I should probably be putting more of my code out there than I have. Here is some stuff though. Most of it is pretty old.
Manage Upload Types – A WordPress Plugin that allows administrators to manage what types of files may be uploaded to the media library.
Jpgtn – A JPEG thumbnailer.
File::Signature – Perl module for detecting changes to a file’s content or attributes. (Unix/Linux only.)
Template::Plain – A Perl extension for very simple templates.
You might want to have a look at my github profile.