[TUHS] PDP-7 UNIX file systam

[Doug McIlroy]

> As noted in the jargon file, the dd(1) syntax is deliberately reminiscent
> of the DD statement in IBM JCL.  This was presumably a joke

That is certainly true and reflects its major early usage to
prepare tapes to carry to other systems.

 Though I haven't use dit in ages, I recall that the joke was
so fully engtained that the command was more likely to be
written "dd  ifile=x ofile=y" than "dd <x >y"

Doug