Nohup: Running in the Background

When you want to keep your script running after you close your terminal or log out from the server, you can use nohup. This is especially useful for long-running processes, like a server, bot, or scheduled task. Here's how to do it step by step.

Basic Usage

To run a Python script (or any) in the background using nohup, use this command:

nohup python3 main.py > output.log 2>&1 &

Explanation:

• nohup: Stands for "no hangup", it ensures the process won't terminate when the terminal is closed.

• python3 main.py: The script you want to run (replace main.py with your script).

• > output.log: Redirects the standard output (stdout) to a file called output.log (you can choose any filename).

• 2>&1: Redirects the error output (stderr) to the same file (output.log).

• &: Runs the process in the background.

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Checking if the Process is Running

To verify that your script is running, you can check the process list:

ps aux | grep main.py

This command will list all processes that match main.py (replace main.py with your script's name). You should see an entry for your running Python script.

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Stopping the Process

If you need to stop the script later, first find its process ID (PID) with the ps command:

ps aux | grep main.py

Then, kill the process using kill followed by the PID:

kill <PID>

If the process doesn't stop with a regular kill, you can force it to stop using:

kill -9 <PID>