Display Managers

 Linux has everything from Terminal Cli (black and dark) users to old guy like me using Enlightenment Desktop

 

Display Managers

What is GDM in Linux?
GDM is the GNOME Display Manager , which provides a graphical login environment. 

For me Gnome Display Manager is the best, for the simple reason it stays like the trunk of a Giant  Tree and lets other Desktop Environments branches, themselves.

One can use only one Desktop Environment at a time but Gnome Does is to Select one out of the many. There is little wheel like icon on the right and one clicks it and select the desired environment.

 

What really made me to enter Linux is not Gnome but Animated Enlightenment (Now of Elive) of yesteryear.

 

I started with KDE of Mandrake with a nicely integrated booting environment which Suse made famous. Over the years I started hating KDE and moved to muck simple bur sleek Gnome.

 

But bulk of my work was done on Emmabantus XFCE Desktop which made Cairo Environment.

  

Cairo Dock

Cairo as a desktop environment

Cairo is a customizable desktop environment for Linux.  It allows one to browse the desktop without opening a file explorer.

Cairo's pop-up navigation makes it easy to move around the desktop.
Cairo's dock software allows one to customize the desktop with docks that have their own behavior, animations, themes, icons, and applets. It simply looks like MacOS.  

Of course Cairo has progressed into  is an open-source graphics library for Linux. Cairo provides a vector graphics API for software developers. It offers primitives for two-dimensional drawing across various back-ends. Cairo uses hardware acceleration when it is available.

What is SDDM in Linux?
Simple Desktop Display Manager
Simple Desktop Display Manager (SDDM) is a display manager (a graphical login program) for the X11 and Wayland windowing systems. SDDM was written from scratch in C++11 and supports theming via QML. 

 
Which display manager is best for Linux?
Regarding which display manager to use, most of them serve the same basic function. 

If you're looking for stability and user-friendliness, GDM is a good choice.
 

GDM (GNOME Display Manager), SDDM (Simple Desktop Display Manager), and LightDM are all display managers for Linux. 

They are graphical login programs that manage sessions and provide a login screen.
 

How they work?

GDM 

The default display manager for the GNOME desktop environment. 

It supports X and Wayland windowing systems.

SDDM
The recommended display manager for the KDE Plasma and LXQt desktop environments. 

It supports X11 and Wayland windowing systems.

SDDM does not support GDM.

 

When installing Linux if one selects this (I select GDM by default) one gets only one desktop and one id deprived of Enlightenment, MATE, Budgie, Cinnamon and Wayfire is a Wayland compositor based minimal desktop.
 

LightDM
A cross-desktop display manager developed by Ubuntu for the Unity desktop. 

It can use various front-ends.

Other display managers XDM (X Display Manager), LXDM (LXDE display manager), and SLiM (Lightweight and elegant graphical login solution).
 

Display manager features   

 

Automatic login 

Hiding the user list 

Passwordless login 

Custom sessions 

Built-in themes 

Multiple user login 

Fast session switching 

Fingerprint scanning 

Smart card authentication

Display managers are separate programs, though they are often developed by the same team as the desktop environment.
 

Graphical. Entrance

Enlightenment display manager. 

Highly experimental, and does not have proper systemd support.

Linux Display Managers 

 

LightDM, 

 

SLiM, 

 

XDM, 

 

GDM, 

 

SDDM, 

 

KDM, 

 

Ly

Ly is a free, open-source, and lightweight display manager for Linux and BSD. It's a Terminal-Based user Interface (TUI) that's similar to ncurses. Ly is a good choice for people who are used to using the terminal window