Is there a reason it needs to be stored in the external file as perl code for hashes? Typically, you would store the data in a data format (CSV, XML, YAML, etc.), and read the data from the file in to build your Perl data structure (hash).

Alternately, if the data is more than a few entries, you might be better off leaving the data on disk, and accessing it on demand. My personal preference for that is SQLite (unless I have specific requirements that suggest something else). For your case, you might want to look at Tie::Hash or something alone that line. This type of module will store the contents of your hash in a database file. To your program, the hash looks and acts pretty much like a standard hash, but the data isn't stored in memory, it's stored on disk.

You could also use a module to implement data structure persistence. Something like Storable (or the numerous similar modules) might be useful for you. It will let you store a data structure (including a hash) on disk, and read it back into your program.

If you are insistent on storing the data as raw Perl code, you should review the documentation on require and do. These can be used to read in perl code from an external source.