Starting X installation Graphical login

The default X installation provides a graphical login after you have installed X and rebooted. This graphical login screen is actually an X program known as gdm, or the GNOME Display Manager. In addition to prompting for username and password, gdm implements authentication using the X standard, host-based access control, and other security-conscious facilities.

Question: Is the GNOME Display Manager still used in RHEL 8?
Yes, the GNOME Display Manager (GDM) is still used in RHEL 8. It is the default display manager for RHEL 8, and it is responsible for managing graphical user logins. GDM provides a graphical login prompt, and it allows users to choose between different graphical desktop environments, such as GNOME Shell and KDE Plasma. GDM also provides a number of security features, such as password authentication and session management.
Here are some of the benefits of using GDM:

1. It is a stable and reliable display manager.
2. It is easy to use and configure.
3. It provides a number of security features.
4. It is compatible with a wide range of graphical desktop environments.

However, there are also some drawbacks to using GDM:

1. It can be resource-intensive.
2. It can be slow to start up.
3. It can be difficult to troubleshoot problems.

Overall, GDM is a good choice for a display manager for RHEL 8. It is stable, reliable, and easy to use. However, it is important to be aware of its limitations before using it.

If you change your default run-level, gdm might not start automatically. Run-levels describe Linux boot states and include graphical, multi-user, and standalone modes of operation. The run-level a Linux system boots to is specified in /etc/inittab, and is rarely modified once set.

If you are not in the graphical run-level and you want to start the X server, then you may use the startx script. This script is simply a front-end for xinit, which actually starts the X server and any user-configured clients.
The xinit program checks to make certain no X server is already running, sets up lock files and other server-related details, then executes the X server proper.

Do not call xinit directly. The startx script performs setup activities that, if not performed, would make using your X session practically useless for productive purposes. X will not be initiated with the proper options. startx takes care of all of this.
Sometimes you might want to pass options directly to the X server to change its behavior from the default. The startx script sends all its command line arguments after a -- to the X server.
For example,

startx -- -bpp 8

will instruct the X server to use 8-bit color instead of its configured default.
The next lesson discusses configuring the X server startup with .xinitrc.