The MDM Display Manager
MDM is a replacement for XDM, the X Display Manager. Unlike its competitors (X3DM, KDM, WDM) MDM was written from scratch and does not contain any original XDM / X Consortium code. MDM runs and manages the X servers for both local and remote logins (using XDMCP). See https://github.com/linuxmint/mdm/ for more details.
mdm is main executable. mdmsetup is a graphical tool for easily changing the most commonly used options.
For full documentation see the GNOME help browser under the Applications / System Tools section.
mdm and thus also mdm accept the following options:
Do not fork into the background
No console (local) servers to be run
Preserve LD_* variables
Print the MDM version
Print simple description of accepted options
mdmsetup accepts all standard GNOME options.
Configuration is done either by running mdmsetup or by editting the /etc/X11/mdm/mdm.conf (usually, could also be /etc/mdm/mdm.conf) file. The graphical tool does not support all the options possible so editting the configuration file is sometimes necessary.
X(7x), xdm(1), Xsecurity(7x), Xserver(1),
MDM is being written and maintained by George (Jiri) Lebl <firstname.lastname@example.org> based on the original codebase by Martin K. Peterson <email@example.com>.