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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 withfoo
. 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 nocompctl -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 nocompctl -D
command has been issued, filenames are completed. -
-T
supplies completion flags to be used before any other processing is done, even before processing forcompctl
s 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 usecompctl -T -x 's[~] C[0,[^/]#]' -k friends -S/ -tn
to complete the strings in the array
friends
after a ‘~
’. TheC[``...``]
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 ofoptions
, 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 thekill
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 argumentarray
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
Theglobstring
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. Thefignore
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
Thesubststring
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. Thefignore
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 theread
builtin. The function should set the variablereply
to an array containing the completions (one completion per element); note thatreply
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 theread
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 lastnum
history lines. Only words matchingpattern
are taken. Ifnum
is zero or negative the whole history is searched and ifpattern
is the empty string all words are taken (as with ‘*
’). A typical use iscompctl -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
Theprefix
is inserted just before the completed string; any initial part already typed will be completed and the wholeprefix
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 thesuffix
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 directoryfile-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. Thefile-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 theAUTO_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 thecmd
supplied with the option. If thecmd
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 givencmd
. Ifcmd
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 theread
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 ifAUTO_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, iffunc-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 arrayreply
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
Printexplanation
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 theexplanation
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
Thecontinue
-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, whencompctl
would usually continue with ordinary processing after finding matches; this can be suppressed with ‘-tn
’.(ii) With a list of alternatives separated by
+
, whencompctl
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 nameddefault
. 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 thematch-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. Thestring
is not removed and is not part of the completion. -
S[``string``]
...
Likes[``string``]
except that thestring
is part of the completion. -
p[``from``,``to``]
...
Matches if the number of the current word is between one of thefrom
andto
pairs inclusive. The comma andto
are optional;to
defaults to the same value asfrom
. The numbers may be negative:-``n
refers to then
’th last word on the line. -
c[``offset``,``string``]
...
Matches if thestring
matches the word offset byoffset
from the current word position. Usuallyoffset
will be negative. -
C[``offset``,``pattern``]
...
Likec
but using pattern matching instead. -
w[``index``,``string``]
...
Matches if the word in positionindex
is equal to the correspondingstring
. Note that the word count is made after any alias expansion. -
W[``index``,``pattern``]
...
Likew
but using pattern matching instead. -
n[``index``,``string``]
...
Matches if the current word containsstring
. Anything up to and including theindex
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 arrayhosts
(assumed to contain hostnames, though you must make the array yourself) will be completed. Other commands such asrcp
can be handled similarly. -
N[``index``,``string``]
...
Liken
except that the string will be taken as a character class. Anything up to and including theindex
th occurrence of any of the characters instring
will not be considered part of the completion. -
m[``min``,``max``]
...
Matches if the total number of words lies betweenmin
andmax
inclusive. -
r[``str1``,``str2``]
...
Matches if the cursor is after a word with prefixstr1
. If there is also a word with prefixstr2
on the command line after the one matched bystr1
it matches only if the cursor is before this word. If the comma andstr2
are omitted, it matches if the cursor is after a word with prefixstr1
. -
R[``str1``,``str2``]
...
Liker
but using pattern matching instead. -
q[``str``]
...
Matches the word currently being completed is in single quotes and thestr
begins with the letter ‘s’, or if completion is done in double quotes andstr
starts with the letter ‘d’, or if completion is done in backticks andstr
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 directoryif the current word begins with
-f
or the previous word was-f
, then complete any file; elsecomplete user names.
This document was generated on February 15, 2020 using
texi2html 5.0.
Zsh version 5.8, released on February 14, 2020.