Giant.pl is a demonstration of the use of Getopt::OO. It uses almost every feature of the parser. Please note that I don't suggest that you write your code like this. This is a demonstration only. In particular, the I would use the callback below to validate that the giant isn't exceeding his vocabulary, but I would not use the ClientData method just to echo what he said with code references.
Try Giant.pl -w -b --roars fe fum fo fi -s for fun!
To install Getopt::OO, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Getopt::OO
CPAN shell
perl -MCPAN -e shell install Getopt::OO
For more information on module installation, please visit the detailed CPAN module installation guide.