How to overwrite your hard disk with random characters
dd if=/dev/random of=/dev/sda
How to overwrite your hard disk with zero characters
dd if=/dev/random of=/dev/sda
Replace sda / hda with your hard disk identifier.
As a security measure to prevent potential viruses, Gmail doesn't allow you to send or receive executable files (such as files ending in .exe) that could contain damaging executable code.
