best fedora solution to securely erase folders/clean free space?

[M. Fioretti]

Greatings,

I started reading online to refresh what I knew about secure deletion
of files, and being sure that "free space" on an ext3/ext4 partition is
surely "free", that is you can't recover the files that _were_ there.

After reading this article:

http://techthrob.com/2009/03/02/howto-delete-files-permanently-and-securely-in-linux/

I found that there is a Fedora RPM for srm, and that the source code
for sfill is at http://www.thc.org/releases.php

I will (re)study these topics in detail in the next days. My first
interest is to understand if those (or other) tools are enough to be
sure, without reformatting/reinstalling, that, besides the files one
DOES want to keep, there really is nothing else recoverable on the
drive.

I'm very interested to know your opinion/experiences/suggestions about
this.

TIA,
Marco