at(1)                               CLIX                               at(1)



  NAME

    at, batch - Reads commands for later execution

  SYNOPSIS

    at [-q queue] time [date] [+increment]

    at -r job ...

    at -l [job ... ]

    batch

  DESCRIPTION

    The at and batch commands read commands from stdin to be executed at a
    later time.  The at command allows you to specify when the commands should
    be executed, while jobs queued with batch will execute when system load
    level permits.  The at command may be used with the following flags:

    -r         Removes jobs previously scheduled with at.

    -l         Reports all jobs scheduled for the invoking user.

    -q queue   Specifies queue to which a job will be sent.  Valid options are
               a-z.  The default is a.

    Any output to stdout and stderr is mailed to the user unless they are
    redirected elsewhere.  The shell environment variables, current directory,
    umask, and ulimit are retained when the commands are executed.  Open file
    descriptors, traps, and priority are lost.

    Users are permitted to use at if their name appears in the file
    /usr/lib/cron/at.allow.  If that file does not exist, the file
    /usr/lib/cron/at.deny is checked to determine if the user should be denied
    access to at.  If neither file exists, only root is allowed to submit a
    job.  If at.deny is empty, global usage is permitted.  The allow/deny
    files consist of one username per line.  These files can only be modified
    by the superuser.

    The time may be specified as 1, 2, or 4 digits.  One and two digit numbers
    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 indicate 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



  2/94 - Intergraph Corporation                                              1

  at(1)                               CLIX                               at(1)



    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
    following: 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

    The at and batch commands write the job number and schedule time to
    stderr.

    The batch command submits a batch job.  It is almost equivalent to ``at
    now'', but not quite.  For one, it goes into a different queue.  For
    another, ``at now'' will respond with the error message too late.  The
    designated queue for batch is b.


    The at -r command removes jobs previously scheduled by at or batch.  The
    job number is the number given to you previously by the at or batch
    command.  You can also get job numbers by typing at -l.  You can only
    remove your own jobs unless you are the superuser.

  EXAMPLES

    The at and batch commands read from stdin the commands to be executed at a
    later time.  The sh command provides different ways of specifying stdin.

    1.  To redirect stdout at the terminal command line:

        batch
        sort filename >outfile<Ctrl-D>


    2.  To redirect stderr to a pipe, is useful in a shell procedure (the
        sequence of output redirection specifications is significant):

        batch <<!
        sort filename 2>&1 >outfile|mail loginid
        !


    3.  To have a job reschedule itself, invoke at from within the shell
        procedure, by including code similar to the following within the shell



  2                                              Intergraph Corporation - 2/94

  at(1)                               CLIX                               at(1)



        file:

        echo "sh shellfile"|at 1900 thursday next week


  FILES

    /usr/lib/cron            Main cron directory

    /usr/lib/cron/at.allow   List of allowed users

    /usr/lib/cron/at.deny    List of denied users

    /usr/lib/cron/queue      Scheduling information

    /usr/spool/cron/atjobs   Spool area

  DIAGNOSTICS

    Complains about various syntax errors and times out of range.

  RELATED INFORMATION

    Commands: kill(1), mail(1), nice(1), ps(1), sh(1), sort(1), cron(8)

    Files: queuedefs(4)




























  2/94 - Intergraph Corporation                                              3