Re: Erasing File Data

"Sebastian G." <seppi@xxxxxxxxx> (07-05-15 04:04:13):

There is, and I've already told: shred does a very bad job.

But in what way?

shred doesn't care for journaling file systems. dd simply ignores any
journal and writes to the raw partition or drive.

shred doesn't care for caches. dd only hits the kernel buffers, with
guarantees of write commitment.

*Sigh*, I'm still talking about an entire partition/disk. shred does
exactly the same as dd, just with a computed pattern instead of the
input from a file/device, and it overwrites multiple times by default.

And for simply overwriting files or free space, there are serious
alternatives which do the job right.

Are there any free (in terms of free speech) alternatives?

That wasn't meant to be special for zeroes. What if the cache
contains a block N with the value X and you want to write the same
block X to the same position N again? I don't know, but it would
make sense to just ignore it.

If N wasn't written to the platers yet, the same would be true for
'shred', and a simply 'sync' would resolve the issue - and the command
merging would be justified anyway. If N was already written, then
there's simply no need to write it again.

However, cache hitting is unlikely in partition/disk overwriting anyway,
since with both methods you always overwrite from the first block to the

Ertugrul Söylemez.

Security is the one concept, which makes things in your life stay as
they are. Otto is a man, who is afraid of changes in his life; so
naturally he does not employ security.