User Commands at(1)
NAME
at, batch - execute commands at a later time
SYNOPSIS
/usr/bin/at [-c | -k | -s] [-m] [-f file] [-p project] [-
q queuename] -t time
/usr/bin/at [-c | -k | -s] [-m] [-f file] [-p project] [-
q queuename] timespec...
/usr/bin/at -l [-p project] [-q queuename] [ at_job_id. ..]
/usr/bin/at -r at_job_id. ..
/usr/bin/batch [-p project]
/usr/xpg4/bin/at [-c | -k | -s] [-m] [-f file] [-p project]
[-q queuename] -t time
/usr/xpg4/bin/at [-c | -k | -s] [-m] [-f file] [-p project]
[-q queuename] timespec...
/usr/xpg4/bin/at -l [-p project] [-q queuename] [ at_job_id.
..]
/usr/xpg4/bin/at -r at_job_id. ..
/usr/xpg4/bin/batch [-p project]
DESCRIPTION
at
The at utility reads commands from standard input and groups
them together as an at-job, to be executed at a later time.
The at-job is executed in a separate invocation of the
shell, running in a separate process group with no control-
ling terminal, except that the environment variables,
current working directory, file creation mask (see
umask(1)), and system resource limits (for sh and ksh only,
see ulimit(1)) in effect when the at utility is executed is
retained and used when the at-job is executed.
When the at-job is submitted, the at_job_id and scheduled
time are written to standard error. The at_job_id is an
identifier that is a string consisting solely of
alphanumeric characters and the period character. The
at_job_id is assigned by the system when the job is
scheduled such that it uniquely identifies a particular job.
User notification and the processing of the job's standard
output and standard error are described under the -m option.
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Users are permitted to use at and batch (see below) 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 a user with the
solaris.jobs.user authorization is allowed to submit a job.
If only at.deny exists and is empty, global usage is permit-
ted. The at.allow and at.deny files consist of one user name
per line.
cron and at jobs are not be executed if the user's account
is locked. Only accounts which are not locked as defined in
shadow(4) will have their job or process executed.
batch
The batch utility reads commands to be executed at a later
time.
Commands of the forms:
/usr/bin/batch [-p project]
/usr/xpg4/bin/batch [-p project]
are respectively equivalent to:
/usr/bin/at -q b [-p project] now
/usr/xpg4/bin/at -q b -m [-p project] now
where queue b is a special at queue, specifically for batch
jobs. Batch jobs are submitted to the batch queue for
immediate execution. Execution of submitted jobs can be
delayed by limits on the number of jobs allowed to run con-
currently. See queuedefs(4).
OPTIONS
If the -c, -k, or -s options are not specified, the SHELL
environment variable by default determines which shell to
use.
For /usr/xpg4/bin/at and /usr/xpg4/bin/batch, if SHELL is
unset or NULL, /usr/xpg4/bin/sh is used.
For usr/bin/at and /usr/bin/batch, if SHELL is unset or
NULL, /bin/sh is used.
The following options are supported:
-c C shell. csh(1) is used to execute the at-
job.
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-k Korn shell. ksh(1) is used to execute the
at-job.
-s Bourne shell. sh(1) is used to execute the
at-job.
-f file Specifies the path of a file to be used as
the source of the at-job, instead of stan-
dard input.
-l (The letter ell.) Reports all jobs scheduled
for the invoking user if no at_job_id
operands are specified. If at_job_ids are
specified, reports only information for
these jobs.
-m Sends mail to the invoking user after the
at-job has run, announcing its completion.
Standard output and standard error produced
by the at-job are mailed to the user as
well, unless redirected elsewhere. Mail is
sent even if the job produces no output.
If -m is not used, the job's standard output
and standard error is provided to the user
by means of mail, unless they are redirected
elsewhere; if there is no such output to
provide, the user is not notified of the
job's completion.
-p project Specifies under which project the at or
batch job is run. When used with the -l
option, limits the search to that particular
project. Values for project is interpreted
first as a project name, and then as a pos-
sible project ID, if entirely numeric. By
default, the user's current project is used.
-q queuename Specifies in which queue to schedule a job
for submission. When used with the -l
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option, limits the search to that particular
queue. Values for queuename are limited to
the lower case letters a through z. By
default, at-jobs are scheduled in queue a.
In contrast, queue b is reserved for batch
jobs. Since queue c is reserved for cron
jobs, it can not be used with the -q option.
-r at_job_id Removes the jobs with the specified
at_job_id operands that were previously
scheduled by the at utility.
-t time Submits the job to be run at the time speci-
fied by the time option-argument, which must
have the format as specified by the touch(1)
utility.
OPERANDS
The following operands are supported:
at_job_id The name reported by a previous invocation
of the at utility at the time the job was
scheduled.
timespec Submit the job to be run at the date and
time specified. All of the timespec operands
are interpreted as if they were separated by
space characters and concatenated. The date
and time are interpreted as being in the
timezone of the user (as determined by the
TZ variable), unless a timezone name appears
as part of time below.
In the "C" locale, the following describes
the three parts of the time specification
string. All of the values from the LC_TIME
categories in the "C" locale are recognized
in a case-insensitive manner.
time The time can be specified as
one, two or four digits.
One- and two-digit numbers
are taken to be hours,
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four-digit numbers to be
hours and minutes. The time
can alternatively be speci-
fied as two numbers
separated by a colon, mean-
ing hour:minute. An AM/PM
indication (one of the
values from the am_pm key-
words in the LC_TIME locale
category) can follow the
time; otherwise, a 24-hour
clock time is understood. A
timezone name of GMT, UCT,
or ZULU (case insensitive)
can follow to specify that
the time is in Coordinated
Universal Time. Other
timezones can be specified
using the TZ environment
variable. The time field can
also be one of the following
tokens in the "C" locale:
midnight Indicates the time
12:00 am (00:00).
noon Indicates the time
12:00 pm.
now Indicate the
current day and
time. Invoking at
now submits an at-
job for potentially
immediate execution
(that is, subject
only to unspecified
scheduling delays).
date An optional date can be
specified as either a month
name (one of the values from
the mon or abmon keywords in
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the LC_TIME locale category)
followed by a day number
(and possibly year number
preceded by a comma) or a
day of the week (one of the
values from the day or abday
keywords in the LC_TIME
locale category). Two spe-
cial days are recognized in
the "C" locale:
today Indicates the
current day.
tomorrow Indicates the day
following the
current day.
If no date is given, today
is assumed if the given time
is greater than the current
time, 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.
increment The optional increment is a
number preceded by a plus
sign (+) and suffixed by one
of the following: minutes,
hours, days, weeks, months,
or years. (The singular
forms are also accepted.)
The keyword next is
equivalent to an increment
number of + 1. For example,
the following are equivalent
commands:
at 2pm + 1 week
at 2pm next week
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USAGE
The format of the at command line shown here is guaranteed
only for the "C" locale. Other locales are not supported for
midnight, noon, now, mon, abmon, day, abday, today, tomor-
row, minutes, hours, days, weeks, months, years, and next.
Since the commands run in a separate shell invocation, run-
ning in a separate process group with no controlling termi-
nal, open file descriptors, traps and priority inherited
from the invoking environment are lost.
EXAMPLES
at
Example 1: Typical Sequence at a Terminal
This sequence can be used at a terminal:
$ at -m 0730 tomorrow
sort < file >outfile
<EOT>
Example 2: Redirecting Output
This sequence, which demonstrates redirecting standard error
to a pipe, is useful in a command procedure (the sequence of
output redirection specifications is significant):
$ at now + 1 hour <<!
diff file1 file2 2>&1 >outfile | mailx mygroup
Example 3: Self-rescheduling a Job
To have a job reschedule itself, at can be invoked from
within the at-job. For example, this "daily-processing"
script named my.daily runs every day (although crontab is a
more appropriate vehicle for such work):
# my.daily runs every day
at now tomorrow < my.daily
daily-processing
Example 4: Various Time and Operand Presentations
The spacing of the three portions of the "C" locale timespec
is quite flexible as long as there are no ambiguities. Exam-
ples of various times and operand presentations include:
at 0815am Jan 24
at 8 :15amjan24
at now "+ 1day"
at 5 pm FRIday
at '17
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utc+
30minutes'
batch
Example 5: Typical Sequence at a Terminal
This sequence can be used at a terminal:
$ batch
sort <file >outfile
<EOT>
Example 6: Redirecting Output
This sequence, which demonstrates redirecting standard error
to a pipe, is useful in a command procedure (the sequence of
output redirection specifications is significant):
$ batch <<!
diff file1 file2 2>&1 >outfile | mailx mygroup
!
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of at and batch: LANG,
LC_ALL, LC_CTYPE, LC_MESSAGES, NLSPATH, and LC_TIME.
DATEMSK If the environment variable DATEMSK is set,
at uses its value as the full path name of a
template file containing format strings. The
strings consist of format specifiers and
text characters that are used to provide a
richer set of allowable date formats in dif-
ferent languages by appropriate settings of
the environment variable LANG or LC_TIME.
The list of allowable format specifiers is
located in the getdate(3C) manual page. The
formats described in the OPERANDS section
for the time and date arguments, the special
names noon, midnight, now, next, today,
tomorrow, and the increment argument are not
recognized when DATEMSK is set.
SHELL Determine a name of a command interpreter to
be used to invoke the at-job. If the vari-
able is unset or NULL, sh is used. If it is
set to a value other than sh, the implemen-
tation uses that shell; a warning diagnostic
is printed telling which shell will be used.
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TZ Determine the timezone. The job is submitted
for execution at the time specified by
timespec or -t time relative to the timezone
specified by the TZ variable. If timespec
specifies a timezone, it overrides TZ. If
timespec does not specify a timezone and TZ
is unset or NULL, an unspecified default
timezone is used.
EXIT STATUS
The following exit values are returned:
0 The at utility successfully submitted, removed or
listed a job or jobs.
>0 An error occurred, and the job will not be
scheduled.
FILES
/usr/lib/cron/at.allow names of users, one per
line, who are authorized
access to the at and batch
utilities
/usr/lib/cron/at.deny names of users, one per
line, who are denied access
to the at and batch utili-
ties
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/at
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____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| CSI | Not enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
/usr/xpg4/bin/at
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | Not enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
/usr/bin/batch
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWesu |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
/usr/xpg4/bin/batch
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | Enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
SEE ALSO
auths(1), crontab(1), csh(1), date(1), ksh(1), sh(1),
touch(1), ulimit(1), umask(1), cron(1M), getdate(3C),
auth_attr(4), shadow(4), queuedefs(4), attributes(5),
environ(5), standards(5)
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NOTES
Regardless of queue used, cron(1M) has a limit of 100 jobs
in execution at any time.
There can be delays in cron at job execution. In some cases,
these delays can compound to the point that cron job pro-
cessing appears to be hung. All jobs are executed eventu-
ally. When the delays are excessive, the only workaround is
to kill and restart cron.
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