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

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

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

DESCRIPTION
       at and batch read commands from standard input or a speci-
       fied  file which are to be 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 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
               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 specific 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 specification 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.

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

       For both at and batch, commands  are  read  from  standard
       input  or  the  file specified with the -f option and exe-
       cuted.  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  stan-
       dard  output from his commands, 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 username 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 commands, 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  designa-
               tions 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 upper-
       case 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      For atq, shows completed but not yet deleted  jobs
               in  the  queue;  otherwise  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  stan-
              dart output.

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 cur-
       rent 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                           1