Re: [Trisquel-users] Erasing Harddrive.

[cooloutac]

-z  with shred will overwrite with zeros on the final pass if you really want  
to.  But its not nescessary especially if you are going to use the disk again  
for reinstall.

-n  tells it how many passes to do. (default is 3 passes)
so shred -n 1 -z -v /dev/sda  will probably take like 4 hours on a 1tb, maybe  
longer.

But i would recommend just doing shred -v /dev/sda,   think it took maybe 30  
mins to an  hour  with my 1tb 7200 sata.