Description:

This module provides a quick and easy way to add tab completion feature to
your scripts, including scripts already written using the venerable the
Getopt::Long manpage module.

This module is basically just a thin wrapper for Getopt::Long. Its
'GetOptions' function just checks for COMP_LINE/COMP_POINT environment
variable before passing its arguments to Getopt::Long's GetOptions. If
COMP_LINE is defined, completion reply will be printed to STDOUT and then
the program will exit. Otherwise, Getopt::Long's GetOptions is called.

To keep completion quick, you should do 'GetOptions()' or
'GetOptionsWithCompletion()' as early as possible in your script.
Preferably before loading lots of other Perl modules.