Un poco de humor geek:

(% represents the csh, $ represents the bourne shell)

% «How poorly would you rate the UNIX (so-called) user interface?
Unmatched «.

% rm congressional-ethics
rm: congressional-ethics nonexistent

% ar m God
ar: God does not exist

% [Where is Jimmy Hoffa?
Missing ].

% ^How did the sex change^ operation go?
Modifier failed.

% If I had a ( for every $ Congress spent, what would I have?
Too many (‘s.

%make love
Make: Don’t know how to make love. Stop.

% sleep with me
bad character

% got a light?
No match.

% man: why did you get a divorce?
man:: Too many arguments.

% ^What is saccharine?
Bad substitute.

% \(-
(-: Command not found.

% sh

$ PATH=pretending! /usr/ucb/which sense
no sense in pretending

$ drink
bottle: cannot open
opener: not found

$ mkdir matter; cat >matter
matter: cannot create

Or, in a System V (att) universe:

$ cat «can of food»
cat: cannot open can of food
fuente: http://www.gnu.org/fun/jokes/