The Deadly dd Command
Copy a drive to another
dd if=/dev/sda of=/dev/sdb
Create an ISO image from DVD
dd if=/dev/dvd of=dvd.iso
Wipe the partition (like wipedisk)
dd if=/dev/zero of=/dev/sda
Copy drive to compressed archive (make sure destination is not the same)
dd if=/dev/hda | gzip > hda.img.gz
Backup image of MBR and partition table
dd if=/dev/sda of=/home/sam/MBR.image bs=512 count=1