1 .\" $FreeBSD: src/usr.bin/at/at.man,v 1.13.2.10 2003/05/03 21:55:26 keramida Exp $
10 .Nd queue, examine or delete jobs for later execution
20 .Fl c Ar job Op Ar job ...
42 read commands from standard input or a specified file which are to
43 be executed at a later time, using
45 .Bl -tag -width indent
47 executes commands at a specified time;
49 lists the user's pending jobs, unless the user is the superuser; in that
50 case, everybody's jobs are listed;
54 executes commands when system load levels permit; in other words, when the load average
55 drops below _LOADAVG_MX, or the value specified in the invocation of
60 allows some moderately complex
63 It accepts times of the form
67 to run a job at a specific time of day.
68 (If that time is already past, the next day is assumed.)
69 As an alternative, the following keywords may be specified:
75 and time-of-day may be suffixed with
79 for running in the morning or the evening.
80 The day on which the job is to be run may also be specified
81 by giving a date in the form
85 or giving a date of the forms
92 The specification of a date must follow the specification of
94 Time can also be specified as:
96 .Em + Ar count \%time-units ,
97 where the time-units can be
107 to run the job today by suffixing the time with
109 and to run the job tomorrow by suffixing the time with
112 For example, to run a job at 4pm three days from now, you would do
113 .Nm at Ar 4pm + 3 days ,
114 to run a job at 10:00am on July 31, you would do
115 .Nm at Ar 10am Jul 31
116 and to run a job at 1am tomorrow, you would do
117 .Nm at Ar 1am tomorrow .
123 commands are read from standard input or the file specified
127 The working directory, the environment (except for the variables
135 are retained from the time of invocation.
140 command invoked from a
142 shell will retain the current userid.
143 The user will be mailed standard error and standard output from his
145 Mail will be sent using the command
151 shell, the owner of the login shell will receive the mail.
153 The superuser may use these commands in any case.
154 For other users, permission to use
156 is determined by the files
157 .Pa _PERM_PATH/at.allow
159 .Pa _PERM_PATH/at.deny .
162 .Pa _PERM_PATH/at.allow
163 exists, only usernames mentioned in it are allowed to use
165 In these two files, a user is considered to be listed only if the user
166 name has no blank or other characters before it on its line and a
167 newline character immediately after the name, even at the end of
169 Other lines are ignored and may be used for comments.
172 .Pa _PERM_PATH/at.allow
174 .Pa _PERM_PATH/at.deny
175 is checked, every username not mentioned in it is then allowed
179 If neither exists, only the superuser is allowed use of
181 This is the default configuration.
183 .Bl -tag -width indent
185 Print the version number to standard error.
187 Use the specified queue.
188 A queue designation consists of a single letter; valid queue designations
198 .Ar _DEFAULT_AT_QUEUE
199 queue is the default for
202 .Ar _DEFAULT_BATCH_QUEUE
205 Queues with higher letters run with increased niceness.
206 If a job is submitted to a queue designated with an uppercase letter, it
207 is treated as if it had been submitted to batch at that time.
210 is given a specific queue, it will only show jobs pending in that queue.
212 Send mail to the user when the job has completed even if there was no
217 rather than standard input.
230 shows completed but not yet deleted jobs in the queue; otherwise
231 shows the time the job will be executed.
233 Cat the jobs listed on the command line to standard output.
236 .Bl -tag -width _ATJOB_DIR/_LOCKFILE -compact
238 directory containing job files
240 directory containing output spool files
243 .It Pa _PERM_PATH/at.allow
244 allow permission control
245 .It Pa _PERM_PATH/at.deny
246 deny permission control
247 .It Pa _ATJOB_DIR/_LOCKFILE
248 job-creation lock file
260 is not available or corrupted, or if the user is not logged on at the
263 is invoked, the mail is sent to the userid found
264 in the environment variable
266 If that is undefined or empty, the current userid is assumed.
271 as presently implemented are not suitable when users are competing for
273 If this is the case for your site, you might want to consider another
274 batch system, such as
277 At was mostly written by
278 .An Thomas Koenig Aq ig25@rz.uni-karlsruhe.de .
279 The time parsing routines are by
280 .An David Parsons Aq orc@pell.chi.il.us .