This is a role that does
git diff .... See http://www.kernel.org/pub/software/scm/git-core/docs/git-diff.html for details.
Kenichi Ishigaki, <email@example.com>
Copyright (C) 2009 by Kenichi Ishigaki.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.