gdm-binary

View documentation for the original command

$ tldr gdm

gdm-binary [OPTION…]

--help
    Display help message and exit

--version
    Print version information and exit

--test
    Run in test mode without daemonizing

--verbose[=LEVEL]
    Enable verbose logging at specified level

--log-verbose
    Enable verbose logging

--replace
    Replace any running display manager

--no-daemon
    Do not daemonize the process

--display=DISPLAY
    Specify display to manage (internal use)

The gdm-binary is the primary executable component of the GNOME Display Manager (GDM), a program that provides graphical login capabilities for GNOME-based Linux systems.

It handles the display of login screens, user authentication, session management, and starting user graphical sessions. Typically, gdm-binary is not invoked directly by users; instead, it is launched automatically by the system's init system (e.g., systemd via gdm.service). The /usr/sbin/gdm wrapper script sets up the environment and executes gdm-binary with appropriate arguments.

GDM supports both X11 and Wayland protocols, automatic VT switching, and integration with AccountService for user management. It reads configuration from files like /etc/gdm/custom.conf and /etc/gdm/daemon.conf (legacy). Features include themed greeters, remote logins via XDMCP, and automatic login options.

Direct usage is rare and mainly for debugging or testing, such as running on a specific display with --test or replacing a running manager with --replace. Verbose logging aids troubleshooting login issues.

Not intended for direct user invocation; manage via systemctl (e.g., systemctl start gdm). Running manually may conflict with system services or require root privileges. Limited Wayland support in older versions.

Main config: /etc/gdm/custom.conf. Sections for daemon, greeter, and security.

View logs with journalctl -u gdm or in /var/log/gdm/*.

Developed as part of GNOME since 1998 (GDM 1.x). Major rewrites in GDM 2.x (2000s) for modularity, GDM 3.x (2011+) introduced Wayland support, Mutter integration, and systemd compatibility. Current versions (43+) focus on security, theming, and gesture-based greeters.

gdm(8), lightdm(1), sddm(1), systemd-logind(8)