Getopt::Long::EvenLess - Like Getopt::Long::Less, but with even less features


This document describes version 0.111 of Getopt::Long::EvenLess (from Perl distribution Getopt-Long-EvenLess), released on 2017-08-09.


This module (GLEL for short) is a reimplementation of Getopt::Long (GL for short), but with much less features. It's an even more stripped down version of Getopt::Long::Less (GLL for short) and is perhaps less convenient to use for day-to-day scripting work.

The main goal is minimum amount of code and small startup overhead. This module is an experiment of how little code I can use to support the stuffs I usually do with GL.

Compared to GL and GLL, it:

  • has minimum Configure() support

    Only these configurations are known: pass_through, no_pass_through (default).

    GLEL is equivalent to GL in this mode: bundling, no_ignore_case, no_getopt_compat, gnu_compat, permute.

    No support for configuring via import options e.g.:

     use Getopt::Long qw(:config pass_through);
  • does not support increment (foo+)

  • no type checking (foo=i, foo=f, foo=s all accept any string)

  • does not support optional value (foo:s), only no value (foo) or required value (foo=s)

  • does not support desttypes (foo=s@)

  • does not support handler other than coderef (so no "foo=s" => \$scalar, "foo=s" => \@ary, only "foo=s" => sub { ... })

    Also, in coderef handler, code will get a simple hash instead of a "callback" object as its first argument.

  • does not support hashref as first argument

  • does not support bool/negation (no foo!, so you have to declare both foo and no-foo manually)

The result?

Amount of code. GLEL 0.07 is about 175 lines of code, while GL is about 1500. Sure, if you really want to be minimalistic, you can use this single line of code to get options:

 @ARGV = grep { /^--([^=]+)(=(.*))?/ ? ($opts{$1} = $2 ? $3 : 1, 0) : 1 } @ARGV;

and you're already able to extract --flag or --opt=val from @ARGV but you also lose a lot of stuffs like autoabbreviation, --opt val syntax support syntax (which is more common, but requires you specify an option spec), custom handler, etc.

Startup overhead. Here's a sample startup overhead benchmark:

                             Rate        run_gl     load_gl run_gl_evenless load_gl_evenless run_gl_less load_gl_less   perl
 run_gl           64.096+-0.092/s            --       -0.5%          -68.6%           -69.2%      -70.1%       -70.4% -90.6%
 load_gl            64.39+-0.16/s   0.46+-0.29%          --          -68.4%           -69.1%      -70.0%       -70.3% -90.5%
 run_gl_evenless   203.88+-0.74/s   218.1+-1.2% 216.6+-1.4%              --            -2.1%       -4.9%        -5.8% -70.0%
 load_gl_evenless  208.24+-0.57/s     224.9+-1% 223.4+-1.2%     2.14+-0.46%               --       -2.8%        -3.8% -69.4%
 run_gl_less       214.28+-0.62/s   234.3+-1.1% 232.8+-1.3%      5.1+-0.49%       2.9+-0.41%          --        -1.0% -68.5%
 load_gl_less      216.44+-0.45/s 237.68+-0.85% 236.1+-1.1%     6.16+-0.44%      3.94+-0.36% 1.01+-0.36%           -- -68.2%
 perl                679.7+-3.7/s     960.5+-6% 955.7+-6.4%     233.4+-2.2%        226.4+-2%   217.2+-2%  214.1+-1.8%     --
 Average times:
   perl            :     1.4712ms
   load_gl_less    :     4.6202ms
   run_gl_less     :     4.6668ms
   load_gl_evenless:     4.8022ms
   run_gl_evenless :     4.9048ms
   load_gl         :    15.5304ms
   run_gl          :    15.6016ms


Configure(@configs | \%config) => hash

Set configuration. Known configurations:

  • pass_through

    Ignore errors (unknown/ambiguous option) and still make GetOptions return true.

  • no_pass_through (default)

  • no_auto_abbrev

  • auto_abbrev (default)

  • no_ignore_case

  • no_getopt_compat

  • gnu_compat

  • bundling

  • permute

Return old configuration data. To restore old configuration data you can pass it back to Configure(), e.g.:

 my $orig_conf = Getopt::Long::EvenLess::Configure("pass_through");
 # ...

GetOptions(%spec) => bool

Shortcut for:

 GetOptionsFromArray(\@ARGV, %spec)

GetOptionsFromArray(\@ary, %spec) => bool

Get (and strip) options from @ary. Return true on success or false on failure (unknown option, etc).


Please visit the project's homepage at


Source repository is at


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.




If you want more features intead of less, try Getopt::Long::More.


perlancar <>


This software is copyright (c) 2017, 2016, 2015 by

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