WTMP(5)

NAME
wtmp - user login history

DESCRIPTION
This file records all logins and logouts. Its format is exactly like utmp(5) except that a null user name indicates a logout on the associated typewriter. Furthermore, the typewriter name `~' indicates that the system was rebooted at the indicated time; the adjacent pair of entries with typewriter names `|' and `}' indicate the system-maintained time just before and just after a date command has changed the system's idea of the time.

Wtmp is maintained by login(1) and init(8). Neither of these programs creates the file, so if it is removed record-keeping is turned off. It is summarized by ac(1).

FILES
/usr/adm/wtmp

SEE ALSO
utmp(5), login(1), init(8), ac(1), who(1)