AT, BATCH(1,C) AIX Commands Reference AT, BATCH(1,C)
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at, batch
PURPOSE
Runs commands at a later time.
SYNTAX
+-----------+ +- today -+ +-------------+ +--------+
at ---| +-------+ |--- time ---| |---| |---| |-+
+-| -m -k |-+ +- date --+ +- increment -+ +- file -+ |
|| -c -s | |---|
|+-------+ |
|+--- -l ---+ |
+| |------------------------------------------------------+
+- -r job -+
+-----------+ +--------+
+-| +-------+ |---| |-+
| +-| -m -k |-+ +- file -+ |
batch ---| | -c -s | |---|
| +-------+ |
|------ -l ------------------|
+------ -r job --------------+
DESCRIPTION
The at and batch commands read the names of commands to be run at a later time
from file or standard input:
o at allows you to specify when the commands should be run.
o batch runs jobs when the system load level permits.
Both at and batch mail you all output from standard output and standard error
for the scheduled commands, unless you redirect that output. They also write
the job number and the scheduled time to standard error.
Variables in the shell environment, the current directory, umask, and ulimit
are retained when the commands are run. Open file descriptors, traps, and
priority are lost.
You can use at if your name appears in the file /usr/adm/cron/at.allow. If
that file does not exist, at checks the file /usr/adm/cron/at.deny to determine
if you should be denied access to at. If neither file exists, only the
superuser can submit a job. The allow/deny files contain one user name per
line. If at.allow does exist, the superuser's login name must be included in
it for the superuser to be able to use the command.
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The required time parameter can be one of the following:
1. A number followed by an optional suffix. The at command interprets one-
and two-digit numbers as hours. It interprets four digits as hours and
minutes. The default order is the hour followed by the minute. You can
also separate hours and minutes with a : (colon). The default order is
hour:minute.
In addition, you may specify a suffix of am, pm, or zulu. (a.m. can be
abbreviated a and p.m. can be abbreviated p.) If you do not specify am or
pm, at uses a 24-hour clock. The suffix zulu indicates that the time is
GMT (Greenwich Mean Time).
2. The at command also recognizes the following keywords as special times:
noon, midnight, and now. (noon can be abbreviated N and midnight can be
abbreviated M.) You can use the special word now only if you also specify
a date or an increment. Otherwise, at tells you: "too late".
The default format and English words recognized by the at and batch commands
are replaced by their locale-specific equivalents found in the environment
file. For more information, see the setlocale subroutine in the AIX Technical
Reference.
The at command recognizes two special days, today and tomorrow, by default.
The today is the default date if the specified time is later than the current
hour; tomorrow is the default if the time is earlier than the current hour.
If the specified month is less than the current month (and a year is not
given), next year is the default year.
The optional increment can be one of the following:
o A + (plus sign) followed by a number and one of the following words:
minute[s], hour[s], day[s], week[s], month[s], year[s] (or their
non-English equivalents).
o The special word next followed by one of the following words: minute[s],
hour[s], day[s], week[s], month[s], year[s] (or their non-English
equivalents).
The LANG environment variable specifies the non-English equivalents of the
English defaults.
The optional file is as follows:
o Only shell scripts can be specified on the command line. If the program is
a real program, it must come from standard input (or placed into a shell
file).
FLAGS
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-r job... Removes jobs previously scheduled by at or batch, where job is the
number assigned by at or batch. If you do not have superuser
authority (see "su"), you can remove only your own jobs.
-c Runs commands using csh as the shell.
-k Runs commands using ksh as the shell, if ksh is present.
-l Reports your scheduled jobs, including the job number.
-m Mails a message to the user about the successful execution of the
command.
-s Run the commands using the Bourne shell.
EXAMPLES
1. To schedule the command uucleanup (which deletes old spool files) from the
terminal, use a command similar to one of the following:
at 5 pm tomorrow
/usr/lib/uucp/uucleanup
Ctrl-D
at now + 2 days
/usr/lib/uucp/uucleanup
Ctrl-D
These examples run uucp to delete the old uucp files at 5:00 PM tomorrow,
or two days in the future, respectively.
2. To run uucleanup to delete the old uucp spool files at 3:00 in the
afternoon on the 24th of January, use any one of the following commands:
echo /usr/lib/uucp/uucleanup | at 3:00 pm January 24
echo /usr/lib/uucp/uucleanup | at 3pm Jan 24
echo /usr/lib/uucp/uucleanup | at 1500 Jan 24
3. To run a job when the system load permits:
batch <<!
longjob 2>&1 >outfile | mail myID
!
This example shows the use of a here document to send standard input to at
(see "Inline Input Documents"). The order of redirections is important
here, so that only error messages are sent into the pipe to the mail
command. If you reverse the order, both standard error and standard output
are sent to "outfile" (see the discussion of "Input and Output Redirection
Using File Descriptors" for details).
4. To have a job reschedule itself, invoke at from within the shell procedure
by including code similar to the following within the shell file:
echo "sh shellfile" | at now tomorrow
5. To list the jobs you have sent to be run later:
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at -l
6. To cancel jobs:
at -r 103 227
This cancels jobs "103" and "227". Use at -l to list the job numbers
assigned to your jobs.
FILES
/usr/adm/cron Main cron directory.
/usr/adm/cron/at.allow List of allowed users.
/usr/adm/cron/at.deny List of denied users.
/usr/spool/cron/atjobs Spool area.
RELATED INFORMATION
See the following commands: "cron," "kill," "mail, Mail," "nice," "ps" and
"sh, Rsh."
See the environment special facility in AIX Operating System Technical
Reference.
See "Running Commands at Pre-set Times" and "Introduction to International
Character Support" in Managing the AIX Operating System.
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