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AT(1)                       General Commands Manual                      AT(1)



NAME
       at, batch - execute a command or script at a specified time

SYNOPSIS
       at [ -csm ] [ -qqueue ] time [ date ] [ + increment ]
            [ script ]
       at -r jobs...
       at -l [ jobs...  ]

       batch [ -csm ] [ script ]

DESCRIPTION
       at  and  batch  read  commands  from standard input to be executed at a
       later time.  at allows you to specify when the commands should be  exe-
       cuted,  while jobs queued with batch will execute as soon as the system
       load level permits.  script is the name of a file to be used as command
       input for the Bourne shell, sh(1), the C shell, csh(1), or an arbitrary
       shell specified by the SHELL environment variable.  If script is  omit-
       ted, command input is accepted from the standard input.

       Standard output and standard error output are mailed to the user unless
       they are redirected elsewhere.  The shell environment  variables,  cur-
       rent  directory,  and umask(2V) are retained when the commands are exe-
       cuted.  Open file descriptors, traps, and priority are lost.

       Users are permitted to use  at  if  their  name  appears  in  the  file
       /var/spool/cron/at.allow.   If  that  file  does  not  exist,  the file
       /var/spool/cron/at.deny is checked to determine if the user  should  be
       denied  access  to  at.  If neither file exists, only the super-user is
       allowed to submit a job.  If at.deny is empty, global usage is  permit-
       ted.  The allow/deny files consist of one user name per line.

       The time may be specified as 1, 2, or 4 digits.  One and two digit num-
       bers are taken to be hours, four digits to be hours and  minutes.   The
       time  may alternately be specified as two numbers separated by a colon,
       meaning hour:minute.  A suffix am or pm may be  appended;  otherwise  a
       24-hour clock time is understood.  The suffix zulu may be used to indi-
       cate GMT.  The special names noon, midnight, now,  and  next  are  also
       recognized.

       An  optional date may be specified as either a month name followed by a
       day number (and possibly year number preceded by an optional comma)  or
       a  day  of the week (fully spelled or abbreviated to three characters).
       Two special ``days'', today and tomorrow are recognized.  If no date is
       given,  today  is assumed if the given hour is greater than the current
       hour and tomorrow is assumed if it is less.  If the given month is less
       than the current month (and no year is given), next year is assumed.

       The  optional  increment is simply a number suffixed by one of the fol-
       lowing: minutes, hours, days, weeks, months, or years.   (The  singular
       form is also accepted.)

       Thus legitimate commands include:

              at 0815am Jan 24
              at 8:15am Jan 24
              at now + 1 day
              at 5 pm Friday

       at and batch write the job number and schedule time to standard error.

       batch  submits  batch jobs to queue b; this ``batch'' queue is for jobs
       to be run as soon as possible.  A job submitted to b  is  scheduled  to
       run  immediately  and  its  arguments  will not be interpreted as time,
       date, or + increment.

       batch is similar to `at now', but does not, for example,  go  into  the
       same queue or respond with the error message `too late'.

OPTIONS
       -c        C shell.  csh is used to execute script.

       -s        Standard  (Bourne) shell.  sh is used to execute the job.  By
                 default, the  SHELL  environment  variable  determines  which
                 shell to use.

       -m        Mail.   Send mail after the job has been run, even if the job
                 completes successfully.

       -qqueue   Submit the job in queue queue rather than the  default  queue
                 a.   The valid queues are a through z.  batch submits jobs in
                 queue b.  Queue c is reserved for cron(8) and jobs cannot  be
                 submitted to that queue.

       -r jobs ...
                 Remove  the  specified  jobs  previously  scheduled  by at or
                 batch.  The job numbers are the numbers of the jobs given  to
                 you  previously  by  the  at or batch commands.  You can only
                 remove your own jobs unless you are the super-user.

       -l [jobs ...]
                 If jobs is specified, print the queue entry for  those  jobs;
                 if  jobs  is  not  specified, print the queue entries for all
                 jobs for the user.

ENVIRONMENT
       If neither at.allow nor at.deny exists, only the super-user is  allowed
       to  submit  a  job.   If at.deny is present, but empty, global usage is
       permitted.  The allow/deny files consist of one user name per line.

EXAMPLES
       Unless a script is specified, the at and batch commands read from stan-
       dard  input  the  commands  to be executed at a later time.  sh and csh
       provide different ways of specifying standard input.  Within your  com-
       mands, it may be useful to redirect standard output.

       This sequence can be used at a terminal:

              batch
              nroff filename >> outfile
              CTRL-D (hold down `control' and depress `D')

       This sequence, which demonstrates redirecting standard error to a pipe,
       is useful in a shell procedure  (the  sequence  of  output  redirection
       specifications is significant):

              batch <&lt;<&lt;!
              nroff filename 2>&gt;&&amp;1 >&gt; outfile  |  mail loginid
              !

       To have a job reschedule itself, invoke at from within the shell proce-
       dure, by including code similar to the following within the shell file:

              at 1900 thursday next week shellfile

FILES
       /var/spool/cron          main cron directory
       /var/spool/cron/at.allow list of allowed users
       /var/spool/cron/at.deny  list of denied users
       /var/spool/cron/atjobs   spool area

SEE ALSO
       atq(1), atrm(1),  csh(1),  kill(1),  mail(1),  nice(1),  ps(1),  sh(1),
       umask(2V), cron(8)

DIAGNOSTICS
       Complaints about various syntax errors and times out of range.

BUGS
       If  the  system crashes, mail stating that the job was not completed is
       not sent to the user.

       Shell interpreter specifiers (such as, !/bin/csh) in the  beginning  of
       script are ignored.




                                31 October 1988                          AT(1)