The Jargon File (version 4.4.7, 29 Dec 2003):

brain fart
 n.

    The actual result of a braino, as opposed to the mental glitch that is
    the braino itself. E.g., typing dir on a Unix box after a session with DOS.


The Free On-line Dictionary of Computing (30 December 2018):

brain fart

    1. The actual result of a braino, as
   opposed to the mental glitch that is the braino itself.
   E.g. typing "dir" on a Unix box after a session with
   MS-DOS.

   2. A biproduct of a bloated mind producing information
   effortlessly.  A burst of useful information. "I know you're
   busy on the Microsoft story, but can you give us a brain fart
   on the Mitnik bust?"

   (1997-04-29)