Background Jobs & Job Control

Some commands run a long time. Instead of blocking your terminal, you can push them to the background and keep working in the same shell.

Append & to a command to launch it in the background. The shell prints a job number and a PID, then returns the prompt immediately.

The jobs command lists background and stopped jobs for the current shell, each with a job number in brackets.

Press Ctrl+Z to suspend the foreground command. It stops (does not quit) and returns the prompt.

bg resumes the most recent stopped job in the background so it keeps running while you work.

fg pulls a background or stopped job back to the foreground. Target a specific one with fg %n.

Use %n to reference a job by number in commands like fg, bg, and kill.

Job numbers are shell-local conveniences; PIDs are system-wide. Use job numbers within your shell, but PIDs with system tools like kill from another terminal.

Normally background jobs die when you log out. nohup detaches a command from the terminal so it keeps running after you leave.

disown removes a running job from the shell job table, so closing the shell will not send it a hangup signal.

For serious long-running or remote sessions, terminal multiplexers like tmux or screen keep whole sessions alive and reattachable after disconnect.

Test your understanding.

You learned job control: launch with &, list with jobs, suspend with Ctrl+Z, move with bg/fg and %n, and keep tasks alive after logout with nohup, disown, or tmux/screen.