Dd

dd is a utility to create a disk dump by reading every single block on a disk, e.g. your hard drive. Its architecture is laid out so it can do much more than creating a dump. Here is what dd can do for you:

• manage a disk backup
  • create a backup from a disk to a file
  • restore a backup from a file to a disk
  • clone a harddisk
  • create a disk image and transfer it over the network
• create an iso image of a CD
• rescue a file that contains bad blocks
• analyze your disk by displaying selected blocks
• create your own operating system by dumping your bootloader to the boot sector