusive alternative completions. For example, in
compctl -f -J files -t+ + -v -J variables foo
both files and variables are possible completions, as the -t+ forces both sets of alternatives before and after the + to be considered at once. Because of the -J options, however, all files are listed before all variables.
-V name
Like -J, but matches within the group will not be sorted in listings nor
in menu completion. These unsorted groups are in a different name space
from the sorted ones, so groups defined as -J files and -V files are
distinct.
-1
If given together with the -V option, makes only consecutive duplicates
in the group be removed. Note that groups with and without this flag are
in different name spaces.
-2
If given together with the -J or -V option, makes all duplicates be
kept. Again, groups with and without this flag are in different name
spaces.
-M match-spec
This defines additional matching control specifications that should be
used only when testing words for the list of flags this flag appears in.
The format of the match-spec
string is described in Completion
Matching Control.
21.5 Alternative Completion
compctl [ -CDT ] options
+ options
[ + ... ] [ + ] command
...
The form with ‘+’ specifies alternative options. Completion is tried with the options before the first ‘+’. If this produces no matches completion is tried with the flags after the ‘+’ and so on. If there are no flags after the last ‘+’ and a match has not been found up to that point, default completion is tried. If the list of flags contains a -t with a + character, the next list of flags is used even if the current list produced matches.
Additional options are available that restrict completion to some part of the command line; this is referred to as ‘extended completion’.
21.6 Extended Completion
compctl [ -CDT ] options
-x pattern
options
- ... --
[ command
... ]
compctl [ -CDT ] options
[ -x pattern
options
- ... -- ]
[ + options
[ -x ... -- ] ... [+] ] [ command
... ]
The form with ‘-x’ specifies extended completion for the commands given;
as shown, it may be combined with alternative completion using ‘+’. Each
pattern
is examined in turn; when a match is found, the corresponding
options
, as described in Option Flags above, are used
to generate possible completions. If no pattern
matches, the options
given before the -x are used.
Note that each pattern should be supplied as a single argument and should be quoted to prevent expansion of metacharacters by the shell.
A pattern
is built of sub-patterns separated by commas; it matches if
at least one of these sub-patterns matches (they are ‘or’ed). These
sub-patterns are in turn composed of other sub-patterns separated by
white spaces which match if all of the sub-patterns match (they are
‘and’ed). An element of the sub-patterns is of the form
‘c
[...][...]’, where the pairs of brackets may be repeated as
often as necessary, and matches if any of the sets of brackets match (an
‘or’). The example below makes this clearer.
The elements may be any of the following:
s[string
]...
Matches if the current word on the command line starts with one of the
strings given in brackets. The string
is not removed and is not part
of the completion.
S[string
]...
Like s[string
] except that the string
is part of the completion.
p[from
,to
]...
Matches if the number of the current word is between one of the from
and to
pairs inclusive. The comma and to
are optional; to
defaults
to the same value as from
. The numbers may be negative: -n
refers to
the n
’th last word on the line.
c[offset
,string
]...
Matches if the string
matches the word offset by offset
from the
current word position. Usually offset
will be negative.
C[offset
,pattern
]...
Like c but using pattern matching instead.
w[index
,string
]...
Matches if the word in position index
is equal to the corresponding
string
. Note that the word count is made after any alias expansion.
W[index
,pattern
]...
Like w but using pattern matching instead.
n[index
,string
]...
Matches if the current word contains string
. Anything up to and
including the index
th occurrence of this string will not be considered
part of the completion, but the rest will. index
may be negative to
count from the end: in most cases, index
will be 1 or -1. For example,
compctl -s '`users`' -x 'n[1,@]' -k hosts -- talk
will usually complete usernames, but if you insert an @ after the name,
names from the array hosts
(assumed to contain hostnames, though you
must make the array yourself) will be completed. Other commands such as
rcp can be handled similarly.
N[index
,string
]...
Like n except that the string will be taken as a character class.
Anything up to and including the index
th occurrence of any of the
characters in string
will not be considered part of the completion.
m[min
,max
]...
Matches if the total number of words lies between min
and max
inclusive.
r[str1
,str2
]...
Matches if the cursor is after a word with prefix str1
. If there is
also a word with prefix str2
on the command line after the one matched
by str1
it matches only if the cursor is before this word. If the
comma and str2
are omitted, it matches if the cursor is after a word
with prefix str1
.
R[str1
,str2
]...
Like r but using pattern matching instead.
q[str
]...
Matches the word currently being completed is in single quotes and the
str
begins with the letter ‘s’, or if completion is done in double
quotes and str
starts with the letter ‘d’, or if completion is done in
backticks and str
starts with a ‘b’.
21.7 Example
compctl -u -x 's[+] c[-1,-f],s[-f+]' \
-g '~/Mail/*(:t)' - 's[-f],c[-1,-f]' -f -- mail
This is to be interpreted as follows:
If the current command is mail, then
if ((the current word begins with + and the previous word is -f) or (the current word begins with -f+)), then complete the non-directory part (the ‘:t’ glob modifier) of files in the directory ~/Mail; else
if the current word begins with -f or the previous word was -f, then complete any file; else
complete user names.
This document was generated on May 14, 2022 using texi2html
5.0.
Zsh version 5.9, released on May 14, 2022.