Cron is a daemon that can be used to schedule the execution of recurring tasks according to a combination of the time, day of the month, month, day of the week, and week. Cron assumes that the system is on continuously. If the system is not on when a task is scheduled, it is not
The at command is used to schedule a one-time task at a specific time. batch command is used to schedule a one-time task to be executed when the systems load average drops below 0.8.