LXDM

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LXDM is a lightweight display manager for the LXDE desktop environment. The UI is implemented with GTK+ 2.

LXDM does not support the XDMCP protocol. An alternative that does is LightDM.

Installation

Install the lxdm package. The development package is lxdm-gitAUR.

lxdm provides the lxdm systemd service. Enable it to start LXDM at boot.

Configuration

The configuration files for LXDM are all located in /etc/lxdm/. The main configuration file is lxdm.conf, and is well documented in its comments. Another file, Xsession, is the systemwide x session configuration file and should generally not be edited. The other files in this folder are all shell scripts, which are run when certain events happen in LXDM.

These are:

  1. LoginReady is executed with root privileges when LXDM is ready to show the login window.
  2. PreLogin is run as root before logging a user in.
  3. PostLogin is run as the logged-in user right after he has logged in.
  4. PostLogout is run as the logged-in user right after he has logged out.
  5. PreReboot is run as root before rebooting with LXDM.
  6. PreShutdown is run as root before poweroff with LXDM.

Default session

It can be specified which session will be loaded when the users select the 'Default' session from the session list. Note that the user setting takes preference over global setting.

Globally

Edit /etc/lxdm/lxdm.conf and change the session line to whatever session or DE is desired:

session=/usr/bin/startlxde

Example using Xfce:

session=/usr/bin/startxfce4

Example using Openbox:

session=/usr/bin/openbox-session

Example using GNOME:

session=/usr/bin/gnome-session

This is useful for themes that have no visible session selection box, and if experiencing trouble using autologin.

Per user

To define an individual user's preferred session, simply edit his/her respective ~/.dmrc to define the selection.

Example: user1 wants Xfce4, user2 wants Cinnamon, and user3 wants GNOME:

For user1:

[Desktop]
Session=xfce

For user2:

[Desktop]
Session=cinnamon

For user3:

[Desktop]
Session=gnome

Autologin

To log in to one account automatically on startup, without providing a password, find the line in /etc/lxdm/lxdm.conf that looks like this:

#autologin=dgod

Uncomment it, substituting the target user instead of dgod.

Last used options

It stores information about last used options in the:

/var/lib/lxdm/lxdm.conf
[base]
last_session=/usr/share/xsessions/LXDE.desktop
last_lang=sv_SE.UTF-8
last_langs=sv_SE.UTF-8 fa_IR.UTF-8 en_US.UTF-8
Note: This file is not removed after uninstallation. And must be removed manually if you want to remove all traces of LXDM used options.

Tips and tricks

Adding face icons

A 96x96 px image (jpg or png) can optionally be displayed on a per-user basis replacing the stock icon. Simply copy or symlink the target image to $HOME/.face. The gnome-control-center package supplies some default icons suitable for the lxdm screen. Look under /usr/share/pixmaps/faces after installing that package.

Note: Users need not keep gnome-control-center installed to use this images. Simply install it, copy them elsewhere, and remove it.
Note: The user's directory needs have r-x permissions for others and the .face file needs have r-- permissions for others. Obviously though this has security and access implications as now anyone can browse your home directory.
Note: A graphical tool lxdm-config shipped with lxdm can be used to place a .face file in the home directory, along with other configuration.

Simultaneous users and switching users

LXDM allows multiple users to be logged into different ttys at the same time. The following command is used to allow another user to login without logging out the current user:

$ lxdm -c USER_SWITCH
Note: When the new user logs in, his/her session is now on the NEXT tty from tty7. For example, user1 logs in and issues the USER_SWITCH command. Now user2 logs in. User2 will be on tty7 while user1 will be on tty1.

If you use the Xfce desktop, the Switch User functionality of its Action Button panel item specifically looks for the gdmflexiserver executable in order to enable itself. If you provide it with an executable shell script /usr/bin/gdmflexiserver consisting of

#!/bin/sh
/usr/bin/lxdm -c USER_SWITCH

then user switching in Xfce should work fine also with LXDM.

XScreenSaver can also perform this task. For more, see the this section of the Xscreensaver article.

Themes

The LXDM themes are located in /usr/share/lxdm/themes.

There is only one theme provided with LXDM, namely Industrial. To display the background file wave.svg which is part of this theme, make sure you have librsvg installed.

lxdm-themesAUR provides 6 extra themes. Archlinux, ArchlinuxFull, ArchlinuxTop, Arch-Dark, Arch-Stripes and IndustrialArch. The ArchStripes and ArchDark themes are also provided with lxdm-gitAUR (with different names to avoid file conflicts).

You can configure them on /etc/lxdm/lxdm.conf:

## the theme of greeter
theme=theme_name

You can also configure LXDM to use a GTK theme (stored in /usr/share/themes) on the mentioned configuration file:

## GTK theme
gtk_theme=gtk_theme_name

Advanced Session Configuration

After a user logs on, LXDM sources all of the following files, in order:

  1. /etc/profile
  2. ~/.profile
  3. /etc/xprofile
  4. ~/.xprofile

These files can be used to set session environment variables and to start services which must set certain environment variables in order for clients in the session to be able to use the service, like ssh-agent. See Xprofile for details.

Note that LXDM does not source ~/.xinitrc, so those migrating from a DM that does use this file, like SLiM, will have to move their settings elsewhere — probably ~/.xprofile. Also note LXDM does not source ~/.bash_profile.

LXDM also makes use of .Xresources, .Xkbmap, and .Xmodmap. See /etc/lxdm/Xsession for details on how LXDM uses system-wide and per-user configuration files to configure the session.[1]