The Free On-line Dictionary of Computing (19 January 2023):

RTBM

   (Unix) Read The Bloody Manual.

   Commonwealth Hackish variant of RTFM.  RTBM is often the
   entire text of the first reply to a question from a newbie;
   the *second* would escalate to "RTFM".

   [Jargon File]

   (1994-12-08)


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

RTBM
 /R·T·B·M/, imp.

    [Unix] Commonwealth Hackish variant of RTFM; expands to ‘Read The Bloody
    Manual’. RTBM is often the entire text of the first reply to a question
    from a newbie; the second would escalate to “RTFM”.