AT(1) 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 controlling 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.


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 permitted. 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 concurrently. 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.


If SHELL is unset or NULL, /usr/bin/sh is used.


The following options are supported:

-c
C shell. csh(1) is used to execute the at-job.


-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 standard 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
possible 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 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 specified 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, four-digit numbers to be hours
and minutes. The time can alternatively be
specified as two numbers separated by a
colon, meaning hour:minute. An AM/PM
indication (one of the values from the am_pm
keywords 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 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 special 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


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, tomorrow, minutes, hours, days, weeks, months,
years, and next.


Since the commands run in a separate shell invocation, running in a
separate process group with no controlling terminal, 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. Examples of various times
and operand presentations include:


at 0815am Jan 24
at 8 :15amjan24
at now "+ 1day"
at 5 pm FRIday
at '17
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 different 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 variable is unset or NULL, sh is
used. If it is set to a value other than sh, the
implementation uses that shell; a warning diagnostic is
printed telling which shell will be used.


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 utilities


ATTRIBUTES


See attributes(5) for descriptions of the following attributes:

/usr/bin/at

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|CSI | Not enabled |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

/usr/xpg4/bin/at

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|CSI | Not enabled |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

/usr/bin/batch

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|CSI | Enabled |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+

/usr/xpg4/bin/batch

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|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)

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 processing appears to be hung.
All jobs are executed eventually. When the delays are excessive, the only
workaround is to kill and restart cron.


April 13, 2005 AT(1)