Processes and jobs
Linux commands: nohup
Learn how the Linux nohup command keeps a process running after you log out or close the terminal, which is handy for long-lived jobs on a remote server.
8 minute lesson
Closing a terminal normally sends a hangup signal to jobs associated with that session. nohup starts a command with that signal ignored:
nohup ./generate-report >report.log 2>&1 &Each part has a job:
nohupprotects the command from the hangup signal.>report.logrecords standard output.2>&1sends errors to the same file.&returns the shell prompt while the process runs in the background.
Without explicit redirection, many implementations write to nohup.out. Record the process ID immediately with echo $!, then verify the process and watch its log:
job_pid=$!
ps -p "$job_pid"
tail -f report.lognohup is not a service manager. It does not restart a crashed process, start it after a reboot, rotate logs, manage dependencies, or expose structured status. Use systemd, a container orchestrator, or another supervisor for a production service. Use tmux or screen when you want to reconnect to an interactive terminal rather than detach a non-interactive job.
Also check whether the program needs input. A background command waiting on the closed terminal can still fail or stop.
Try it with nohup sh -c 'sleep 10; date' >result.log 2>&1 &, close or detach the session, then confirm the timestamp appears.
Lesson completed