{
    "mode": "man",
    "parameter": "ac",
    "section": "1",
    "url": "https://www.chedong.com/phpMan.php/man/ac/1/json",
    "generated": "2026-06-13T22:07:57Z",
    "synopsis": "ac     [ -d | --daily-totals ] [ -y | --print-year ]\n[ -p | --individual-totals ] [ people ]\n[ -f | --file filename ] [ -a | --all-days ]\n[ --complain ] [ --reboots ] [ --supplants ]\n[ --timewarps ] [ --compatibility ]\n[ --tw-leniency num ] [ --tw-suspicious num ]\n[ -z | --print-zeros ] [ --debug ]\n[ -V | --version ] [ -h | --help ]",
    "sections": {
        "NAME": {
            "content": "ac -  print statistics about users' connect time\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "ac     [ -d | --daily-totals ] [ -y | --print-year ]\n[ -p | --individual-totals ] [ people ]\n[ -f | --file filename ] [ -a | --all-days ]\n[ --complain ] [ --reboots ] [ --supplants ]\n[ --timewarps ] [ --compatibility ]\n[ --tw-leniency num ] [ --tw-suspicious num ]\n[ -z | --print-zeros ] [ --debug ]\n[ -V | --version ] [ -h | --help ]\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "ac  prints out a report of connect time (in hours) based on the logins/logouts in the current\nwtmp file.  A total is also printed out.\n\nThe accounting file wtmp is maintained by init(8) and login(1).  Neither ac nor login creates\nthe  wtmp  if  it doesn't exist, no accounting is done.  To begin accounting, create the file\nwith a length of zero.\n\nNOTE:  The wtmp file can get really big, really fast.  You might want to trim it  every  once\nand a while.\n\nGNU  ac  works  nearly  the  same UNIX ac, though it's a little smarter in several ways.  You\nshould therefore expect differences in the output of GNU ac and the output of ac's  on  other\nsystems.  Use the command info accounting to get additional information.\n",
            "subsections": []
        },
        "OPTIONS": {
            "content": "",
            "subsections": [
                {
                    "name": "-d, --daily-totals",
                    "content": "Print totals for each day rather than just one big total at the end.  The output looks\nlike this:\nJul  3  total     1.17\nJul  4  total     2.10\nJul  5  total     8.23\nJul  6  total     2.10\nJul  7  total     0.30",
                    "flag": "-d",
                    "long": "--daily-totals"
                },
                {
                    "name": "-p, --individual-totals",
                    "content": "Print time totals for each user in addition to  the  usual  everything-lumped-into-one\nvalue.  It looks like:\nbob       8.06\ngoff      0.60\nmaley     7.37\nroot      0.12\ntotal    16.15\npeople Print  out the sum total of the connect time used by all of the users included in peo‐\nple.  Note that people is a space separated list of valid user  names;  wildcards  are\nnot allowed.",
                    "flag": "-p",
                    "long": "--individual-totals"
                },
                {
                    "name": "-f, --file",
                    "content": "Read from the file filename instead of the system's wtmp file.",
                    "flag": "-f",
                    "long": "--file"
                },
                {
                    "name": "--complain",
                    "content": "When the wtmp file has a problem (a time-warp, missing record, or whatever), print out\nan appropriate error.",
                    "long": "--complain"
                },
                {
                    "name": "--reboots",
                    "content": "Reboot records are NOT written at the time of a reboot, but when the system  restarts;\ntherefore,  it is impossible to know exactly when the reboot occurred.  Users may have\nbeen logged into the system at the time of the reboot,  and  many  ac's  automatically\ncount  the  time between the login and the reboot record against the user (even though\nall of that time shouldn't be, perhaps, if the system is down for a long time, for in‐\nstance).   If you want to count this time, include the flag.  *For vanilla ac compati‐\nbility, include this flag.*",
                    "long": "--reboots"
                },
                {
                    "name": "--supplants",
                    "content": "Sometimes, a logout record is not written for a specific terminal, so  the  time  that\nthe  last user accrued cannot be calculated.  If you want to include the time from the\nuser's login to the next login on the terminal (though  probably  incorrect),  include\nthis  you want to include the time from the user's login to the next login on the ter‐\nminal (though probably incorrect), include this flag.  *For vanilla ac  compatibility,\ninclude this flag.*",
                    "long": "--supplants"
                },
                {
                    "name": "--timewarps",
                    "content": "Sometimes,  entries  in  a  wtmp  file will suddenly jump back into the past without a\nclock change record occurring.  It is impossible to know how long a user was logged in\nwhen  this  occurs.  If you want to count the time between the login and the time warp\nagainst the user, include this flag.  *For  vanilla  ac  compatibility,  include  this\nflag.*",
                    "long": "--timewarps"
                },
                {
                    "name": "--compatibility",
                    "content": "This is shorthand for typing out the three above options.",
                    "long": "--compatibility"
                },
                {
                    "name": "-a, --all-days",
                    "content": "If  we're  printing daily totals, print a record for every day instead of skipping in‐\ntervening days where there is no login activity.  Without this flag, time accrued dur‐\ning those intervening days gets listed under the next day where there is login activi‐\nty.\n--tw-leniency num\nSet the time warp leniency to num seconds.  Records in wtmp files  might  be  slightly\nout of order (most notably when two logins occur within a one-second period - the sec‐\nond one gets written first).  By default, this value is set to 60.  If the program no‐\ntices this problem, time is not assigned to users unless the --timewarps flag is used.\n--tw-suspicious num\nSet  the  time  warp suspicious value to num seconds.  If two records in the wtmp file\nare farther than this number of seconds apart, there is a problem with the  wtmp  file\n(or  your  machine  hasn't been used in a year).  If the program notices this problem,\ntime is not assigned to users unless the --timewarps flag is used.",
                    "flag": "-a",
                    "long": "--all-days"
                },
                {
                    "name": "-y, --print-year",
                    "content": "Print year when displaying dates.",
                    "flag": "-y",
                    "long": "--print-year"
                },
                {
                    "name": "-z, --print-zeros",
                    "content": "If a total for any category (save the grand total) is zero, print it.  The default  is\nto suppress printing.",
                    "flag": "-z",
                    "long": "--print-zeros"
                },
                {
                    "name": "--debug",
                    "content": "Print verbose internal information.",
                    "long": "--debug"
                },
                {
                    "name": "-V, --version",
                    "content": "Print the version number of ac to standard output and quit.",
                    "flag": "-V",
                    "long": "--version"
                },
                {
                    "name": "-h, --help",
                    "content": "Prints  the  usage string and default locations of system files to standard output and\nexits.",
                    "flag": "-h",
                    "long": "--help"
                }
            ]
        },
        "FILES": {
            "content": "wtmp\nThe system wide login record file. See wtmp(5) for further details.",
            "subsections": []
        },
        "AUTHOR": {
            "content": "The GNU accounting utilities were written by Noel Cragg <noel@gnu.ai.mit.edu>. The  man  page\nwas adapted from the accounting texinfo page by Susan Kleinmann <sgk@sgk.tiac.net>.",
            "subsections": []
        },
        "SEE ALSO": {
            "content": "login(1), wtmp(5), init(8), sa(8)\n\n\n\n2010 August 16                                      AC(1)",
            "subsections": []
        }
    },
    "summary": "ac -  print statistics about users' connect time",
    "flags": [
        {
            "flag": "-d",
            "long": "--daily-totals",
            "arg": null,
            "description": "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"
        },
        {
            "flag": "-p",
            "long": "--individual-totals",
            "arg": null,
            "description": "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 peo‐ ple. Note that people is a space separated list of valid user names; wildcards are not allowed."
        },
        {
            "flag": "-f",
            "long": "--file",
            "arg": null,
            "description": "Read from the file filename instead of the system's wtmp file."
        },
        {
            "flag": "",
            "long": "--complain",
            "arg": null,
            "description": "When the wtmp file has a problem (a time-warp, missing record, or whatever), print out an appropriate error."
        },
        {
            "flag": "",
            "long": "--reboots",
            "arg": null,
            "description": "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 in‐ stance). If you want to count this time, include the flag. *For vanilla ac compati‐ bility, include this flag.*"
        },
        {
            "flag": "",
            "long": "--supplants",
            "arg": null,
            "description": "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 ter‐ minal (though probably incorrect), include this flag. *For vanilla ac compatibility, include this flag.*"
        },
        {
            "flag": "",
            "long": "--timewarps",
            "arg": null,
            "description": "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.*"
        },
        {
            "flag": "",
            "long": "--compatibility",
            "arg": null,
            "description": "This is shorthand for typing out the three above options."
        },
        {
            "flag": "-a",
            "long": "--all-days",
            "arg": null,
            "description": "If we're printing daily totals, print a record for every day instead of skipping in‐ tervening days where there is no login activity. Without this flag, time accrued dur‐ ing those intervening days gets listed under the next day where there is login activi‐ ty. --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 sec‐ ond one gets written first). By default, this value is set to 60. If the program no‐ tices 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."
        },
        {
            "flag": "-y",
            "long": "--print-year",
            "arg": null,
            "description": "Print year when displaying dates."
        },
        {
            "flag": "-z",
            "long": "--print-zeros",
            "arg": null,
            "description": "If a total for any category (save the grand total) is zero, print it. The default is to suppress printing."
        },
        {
            "flag": "",
            "long": "--debug",
            "arg": null,
            "description": "Print verbose internal information."
        },
        {
            "flag": "-V",
            "long": "--version",
            "arg": null,
            "description": "Print the version number of ac to standard output and quit."
        },
        {
            "flag": "-h",
            "long": "--help",
            "arg": null,
            "description": "Prints the usage string and default locations of system files to standard output and exits."
        }
    ],
    "examples": [],
    "see_also": [
        {
            "name": "login",
            "section": "1",
            "url": "https://www.chedong.com/phpMan.php/man/login/1/json"
        },
        {
            "name": "wtmp",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/wtmp/5/json"
        },
        {
            "name": "init",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/init/8/json"
        },
        {
            "name": "sa",
            "section": "8",
            "url": "https://www.chedong.com/phpMan.php/man/sa/8/json"
        }
    ],
    "tldr": {
        "source": "official",
        "description": "Print statistics on how long users have been connected.",
        "examples": [
            {
                "description": "Print how long the current user has been connected in hours",
                "command": "ac"
            },
            {
                "description": "Print how long users have been connected in hours",
                "command": "ac -p"
            },
            {
                "description": "Print how long a particular user has been connected in hours",
                "command": "ac -p {{username}}"
            },
            {
                "description": "Print how long a particular user has been connected in hours per [d]ay (with total)",
                "command": "ac -dp {{username}}"
            }
        ]
    }
}