UNIX for Dummies Questions & Answers

Hi there,
When I want to make a file unrecoverable, I use the following command:

Code:

foo:~$ shred -fuz filename

The problem is that I deleted many files using:

Code:

foo:~$ rm -f filename

How can I make those files unrecoverable?
Is there a command that shreds the disk free space?
So that no file can be recovered from the "supposedly" free space.
Thanks for your help.
Santiago

Code:

dd if=/dev/zero of=dummyfile; rm dummyfile

Which just fills all available disk space with zeroes. You might want to follow with

Code:

dd if=/dev/urandom of=dummyfile; rm dummyfile

to overwrite with random data.

Note, if the machine in question is an ssh or https server, you don't want to exhaust the available entropy; consider generating one one machine and piping through ssh onto the other.

Code:

dd if=/dev/urandom | ssh other 'cat >dummyfile; rm dummyfile'

Note also that if this involves the root filesystem or a multi-user system this will cause problems when the disk fills. Think carefully before doing this on critical systems.

Forgot to say thanks.
Maybe not too late?