The Linux at Command
I recently wanted to run a set of commands on a Linux machine at some point in the future. I knew about using cron to schedule a set of commands at defined intervals, but I only wanted to run the commands once at a specific time on a specific date. After searching the internet I found the at command, which allowed me to do exactly what I wanted.
The at command will execute a command or a script at a later time or date and allows for some fairly complex time specifications. Below are two examples of the at command:
1) using at to execute commands taken from stdin at 17:00 on the same day:
$ at 17:00 at> ... at> ... at> <EOT> job 1 at 2009-06-22 17:00
2) using at to execute commands from a file on a June 19 at 17:00:
$ at -f myscript.sh 17:00 Jun 26 job 2 at 2009-06-26 17:00
You can also use atq to list the scheduled jobs, as follows:
$ atq 1 Mon Jun 22 17:00:00 2009 a ajones 2 Fri Jun 26 17:00:00 2009 a ajones
The atrm command allows you to remove a scheduled job:
$ atrm 1 $ atq 2 Fri Jun 26 17:00:00 2009 a ajones