Using Dban

[Matt Graham]

On 2014-12-14 11:00, Todd Millecam wrote:
> $~  for i in `seq 10` ; do dd if=/dev/random of=/dev/sda && dd
> if=/dev/zero of=/dev/sda ; done

This will work, but it will take days.  /dev/random is a 
super-high-quality random device, and it will run out of 
super-high-quality random bits very quickly and wait for multiple 
seconds to generate more from various entropy sources.  You probably 
want to do this instead:

for i in `seq 10` ; do
   dd if=/dev/urandom of=/dev/sdX bs=32k
   dd if=/dev/zero of=/dev/sdX bs=32k
   done

/dev/urandom is much much faster, though its randomness is not as 
guaranteed.  Using a bs= on the dd command is also a good idea as it 
defaults to a bs of 512 bytes.

> Dban or wipe will do all this for you, but you can do it yourself.

Yes.  And if you do it yourself from a shell, you know exactly what's 
going on and can use the computer for other stuff while you're erasing 
whichever disk you wanted to erase....

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