crontab -e
Edits the current crontab using the editor specified by the VISUAL or EDITOR environment variables.
The atd service needs to be running to run one-time only jobs.
at 11:25AM to schedule job.
You enter an interactive shell and you use Ctrl-D to close it.
Use at -l to list all pending jobs.
To see the contents of a scheduled job. at -c [job_number]
Use atrm to remove jobs from the list.