AT(1)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]
DESCRIPTIONat
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 stan‐
dard 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 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 are 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 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 recog‐
nized 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 alterna‐
tively be specified as two numbers sepa‐
rated 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 time‐
zone name of GMT, UCT, or ZULU (case insen‐
sitive) 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 equiva‐
lent to an increment number of + 1. For
example, the following are equivalent com‐
mands:
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 descrip‐
tors, traps and priority inherited from the invoking environment are
lost.
EXAMPLESat
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 appro‐
priate 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 implemen‐
tation 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 autho‐
rized 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 ALSOauths(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.
Apr 13, 2005 AT(1)