Shell job control
Shells can run processes in the background, where they execute on their own, or in the foreground, attached to a terminal. Each process handled in this way is known as a job. Jobs are manipulated using job control commands:
jobspecin the background as if it had been started with
jobspecin the foreground, making it the current job.
jobspecson standard output.
command, detach it from the terminal, and allow it to continue running after the user logs out.