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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

DESCRIPTION
       at and batch read commands from standard  input  or  a  specified  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 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, queue, and username.

       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 1.5, or the value
               specified in the invocation of atd.

       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.

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

       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,
       the job is treated as if it were submitted to batch at the time of  the
       job.  Once the time is reached, the batch processing rules with respect
       to load average apply.  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 before reading the job.

       Times displayed will be in the format "Thu Feb 20 14:50:00 1997".

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

FILES
       /var/spool/cron/atjobs
       /var/spool/cron/atspool
       /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, ig25ATrz.de.



local                              Nov 1996                              AT(1)