In the article, this is what he/she wrote:
Wipe a hard drive of all data (you would want to boot from a cd to do this) http://www.efense.com/helix
is a good boot cd The helix boot environment contains the DoD version of dd called dcfldd. It works the same way, but is has a progress bar.
dcfldd if=/dev/zero of=/dev/sda conv=notrunc
They mention getting a different CD called Helix, as far as I can tell the only difference is that the Helix CD has a progress bar to let you see what's happening as it will not happen in a flash depending on what kind of hardware you have and the size of the partition. If /dev/sda2 is the /home partition you want to wipe than the dd command should look like this:
dd if=/dev/zero of=/dev/sda2 conv=notrunc
You will probably have to wait till the prompt comes back before doing anything else, as I mentioned, I have not used dd but according to the article, this is how to write 0's across the second partition presumably /home on a SATA HDD. To do the entire drive, remove the (2) next to sda.