GDM is the GNOME Display Manager, a graphical login program for Redhat, RHEL, Fedora and CentOS Linux based systems. The X Window System by default uses the XDM display manager which needs editing files. GDM allows to customize login using GUI based tools. It also supports customization with themes.
Fig.01: CentOS GNOME Display Manager
Method # 1: Delete GDM and X Window
Type the following command:
# <a href="http://www.cyberciti.biz/faq/rhel-centos-fedora-linux-yum-command-howto/">yum groupremove "X Window System"</a>
Reboot the systems:
# reboot
Method # 2: Disable GDM and X Windows Login For All Sessions
Edit /etc/inittab, enter:
# vi /etc/inittab
Find:
id:5:initdefault:
Replace with:
id:3:initdefault:
Save and close the file. Stop currently running GUI session:
# init 3
Method # 3: Temporarily Disable GDM and X Windows Login ForCurrent Sessions
Just type the following command:
# init 3
To get back to GUI login session again, enter:
# init 5