at(1)
NAME
at, batch - execute commands at a later time
SYNOPSIS
at [-c | -k | -s] [-m] [-f file] [-p project] [-
q queuename] -t time
at [-c | -k | -s] [-m] [-f file] [-p project] [-
q queuename] timespec...
at -l [-p project] [-q queuename] [ at_job_id. ..]
at -r at_job_id. ..
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 will be 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
will be 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 will be 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 permit-
ted. The at.allow and at.deny files consist of one user name
per line.
cron and at jobs will be 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. It is the equivalent of the command:
at -q b -m now
where queue b is a special at queue, specifically for batch
jobs. Batch jobs will be submitted to the batch queue for
immediate execution.
OPTIONS
The following options are supported. If the -c, -k, or -s
options are not specified, the SHELL environment variable by
default determines which shell to use.
-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 will be mailed
to the user as well, unless redirected elsewhere. Mail
will be sent even if the job produces no output.
If -m is not used, the job's standard output and stan-
dard error will be 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 will
be run. When used with the -l option, limits the
search to that particular project. Values for project
will be 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 submis-
sion. 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 will be scheduled in queue a. In con-
trast, 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 speci-
fied. All of the timespec operands are interpreted as
if they were separated by space characters and con-
catenated. 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 Coordi-
nated 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. Invok-
ing at now will submit 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 key-
words 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 will be 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, 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 will run 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
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 will
use its value as the full path name of a template file
containing format strings. The strings consist of for-
mat 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, tomor-
row, 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 will be used. If it is set to a value other
than sh, the implementation will use that shell; a
warning diagnostic will be printed telling which shell
will be used.
TZ Determine the timezone. The job will be 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 will override TZ.
If timespec does not specify a timezone and TZ is
unset or NULL, an unspecified default timezone will be
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 attri-
butes:
at
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| CSI | Not enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
batch
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWesu |
|_____________________________|_____________________________|
| 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), attributes(5), environ(5), stan-
dards(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 pro-
cessing appears to be hung. All jobs will be executed even-
tually. When the delays are excessive, the only workaround
is to kill and restart cron.
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