I use cat /dev/zero to write on free space on Each drive one by one but my question should I use;
cat /dev/zero > wipe_space or cat /dev/urandom > wipe_space
2.I know that first write zero and the second write random data, but zeros is much faster, so whats the difference?
3.and Is there any difference between cat , dd command?
4.last question is this way secure just dont want the one who will get my pc restore any thing with recovery tools.
Note:I'll not erase every thing, 'll delete personal stuff and wipe free space!