The shred command and security?

[Alan Cox]

> Yes I am aware of both these which are great for total inaccessibility to
> others for an entire disk. In this case I was looking for deletion of a 
> small number of files which may have sensitive info but to retain the
> system, including the HD, in a working fashion for the new owner.

The disk itself doesn't provide this facility. Because of the way files
can get relocated, data can end up in swap etc it would be a bad idea at
the Linux level.

At the hardware level you are not guaranteed that a disk will choose to
use the same physical block for the same logical block so the only proper
way to do erasure is to issue a secure erase command to the drive (if
supported), this will erase the entire media.