btrott and chromatic both have great suggestions.

As you are starting to look at storing structured data, there some techniques you shoud consider:

If you have access to a database, you should use it. Perl has a robust DBI module that provides interfaces to many SQL databases (it even has drivers that allow you to use flat files as if they were SQL databases). You may also want to check out the FreezeThaw, Data::Dumper and Storable modules. All of those modules provide ways to taking an in-memory data-structure and extracting it so it can be stored (on disk or otherwise) for later retrieval. If you have access to Advanced Perl Programming it has an excellent chapter on data-persistance that should really be in-line with what you're working on.