at(1) DG/UX 4.30 at(1)
NAME
at, batch - execute DG/UX commands at a later time
SYNOPSIS
at time [ date ] [ + increment ]
at -r job...
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 /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 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 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
Licensed material--property of copyright holder(s) Page 1
at(1) DG/UX 4.30 at(1)
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.
It 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.
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. 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.
Licensed material--property of copyright holder(s) Page 2
at(1) DG/UX 4.30 at(1)
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.
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/queuedefs scheduling information
/var/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 can detect syntax errors and times out of range.
Licensed material--property of copyright holder(s) Page 3