GDM is the GNOME Display Manager which handles graphical login for GNOME based systems. The disable-user-list option controls if a list of users is displayed on the login screen Displaying the user list eliminates half of the Userid/Password equation that an unauthorized person would need to log on.
Solution
Run the following script to enable the disable-user-list option: Note: the l_gdm_profile variable in the script can be changed if a different profile name is desired in accordance with local site policy. #!/usr/bin/env bash { l_gdmprofile="gdm" if [ ! -f "/etc/dconf/profile/$l_gdmprofile" ]; then echo "Creating profile \"$l_gdmprofile\"" echo -e "user-db:user system-db:$l_gdmprofile file-db:/usr/share/$l_gdmprofile/greeter-dconf-defaults" > /etc/dconf/profile/$l_gdmprofile fi if [ ! -d "/etc/dconf/db/$l_gdmprofile.d/" ]; then echo "Creating dconf database directory \"/etc/dconf/db/$l_gdmprofile.d/\"" mkdir /etc/dconf/db/$l_gdmprofile.d/ fi if ! grep -Piq '^h*disable-user-listh*=h*trueb' /etc/dconf/db/$l_gdmprofile.d/*; then echo "creating gdm keyfile for machine-wide settings" if ! grep -Piq -- '^h*[org/gnome/login-screen]' /etc/dconf/db/$l_gdmprofile.d/*; then echo -e " [org/gnome/login-screen] # Do not show the user list disable-user-list=true" >> /etc/dconf/db/$l_gdmprofile.d/00-login-screen else sed -ri '/^s*[org/gnome/login-screen]/ a# Do not show the user list disable-user-list=true' $(grep -Pil -- '^h*[org/gnome/login-screen]' /etc/dconf/db/$l_gdmprofile.d/*) fi fi dconf update } Note: When the user profile is created or changed, the user will need to log out and log in again before the changes will be applied. OR Run the following command to remove the GNOME package: # dnf remove gdm