From Wsms

Note: This page should be titled dd (all lowercase). It is Dd due to technical limitations of Mediawiki.

dd copies bytes from one file to another.

common usage

Make an .iso image from a CD or DVD:

[ggeller@harrison sda1]$ dd if=/dev/hdc of=Goodies.iso

Make a backup of your master boot record:

[ggeller@harrison sda1]$ dd if=/dev/hda of=backup-hda.mbr count=1 bs=512

see also

man dd
Linux_commands