AT(1)                   FreeBSD General Commands Manual                  AT(1)

NAME
     at, batch, atq, atrm - queue, examine or delete jobs for later execution

SYNOPSIS
     at [-q queue] [-f file] [-mldbv] time
     at [-q queue] [-f file] [-mldbv] -t [[CC]YY]MMDDhhmm[.SS]
     at -c job [job ...]
     at -l [job ...]
     at -l -q queue
     at -r job [job ...]

     atq [-q queue] [-v]

     atrm job [job ...]

     batch [-q queue] [-f file] [-mv] [time]

DESCRIPTION
     The at and batch utilities read commands from standard input or a
     specified file which are to be executed at a later time, using sh(1).

     at      executes commands at a specified time;

     atq     lists the user's pending jobs, unless the user is the superuser;
             in that case, everybody's jobs are listed;

     atrm    deletes jobs;

     batch   executes commands when system load levels permit; in other words,
             when the load average drops below 1.5 times number of active
             CPUs, or the value specified in the invocation of atrun.

     The at utility allows some moderately complex time specifications.  It
     accepts times of the form HHMM or HH:MM to run a job at a specific time
     of day.  (If that time is already past, the next day is assumed.)  As an
     alternative, the following keywords may be specified: midnight, noon, or
     teatime (4pm) and time-of-day may be suffixed with AM or PM for running
     in the morning or the evening.  The day on which the job is to be run may
     also be specified by giving a date in the form month-name day with an
     optional year, or giving a date of the forms DD.MM.YYYY, DD.MM.YY,
     MM/DD/YYYY, MM/DD/YY, MMDDYYYY, or MMDDYY.  The specification of a date
     must follow the specification of the time of day.  Time can also be
     specified as: [now] + count time-units, where the time-units can be
     minutes, hours, days, weeks, months or years and at may be told to run
     the job today by suffixing the time with today and to run the job
     tomorrow by suffixing the time with tomorrow.

     For example, to run a job at 4pm three days from now, use at 4pm + 3
     days, to run a job at 10:00am on July 31, use at 10am Jul 31 and to run a
     job at 1am tomorrow, use at 1am tomorrow.

     The at utility also supports the POSIX time format (see -t option).

     For both at and batch, commands are read from standard input or the file
     specified with the -f option and executed.  The working directory, the
     environment (except for the variables TERM, TERMCAP, DISPLAY and _) and
     the umask are retained from the time of invocation.  An at or batch
     command invoked from a su(1) shell will retain the current userid.  The
     user will be mailed standard error and standard output from his commands,
     if any.  Mail will be sent using the command sendmail(8).  If at is
     executed from a su(1) shell, the owner of the login shell will receive
     the mail.

     The superuser may use these commands in any case.  For other users,
     permission to use at is determined by the files /var/at/at.allow and
     /var/at/at.deny.

     If the file /var/at/at.allow exists, only usernames mentioned in it are
     allowed to use at.  In these two files, a user is considered to be listed
     only if the user name has no blank or other characters before it on its
     line and a newline character immediately after the name, even at the end
     of the file.  Other lines are ignored and may be used for comments.

     If /var/at/at.allow does not exist, /var/at/at.deny is checked, every
     username not mentioned in it is then allowed to use at.

     If neither exists, only the superuser is allowed use of at.  This is the
     default configuration.

IMPLEMENTATION NOTES
     Note that at is implemented through the cron(8) daemon by calling
     atrun(8) every five minutes.  This implies that the granularity of at
     might not be optimal for every deployment.  If a finer granularity is
     desired, the /etc/cron.d/at file can be edited and will be read by the
     system crontab, from which the SHELL and PATH environment variables are
     inherited.

OPTIONS
     -q queue
             Use the specified queue.  A queue designation consists of a
             single letter; valid queue designations range from a to z and A
             to Z.  The c queue is the default for at and the E queue for
             batch.  Queues with higher letters run with increased niceness.
             If a job is submitted to a queue designated with an uppercase
             letter, it is treated as if it had been submitted to batch at
             that time.  If atq is given a specific queue, it will only show
             jobs pending in that queue.

     -m      Send mail to the user when the job has completed even if there
             was no output.

     -f file
             Read the job from file rather than standard input.

     -l      With no arguments, list all jobs for the invoking user.  If one
             or more job numbers are given, list only those jobs.

     -d      Is an alias for atrm (this option is deprecated; use -r instead).

     -b      Is an alias for batch.

     -v      For atq, shows completed but not yet deleted jobs in the queue;
             otherwise shows the time the job will be executed.

     -c      Cat the jobs listed on the command line to standard output.

     -r      Remove the specified jobs.

     -t      Specify the job time using the POSIX time format.  The argument
             should be in the form [[CC]YY]MMDDhhmm[.SS] where each pair of
             letters represents the following:

                   CC      The first two digits of the year (the century).
                   YY      The second two digits of the year.
                   MM      The month of the year, from 1 to 12.
                   DD      the day of the month, from 1 to 31.
                   hh      The hour of the day, from 0 to 23.
                   mm      The minute of the hour, from 0 to 59.
                   SS      The second of the minute, from 0 to 60.

             If the CC and YY letter pairs are not specified, the values
             default to the current year.  If the SS letter pair is not
             specified, the value defaults to 0.

FILES
     /var/at/jobs            directory containing job files
     /var/at/spool           directory containing output spool files
     /var/run/utx.active     login records
     /var/at/at.allow        allow permission control
     /var/at/at.deny         deny permission control
     /var/at/jobs/.lockfile  job-creation lock file

SEE ALSO
     nice(1), sh(1), umask(2), atrun(8), cron(8), sendmail(8)

AUTHORS
     At was mostly written by Thomas Koenig <ig25@rz.uni-karlsruhe.de>.  The
     time parsing routines are by David Parsons <orc@pell.chi.il.us>, with
     minor enhancements by Joe Halpin <joe.halpin@attbi.com>.

BUGS
     If the file /var/run/utx.active is not available or corrupted, or if the
     user is not logged on at the time at is invoked, the mail is sent to the
     userid found in the environment variable LOGNAME.  If that is undefined
     or empty, the current userid is assumed.

     The at and batch utilities as presently implemented are not suitable when
     users are competing for resources.  If this is the case, another batch
     system such as nqs may be more suitable.

     Specifying a date past 2038 may not work on some systems.

FreeBSD 13.1-RELEASE-p6         August 11, 2018        FreeBSD 13.1-RELEASE-p6