.\" $OpenBSD: at.1,v 1.12 1999/09/14 05:28:23 deraadt Exp $ .\" $FreeBSD: at.man,v 1.6 1997/02/22 19:54:05 peter Exp $ .Dd April 12, 1995 .Dt AT 1 .Os .Sh NAME .Nm at , .Nm atq , .Nm atrm , .Nm batch .Nd queue, examine or delete jobs for later execution .Sh SYNOPSIS .Nm at .Op Fl V .Op Fl q Ar queue .Op Fl f Ar file .Op Fl mldbv .Ar time .Nm at .Op Fl V .Fl c Ar job Op Ar job ... .Nm atq .Op Fl V .Op Fl q Ar queue .Op Fl v .Nm atrm .Op Fl V .Ar job .Op Ar job ... .Nm batch .Op Fl V .Op Fl q Ar queue .Op Fl f Ar file .Op Fl mv .Op Ar time .Sh DESCRIPTION .Nm and .Nm batch read commands from standard input or a specified file which are to be executed at a later time, using .Xr sh 1 . .Bl -tag -width indent .It Nm at Executes commands at a specified time. .It Nm atq Lists the user's pending jobs, unless the user is the superuser. In that case, all users' jobs are listed. .It Nm atrm Deletes jobs. .It Nm batch Executes commands when system load levels permit. In other words, when the load average drops below 1.5, or the value specified in the invocation of .Nm atrun . .El .Pp .Nm allows some moderately complex .Ar time specifications. It accepts times of the form .Ar HHMM or .Ar 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 specify .Nm midnight , .Nm noon , or .Nm teatime (4pm) and you can have a time-of-day suffixed with .Nm AM or .Nm 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 .Ar \%month-name day with an optional .Ar year , or giving a date of the form .Ar MMDDYY , .Ar MM/DD/YY or .Ar 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 specification of a date must follow the specification of the time of day. You can also give times like .Op Nm now .Nm + Ar count \%time-units , where the time-units can be .Nm minutes , .Nm hours , .Nm days , or .Nm weeks and you can tell .Nm to run the job today by suffixing the time with .Nm today and to run the job tomorrow by suffixing the time with .Nm tomorrow . .Pp For example, to run a job at 4pm three days from now, you would do .Nm at 4pm + 3 days . To run a job at 10:00am on July 31, you would do .Nm at 10am Jul 31 . To run a job at 1am tomorrow, you would do .Nm at 1am tomorrow . .Pp For both .Nm and .Nm batch , commands are read from standard input or the file specified with the .Fl f option and executed. The working directory, the environment (except for the variables .Ev TERM , .Ev TERMCAP , .Ev DISPLAY , and .Ev _ ) and the .Ar umask are retained from the time of invocation. An .Nm or .Nm batch command invoked from a .Xr su 1 shell will retain the current user ID. The user will be mailed standard error and standard output from his commands, if any. Mail will be sent using the command .Xr sendmail 8 . If .Nm is executed from a .Xr su 1 shell, the owner of the login shell will receive the mail. .Pp The superuser may use these commands in any case. For other users, permission to use at is determined by the files .Pa /var/at/at.allow and .Pa /var/at/at.deny . .Pp If the file .Pa /var/at/at.allow exists, only usernames mentioned in it are allowed to use .Nm at . .Pp If .Pa /var/at/at.allow does not exist, .Pa /var/at/at.deny is checked. Every username not mentioned in it is then allowed to use .Nm at . .Pp If neither exists, only the superuser is allowed use of .Nm at . .Pp An empty .Pa /var/at/at.deny means that every user is allowed use these commands. This is the default configuration. .Sh OPTIONS .Bl -tag -width indent .It Fl V Prints the version number to standard error. .It Fl q Ar queue Uses the specified queue. A queue designation consists of a single letter. Valid queue designations range from .Nm a to .Nm z and .Nm A to .Nm Z . The .Nm c queue is the default for .Nm and the .Nm E queue for .Nm 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 .Nm atq is given a specific queue, it will only show jobs pending in that queue. .It Fl m Send mail to the user when the job has completed, even if there was no output. .It Fl f Ar file Reads the job from .Ar file rather than standard input. .It Fl l Is an alias for .Nm atq . .It Fl d Is an alias for .Nm atrm . .It Fl b Is an alias for .Nm batch . .It Fl v For .Nm atq , shows completed but not yet deleted jobs in the queue. Otherwise shows the time the job will be executed. .It Fl c Prints the jobs listed on the command line to standard output. .Sh FILES .Bl -tag -width /var/at/.lockfile -compact .It Pa /var/at/jobs directory containing job files .It Pa /var/at/spool directory containing output spool files .It Pa /var/run/utmp login records .It Pa /var/at/at.allow allow permission control .It Pa /var/at/at.deny deny permission control .It Pa /var/at/.lockfile job-creation lock file .Sh SEE ALSO .Xr nice 1 , .Xr sh 1 , .Xr umask 2 , .Xr atrun 8 , .Xr cron 8 , .Xr sendmail 8 .El .Sh BUGS If the file .Pa /var/run/utmp is not available or corrupted, or if the user is not logged on at the time .Nm is invoked, the mail is sent to the user ID found in the environment variable .Ev LOGNAME . If that is undefined or empty, the current user ID is assumed. .Pp .Nm and .Nm 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 .Nm nqs . .Pp .Nm atq always prints the year as two digits. Since .Nm at only permits submission of jobs in the future, it is somewhat clear which century the job will run in. .Sh AUTHORS .Nm was mostly written by Thomas Koenig . The time parsing routines are by David Parsons .