2026-08-09 09:31 @2600:1f28:365:80b0:50b3:453e:ff52:20f7
CrawledBy CCBot/2.0 (https://commoncrawl.org/faq/)
Enhanced by LLM: deepseek-v4-flash / taotoken.net / www.chedong.com - original format
at, batch, atq, atrm — queue, examine, or delete jobs for later execution.
| Use Case | Command | Description |
|---|---|---|
| ⏰ Schedule a one-time job | echo "command" | at HH:MM | Executes a command at a specified time. |
| 📋 List pending jobs | atq or at -l | Lists the user's pending jobs. |
| 🗑️ Delete a scheduled job | atrm JOBNUM or at -r JOBNUM | Deletes a job by its job number. |
| ⚖️ Run job when system load is low | batch or at -b | Executes commands when the load average drops below 1.5. |
| 📅 Schedule with relative time | at now + 1 hour | Runs a job at a specific offset from now. |
| 📄 Read job from file | at -f script.sh HH:MM | Reads the job script from a file instead of stdin. |
| ✉️ Force mail notification | at -m | Sends mail when the job completes, even if there was no output. |
| 🔍 Show job details | at -c JOBNUM | Cats the job script to standard output. |
at [-V] [-q queue] [-f file] [-u username] [-mMlv] timespec ...
at [-V] [-q queue] [-f file] [-u username] [-mMkv] [-t time]
at -c job [...]
at [-V] -l [-o timeformat] [job ...]
atq [-V] [-q queue] [-o timeformat] [job ...]
at [-rd] job [...]
atrm [-V] job [...]
batch
at -bat and batch read commands from standard input or a specified file which are to be executed at a later time, using /bin/sh.
executes commands at a specified time.
lists the user's pending jobs, unless the user is the superuser; in that case, everybody's jobs are listed. The format of the output lines (one for each job) is: Job number, date, hour, queue, and username.
deletes jobs, identified by their job number.
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 atd.
At allows fairly complex time specifications, extending the POSIX.2 standard. It accepts times of the form 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 MMDD[CC]YY, MM/DD/[CC]YY, DD.MM.[CC]YY or [CC]YY-MM-DD. The specification of a date must follow the specification of the time of day. You can also give times like now + count time-units, where the time-units can be minutes, hours, days, or weeks 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, to run a job at 10:00am on July 31, you would do at 10am Jul 31 and to run a job at 1am tomorrow, you would do at 1am tomorrow.
If you specify a job to absolutely run at a specific time and date in the past, the job will run as soon as possible. For example, if it is 8pm and you do a at 6pm today, it will run more likely at 8:05pm.
The definition of the time specification can be found in /usr/share/doc/at/timespec.
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 BASH_VERSINFO, DISPLAY, EUID, GROUPS, SHELLOPTS, TERM, UID, and _) and the umask are retained from the time of invocation.
As at is currently implemented as a setuid program, other environment variables (e.g., LD_LIBRARY_PATH or LD_PRELOAD) are also not exported. This may change in the future. As a workaround, set these variables explicitly in your job.
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 /usr/sbin/sendmail. 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 /etc/at.allow and /etc/at.deny. See at.allow(5) for details.
If a job is submitted to a queue designated with an uppercase letter, the job is treated as if it were submitted to batch at the time of the job. Once the time is reached, the batch processing rules with respect to load average apply. If atq is given a specific queue, it will only show jobs pending in that queue.
/var/spool/cron/atjobs/var/spool/cron/atspool/proc/loadavg/var/run/utmp/etc/at.allow/etc/at.denyat.allow(5), at.deny(5), atd(8), cron(1), nice(1), sh(1), umask(2).
The correct operation of batch for Linux depends on the presence of a proc- type directory mounted on /proc.
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.
At was mostly written by Thomas Koenig.
Generated by phpman v4.9.26-1-g511901d · Markdown · JSON · MCP Author: Che Dong Under GNU General Public License
2026-08-09 09:31 @2600:1f28:365:80b0:50b3:453e:ff52:20f7
CrawledBy CCBot/2.0 (https://commoncrawl.org/faq/)
Enhanced by LLM: deepseek-v4-flash / taotoken.net / www.chedong.com - original format