Which command is used in CRON for scheduling a one-time event?

The command used for scheduling a one-time event is "at." This utility allows users to schedule a command to run at a specific time in the future, ideal for tasks that need to be executed only once. When you use the "at" command, you specify the time and date, and the command to be executed.

In contrast, "crontab" is utilized for scheduling recurring tasks at specified intervals, not for one-time events. "batch" is similar to "at," allowing commands to be executed when the system load levels drop to a defined limit, but it is specifically designed for running jobs that can be deferred until there's less demand on the system. "scheduled" is not a recognized command in the context of scheduling tasks in Linux. Therefore, "at" is the appropriate choice for one-time event scheduling.