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8.7 Programmable Completion Builtins

Two builtin commands are available to manipulate the programmable completion facilities.

compgen

compgen [option] [word]

Generate possible completion matches for word according to the options, which may be any option accepted by the complete builtin with the exception of -p and -r, and write the matches to the standard output. When using the -F or -C options, the various shell variables set by the programmable completion facilities, while available, will not have useful values. The matches will be generated in the same way as if the programmable completion code had generated them directly from a completion specification with the same flags. If word is specified, only those completions matching word will be displayed. The return value is true unless an invalid option is supplied, or no matches were generated.

complete

complete [-abcdefgjksuv] [-o comp-option] 
[-A action] [-G globpat] [-W wordlist]
[-P prefix] [-S suffix] [-X filterpat] [-F function]
[-C command] name [name ...]
complete -pr [name ...]

Specify how arguments to each name should be completed. If the -p option is supplied, or if no options are supplied, existing completion specifications are printed in a way that allows them to be reused as input. The -r option removes a completion specification for each name, or, if no names are supplied, all completion specifications. The process of applying these completion specifications when word completion is attempted is described above (see section 8.6 Programmable Completion). Other options, if specified, have the following meanings. The arguments to the -G, -W, and -X options (and, if necessary, the -P and -S options) should be quoted to protect them from expansion before the complete builtin is invoked.

-o comp-option

The comp-option controls several aspects of the compspec's behavior beyond the simple generation of completions. comp-option may be one of:

bashdefault

Perform the rest of the default Bash completions if the compspec generates no matches.

default

Use Readline's default filename completion if the compspec generates no matches.

dirnames

Perform directory name completion if the compspec generates no matches.

filenames

Tell Readline that the compspec generates filenames, so it can perform any filename-specific processing (like adding a slash to directory names or suppressing trailing spaces). This option is intended to be used with shell functions specified with -F.

nospace

Tell Readline not to append a space (the default) to words completed at the end of the line.

plusdirs

After any matches defined by the compspec are generated, directory name completion is attempted and any matches are added to the results of the other actions.

-A action

The action may be one of the following to generate a list of possible completions:

alias

Alias names. May also be specified as -a.

arrayvar

Array variable names.

binding

Readline key binding names (see section 8.4 Bindable Readline Commands).

builtin

Names of shell builtin commands. May also be specified as -b.

command

Command names. May also be specified as -c.

directory

Directory names. May also be specified as -d.

disabled

Names of disabled shell builtins.

enabled

Names of enabled shell builtins.

export

Names of exported shell variables. May also be specified as -e.

file

File names. May also be specified as -f.

function

Names of shell functions.

group

Group names. May also be specified as -g.

helptopic

Help topics as accepted by the help builtin (see section 4.2 Bash Builtin Commands).

hostname

Hostnames, as taken from the file specified by the HOSTFILE shell variable (see section 5.2 Bash Variables).

job

Job names, if job control is active. May also be specified as -j.

keyword

Shell reserved words. May also be specified as -k.

running

Names of running jobs, if job control is active.

service

Service names. May also be specified as -s.

setopt

Valid arguments for the -o option to the set builtin (see section 4.3 The Set Builtin).

shopt

Shell option names as accepted by the shopt builtin (see section 4.2 Bash Builtin Commands).

signal

Signal names.

stopped

Names of stopped jobs, if job control is active.

user

User names. May also be specified as -u.

variable

Names of all shell variables. May also be specified as -v.

-G globpat

The filename expansion pattern globpat is expanded to generate the possible completions.

-W wordlist

The wordlist is split using the characters in the IFS special variable as delimiters, and each resultant word is expanded. The possible completions are the members of the resultant list which match the word being completed.

-C command

command is executed in a subshell environment, and its output is used as the possible completions.

-F function

The shell function function is executed in the current shell environment. When it finishes, the possible completions are retrieved from the value of the COMPREPLY array variable.

-X filterpat

filterpat is a pattern as used for filename expansion. It is applied to the list of possible completions generated by the preceding options and arguments, and each completion matching filterpat is removed from the list. A leading ‘!’ in filterpat negates the pattern; in this case, any completion not matching filterpat is removed.

-P prefix

prefix is added at the beginning of each possible completion after all other options have been applied.

-S suffix

suffix is appended to each possible completion after all other options have been applied.

The return value is true unless an invalid option is supplied, an option other than -p or -r is supplied without a name argument, an attempt is made to remove a completion specification for a name for which no specification exists, or an error occurs adding a completion specification.