at - Command for scheduling programs

at - Command for scheduling jobs on Linux

The at command schedules a command to be run once at a particular time. This can be any command that you normally have permission to run; anything from a simple reminder message, to a complex script.

The command <at> can be used for scheduling jobs on Hydra, Dozer and Xeon servers.

You start by running the at command at the command line, passing it the scheduled time as the option. It places you at a special prompt, where you can type in the command (or series of commands) to be run at the scheduled time.

When you're done, press Control-D on a new line, and your command will be placed in the queue.

Example:

at -m now + 1 hour

at> bpsh 10 ./matrixMult 4 1 > result-matmult.txt
at> ^D

where:

-m : send a message when the job finishes

now + 1 hours : the job statrts in one hour from now.

In this example, a job will created in order to execute helloworld and matrixMult programs on node 10.

Use different jobs for each program if you intend to run programs in different nodes.

The job will start in one hour from now, but it is optinal and you can start your job right away, just do not use <+ 1 hour> clause.

The results will be record in two different txt files: result-matmult.txt. You can choose any name to the result file .

The advantage of using <at> is that you can logoff and walk away from your computer while your results are generating.

In order to manage the jobs created by <at> you can use:

atq: List pending jobs

atrm: Cancel pending jobs

You can use the commant top in order to check the processes running on linux

For more information abou <at> visit:

http://www.computerhope.com/unix/uat.htm

* results from at are mailed to /var/spool/mail/user_name