MAN page from RedHat Other at-3.1.8-1.i386.rpm

AT

Section: Linux Programmer's Manual (1)
Updated: Nov 1996
Index

NAME

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

SYNOPSIS

at[-V][-qqueue][-ffile][-mldbv]TIME
at -cjob[job...]
atq[-V][-qqueue]
atrm[-V]job[job...]
batch[-V][-qqueue][-ffile][-mv][TIME]

DESCRIPTION

atandbatchread commands from standard input or a specified file which are tobe executed at a later time, using/bin/sh.

at: executes commands at a specified time.
atq: lists the user's pending jobs, unless the user is the superuser; in thatcase, everybody's jobs are listed. The format of the output lines (onefor each job) is: Job number, date, hour, job class.
atrm: deletes jobs, identified by their job number.
batch: executes commands when system load levels permit; in other words, when the load averagedrops below 0.8, or the value specified in the invocation ofatrun.

Atallows fairly complex timespecifications, extending the POSIX.2 standard. It accepts timesof the form HH:MMto run a job at a specific time of day.(If that time is already past, the next day is assumed.)You may also specifymidnight,noon,orteatime(4pm)and you can have a time-of-day suffixed withAMorPMfor running in the morning or the evening.You can also say what day the job will be run,by giving a date in the formmonth-namedaywith an optionalyear,or giving a date of the formMMDDYYorMM/DD/YYorDD.MM.YY.The specification of a datemustfollow the specification of the time of day.You can also give times likenow+counttime-units,where the time-units can beminutes,hours,days,orweeksand you can tellatto run the job today by suffixing the time withtodayand to run the job tomorrow by suffixing the time withtomorrow.

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

The exact definition of the time specification can be found in/usr/doc/at-3.1.7/timespec.

For bothat and batch,commands are read from standard input or the file specifiedwith the-foption and executed.The working directory, the environment (except for the variablesTERM,DISPLAYand_)and the umask are retained from the time of invocation.Anat -orbatch -command invoked from a su(1)shell will retain the current userid.The user will be mailed standard error and standard output from hiscommands, if any.Mail will be sent using the command/usr/sbin/sendmail.Ifatis 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/etc/at.allowand/etc/at.deny.

If the file/etc/at.allowexists, only usernames mentioned in it are allowed to useat.

If/etc/at.allowdoes not exist,/etc/at.denyis checked, every username not mentioned in it is then allowedto useat.

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

An empty /etc/at.denymeans that every user is allowed use these commands, this is thedefault configuration.

OPTIONS

-V: prints the version number to standard error.
-q queue: uses the specified queue.A queue designation consists of a single letter; valid queue designationsrange fromato z.andAtoZ.Theaqueue is the default foratand thebqueue forbatch.Queues with higher letters run with increased niceness. The specialqueue "=" is reserved for jobs which are currently running.

If a job is submitted to a queue designated with an uppercase letter, itis treated as if it had been submitted to batch at that time.Ifatqis 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 nooutput.
-f file: Reads the job fromfilerather than standard input.
-l: Is an alias foratq.
-d: Is an alias foratrm.

-v: Shows the time the job will be executed.

Times displayed will be in the format "1997-02-20 14:50" unless theenvironment variablePOSIXLY_CORRECT is set; then, it will be "Thu Feb 20 14:50:00 1996".

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

FILES

/var/spool/at
/var/spool/at/spool
/proc/loadavg
/var/run/utmp
/etc/at.allow
/etc/at.deny

BUGS

The correct operation ofbatchfor Linux depends on the presence of aproc-type directory mounted on/proc.

If the file/var/run/utmpis not available or corrupted, or if the user is not logged on at thetime atis invoked, the mail is sent to the userid foundin the environment variableLOGNAME.If that is undefined or empty, the current userid is assumed.

Atandbatchas presently implemented are not suitable when users are competing forresources.If this is the case for your site, you might want to consider anotherbatch system, such asnqs.

AUTHOR

At was mostly written by Thomas Koenig, ig25AATTrz.uni-karlsruhe.de.

This document was created byman2html,using the manual pages.

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