NAME
at
, batch
,
atq
, atrm
—
queue, examine or delete jobs for later
execution
SYNOPSIS
at |
[-bdlmrVv ] [-f
file] [-q
queue] -t
[[CC]YY]MMDDhhmm[.SS] |
at |
[-bdlmrVv ] [-f
file] [-q
queue] time |
at |
[-V ] -c
job [job ...] |
atq |
[-Vv ] [-q
queue] |
atrm |
[-V ] job
[job ...] |
batch |
[-mVv ] [-f
file] [-q
queue] [-t
[[CC]YY]MMDDhhmm[.SS]] |
batch |
[-mVv ] [-f
file] [-q
queue] [time] |
DESCRIPTION
at
and batch
read commands from
standard input or a specified file which are to be executed at a later time,
using sh(1).
at
- Executes commands at a specified time.
atq
- Lists the user's pending jobs, unless the user is the superuser. In that case, everybody's jobs are listed.
atrm
- Deletes jobs.
batch
- Executes commands when system load levels permit. In other words, when the load average drops below 1.5, or the value specified in the invocation of atrun(8).
at
allows some moderately complex
time specifications. It accepts times of the form
HHMM or HH:MM to run a job at a
specific time of day. (If that time is already past, the next day is
assumed.) You may also specify ‘midnight’,
‘noon’, or ‘teatime’ (4pm) and you can have a
time-of-day suffixed with ‘AM’ or ‘PM’ for
running in the morning or the evening. You can also say what day the job
will be run, by giving a date in the form %month-name
day with an optional year, or giving a date of
the form MMDDYY or MM/DD/YY or
DD.MM.YY. The specification of a date must follow the
specification of the time of day. You can also give times like
[now
] or [now
] ‘+
count %time-units’, where the time-units can be
‘minutes’, ‘hours’, ‘days’,
‘weeks’, ‘months’, or ‘years’ and
you can tell at
to run the job today by suffixing
the time with ‘today’ and to run the job tomorrow by suffixing
the time with ‘tomorrow’.
For example, to run a job at 4pm three days from now, you would do
at 4pm + 3 days
at 10am Jul 31
at 1am tomorrow
Alternatively the time may be specified in a language-neutral
fashion by using the -t
options.
For both at
and
batch
, commands are read from standard input or the
file specified with the -f
option and executed. The
working directory, the environment (except for the variables
TERM
, TERMCAP
,
DISPLAY
and _
) and the
umask are retained from the time of invocation. An
at
or batch
command invoked
from a su(1) shell will retain the current userid. The user will be mailed
standard error and standard output from his commands, if any. Mail will be
sent using the command
sendmail(1). If at
is executed from a
su(1)
shell, the owner of the login shell will receive the mail.
The superuser may use these commands in any case. For other users,
permission to use at
is determined by the files
/var/at/at.allow and
/var/at/at.deny.
If the file /var/at/at.allow exists, only
usernames mentioned in it are allowed to use at
.
If /var/at/at.allow does not exist,
/var/at/at.deny is checked; every username not
mentioned in it is then allowed to use at
.
If neither exists, only the superuser is allowed use of
at
.
An empty /var/at/at.deny means that every user is allowed use these commands. This is the default configuration.
OPTIONS
-b
- Is an alias for
batch
. -c
- Cats the jobs listed on the command line to standard output.
-d
- Is an alias for
atrm
. -f
file- Reads the job from file rather than standard input.
-l
- Is an alias for
atq
. -m
- Send mail to the user when the job has completed even if there was no output.
-q
queue- Uses the specified queue. A queue designation consists of a single letter.
Valid queue designations range from ‘a’ to ‘z’
and ‘A’ to ‘Z’. The ‘c’ queue is
the default for
at
and the ‘E’ queue forbatch
. Queues with higher letters run with increased niceness. If a job is submitted to a queue designated with an uppercase letter, it is treated as if it had been submitted to batch at that time. Ifatq
is given a specific queue, it will only show jobs pending in that queue. -r
- Is an alias for
atrm
. -t
- For both
at
andbatch
, the time may be specified in a language-neutral format consisting of:- CC
- The first two digits of the year (the century).
- YY
- The second two digits of the year. If YY is specified, but CC is not, a value for YY between 69 and 99 results in a CC value of 19. Otherwise, a CC value of 20 is used.
- MM
- The month of the year, from 01 to 12.
- DD
- The day of the month, from 01 to 31.
- hh
- The hour of the day, from 00 to 23.
- mm
- The minute of the hour, from 00 to 59.
- SS
- The second of the minute, from 00 to 61.
-V
- Prints the version number to standard error.
-v
- For
atq
, shows completed but not yet deleted jobs in the queue. Otherwise shows the time the job will be executed.
FILES
- /var/at/jobs
- Directory containing job files
- /var/at/spool
- Directory containing output spool files
- /var/run/utmp
- Login records
- /var/at/at.allow
- Allow permission control
- /var/at/at.deny
- Deny permission control
- /var/at/.lockfile
- Job-creation lock file.
SEE ALSO
STANDARDS
The at
and batch
utilities conform to IEEE Std 1003.2-1992
(“POSIX.2”).
AUTHORS
at
was mostly written by
Thomas Koenig
<ig25@rz.uni-karlsruhe.de>.
The time parsing routines are implemented by David
Parsons
<orc@pell.chi.il.us>.
BUGS
If the file /var/run/utmp is not available
or corrupted, or if the user is not logged on at the time
at
is invoked, the mail is sent to the userid found
in the environment variable LOGNAME
. If that is
undefined or empty, the current userid is assumed.
at
and batch
as
presently implemented are not suitable when users are competing for
resources. If this is the case for your site, you might want to consider
another batch system, such as nqs
.