Deleting?

[genlee]

Ok, I need a good method to delete a file so it can not be recovered at all without wiping the entire partition or disk. Anyone have any ideas?

[genlee]

How well does shred work?

EDIT
Just checked and shred won't work on any journaled filesystem.

[Dolda2000]

Can't you do like this?

dd if=/dev/zero of=$filename bs=1024 count=$(((`ls -l $filename | awk '{print $5;}'` / 1024) + 1))

That should zero all blocks in the file, right? I guess you could tweak 1024 to the actual blocksize of the underlying device for greater performance, but... big deal...

[wassy121]

ah yes, you could zero them out, but there is still a residual magnetic signature. There have been cases of files that were "shredded" like that over 5 times that were still recoverable. The only real way to do it is melt the platter

[Dolda2000]

You're right of course. Like this then?

for i in `seq 1 10`; do
    dd if=/dev/random of=$filename bs=1024 count=$(((`ls -l $filename | awk '{print $5;}'` / 1024) + 1))
don

That should make it far less traceable, right? (Of course, /dev/random isn't the fastest solution, so /dev/urandom might be preferrable)

[genlee]

Well I ended up using shred to just overwrite the files to make them unreadable. It worked good, when I cat the outputs it just displays a bunch of stuff which messes up my term as well.

[l_Kriss]

silly me. i was thinking that wipe did the files unrecoverable?

[wassy121]

good idea Dolda, I never thought of using pseudorandomness to cover up files like that. There was a thread on LKML (maybe it was somewhere else?) where no one thought of that.