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In OSX, I can get login history and account usage :

  • The command ac -p gives total login time of users on a machine.
  • The command last gives history of login on the machine.

How do I reset these informations?

Documentation points to /var/run/utmpx but erasing the file has no apparent effect. Directory /var/account/ which should contain a lot of interesting stuff does not exist either.


After stumbling on the opensnoop command, I found out that the history is stored in /var/log/asl/*.asl. Deleting these files does the job.

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Even if you find a solution yourself, please post it as an answer below. – grawity May 10 '12 at 16:09
up vote 1 down vote accepted

Login information is stored in the Apple System Log.

Erasing /var/log/asl/*.asl clears the log files containing (among other things) the login history.

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