The acronyms "grep" and "dd"

[Ralf Mardorf]

PS:

"dd = copy and convert (cc was taken by C compiler, but
             not mentioned in the manpage; "common knowledge")"

:D

duplicate data
^         ^   

IMO would be more reasonable ;), so I googled and indeed I found this:

"[snip] The name dd may be an allusion to the DD statement found in
IBM's Job Control Language (JCL),[3] where the initials stand for "Data
Description."[4] The command's syntax resembles the JCL statement more
than it does other Unix commands, so the syntax may have been a joke.[3]
Another explanation for the command's name is that "cc" (for "convert
and copy", as in the command's description) was already taken by the C
compiler.[citation needed]
[snip]
dd can duplicate data across files, devices, partitions and volumes.
[snip]" - http://en.wikipedia.org/wiki/Dd_(Unix)