AC(1)                                                                    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 lo-
       gins/logouts in the current wtmp file.  A total is also printed out.

       The accounting file wtmp is maintained by init(8) and  login(1).   Nei-
       ther  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.


       -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 every-
              thing-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.

              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  acs  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  compati-
              bility, include this flag.*

              Sometimes,  a logout record is not written for a specific termi-
              nal, so the time that the last user accrued cannot be  calculat-
              ed.   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),  in-
              clude  this  flag.   *For vanilla ac compatibility, include this

              Sometimes, entries in a wtmp file will suddenly jump  back  into
              the  past without a clock change record occurring.  It is impos-
              sible 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  com-
              patibility, include this flag.*

              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 in-
              stead of skipping intervening days where there is no  login  ac-
              tivity.   Without this flag, time accrued during those interven-
              ing days gets listed under the next day where there is login ac-

       --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  lo-
              gins  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 un-
              less 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 prob-
              lem, 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.

              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.


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


       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)

                                1995 October 31                          AC(1)

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