dd

• dd is useful when working with block and character devices
• dd’s sole purpose is to read from an input file or stream and write to an output file or stream
• dd copies data in blocks of a fixed size

example usage

dd if=/dev/zero of=new_file bs=1024 count=1

the dd command syntax differs from most other unix style commands. It is based on an old IBM job control language (JCL) style.