Linux Technology Explained

What Is a Linux Display Manager? How to Choose and Set One

Christian Cawley Updated 30-06-2020

You’re probably happy with your Linux operating system, but from time to time its good to refresh things. One way to do this is to replace some of the default applications and components. Think the default file manager, the text editor, or even the desktop environment or kernel.

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One switchable component that is often overlooked is the display manager. But what is this component? How do you switch to a new display manager in Linux? Let’s find out.

What Is a Display Manager?

Also known as a “login manager”, a display manager is responsible for starting the display server and loading the desktop. This happens right after your correctly enter your username and password

Change the Linux display manager for a swish new login box

Simply put, it controls user sessions and manages user authentication. Most of the display manager’s magic occurs “under the hood.” The only visible element is the login window, sometimes referred to as the “greeter”.

What a Display Manager Is Not

You probably already know your Linux computer has a window manager and a display server.

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The display manager is a distinct piece of software. While all three interact, they have different functionality, and perform different jobs.

Examples of a window manager include:

  • KWin
  • Openbox
  • Dwm

Some well-known display servers for Linux are:

  • Wayland
  • Mir
  • Org

(Many Linux distributions feature Wayland as the default display server and a few others are also moving in that direction, so it’s a good idea to know more about using Linux with Wayland Using Linux With Wayland? What You Need to Know You might have heard about the Wayland display server. Here's what that is and how it affects your Linux computer. Read More .)

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Linux display manager configuration

Some display managers, meanwhile, are:

  • GDM (Gnome Display Manager)
  • LightDM
  • LXDM

We’ll look at some more display managers below.

Why Replace a Display Manager?

Why would anyone want to replace a display manager, you ask? Well, here are a few probable scenarios:

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There are several popular display managers for Linux. You’ll notice they’re quite similar in appearance; the main differences are size, complexity, and how they manage users and sessions.

Six Linux Display Managers You Can Switch To

With a new display manager installed, you can have some fun with themes. MDM is the best choice if customization is your priority, since it supports both old GDM and new HTML themes. DeviantART features many collection of themes for various display managers, for example. If you’re using SDDM, you can find theme packages for it in the repositories.

But first, which display manager are you going to switch to?

1. KDM

The display manager for KDE up to KDE Plasma 5, KDM features plenty of customization options. You can easily configure it via the control module in System Settings. There you can choose which KDM theme to use, or switch to the simple greeter that lets you customize the background, welcome message, and font.

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Other features include:

  • Fast user switching
  • Display user list
  • Enable root shutdown
  • Allow passwordless login
  • Autologin
  • Fingerprint scanning

KDM supports X and Wayland and can also detect installed desktop environments and window managers. They are then offered in list form for you to choose which one to start when you enter your credentials.

While some features might overwhelm a beginner, KDM is easy to set up thanks to the straightforward graphical dialog.

2. GDM (GNOME Display Manager)

What KDM is to KDE, GDM3 is to GNOME—the default display manager of a popular Linux desktop environment. Like KDM, it supports X and Wayland and offers:

  • Automatic login
  • Hiding the user list
  • Passwordless login
  • Custom sessions
  • Built-in themes
  • Multiple user login
  • Fast session switching
  • Fingerprint scanning
  • Smart card authentication

Configuring GDM3 can be done either via the dedicated dialog in System Settings or by editing configuration files.

Note that GDM3 is distinct from the legacy GDM. While they may appear similar, GDM3 is not backward compatible with legacy GDM themes, with options hidden in configuration files.

3. SDDM (Simple Desktop Display Manager)

SDDM is a comparatively new display manager scene. Initially released in 2013, it has survived while older rivals such as SLiM and Mint Display Manager have folded.

With support for X and Wayland, SDDM relies on QML theming, and replaced KDM as the default display manager in KDE Plasma 5.

SDDM features:

  • Automatic login
  • Num Lock on
  • Modify greeter users
  • Support for themes

As with other no-frills display managers, you can configure SDDM by editing a config file (sddm.conf). If you’re using SDDM on KDE, it has a configuration module in System Settings. Alternatively, use the handy sddm-config-editor utility.

4. LXDM

LXDM is part of the LXDE environment but runs comfortably on other desktop environments since it doesn’t have many dependencies. You can set it up through its own configuration utility, or edit configuration files in /etc/lxdm (or if you’re on Lubuntu, /etc/xdg/lubuntu/lxdm).

Using LXDM you can expect:

  • Configurable user list
  • Autologin
  • Icons for each user
  • User switching
  • Timed autologin
  • Custom background images

Both the official documentation and unofficial witness accounts on various forums note that LXDM doesn’t terminate user processes on logout. To ensure this happens, modify the /etc/lxdm/PostLogout file.

LXDM might be quirky, but it’s fast, so if that’s an acceptable trade-off for you, try it out.

5. LightDM

Perhaps the most popular and certainly the most versatile display manager is LightDM. Having supplanted older display managers in popular distros, it is customizable and feature-packed. LightDM is also lightweight, and supports X.Org and Mir.

With LightDM you can expect:

  • Greeters for GTK, Qt/KDE, Unity and others
  • Login screen themes
  • User list
  • Custom background image
  • Adjustable window position

Configuration files should be edited to make these tweaks—the easiest way is the LightDM GTK Greeter Settings tool.

6. XDM

This is the default display manager for the X Window System and was first released in 1988. It is a minimalist display manager suitable for low spec systems or those with modest requirements.

Despite this, XDM still offers some features:

  • Themes
  • Set background wallpaper
  • Tweak fonts
  • Adjust login box position
  • Handles multiple X sessions
  • Passwordless login

Most tweaks are applied by editing etc/X11/xdm/Xresources.

How to Replace a Display Manager on Linux?

Seen something you like? Perhaps you want to switch Ubuntu’s display manager to LightDM.

Whatever your preference and distro there are just two steps to replacing your current display manager on Linux:

  1. Install a new display manager
  2. Set it up as the default

The first part of the process is easy, as you only have to find the appropriate package The Linux User's Toolkit for Discovering New Apps Installing Linux is like checking into an all-inclusive resort. Hardware works perfectly, and you get an impressive selection of pre-installed software. But what if you want to try out some new Linux software? Read More for your distribution and install it. You can remove the old display manager if you want to, but in most cases it won’t be necessary.

Setting up the new display manager as the default is different for each distribution. It boils down to editing a few configuration files or running a simple one-line command in the terminal.

Use this short guide to set up your chosen display manager, which you should have already installed.

Debian, Ubuntu, Linux Mint, and Most Ubuntu Derivatives

Installing a new display manager should prompt the dpkg-reconfigure tool to launch. If not, run it manually:

  • Run sudo dpkg-reconfigure gdm3
  • Select the default display manager in the dialog that pops up

Switch your Linux display manager

You can replace “gdm3” with any of the display managers that are currently installed on your system. If this fails, edit the /etc/X11/default-display/manager file with root privileges.

For Arch Linux and Manjaro

Enable the systemd service for your new display manager:

systemctl enable displaymanager.service -f

If this doesn’t work, Manjaro users can try disabling the previous display manager first:

sudo systemctl stop gdm
sudo systemctl disable gdm
sudo systemctl enable lightdm.service
sudo systemctl start lightdm

while on Arch Linux you might have to remove the /etc/systemd/system/default.target file, and create a display-manager.service file in the /etc/systemd/system directory. This new file should be a symlink to your new display manager’s service file in /usr/lib/systemd/system/.

Change the Display Manager on Fedora

Start by disabling the old display manager, enable the newly installed replacement, then reboot:

  • Run systemctl disable [old display manager]
  • Follow this with systemctl enable [new display manager]
  • Then reboot

When Fedora reboots it will be with a fresh display manager.

For PCLinuxOS

You should be able to select your new display manager from the desktop.

  • Open Control Center > Boot
  • Find Set up display manager
  • Select the display manager you installed earlier

If the system doesn’t acknowledge the changes, edit /etc/sysconfig/desktop and set the new display manager.

For openSUSE

To change the display manager in openSUSE, first download your replacement and confirm the installation location.

Next enter

sudo update-alternatives --set default-displaymanager \ [FILEPATH]

Prefer changing the display manager with a desktop tool?

  • Install yast2-alternatives
  • Open the Control Center
  • Browse to Display Manager
  • Set the new display manager

Your new display manager should activate on next reboot.

Change Your Linux Display Manager Today

As you’ve seen, replacing a display manager is not as hard as it sounds. Once you start reading more about their features, you might be tempted to test a few different display managers in search of the best one – and I encourage you to do so.

You don’t have to wait for software to “break” to try something new or to experiment with a new Linux desktop environment The 12 Best Linux Desktop Environments Choosing a Linux desktop environment can be difficult. Here are the best Linux desktop environments to consider. Read More .

Related topics: Display Manager, Linux Tips.

Affiliate Disclosure: By buying the products we recommend, you help keep the site alive. Read more.

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  1. Gerard
    August 14, 2016 at 8:54 am

    Great , thanks I installed lxde but did not know to start it, so now i know and it works , thanks

    • Gerard
      August 14, 2016 at 8:57 am

      Oh and I replaced GDM with lightdm, no reason I just followed some instruction on th einternet to get lxde installed

  2. yehan jaya
    July 31, 2016 at 8:02 pm

    Mdm stands for mdm display manager (not mint display manager and not mate display manager)
    source https://community.linuxmint.com/software/view/mdm

  3. Joshua
    July 4, 2016 at 7:26 am

    Thanks for this helpful blog post. Decided on Gnome and GDM on Ubuntu 14 installed with parallels.

    lightdm was giving me headaches on the vm.

  4. Ted
    May 3, 2016 at 7:56 pm

    I installed LightDM with Linux Mint 17.2 on a triple boot system for a public library, however after many months Linux remain unusable with LightDM's guest account as I intended. The primary problem is no ability to automount USB drives. Lots of people have posted about that and there doesn't appear to be a solution. Also, I found I could not disable logout without also disabling shutdown & restart.

    I really like LightDM's guest mode, and the way each guest session starts cleaned and fresh for each user. Too bad the USB automount is a showstopper.

    Nice review here, but it lacks the info I need concerning support for a guest mode.

  5. Wajid Ali Khan
    April 9, 2016 at 4:16 pm

    Very Nice and informative article. Keep posting.

    • Che
      June 30, 2016 at 6:21 pm

      Such clearly-written articles are a gem, indeed.

      Thanx!

  6. Eduardo
    March 26, 2016 at 2:50 pm

    Nice article! Thank you!

    • Ivana Isadora Devcic
      March 30, 2016 at 6:37 am

      Thank you so much for reading! :)

  7. Anonymous
    March 11, 2016 at 6:47 pm

    Correction: MDM does not stand for “Mint Display Manager”; it (rather playfully & recursively) stands instead for “MDM Display Manager”! ?

    ( see https://community.linuxmint.com/software/view/mdm )

    • Ivana Isadora Devcic
      March 30, 2016 at 6:37 am

      Well, I never...! Thanks for the correction, Bryan :)

  8. Anonymous
    September 26, 2015 at 4:50 pm

    Very informative. Excellent piece. Thank you!

  9. Anonymous
    September 23, 2015 at 2:21 pm

    Can you make a similar comparison for window manager? Nowadays there are about dozen and I couldn't find a "fresh" article on your site. There are a couple new one, there are a couple non-default one and there are a couple distro-specific one (what you can install on any other distro).

    I'm going to switch distro and this part could be a good dicision dealer option. I heard about Hybryde Fusion but it isn't support anymore and it hasn't all of window manager.

    • Ivana Isadora Devcic
      September 24, 2015 at 8:00 am

      That's a great suggestion, thanks so much Károly! We did cover a few window managers for Linux here on MUO, but a comprehensive comparison/overview sounds like something we should definitely do. I'll forward the idea to our editors, so stay tuned & watch this space. :)

      • Anonymous
        September 27, 2015 at 5:28 pm

        I've just read this article about "tiling window managers" ). I know this isn't for everyone but it sounds very good. I hope you will consider about these ones :D

  10. Anonymous
    September 21, 2015 at 9:45 pm

    .