DD Command – What Does ‘dd’ Stand For?

command-namesdd

I know very well what the command does, but man dd, info dd tell me: 'Convert and copy a file', as does GNU Coreutils.

Google says its an abbreviation of everything between medicine and bad webchat slang; except someone saying it means 'data destroyer', something used in PC forensics – I'd be horrified if my dd destroyed my data!

Any insight? 🙂


Update: Of course I had to check the jargon file:

The Unix dd(1) was designed with a
weird, distinctly non-Unixy keyword
option syntax reminiscent of IBM
System/360 JCL (which had an elaborate
DD ‘Dataset Definition’ specification
for I/O devices)

Still sounds pretty ambiguous, but then it says:

though the command filled a need, the interface design was clearly a prank.

Heh 🙂

Best Answer

Wikipedia (dd) asserts it was named after IBM JCL command DD which stands for Data Definition. I always thought it would mean data duplicate, though.