What is the dd command in Linux?

Answer 1

dd is supposedly an acronym for 'disk destroyer'

it basically makes a BINARY COPY of a file into another file. It is different different from the cp command, which copies files. dd copies bytes.

It is useful because in the unix world, everything is a file. For example,

dd if=/dev/zero of=/home/yourname/zerofile bs=1024 count=1024

makes a file called zerofile in your home directory which will be one megabyte long and will have nothing but zeros (empty).

Also, again using device files, you can copy the contents of one hard drive or partition onto another hard drive or partition. Just keep in mind that it is not just copying files, but making a binary copy. The following would copy your first partition onto your second partition:

dd if=/dev/sda1 of=/dev/sda2 bs=1024

and finally, this is how you can get into big trouble. The following would probably run for about two minutes and then your computer would freeze and never boot up again.

dd if=/dev/zero of=/dev/sda bs=1024

Answer 2

dd is used for a wide variety of things - it acts on files as well as block devices (storage devices).

It can be used to copy (clone), or overwrite (wipe) files and disks. Improper usage may cause loss of data, hence the nickname "Disk Destroyer".

see:

linux.die.net/man/1/dd

en.wikipedia.org/wiki/Dd_(Unix)

Answer 3

Copy a file, converting and formatting according to the operands.

Answer 4

The DD command on the Linux system is a command which can help you backup your entire hard drive. You have to be careful when using this command because it can also erase your hard drive.