From Linux Man Pages
ac - print statistics about users' connect time
SYNOPSIS
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 ]
DESCRIPTION
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 out.
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.
OPTIONS
-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 er-
ror.
--reboots
Reboot records are NOT written at the time of a reboot, but when the system restarts; therefore, it is im-
possible 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 ter-
minal (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.*
--timewarps
Sometimes, entries in a wtmp file will suddenly jump back into the past without a clock change record oc-
curring. 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 compat-
ibility, 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 un-
der 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 no-
tably 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.
--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 print-
ing.
--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.
FILES
wtmp
The system wide login record file. See wtmp(5) for further details.
RELATED
login(1), wtmp(5), init(8), sa(8)
CATEGORY