AC(1) - Linux man page online | User commands

Print statistics about users' connect time.

2010 August 16
AC(1) General Commands Manual AC(1)


ac - print statistics about users' connect time


ac [ -d | --daily-totals ] [ -y | --print-year ] [ -p | --individual-totals ] [ people ] [ -f | --file filename ] [ -a | --all-days ] [ --complain ] [ --reboots ] [ --supplants ] [ --timewarps ] [ --compatibility ] [ --tw-leniency num ] [ --tw-suspicious num ] [ -z | --print-zeros ] [ --debug ] [ -V | --version ] [ -h | --help ]


ac prints out a report of connect time (in hours) based on the logins/logouts in the cur‐ rent wtmp file. A total is also printed out. The accounting file wtmp is maintained by init(8) and login(1). Neither ac nor login cre‐ ates the wtmp if it doesn't exist, no accounting is done. To begin accounting, create the file with a length of zero. NOTE: The wtmp file can get really big, really fast. You might want to trim it every once and a while. GNU ac works nearly the same UNIX ac, though it's a little smarter in several ways. You should therefore expect differences in the output of GNU ac and the output of ac's on oth‐ er systems. Use the command info accounting to get additional information.


-d, --daily-totals Print totals for each day rather than just one big total at the end. The output looks like this: Jul 3 total 1.17 Jul 4 total 2.10 Jul 5 total 8.23 Jul 6 total 2.10 Jul 7 total 0.30 -p, --individual-totals Print time totals for each user in addition to the usual everything-lumped-into-one value. It looks like: bob 8.06 goff 0.60 maley 7.37 root 0.12 total 16.15 people Print out the sum total of the connect time used by all of the users included in people. Note that people is a space separated list of valid user names; wildcards are not allowed. -f, --file filename Read from the file filename instead of the system's wtmp file. --complain When the wtmp file has a problem (a time-warp, missing record, or whatever), print out an appropriate error. --reboots Reboot records are NOT written at the time of a reboot, but when the system restarts; therefore, it is impossible to know exactly when the reboot occurred. Users may have been logged into the system at the time of the reboot, and many ac's automatically count the time between the login and the reboot record against the user (even though all of that time shouldn't be, perhaps, if the system is down for a long time, for instance). If you want to count this time, include the flag. *For vanilla ac compatibility, include this flag.* --supplants Sometimes, a logout record is not written for a specific terminal, so the time that the last user accrued cannot be calculated. If you want to include the time from the user's login to the next login on the terminal (though probably incorrect), in‐ clude this you want to include the time from the user's login to the next login on the terminal (though probably incorrect), include this flag. *For vanilla ac com‐ patibility, include this flag.* --timewarps Sometimes, entries in a wtmp file will suddenly jump back into the past without a clock change record occurring. It is impossible to know how long a user was logged in when this occurs. If you want to count the time between the login and the time warp against the user, include this flag. *For vanilla ac compatibility, include this flag.* --compatibility This is shorthand for typing out the three above options. -a, --all-days If we're printing daily totals, print a record for every day instead of skipping intervening days where there is no login activity. Without this flag, time accrued during those intervening days gets listed under the next day where there is login activity. --tw-leniency num Set the time warp leniency to num seconds. Records in wtmp files might be slightly out of order (most notably when two logins occur within a one-second period - the second one gets written first). By default, this value is set to 60. If the pro‐ gram notices this problem, time is not assigned to users unless the --timewarps flag is used. --tw-suspicious num Set the time warp suspicious value to num seconds. If two records in the wtmp file are farther than this number of seconds apart, there is a problem with the wtmp file (or your machine hasn't been used in a year). If the program notices this problem, time is not assigned to users unless the --timewarps flag is used. -y, --print-year Print year when displaying dates. -z, --print-zeros If a total for any category (save the grand total) is zero, print it. The default is to suppress printing. --debug Print verbose internal information. -V, --version Print the version number of ac to standard output and quit. -h, --help Prints the usage string and default locations of system files to standard output and exits.


wtmp The system wide login record file. See wtmp(5) for further details.


The GNU accounting utilities were written by Noel Cragg <>. The man page was adapted from the accounting texinfo page by Susan Kleinmann <>.


login(1), wtmp(5), init(8), sa(8)
2010 August 16 AC(1)
This manual Reference Other manuals
ac(1) referred by acctdump(8) | accton(8) | sa(8) | sac(8) | utmp(5) | wcat(1)
refer to login(1) | sa(8) | utmp(5)
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