🗓️ 01062026 1727

DISPLAY MANAGER

A display manager (DM) is the login screen that runs after boot. It authenticates the user and launches the chosen desktop session (window manager or desktop environment).

Without a DM, you'd boot to a TTY and start your session manually with startx.

How It Works

1. Boot → systemd starts the DM as a service
2. DM presents a greeter (login UI)
3. User authenticates via PAM
4. DM reads available sessions from /usr/share/xsessions/ (X11) or /usr/share/wayland-sessions/ (Wayland)
5. DM launches the selected session and hands off

Common Display Managers

DM	Typical use case
lightdm	Lightweight, works with any DE/WM
GDM	GNOME's default
SDDM	KDE's default
ly	Minimal TUI login screen

Enable / Disable

sudo systemctl enable lightdm      # start on boot
sudo systemctl disable lightdm     # revert to TTY login
sudo systemctl start lightdm       # start now

References

• Arch Wiki: Display manager