I know what these files record, but I'd like to known what 'u','w','b' prefixes mean.

Can anyone shed some light?


The 'u' stands for user. utmp gives information about who is on the system.
The 'w' in wtmp probably comes from 'who'.
The 'b' comes from 'bad', btmp records the bad login attempts.

The names are a bit cryptic, as so often on Unix/Linux.

  • 3
    And the tmp part is for 'temp'? I'm seriously asking.
    – bitofagoob
    May 29 '17 at 21:19
  • 2
    No idea, I searched a bit but could not find anything. utmp of course has fleeting, temporary, information and was the initial file available, but I have no confirmation that that might be the origin of that name part. You should post that as a new question.
    – Anthon
    May 29 '17 at 22:58
  • Does it possible 'w' come from 'when'? Because wtmp records when user logged in and logged out.
    – Lane
    Jan 12 at 3:14

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