Very disappointed after tracking down[1] and doing:

   alias rot13="tr '[A-Za-z]' '[N-ZA-Mn-za-m]'"

and still only getting gibberish out the other end of the pipe (lame pun intended). I thought you were talking about stuff like Xrrc lbhe ybirq bar cyrnfrq.

[1] http://www.commandlinefu.com/commands/view/1792/rot13-using-...