Algorithm::Diff is a Perl module for computing the difference between two files, two strings, or any other two lists of things. It uses an intelligent algorithm similar to (or identical to) the one used by the Unix `diff' program. It is guaranteed to find the smallest possible set of differences.
Apache::Session is a persistence framework whose purpose is to provide session management to Web developers. It is designed to work with Apache and mod_perl, but it does not depend on them and will work with any Web server. This module provides a set of classes that give the developer maximum functionality. Session data can be stored in a database, flat files, or shared memory.
The Archive::Zip module allows a Perl program to create, manipulate, read, and write Zip archive files without calling an external program. Members can be added, removed, extracted, replaced, rearranged, and enumerated. They can also be renamed or have their dates, comments, or other attributes queried or modified. Their data can be compressed or uncompressed as needed, and members can be created from members in existing Zip files, or from existing directories, files, or strings.
The CDDB/CDDB_get Perl module gets the CDDB info for an audio CD. The included script was intended as a demo for CDDB_get, but over time it has gained powerful features like the ability to write to a database, offline mode, HTTP mode (including proxy), saving in standard XMCD format, and writing 'lame' commands.