1AT(1) General Commands Manual AT(1)
2
6 at, batch, atq, atrm - queue, examine or delete jobs for later execu‐
7 tion
8
10 at [-V] [-q queue] [-f file] [-mMlv] timespec...
11 at [-V] [-q queue] [-f file] [-mMkv] [-t time]
12 at -c job [job...]
13 atq [-V] [-q queue]
14 at [-rd] job [job...]
15 atrm [-V] job [job...]
16 batch
17 at -b
18
20 at and batch read commands from standard input or a specified file
21 which are to be executed at a later time, using /bin/sh.
22 at executes commands at a specified time.
24 atq lists the user's pending jobs, unless the user is the supe‐
26 ruser; in that case, everybody's jobs are listed. The format
27 of the output lines (one for each job) is: Job number, date,
28 hour, queue, and username.
29 atrm deletes jobs, identified by their job number.
31 batch executes commands when system load levels permit; in other
33 words, when the load average drops below 0.8, or the value
34 specified in the invocation of atd.
35 At allows fairly complex time specifications, extending the POSIX.2
37 standard. It accepts times of the form HH:MM to run a job at a spe‐
38 cific time of day. (If that time is already past, the next day is
39 assumed.) You may also specify midnight, noon, or teatime (4pm) and
40 you can have a time-of-day suffixed with AM or PM for running in the
41 morning or the evening. You can also say what day the job will be run,
42 by giving a date in the form month-name day with an optional year, or
43 giving a date of the form MMDD[CC]YY, MM/DD/[CC]YY, DD.MM.[CC]YY or
44 [CC]YY-MM-DD. The specification of a date must follow the specifica‐
45 tion of the time of day. You can also give times like now + count
46 time-units, where the time-units can be minutes, hours, days, or weeks
47 and you can tell at to run the job today by suffixing the time with
48 today and to run the job tomorrow by suffixing the time with tomorrow.
49 For example, to run a job at 4pm three days from now, you would do at
51 4pm + 3 days, to run a job at 10:00am on July 31, you would do at 10am
52 Jul 31 and to run a job at 1am tomorrow, you would do at 1am tomorrow.
53 The definition of the time specification can be found in
55 /usr/share/doc/at-3.1.13/timespec.
56 For both at and batch, commands are read from standard input or the
58 file specified with the -f option and executed. The working directory,
59 the environment (except for the variables BASH_VERSINFO, DISPLAY, EUID,
60 GROUPS, SHELLOPTS, TERM, UID, and _) and the umask are retained from
61 the time of invocation.
62 As at is currently implemented as a setuid program, other environment
64 variables (e.g. LD_LIBRARY_PATH or LD_PRELOAD) are also not exported.
65 This may change in the future. As a workaround, set these variables
66 explicitly in your job.
67 An at - or batch - command invoked from a su(1) shell will retain the
69 current userid. The user will be mailed standard error and standard
70 output from his commands, if any. Mail will be sent using the command
71 /usr/sbin/sendmail. If at is executed from a su(1) shell, the owner of
72 the login shell will receive the mail.
73 The superuser may use these commands in any case. For other users,
75 permission to use at is determined by the files /etc/at.allow and
76 /etc/at.deny. See at.allow(5) for details.
77
79 -V prints the version number to standard error and exit success‐
80 fully.
81 -q queue
83 uses the specified queue. A queue designation consists of a
84 single letter; valid queue designations range from a to z and A
85 to Z. The a queue is the default for at and the b queue for
86 batch. Queues with higher letters run with increased niceness.
87 The special queue "=" is reserved for jobs which are currently
88 running.
89 If a job is submitted to a queue designated with an uppercase
91 letter, the job is treated as if it were submitted to batch at
92 the time of the job. Once the time is reached, the batch pro‐
93 cessing rules with respect to load average apply. If atq is
94 given a specific queue, it will only show jobs pending in that
95 queue.
96 -m Send mail to the user when the job has completed even if there
98 was no output.
99 -M Never send mail to the user.
101 -f file Reads the job from file rather than standard input.
103 -t time run the job at time, given in the format [[CC]YY]MMDDhhmm[.ss]
105 -l Is an alias for atq.
107 -r Is an alias for atrm.
109 -d Is an alias for atrm.
111 -b is an alias for batch.
113 -v Shows the time the job will be executed before reading the job.
115 Times displayed will be in the format "Thu Feb 20 14:50:00
117 1997".
118 -c cats the jobs listed on the command line to standard output.
120
122 /var/spool/at
123 /var/spool/at/spool
124 /proc/loadavg
125 /var/run/utmp
126 /etc/at.allow
127 /etc/at.deny
128
130 at.allow(5), at.deny(5), atd(8), cron(1), nice(1), sh(1), umask(2).
131
133 The correct operation of batch for Linux depends on the presence of a
134 proc- type directory mounted on /proc.
135 If the file /var/run/utmp is not available or corrupted, or if the user
137 is not logged on at the time at is invoked, the mail is sent to the
138 userid found in the environment variable LOGNAME. If that is undefined
139 or empty, the current userid is assumed.
140 At and batch as presently implemented are not suitable when users are
142 competing for resources. If this is the case for your site, you might
143 want to consider another batch system, such as nqs.
144
146 At was mostly written by Thomas Koenig, ig25@rz.uni-karlsruhe.de.
147 2009-11-14 AT(1)