The Storable extension brings persistency to your data.

You may recursively store to disk any data structure, no matter
how complex and circular it is, provided it contains only SCALAR,
ARRAY, HASH (possibly tied) and references (possibly blessed) to
those items.

At a later stage, or in another program, you may retrieve data from
the stored file and recreate the same hiearchy in memory. If you
had blessed references, the retrieved references are blessed into
the same package, so you must make sure you have access to the same
perl class as the one used to create the relevant objects.

There is also a dclone() routine which performs an optimized
mirroring of any data structure, preserving its topology.

Objects (blessed references) may also redefine the way storage and
retrieval is performed, and/or what deep cloning should do on those
objects.