* Disable the Display Manager: The Display Manager is the graphical login screen that appears when you start up Debian. You can disable it by stopping the service and preventing it from starting at boot time. Use the following command to stop the service:
sudo systemctl stop display-manager.service
And then disable the service from starting at boot time:
sudo systemctl disable display-manager.service
* Remove the GUI packages: You can remove the GUI packages from your Debian installation by using the following command:
sudo apt-get remove task-gnome-desktop
This will remove the GNOME desktop environment and all its associated packages. If you’re using a different desktop environment, replace “gnome” with the name of your desktop environment.
* Reboot your system: Once you’ve disabled the Display Manager and removed the GUI packages, you’ll need to reboot your system for the changes to take effect. Use the following command to reboot your system:
sudo reboot
After the reboot, your Debian installation should boot into a command-line interface without any GUI.
Keep in mind that disabling the GUI permanently may make some tasks more difficult or time-consuming to perform. It’s recommended to proceed with caution and ensure that you have a backup plan in case you need to re-enable the GUI later.
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Or
systemctl set-default multi-user.target sudo systemctl set-default graphical.target
