Content-type: text/html Man page of at

at

Section: User Commands (1)
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NAME

at, batch - Runs commands at a later time  

SYNOPSIS

at [-c|-s|-k] [-m] [-f file] [-q queuename] time [date] [+increment] [command|file]...

at [-c|-s|-k] [-m] [-f file] [-q queuename] -t [[cc]yy]MMddhhmm[.ss]

at -l -o [-q queuename] [user...]

at -l [job_number]

at -r [-Fi] job_number...|[-u user]

at -n [user]

batch

The at and batch commands read from standard input or accept as arguments the names of commands to be run at a later time. The at command lets you specify when the commands are to be run. The batch command runs jobs when the system load level permits.
 

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

at:  XPG4, XPG4-UNIX

batch:  XPG4, XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.
 

OPTIONS

[Compaq]  Requests that csh be used for executing this job. Specifies the name of the file to use instead of stdin. The specified file contains the list of commands to be executed. [Compaq]  Suppresses delete verification. [Compaq]  Specifies interactive delete. [Compaq]  Requests that ksh be used for executing this job. Reports your scheduled jobs.

[Compaq]  If the root user issues the command with this option, all of the queued at commands are listed with the name of the user who issued each one. The root user can also request a report of scheduled jobs for the specified user only. Mails a message about the successful execution of the command. Standard output and standard error are also mailed if they are generated and are not redirected. This is the default for standard output and standard error. Without the -m option, there is no notification of job completion, and no mail if standard output and standard error were not generated. [Compaq]  Requests the number of files in the queue for the current user. The root user can specify a different user with the user argument. [Compaq]  Lists jobs in scheduled order. This option is useful only when used with the -l option. Specifies the queue you want to use. When used with the -l option, limits the search to the specified queue. A queue name can be specified by a, b, e, or f, as described in the DESCRIPTION section. Removes a job previously scheduled by at or batch, where job_number is the number assigned by at or batch. If you do not have root user authority, you can remove only your own jobs. The atrm command is available to the root user to remove jobs issued by other users or all jobs issued by a specific user. This option can be used in combination with the -i, -f, and -u options. [Compaq]  Requests that the Bourne shell be used for executing this job (default). [Compaq]  Submits the job to be run at the specified time. (See the SYNOPSIS section for the correct time format.) Deletes all jobs for the specified user. This option must be used with the -r option as follows: at -r -u user

 

OPERANDS

[Compaq]  The operands associated with the at command specify the time at which the job should be run. They are described in the section Specifying a Time and Date.
 

DESCRIPTION

Both at and batch mail you the standard output and standard error from the scheduled commands, unless you redirect that output. They also write the job number and the scheduled time to standard error.

If a filename specified on an at command line is executable (that is, has the x permission for the user in question), at assumes that it is a command and the job consists of this command only. If the file is not executable, at assumes that you want its contents to be the instructions for the job (same as BSD at).

[Compaq]  If at cannot find the file at all, the specification is passed to the date parser. If the specification is not recognized by the date parser, the user receives the error Unknown word.

[Compaq]  The at command defaults to the Bourne shell. Use the -c option to specify the C shell, or the -k option to specify the Korn shell. Variables in the shell environment, the current directory, umask, and ulimit are retained when the commands run. The value of SHELL is set to be consistent with the shell actually used. Open file descriptors, traps, and priority are lost.

You can use at if your login name appears in the /usr/lib/cron/at.allow file, if that file exists, or if there is no at.allow file and your name is not in the /usr/lib/cron/at.deny file. The at.allow and at.deny files contain one user name per line. Note that /usr/lib/cron is symbolically linked to /var/adm/cron.

If neither the at.allow nor the at.deny file exists, only someone with root user authority can submit a job.

To allow global access to at, the system administrator can remove the at.allow file and create a zero-length at.deny file.
 

Specifying a Time and Date

You must specify a time argument with these commands. You can specify optionally the date argument. These arguments are affected when the DATEMSK environment variable is set. The next subsection describes the effect of this environment variable.

The required time argument can be one of the following: A number followed by an optional suffix. The at command interprets 1- and 2-digit numbers as hours. It interprets 4 digits as hours and minutes. The LC_TIME environment variable specifies the order of hours and minutes. The default order is the hour followed by the minute. You can also separate hours and minutes with a : (colon). The default order is hour:minute. In addition, you can specify a suffix of am, pm, or zulu. If you do not specify am or pm, at uses a 24-hour clock. The suffix zulu indicates that the time is UTC (Coordinated Universal Time). The at command also recognizes the following keywords as special times: noon, midnight, now, A for a.m., P for p.m., N for noon, and M for midnight. The time argument specifies a time in the future. For example, if the current time is 9:02 p.m., and you specify a time of 9P, the command is executed at 9 p.m. the next day. However, if the current time is 8:58 p.m. and you specify 9P, the command is executed in two minutes. The LC_TIME environment variable controls the keywords that at recognizes. Keywords are defined on a locale basis, however, none of the locales shipped with the base operating system use this feature. All locales use English names for the keywords.

You can specify the date argument as either a month name and a day number (and possibly a year number preceded by a comma), or a day of the week. The LC_TIME environment variable specifies the order of the month name and day number (by default, month followed by day). The at command recognizes two special days, today and tomorrow by default. The special day today is the default date if the specified time is later than the current hour; the special day tomorrow is the default if the time is earlier than the current hour. If the specified month is less than the current month (and a year is not given), next year is the default year.

The optional increment can be one of the following: A + (plus sign) followed by a number and one of the following words: minute[s], hour[s], day[s], week[s], month[s], year[s] (or their non-English equivalents). The special word next followed by one of the following words: minute[s], hour[s], day[s], week[s], month[s], year[s] (or their non-English equivalents).

Job numbers are specified as follows: user.xxxxxxxxx.y

[Compaq]  The user argument identifies the user who scheduled the job; xxxxxxxxx is a 9-digit number (encoded time for the job); and y indicates the job type or queue name as follows:

ArgumentJob Type
aat job
bbatch job
eksh job
fcsh job


 

Setting the DATEMSK Environment Variable

[Compaq]  If the DATEMSK environment variable is set, it points to a template file that the at command uses to determine the valid time and date arguments instead of the values described in the previous section. Specifically, noon, midnight, now, next, today, tomorrow, and increment are not recognized when the DATEMSK environment variable is set.

[Compaq]  The entries in the template file used by the DATEMSK environment variable provide an expansive set of date formats available in different languages depending on the setting of the environment variable LANG or LC_TIME. The setlocale(3) reference page contains the list of field descriptors allowed in the template file. This list is a sublist of the field descriptors supported by the calendar command which are listed on the date(1) reference page.
 

NOTES

[Compaq]  It is recommended that you not use unspecified queues (queues other than a, b, e, f). The results are unspecified.
 

EXIT STATUS

The following exit values are returned: The at command successfully submitted, removed, or listed all specified jobs. An error occurred.
 

EXAMPLES

To schedule a command from a terminal, enter a command similar to one of the following: at 5 pm Friday uuclean at now next week uuclean at now + 2 days uuclean

The preceding commands can be scheduled as shown only if uuclean is in the current directory. To run uuclean at 3:00 in the afternoon on January 24, enter any one of the following commands: echo uuclean | at 3:00 pm January 24 echo uuclean | at 3pm Jan 24 echo uuclean | at 1500 jan 24 To list the jobs you have sent to be run later, enter: at -l To cancel jobs, enter: at -r julie.586748399.a
This cancels job julie.586748399. Use at -l to list the job numbers assigned to your jobs. To execute a command when the system load level permits, enter: batch nroff infile > outfile <Ctrl-d>
where <Ctrl-d> is the End-of-File character. Assume a template file, /var/tmp/AT.TEMPL, contains the following:
%I %p, the %est of %B of the %Y run the following job %I %p, the %end of %B of the %Y run the following job %I %p, the %erd of %B of the %Y run the following job %I %p, the %eth of %B of the %Y run the following job %d/%m/%y %H:%M:%S %I:%M%p
To invoke the at command when the DATEMSK environment variable is set to /var/tmp/AT.TEMPL, and the template file any of the following are valid: at 2 pm, the 3rd of July of the year 2000 run the following job at 3/4/99 at 10:30:30 at 2:30pm

 

FILES

Main cron directory List of allowed users List of denied users Spool area
 

SEE ALSO

Commands:  atq(1), atrm(1), calendar(1), csh(1), cron(8), date(1), kill(1), mail(1), binmail(1), ksh(1), mailx(1), Mail(1), nice(1), ps(1), Bourne shell sh(1b), POSIX shell sh(1p)

Functions:  setlocale(3)

Standards:  standards(5)

System Administration Guide

Network Administration Guide

Command and Shell User's Guide


 

Index

NAME
SYNOPSIS
STANDARDS
OPTIONS
OPERANDS
DESCRIPTION
Specifying a Time and Date
Setting the DATEMSK Environment Variable
NOTES
EXIT STATUS
EXAMPLES
FILES
SEE ALSO

This document was created by man2html, using the manual pages.
Time: 02:42:58 GMT, October 02, 2010