Linux ac command
On Unix-like operating systems, the ac command displays statistics about the time users are connected to the system.
This page covers the Linux version of ac. On some package managers, the ac command is included as part of the package acct.
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 and login. 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.
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 other systems. Use the command info accounting to get additional information.
Syntax
ac [ -d | --daily-totals ] [ -y | --print-year ] [ -p | --individual-totals ] [ people ] [ -f | --file file name ] [ -a | --all-days ] [ --complain ] [ --reboots ] [ --supplants ] [ --timewarps ] [ --compatibility ] [ --tw-leniency num ] [ --tw-suspicious num ] [ -z | --print-zeros ] [ --debug ] [ -V | --version ] [ -h | --help ]
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 1.17Jul 4 total 2.10Jul 5 total 8.23Jul 6 total 2.10Jul 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 8.06goff 0.60maley 7.37root 0.12total 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 file name | Read from the file name 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 be logged in to 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). To count this time, include the flag. For maximum compatibility with all versions of ac, 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. 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 maximum compatibility with all versions of ac, 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. To count the time between the login and the time warp against the user, include this flag. For maximum compatibility with all versions of ac, include this flag. |
| --compatibility | This is shorthand for typing out the three above options. |
| -a, --all-days | If 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 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 (other than 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. |
Examples
ac -d -y
Display daily results with the year as part of the date, similar to the example below:
Mar 6 2013 total 45.41 Mar 7 2013 total 69.84 Mar 8 2013 total 50.96 Mar 10 2013 total 37.69 Mar 11 2013 total 2.21 Mar 12 2013 total 10.20 Mar 14 2013 total 48.00 Mar 15 2013 total 34.34 Mar 16 2013 total 56.76 Mar 17 2013 total 66.41 Mar 18 2013 total 70.18 Mar 19 2013 total 40.90 Mar 20 2013 total 21.29 Mar 23 2013 total 156.54 Mar 24 2013 total 67.71 Today total 133.35
Related commands
login — Begin a session on a system.
netstat — Print information about network connections, routing tables, interface statistics, masquerade connections, and multicast memberships.