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RocketLink!--> Man page versions:
AT(1) OpenBSD Reference Manual AT(1)
at, atq, atrm, batch - queue, examine or delete jobs for later execution
at [-V] [-q queue] [-f file] [-mldbv] time
at [-V] -c job [job ...]
atq [-V] [-q queue] [-v]
atrm [-V] job [job ...]
batch [-V] [-q queue] [-f file] [-mv] [time]
at and batch 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, all users' 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, or the value speci-
fied in the invocation of atrun.
at 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.) You may also speci-
fy midnight, noon, or teatime (4pm) and you can have a time-of-day suf-
fixed with AM or PM for running in the morning or the evening. You can
also say what day the job will be run, by giving a date in the form
month-name day with an optional year, or giving a date of the form
MMDDYY, MM/DD/YY or DD.MM.YY. The year may be given as two digits or four
digits. If the year is given as two digits, it is taken to occur as soon
as possible in the future, which may be in the next century -- unless
it's last year, in which case it's considered to be a typo. The specifi-
cation of a date must follow the specification of the time of day. You
can also give times like [now] + count time-units, where the time-units
can be minutes, hours, days, or weeks and you can tell at 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, you would do at 4pm
+ 3 days. To run a job at 10:00am on July 31, you would do at 10am Jul
31. To run a job at 1am tomorrow, you would do at 1am tomorrow.
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 com-
mand invoked from a su(1) shell will retain the current user ID. The us-
er 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 exe-
cuted from a su(1) shell, the owner of the login shell will receive the
The superuser may use these commands in any case. For other users, per-
mission to use at is determined by the files /var/at/at.allow and
If the file /var/at/at.allow exists, only usernames mentioned in it are
allowed to use at.
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.
An empty /var/at/at.deny means that every user is allowed use these com-
mands. This is the default configuration.
-V Prints the version number to standard error.
Uses the specified queue. A queue designation consists of a sin-
gle 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
-m Send mail to the user when the job has completed, even if there
was no output.
Reads the job from file rather than standard input.
-l Is an alias for atq.
-d Is an alias for atrm.
-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 Prints the jobs listed on the command line to standard output.
/var/at/jobs directory containing job files
/var/at/spool directory containing output spool files
/var/run/utmp login records
/var/at/at.allow allow permission control
/var/at/at.deny deny permission control
/var/at/.lockfile job-creation lock file
nice(1), sh(1), umask(2), atrun(8), cron(8), sendmail(8)
If the file /var/run/utmp 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 user
ID found in the environment variable LOGNAME. If that is undefined or
empty, the current user ID is assumed.
at and batch as presently implemented are not suitable when users are
competing for resources. If this is the case for your site, you might
want to consider another batch system, such as nqs.
atq always prints the year as two digits. Since at only permits submis-
sion of jobs in the future, it is somewhat clear which century the job
will run in.
at was mostly written by Thomas Koenig <firstname.lastname@example.org>. The
time parsing routines are by David Parsons <email@example.com>.
OpenBSD 2.6 April 12, 1995 2
Source: OpenBSD 2.6 man pages. Copyright: Portions are copyrighted by BERKELEY
SOFTWARE DESIGN, INC., The Regents of the University of California, Massachusetts
Institute of Technology, Free Software Foundation, FreeBSD Inc., and others.
(Corrections, notes, and links courtesy of RocketAware.com)
OpenBSD sources for at(1)
Up to: Process Creation and Control - child process control (like sending signals), renice, fork, et al
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