"at" for schedule a job to be launched

1) at   now   +20 hours -f   lance_la_1year_elimobs
to launch the script 20 hours later from now

2) at 2am  tomorrow -f lance_la_1year_elimobs
to launch the script at 2am tomorrow


3) atq
to show the scheduled job


4) atrm jobID
to remove a scheduled job


http://www.techrepublic.com/blog/opensource/one-time-scheduling-of-tasks-with-at/260

http://www.thegeekstuff.com/2009/06/15-practical-crontab-examples/