system_cmds-258.tar.gz

[apple/system_cmds.git] / at.tproj / at.1

.\"
.\" Copyright (c) 1993 Christopher G. Demetriou
.\" All rights reserved.
.\"
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.\" modification, are permitted provided that the following conditions
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.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"      This product includes software developed by Christopher G. Demetriou.
.\" 3. The name of the author may not be used to endorse or promote products
.\"    derived from this software without specific prior written permission
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\"	$Id: at.1,v 1.3 2003/06/05 17:13:32 eseidel Exp $
.\"
.Dd December 5, 1993
.Dt "AT" 1
.Os NetBSD 0.9a
.Sh NAME
.Nm at, batch, atq, atrm
.Nd queue, examine, or delete jobs for later execution
.\"
.Sh SYOPSIS
.Nm at
.Op Fl q Ar queue
.Op Fl f Ar file
.Op Fl m
.Ar time
.Pp
.Nm atq
.Op Fl q Ar queue
.Op Fl v
.Pp
.Nm atrm
.Ar job
.Op Ar job ...
.Pp
.Nm batch
.Op Fl f Ar file
.Op Fl m
.Ar time
.Sh NOTE
.Nm at ,
.Nm batch ,
.Nm atq ,
.Nm atrm
are all disabled by default on Mac OS X.
Each of these commands depend on the execution of 
.Xr atrun 8
which has been disabled due to power management concerns.
Those who would like to use these commands, must first re-enable
.Nm /usr/libexec/atrun
by removing the leading '#' from the line
.Bd -literal
#*/5    *       *       *       *       root    /usr/libexec/atrun
.Ed
in the file
.Pa /etc/crontab .
.Pa /etc/crontab
must be edited by root.
.Sh DESCRIPTION
The
.Nm at
and
.Nm batch
utilities read commands from the standard input or a specified file
which are to be executed at a later time, using
.Xr sh 1 .
.Pp
The functions of the commands are as follows:
.Bl -tag -width indent
.It Nm at
Executes commands at a specified time.
.It Nm atq
Lists the user's pending jobs, unless the user is
the superuser.  In that case, everybody's jobs are
listed.
.It Nm atrm
Deletes jobs.
.It Nm batch
Executes commands when system load levels drop below a user-specifed threshold.
The load threshold for batch jobs is specifed
as an argument when executing
.Xr atrun 8 .
.El
.Pp
For both
.Nm at
and
.Nm batch ,
the working directory, environment (except for the variables
.Nm TERM ,
.Nm TERMCAP ,
.Nm DISPLAY ,
and
.Nm _ )
and the umask are retained from the time of invocation.  The user
will be mailed the standard output and standard error from
his commands if any output is generated.  If
.Nm at
is executed from a
.Xr su 1
shell, the owner of the login shell will receive the mail.
.Sh OPTIONS
.Bl -tag -width indent
The available options are as follows:
.It Fl q Ar queue
Use the specified queue.  A queue designation consists
of a single letter; valid queue designation range from
.Ar a
to
.Ar l .
The
.Ar a
queue is the default, and
.Ar b
is the batch queue.  Queues with higher letters run with
increased niceness.  If
.Nm atq
is given a specific queue, it will only show jobs pending
in that queue.
.It Fl m
Send mail to the user when the job has completed, even if
there was no output.
.It Fl f Ar file
Reads the job from
.Ar file
rather than the standard input.
.It Fl v
Shows completed but not yet deleted jobs in the queue.
.El
.Sh TIME SPECIFICATION
.Nm At
allows some moderately complex time specifications.
It accepts times of the form
.Ar HHMM
or
.Ar HH:MM
to run a job at a specific time of day.  If
that time is already passed, the next day is assumed.
You may also specify
.Nm midnight ,
.Nm noon ,
or
.Nm teatime
(4PM) and you can give a time of day suffixed with
.Nm AM
or
.Nm PM
for running in the morning or the evening.  You can
also specify the date on which the job will be run
by giving a date in the form
.Ar month-name day
with an optional
.Ar year ,
or giving a date of the form
.Ar MMDDYY ,
.Ar MM/DD/YY
or
.Ar DD.MM.YY .
You can also give times like
.Nm now +
.Ar count time-units ,
where the time units can be
.Nm minutes, hours, days,
or
.Nm weeks
You can suffix the time with
.Nm today
to run the job today, or
.Nm tomorrow
to run the job tomorrow.
.Pp
For example, to run a job at 4PM three days from now, you
would specify a time of
.Nm 4PM + 3 days .
To run a job at 10:00AM on on July 31, you would specify
a time of
.Nm 10AM Jul 31 .
Finally, to run a job at 1AM tomorrow, you would specify
a time of
.Nm 1AM tomorrow .
.Sh FILES
.Bl -tag -width /var/at/lockfile -compact
.It Pa /var/at/jobs
Directory containing job files
.It Pa /var/at/spool
Directory containing output spool files
.It Pa /var/at/lockfile
Job-creation lock file.
.It Pa /var/run/utmp
.El
.Sh SEE ALSO
.Xr crond 8 ,
.Xr nice 1 ,
.Xr sh 1 ,
.Xr atrun 8
.Sh AUTHOR
.Bl -tag
Thomas Koenig, ig25@rz.uni-karlsruhe.de
.El
.Sh BUGS
Traditional access control to
.Nm at
and
.Nm batch
via the files
.Pa /var/at/at.allow
and
.Pa /var/at/at.deny
is not implemented.
.Pp
If the file
.Pa /var/run/utmp
is not available or corrupted, or if the user is not
logged in at the time
.Nm at
is invoked, the mail is sent to the userid found in the
environment variable
.Nm LOGNAME .
If that is undefined or empty, the current userid is assumed.