Securely wipes all data from disk(s) and/or partition(s).

This method is based on the information provided by Peter Gutmann from the
Sixth (6th) Annual USENIX Security Symposium in a paper entitled:
"Secure Deletion of Data from Magnetic and Solid-State Memory"

Securely overwrite regular disks
Partitions are overwritten 35 times; rounds 1-4 use /dev/arandom, rounds
5-31 use Guttman's deterministic patterns, and rounds 32-35 use
/dev/arandom. This option implements the method described by Peter
Gutmann in his whitepaper, Secure Deletion of Data from Magnetic and
Solid-State Memory, presented at the 6th USENIX Security Symposium.

Please note that secwipe was written on and for OpenBSD, as it can be downloaded to an OpenBSD install image directly from the below link and used to wipe disks. See instructions here. Maybe someone will use it to donate some disks to OpenBSD that might otherwise have gone in the bitbucket! As such, it may not be suited for other operating systems.

Download the script here.