ac prints out a report of connect time (in hours) based on the
logins/logouts in the current wtmp file. A total is also printed
The accounting file wtmp is maintained by init(8) and login(1).
Neither ac nor login creates 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 u*x 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 other systems. Use the command
info accounting to get additional information.
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
Print time totals for each user in addition to the usual
everything-lumped-into-one value. It looks like:
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.
When the wtmp file has a problem (a time-warp, missing record,
or whatever), print out an appropriate error.
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.*
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), include 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
compatibility, include this flag.*
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.*
This is shorthand for typing out the three above options.
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
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
program notices this problem, time is not assigned to users
unless the --timewarps flag is used.
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.
Print year when displaying dates.
If a total for any category (save the grand total) is zero,
print it. The default is to suppress printing.
Print verbose internal information.
Print the version number of ac to standard output and quit.
Prints the usage string and default locations of system files
to standard output and exits.
This page is part of the psacct (process accounting utilities)
project. Information about the project can be found at
⟨http://www.gnu.org/software/acct/⟩. If you have a bug report for
this manual page, see ⟨http://www.gnu.org/software/acct/⟩. This page
was obtained from the project's upstream Subversion repository
⟨svn://svn.savannah.gnu.org/acct/trunk⟩ on 2016-10-04. If you dis‐
cover any rendering problems in this HTML version of the page, or you
believe there is a better or more up-to-date source for the page, or
you have corrections or improvements to the information in this
COLOPHON (which is not part of the original manual page), send a mail
2010 August 16 AC(1)