at(1)
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at, batch Command
execute DG/UX commands at a later time
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SYNTAX
at time [ date ] [ + increment ]
at -rjob...
at -l[job...]
batch
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 executed, while jobs queued with batch will execute when
system load level permits. At -r removes jobs previously
scheduled with at. The -l option reports all jobs scheduled for
the invoking user.
Standard output and standard error output are 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. The allow/deny files consist of one
user name per line. These files are maintained by the system
administrator.
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 special "days," today and tomorrow are
recognized. If no date is given, today is assumed if the given
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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
At and batch write the job number and schedule time to standard
error.
Batch submits a batch job for execution as soon as possible. Is
is logically equivalent to at now. The checks done by at will
now cause at to fail with the error message too late.
At -r 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 super-user.
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EXAMPLES
$ echo "echo 'Get ready to go home'" | at 1715
The cron process will respond with a number and will queue your
request to echo the message and execute it at 5:15pm.
$ echo "cat meetingnotice" | at 1600 next Friday
The cron process will queue your request to display the contents
of "meeting_notice" next Friday at 4:00pm.
$ echo "docompile" | at midnight
The cron process will queue your request to execute the command
file "do_compile" and will run the compiles at midnight.
$ batch
After entering the above command, the batch command waits for
commands from standard input. These commands are queued by the
system and executed when the system's workload is not heavy.
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Notification of job completion is sent to you through the mail.
$ batch shtrue
"shtrue" is an executable file. The batch command assigns a job
number and executes the file as the system load permits. You
will receive the output of the program through the DG/UX system
mail.
$ batch < test.file
"test.file" is a file containing commands. The batch command
assigns a job number and waits to execute the commands when the
system load permits. You will receive the output of the commands
through the DG/UX system mail.
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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/queuedefs scheduling information
/usr/spool/cron/atjobs - spool area
SEE ALSO
crontab(1), kill(1), mail(1), nice(1), ps(1), sh(1).
cron(1M) in the System Manager's Reference for the DG/UX System
DIAGNOSTICS
At complains about various syntax errors and times out of range.
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