ac(8)

NAME

ac - connect time accounting

ac [-dp] [-t tty] [-w wtmp] [users ...]

If the file /var/log/wtmp exists, a record of individual lo
gin and logout times are written to it by login(1) and init(8), respective
ly. 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. Multi; ple -t flags
may be specified.
-w wtmp Read connect time data from wtmp instead of the
default file,: /var/log/wtmp.
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 not exist.
For example,
ac -p -t "ttyd*" > modems ac -p -t "!ttyd*" > other
allows times recorded in modems to be charged out at a dif
ferent rate than other.

/var/log/wtmp connect time accounting file