Have you ever started a long-running script in your terminal, only to lose all progress when the session closed? Or maybe you wanted to keep a process running in the background while continuing to use the terminal?

That’s where nohup and & come in handy.

What Are nohup and &?

• nohup: Short for no hang up, it allows a command to keep running even after you log out or close the terminal.
• &: Sends the command to the background, freeing up your terminal for other tasks.

Together, they’re a powerful combo for running persistent background processes.

Basic Usage

Here’s the magic one-liner:

nohup your_command > output.log 2>&1 &

Breakdown:

• your_command: The script or program you want to run.
• > output.log: Redirects standard output to a file.
• 2>&1: Redirects standard error to the same file.
• &: Runs the command in the background.

Monitoring the Output

To watch the output in real-time:

tail -f output.log

This is especially useful for debugging or tracking progress.

Cleaning Up: Stopping the Process

To stop the background process:

• Find the process ID (PID):

ps aux | grep your_command

• Kill it:

kill <PID>

• Or, if you want to be sure:

kill -9 <PID>

Pro Tips

• If you forget to redirect output, nohup will write to nohup.out by default.
• You can check running background jobs with:

jobs

• To bring a background job to the foreground:

fg %1

Final Thoughts

Using nohup and & is a simple yet powerful way to manage long-running or persistent processes in Linux. Whether you’re deploying a server, training a model, or crunching data, this trick can save you time and frustration.