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AT(1)			   Linux Programmer's Manual			 AT(1)

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

SYNOPSIS
       at [-V] [-q queue] [-f file] [-mldbv] TIME
       at -c job [job...]
       atq [-V]	[-q queue]
       atrm [-V] job [job...]
       batch [-V] [-q queue] [-f file] [-mv] [TIME]

DESCRIPTION
       at and batch read commands from standard	 input	or  a  specified  file
       which  are  to  be executed at a	later time, using the shell set	by the
       user's environment variable SHELL, the user's  login  shell,  or	 ulti-
       mately /bin/sh.

       at      executes	commands at a specified	time.

       atq     lists  the  user's  pending  jobs, unless the user is the supe-
	       ruser; in that case, everybody's	jobs are listed.   The	format
	       of  the	output	lines (one for 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	average	 drops below 0.8, or the value
	       specified in the	invocation of atrun.

       At allows fairly	complex	time  specifications,  extending  the  POSIX.2
       standard.   It  accepts	times of the form HH:MM	to run a job at	a spe-
       cific time of day.  (If that time is already  past,  the	 next  day  is
       assumed.)   You	may  also specify midnight, noon, or teatime (4pm) and
       you can have a time-of-day suffixed 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	or MM/DD/YY or DD.MM.YY.  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 and to run a job at 1am tomorrow,	you would do at	1am  tomorrow.

       /usr/share/doc/at-3.1.8/timespec	 contains  the exact definition	of the
       time specification.

       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, 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 com-
       mands, if any.  Mail will be sent using the command /usr/sbin/sendmail.
       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 /etc/at.allow and
       /etc/at.deny.

       If the file /etc/at.allow exists, only usernames	mentioned  in  it  are
       allowed to use at.

       If  /etc/at.allow  does not exist, /etc/at.deny is checked, every user-
       name not	mentioned in it	is then	allowed	to use at.

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

       An empty	/etc/at.deny means that	every user is allowed use  these  com-
       mands, this is the default 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 designations range from a to z.  and
	       A  to Z.	 The a queue is	the default for	at and the b queue for
	       batch.  Queues with higher letters run with increased niceness.
	       The  special queue "=" is reserved for jobs which are currently
	       running.

       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 Reads the job from file rather than standard input.

       -l      Is an alias for atq.

       -d      Is an alias for atrm.

	       -v      Shows the time the job will be executed.

       Times displayed will be in the format "1997-02-20 14:50"	 unless
       the  environment	 variable POSIXLY_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 out-
	      put.

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

SEE ALSO
       cron(1),	nice(1), sh(1),	umask(2), atd(8).

BUGS
       The correct operation of	batch for Linux	depends	on the presence
       of a proc- type directory mounted on /proc.

       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 userid found	in the	environment  variable  LOGNAME.
       If that is undefined or empty, the current userid 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.

AUTHOR
       At  was	mostly	written	 by  Thomas  Koenig,  ig25@rz.uni-karl-
       sruhe.de.

local				   Nov 1996				 AT(1)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | SEE ALSO | BUGS | AUTHOR

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