AC(8) BSD System Manager's Manual AC(8)
ac -- connect time accounting
ac [-dp] [-t tty] [-w wtmp] [users ...]
If the file /var/log/wtmp exists, a record of individual login and logout
times are written to it by login(1) and init(8), respectively. The ac
utility examines these records and writes the accumulated connect time
(in hours) for all logins to the standard output.
The options are as follows:
-d Display the connect times in 24 hour chunks.
-p Print individual users' totals.
-t tty Only do accounting logins on certain ttys. The tty specifica-
tion can start with '!' to indicate not this tty and end with
'*' to indicate all similarly named ttys. Multiple -t flags
may be specified.
-w wtmp Read connect time data from wtmp instead of the default file,
users ... Display totals for the given individuals only.
If no arguments are given, ac displays the total connect time for all
accounts with login sessions recorded in wtmp.
The default wtmp file will increase without bound unless it is truncated.
It is normally truncated by the daily scripts run by cron(8), which
rename and rotate the wtmp files, keeping a week's worth of data on hand.
No login or connect time accounting is performed if /var/log/wtmp does
ac -p -t "ttyd*" > modems
ac -p -t "!ttyd*" > other
allows times recorded in modems to be charged out at a different rate
The ac utility exits 0 on success, and >0 if an error occurs.
/var/log/wtmp connect time accounting file
login(1), utmp(5), init(8), sa(8)
BSD March 15, 1994 BSD