Linux DD command

1 The basic format of the DD command

DD if=xxx of=xxx bs=xxx count=xxx

2 about BS

BS reads and writes data in blocks, and every time a piece of data is read and written, BS is the size of the specified block. The size of this block can be arbitrary. This arbitrariness allows DD to do a lot of things, just to set the size of BS as needed.

2.1 Getting the entire MBR

DD IF=/DEV/SDA of=mbr.img bs=512 count=1

2.2 Get the boot code for the MBR

DD IF=/DEV/SDA of=mbr_boot.img bs=446 count=1

Linux DD command