Re: Inquiry:How to totally wipe out the entire hard drive

[Osamu Aoki <osamu@debian.org>]

On Sun, Sep 06, 2009 at 11:13:42AM +0100, hadi motamedi wrote:
> Dear All
> Can you please let me know how can I totally wipe out the entire of my
> hard drive under Debian OS ?  Thank you in advance

http://www.debian.org/doc/manuals/debian-reference/ch10.en.html#_erasing_an_entire_hard_disk

10.2.15. Erasing an entire hard disk

There are several ways to completely erase data from an entire hard disk like
device, e.g., USB memory stick at "/dev/sda".

Caution: Check your USB memory stick location with mount(8) first before
executing commands here. The device pointed by "/dev/sda" may be SCSI hard disk
or serial-ATA hard disk where your entire system resides.

Erase all the disk content by resetting data to 0 with the following.

# dd if=/dev/zero of=/dev/sda

Erase all by overwriting random data with the following.

# dd if=/dev/urandom of=/dev/sda

Erase all by overwriting random data very efficiently with the following.

# shred -v -n 1 /dev/sda

Since dd(1) is available from the shell of many bootable Linux CDs such as
Debian installer CD, you can erase your installed system completely by running
an erase command from such media on the system hard disk, e.g., "/dev/hda",
"/dev/sda", etc.