The London Perl and Raku Workshop takes place on 26th Oct 2024. If your company depends on Perl, please consider sponsoring and/or attending.


Complete::Getopt::Long - Complete command-line argument using Getopt::Long specification


This document describes version 0.481 of Complete::Getopt::Long (from Perl distribution Complete-Getopt-Long), released on 2022-08-28.


See Getopt::Long::Complete for an easy way to use this module.





 complete_cli_arg(%args) -> hash|array

Complete command-line argument using Getopt::Long specification.

This routine can complete option names, where the option names are retrieved from Getopt::Long specification. If you provide completion routine in completion, you can also complete option values and arguments.

Note that this routine does not use Getopt::Long (it does its own parsing) and currently is not affected by Getopt::Long's configuration. Its behavior mimics Getopt::Long under these configuration: no_ignore_case, bundling (or no_bundling if the bundling option is turned off). Which I think is the sensible default. This routine also does not currently support auto_help and auto_version, so you'll need to add those options specifically if you want to recognize --help/-? and --version, respectively.

This function is not exported by default, but exportable.

Arguments ('*' denotes required arguments):

  • bundling => bool (default: 1)

    If you turn off bundling, completion of short-letter options won't support bundling (e.g. -b<tab> won't add more single-letter options), but single-dash multiletter options can be recognized. Currently only those specified with a single dash will be completed. For example if you have -foo=s in your option specification, -f<tab> can complete it.

    This can be used to complete old-style programs, e.g. emacs which has options like -nw, -nbc etc (but also have double-dash options like --no-window-system or --no-blinking-cursor).

  • completion => code

    Completion routine to complete option value/argument.

    Completion code will receive a hash of arguments (%args) containing these keys:

    • type (str, what is being completed, either optval, or arg)

    • word (str, word to be completed)

    • cword (int, position of words in the words array, starts from 0)

    • opt (str, option name, e.g. --str; undef if we're completing argument)

    • ospec (str, Getopt::Long option spec, e.g. str|S=s; undef when completing argument)

    • argpos (int, argument position, zero-based; undef if type='optval')

    • nth (int, the number of times this option has seen before, starts from 0 that means this is the first time this option has been seen; undef when type='arg')

    • seen_opts (hash, all the options seen in words)

    • parsed_opts (hash, options parsed the standard/raw way)

    as well as all keys from extras (but these won't override the above keys).

    and is expected to return a completion answer structure as described in Complete which is either a hash or an array. The simplest form of answer is just to return an array of strings. The various complete_* function like those in Complete::Util or the other Complete::* modules are suitable to use here.

    Completion routine can also return undef to express declination, in which case the default completion routine will then be consulted. The default routine completes from shell environment variables ($FOO), Unix usernames (~foo), and files/directories.


     use Complete::Unix qw(complete_user);
     use Complete::Util qw(complete_array_elem);
         getopt_spec => [
             'help|h'   => sub{...},
             'format=s' => \$format,
             'user=s'   => \$user,
         completion  => sub {
             my %args  = @_;
             my $word  = $args{word};
             my $ospec = $args{ospec};
             if ($ospec && $ospec eq 'format=s') {
                 complete_array_elem(array=>[qw/json text xml yaml/], word=>$word);
             } else {
  • cword* => int

    Index in words of the word we're trying to complete.

    See function parse_cmdline in Complete::Bash on how to produce this (if you're using bash).

  • extras => hash

    Add extra arguments to completion routine.

    The keys from this extras hash will be merged into the final %args passed to completion routines. Note that standard keys like type, word, and so on as described in the function description will not be overwritten by this.

  • getopt_spec* => array

    Getopt::Long specification.

  • words* => array

    Command line arguments, like @ARGV.

    See function parse_cmdline in Complete::Bash on how to produce this (if you're using bash).

Return value: (hash|array)

You can use format_completion function in Complete::Bash module to format the result of this function for bash.



Bool. If set to true, will generated more log statements for debugging (at the trace level).


Bool. Default true. Can be set to false to disable completing from environment variable in default completion.


Bool. Default true. Can be set to false to disable completing from filesystem (file and directory names) in default completion.


Please visit the project's homepage at


Source repository is at





Other modules related to bash shell tab completion: Bash::Completion, Getopt::Complete.

Perinci::CmdLine - an alternative way to easily create command-line applications with completion feature.


perlancar <>


  • Mary Ehlers <>

  • Steven Haryanto <>


To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

 % prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.


This software is copyright (c) 2022, 2020, 2019, 2017, 2016, 2015, 2014 by perlancar <>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.


Please report any bugs or feature requests on the bugtracker website

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.