The Linux login manager or display manager is used to handle the login procedures for the Linux desktop. If you have a login manager and a desktop environment installed on your system the login manager will load in place of the default shell after booting your system.
Display Manager Functions
The Linux desktop login manager will allow you authorise your user account for security purposes, after that your desktop session will load.
Loading The Display Manager
There are two different methods of loading the Linux display manager, you can use inittab or the daemon method. When using the inittab method the display manager will load automatically after startup and will re-spawn in the event of a crash. If you are using the daemon method the display manager will load automatically during startup as a daemon.
Login Manager Themes
Most display managers will use themes. the user also has the ability to customize the theme. This means the look of the login screen can be customized to your liking. This includes the login screen background, fonts, colors and much more.
This is the Gnome display manager, GDM will provide a graphical login manager commonly found on the Gnome desktop. With GDM you can manage attached and remote displays. GDM allows you to authenticate system users or end-user sessions. When GDM starts it will start an X server and then run the init script as the root user, the greeter program will then be displayed.
Here you can find some of the useful commands for the Gnome display manager, and you will also find many other useful features.
This is the display manager for KDE which is used to control user sessions on KDE systems. KDM supports auto-logging, and themes which can be downloaded or created without much trouble. KDM was created to replace the original X display manager on KDE systems.
The KDM display manager also offers easy configuration via a convenient graphical user interface. Many very helpful settings have been provided.
LightDM is a display manager or login manager that was designed to work with many Linux desktop environments. LightDM aims to be the primary display manager used with the X.org server. Many users prefer LightDM because of the simple code base. But this excellent login manager also offers a very cool list of features and a very modern design.
For all of the LXDE lovers out there here is the default display manager which is known as LXDM. This tool provides a fast login interface that still offers several quality customization options.
Another login manager that is light, fast, and still feature filled. The SLiM display manager is easy to setup and easy to use.
This display manager offers a very attractive default theme, though it does remain extremely simple.
Here is another display manager for X11, unfortunately less information is available about this tool.
The WDM display manager is also known as the WINGs display manager because it uses the WINGs widget toolkit.
XDM is the default tool used to handle local or remote X server logins on any Linux desktop. When XDM starts an X server will start also, it then displays the login screen. After authenticating your username and password you will arrive at your desktop.
You can run a Linux display manager on your local computer, or on a remote system. You can use XDMCP for logging into a system remotely. When using XDMCP the X server will run on your local system, while applications and the display manager will run on the remote system.