data shredder

[Fred Roller]

Amedee Van Gasse (ub) wrote:
> On Mon, December 21, 2009 14:08, Fred Roller wrote:
>   
>> Gilles Gravier wrote:
>>     
>>>> The other suggestions are good, and if you want a low-tech solution:
>>>>
>>>> 1) delete your files with rm as usual
>>>> 2) overwrite the empty disk space with zeroes or random data
>>>> Use either one of these commands:
>>>>
>>>> dd if=/dev/null of=nullfile bs=1M
>>>> dd if=/dev/random of=randomfile bs=1M
>>>>         
>
>   
>> Amedee - I am used to the zero/random clearing of disks but not quite
>> clear on why you create an empty image.  Could you clarify?
>>     
>
> Fred,
>
> Suppose I have a 10MB filesystem with 3 files:
> alice.txt - 1MB
> bob.txt - 2MB
> eve.txt - 3MB
> I have 4 MB free disk space
>
> I delete eve.txt but I keep Alice and Bob.
>
> I want to wipe the free space on the filesystem, so I fill it up with a
> zero file called charlie.txt. It will be 7MB: 4MB of the original free
> space, and 3MB from eve.txt.
>
> If I would zero/random clear the entire disk, then I would destroy the
> filesystem and loose Alice and Bob.
>
>   
Thank you.

-- 
Fred
www.fwrgallery.com

"Life is like linux, simple.  If you are fighting it you are doing something wrong."