Replacement for the Linux Wipe Tools scripts by Thomas C. Greene (uses the same methods, but much more usable). This script will wipe your swap partitions and all the free space on any partitions/disks you tell it, with a configurable number of passes with random data. Can automatically determine partitions available to wipe, contains test and interactive modes for the less confident, and full instructions. Intended for periodic scheduled wiping of your system, and targeted wipes of removable media, as part of your overall information security strategy.
For normal disk partitions, the wipe method is to write a big file of random data in any free space on the partition. Slack space at the end of files is not wiped, and journalled file systems (ext3, etc.) may also retain traces of old data in areas that cannot be overwritten by this program. For swap partitions, the swap partition is turned off, overwritten with random data, then turned back on again. You should do your own research regarding what the methods implemented by this script do (the Linux Wipe Tools README file has a good description), and what they do NOT do, and make your own decisions regarding the security provided, as (in common with most GPL software) it comes with NO WARRANTY.
This is a shell script which has been tested on Linux systems; it may work on other Unix-like systems, but no guarantees. No further additions or developments are planned in the foreseeable future, unless you find a problem causing it not to work on your system, in which case I'll do my best to help out.