I did an article a while back about cron and scheduling tasks in linux (I also mentioned kron which is a graphical interface for cron scheduling…). That works well and good for things that happen on a recurring basis, but the next question is what if I want to schedule a command (or series of commands) to happen once and not again? Well, to tell the truth I’ve used cron for this on occasion, being sure to revisit the crontab and remove the entry before it repeats again, but there is a better way. At.
I could probably do a bad vaudeville-esque bit and say “at what..”, but there is a very powerful and simple scheduler called at in linux. If you open up a command shell and want to run the command “killall mplayer” to end all running mplayer processes at 10 pm, here’s how you’d do it…..
$at 10 pm
warning: commands will be executed using (in order) a) $SHELL b) login shell c) /bin/sh
at> killall mplayer
job 12 at 2006-01-16 22:00
So, I typed “at 10 pm” (without the quotes) a the $ prompt… it gave me an interactive way of entering commands…. next I typed “killall mplayer” (and pressed enter), then since I didn’t have another command I wanted to schedule, I merely pressed ctrl-d to exit and was promptly told that the task was scheduled for 2200 hours tonight (which is 10 pm).
at can handle fairly human-friendly time scheduling…. at 5 tuesday for instance would schedule for 5 am on tuesday (today is Monday and so it schedules for tomorrow, but it is swift enough to figure that if the time has already passed for the week, then it will do it the next time it comes around.)
atq can show what’s scheduled…
13 2006-01-17 05:00 a avery
12 2006-01-16 22:00 a avery
atrm can remove scheduled tasks…. atrm 13
for instance removes the above entries….
it’s also possible to feed at a file with a list of commands…. at -f listofcommands.txt
the format is usually one command per line. More information on at is available by typing “man at”
(again without the quotes) at the command line.
Related PostsRelated Posts
- Scheduling tasks in linux cron Windows has scheduled tasks which most people are only halfway aware of. Linux has very powerful scheduling capabilities coming from it's unix heritage. cron is the daemon that deals with scheduled tasks under most linux distributions. There are a couple ways that you can schedule cron tasks. The first is......
- Codeweavers releases beta of Windows compatibility software for Apple Mac OS X Yesterday codeweavers announced a beta release of their Crossover Office product geared towards Apple Mac OS X users. The software will allow certain windows applications to run on top of Apple's operating system. They're of course, seeking feedback and suggestions for what direction to take the project. This is based......
- Remote Tech Support using VNC (Ultravnc SC and x11vnc+wrapper script) Ok, some time back I'd done a writeup on UltraVNC SC, which is a nice customizable (windows version) VNC server that essentially let's someone doing remote support build their own downloadable .exe that runs and automatically tries to make a direct connection to a "listening" vnc viewer. It's good for......
- Are Demons forced to do as Christ commands? Are Demons forced to do as Christ commands: God is omnipotent. Meaning he can do all things. If Christ, as the incarnation of God, were unable to command demons then one could not say Christ is omnipotent. According to Scripture, all things are subject to the permissive will of God.......
- French Open Gets Started The French Open got underway this week with much anticipation as to what would be seen from some of the greatest players on the circuit. There were some immediate disappointments with players like Hewitt out of the French Open due to an ankle injury. Marin Cilic was eliminated early by......
- Pleasanton Golf Center Pleasanton Golf Center is located in Pleasanton, CA Phone: (925) 462-4653 Website: http://www.pleasantongolfcenter.com Course History: Pleasanton Golf Course is a fun course that is open to the public and offers a great way to spend an afternoon. The prices are very reasonable and the on staff pros are incredibly helpful.......
- Scheduling tasks in linux kcron
- Scheduling tasks in linux cron
- Using the command line in linux – part 1
- Using the command line in linux – part 4
- Fantastic command reference for Windows, Linux, Apple and Oracle