The best thing about an open source operating system such as Linux is that you can customize it the way you want it, from standard applications like file managers, music players, web browsers, text editors, etc. . D., To a more important system. components such as the kernel, dispatcher displays, and terminal consoles. This can be done by simply downloading the new application software and replacing it with the old one, or by editing the system components, making changes to the source code of your operating system. Display Manager is one such system component that can be replaced simply by running the few commands mentioned in this article.
What is a display manager?
The display manager is a component of your operating system that is responsible for starting the display server and the login session. For this reason, it is sometimes called the login manager. The screen layout that you see when you enter your username and password (welcoming), the login session, and user authorization are some of the tasks that the display manager does. Some common default display types are: Gdm, gdm3, Lightdm, and KDM etc.
LightDM Login Screen
Why and how to switch between displays?
Although all display displays serve the same purpose, controlling the appearance and management of user login sessions, they vary in size, complexity and operation. You will also notice that they are almost, but not quite, alike. You can upgrade to a specific version depending on your OS and system specifications. For example, a lighter weight display manager is ideal for a slightly outdated computer system. Another reason for switching to a new one may be the inaccessibility of catchy themes for the input background. The lighter and less complex display manager may not have this feature. A few days ago I changed my display manager because my default default one broke due to some settings that I made. Therefore, instead of wasting time and energy fixing it, I preferred to switch to an alternative display manager.
When working with displays and switching between them, you will mainly use the following commands:
Check Current Display Manager
To check which display manager works on your system, enter the following command in your Ubuntu terminal:
$ cat /etc/X11/default-display-manager
The image above shows that my gdm3 display manager is currently running on my system.
Install / Uninstall Display Manager
Use the following commands to add / remove a display manager from your system:
$ sudo apt-get install [displaymanagername]
$ sudo apt-get install gdm3
$ sudo apt-get remove [displaymanagername]
sudo apt-get remove gdm3
Switch to another Display Manager
You can switch from one display manager to another by first installing this display manager if it is not already installed, and then using the following command switch to a new one:
$ sudo dpkg-reconfigure gdm3
When you enter your username and password, the following window appears, giving you an idea of how the displays work in the system.
Press enter for OK; The following window will appear. You can configure the new display manager using the up and down arrow keys, and then press Enter to OK.
The display manager of your choice will be configured as the default manager when the system reboots.
Some Common Displays for Ubuntu
Here are some popular Ubuntu display managers you can choose from:
GDM, the Gnome display manager, is the default display for the popular Gnome desktop environment. X11 and Wayland window systems are supported. You can easily configure it to allow login without a password, to hide the list of other users and to configure themes, user sessions and login screens. Basic configurations for GDM can be made through the user interface through system settings. For advanced settings, you need to edit the GDM configuration files as an authorized user. Here is a list of some files that let you customize your login session and display options:
/etc/X11/gdm/gdm.conf /etc/gdm/gdm.conf /etc/dconf/db/gdm.d(for advanced tweaking)
GDM3 is the default display manager that comes with the latest versions of Ubuntu, such as Ubuntu 18. This is a redesigned version of GDM; although its appearance is almost the same as that of GDM, in the background it is very different. It is easier and faster, but it lacks some of the features that you could use in legacy GDM. For example, most of the custom functions are accessible through conf files, and not through the user interface settings utility. You can make changes to the following file to configure the login interface and session management:
LightDM is also an alternative display manager for the older GDM. It has various welcome themes to customize. It supports Canonical server and X.org, so it is a good choice for Ubuntu. Through LightDM, you can set up welcome sessions, disconnect the guest account and show / hide the list of other users at the entrance. Here is a list of files that allow you to set up a login session and display settings in Ubuntu:
/etc/lightdm/(includes various configuration files) /etc/lightdm/lightdm.conf.d/
KDM is the default display manager for KDE. It comes with many customizable features through the user interface module: System Preferences. You can customize the small details of your greeting, such as a greeting message, font, and background wallpaper. An important feature of KDM is that it prevents shutdowns on the login screen, so only registered users can turn off the computer system. Other settings include disabling root, user login, and auto-login.
After reading this article, we hope that you are familiar with the concept of the Linux display manager and the fact that you need to choose one of them. You can load and switch between the various display managers installed on your system using the simple commands described in this article.
Some common Ubuntu displays and how to switch between them