[CentOS] help fdisk and dd

From: chloe K <chloekcy2000 at yahoo.ca>
> What is the best practice to remove all data in the disk?
> ls fdisk ok or use dd 

Maybe something like (replace the ?):
 - fast but not secure:
   dd if=/dev/zero of=/dev/?d? bs=4096
 - slow but more secure:
   dd if=/dev/zero of=/dev/?d? bs=4096
 - n times slower but n times more secure:
   for ((i=1; i<=n; i++)); do dd if=/dev/zero of=/dev/?d? bs=4096; done

JD