a few ways to keep your Python application running after closing the terminal

when you run a Python application like python app.py in a terminal, the process will be terminated when you close the terminal, unless you take steps to ensure the process continues running in the background.

Here are a few ways to keep your Python application running after closing the terminal:

1. Use nohup (No Hang Up)

The nohup command allows the process to continue running even after you close the terminal. You can use it like this:

nohup python app.py &

• nohup makes the process immune to hangups.
• & runs the process in the background.
• By default, the output will be saved in a file named nohup.out.

You can check the output by:

tail -f nohup.out

2. Use screen

The screen utility allows you to create a session that you can disconnect from and reconnect to later, even if the terminal is closed.

• Start a new screen session:

  screen

• Run your application:

  python app.py

• Detach from the screen session (keep it running): Press Ctrl + A, then D to detach.

• To reattach to the session:

  screen -r

If screen is not installed, you can install it:

sudo apt install screen

3. Use tmux

Similar to screen, tmux is another terminal multiplexer that lets you run processes in the background.

• Start a new tmux session:

  tmux

• Run your application:

  python app.py

• Detach from the tmux session (keep it running): Press Ctrl + B, then D to detach.

• To reattach to the session:

  tmux attach

If tmux is not installed, you can install it:

sudo apt install tmux

4. Use systemd (for Linux systems)

If you want to run your Python script as a service that starts automatically with the system and continues running after the terminal is closed, you can create a systemd service.

• Create a new systemd service file (e.g., /etc/systemd/system/myapp.service):

  [Unit] Description=My Python Application After=network.target [Service] ExecStart=/usr/bin/python3 /path/to/your/app.py Restart=always User=your-username WorkingDirectory=/path/to/your/application [Install] WantedBy=multi-user.target

• Reload systemd:

  sudo systemctl daemon-reload

• Start the service:

  sudo systemctl start myapp

• Enable it to start on boot:

  sudo systemctl enable myapp

5. Use & (Background Execution)

Running a script with & allows it to run in the background, but unlike nohup, it will still be terminated if the terminal session ends.

python app.py &

Conclusion

The most robust solutions for keeping a Python app running after closing the terminal are using nohup, screen, or tmux. If you're looking for a solution that allows you to disconnect and reconnect later, screen or tmux are great choices. If you want to make your application run as a background service (especially for server-side applications), using systemd is the best option.