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 groupsthem 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 isretained and used when the at-job is executed.
SunOS 5.11 Last change: 13 Apr 2005 1
User Commands at(1)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. Theat_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 standardoutput 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 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 runSunOS 5.11 Last change: 13 Apr 2005 2
User Commands at(1) concurrently. See queuedefs(4). OPTIONSIf 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.-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 noat_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 producedby 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 out-
put and standard error is provided to the user by means of mail, unless they areSunOS 5.11 Last change: 13 Apr 2005 3
User Commands at(1) 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 particu-
lar project. Values for project is inter-
preted 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 particu-
lar queue. Values for queuename are limited to the lower case letters a through z. Bydefault, at-jobs are scheduled in queue a.
In contrast, queue b is reserved for batch
jobs. Since queue c is reserved for cronjobs, 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),SunOS 5.11 Last change: 13 Apr 2005 4
User Commands at(1) 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 asone, two or four digits. One-
and two-digit numbers are taken
to be hours, four-digit numbers
to be hours and minutes. Thetime can alternatively be speci-
fied as two numbers separated by a colon, meaning hour:minute. AnAM/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 under-
stood. 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 bespecified using the TZ environ-
ment 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 atnow submits an at-
job for potentially immediate execution (that is, subject only to unspecified scheduling delays).SunOS 5.11 Last change: 13 Apr 2005 5
User Commands at(1)date An optional date can be speci-
fied as either a month name (one of the values from the mon orabmon 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 abdaykeywords 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, thefollowing are equivalent com-
mands: at 2pm + 1 week at 2pm next weekUSAGE
SunOS 5.11 Last change: 13 Apr 2005 6
User Commands at(1) The format of the at command line shown here is guaranteed only for the "C" locale. Other locales are not supported formidnight, 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 >outfileExample 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 fromwithin 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.dailydaily-processing
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User Commands at(1) Example 4 Various Time and Operand Presentations The spacing of the three portions of the "C" locale timespecis 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
sortoutfile 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 aSunOS 5.11 Last change: 13 Apr 2005 8
User Commands at(1) 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 languagesby appropriate settings of the environment vari-
able LANG or LC_TIME. The list of allowable for-
mat specifiers is located in the getdate(3C) manual page. The formats described in theOPERANDS section for the time and date argu-
ments, the special names noon, midnight, now,next, today, tomorrow, and the increment argu-
ment are not recognized when DATEMSK is set. SHELL Determine a name of a command interpreter to beused 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 usesthat shell; a warning diagnostic is printed tel-
ling 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 atand batch utilities
/usr/lib/cron/at.deny names of users, one per line, who are denied access to the at andbatch utilities
SunOS 5.11 Last change: 13 Apr 2005 9
User Commands at(1)ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes: /usr/bin/at____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcs ||_____________________________|_____________________________|
| CSI | Not enabled ||_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| Standard | See standards(5). ||_____________________________|_____________________________|
/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
SunOS 5.11 Last change: 13 Apr 2005 10
User Commands at(1)____________________________________________________________
| 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) 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.SunOS 5.11 Last change: 13 Apr 2005 11