Red Hat Enterprise Linux 8 is shipped with the default desktop environment GNOME 3.

GNOME 3 represents a presentation layer that provides a graphical user interface as well as the focused working environment, which enables you to access all your work from one place.

GNOME 3 provides two essential environments:

Both environments can use two different protocols to build a graphical user interface:

The default combination in Red Hat Enterprise Linux 8 is GNOME Standard environment using GNOME Shell on Wayland as the display server.

However, due to Section 2.2, “Current Wayland limitations”, you may want to switch the graphics protocol stack.

You may also want to swich from GNOME Standard to GNOME Classic.

For more information about graphics based on the Wayland protocol, see Section 2.1, “Key differences between the Wayland and X11 protocol”.

For information on how to switch the environments, see Selecting GNOME environment.

The GNOME environment provides the hot corner functionality, which is enabled by default. This means that when you move the cursor to the area of the top left corner and press the cursor in this area, the Activities Overview menu opens automatically.

However, you may want to disable this feature to not open Activities Overview unintentionally.

To do so, you can use the following tools:

The selection of the tool might depend on whether you want to disable the hot corner functionality for a single user or for all users on the system. By using dconf Editor or gsettings, you can disable hot corner only for a single user. To disable hor corner system-wide, use the No topleft hot corner extension.

The default desktop environment for Red Hat Enterprise Linux 8 is GNOME Standard with GNOME Shell on Wayland as the display server.

However, due to Section 2.2, “Current Wayland limitations”, you may want to switch the graphics protocol stack.

You may also want to swich from GNOME Standard to GNOME Classic. See Section 1.2, “GNOME environments” for differences between these two environments.

For switching between various combinations of GNOME environment and graphics protocol stacks, use the following procedure.

This section describes various approaches that you can use to launch available applications in GNOME 3.

This approach works both in GNOME Standard and GNOME Classic environment.

This approach works both in GNOME Standard and GNOME Classic environment.

This section describes various approaches that you can use to install a new application in GNOME 3.

GNOME will automatically find the application in a respective repository, and will display the application’s icon.

In RHEL 8, the Desktop icons functionality is no longer provided by the Nautilus file manager, but by the desktop icons gnome-shell extension available in the gnome-shell-extension-desktop-icons package.

Desktop icons in GNOME Classic

The GNOME Classic environment includes the gnome-shell-extension-desktop-icons package by default. Desktop icons are always on, and cannot be turned off. If you want to create a desktop icon for a file, you just need to put this file into the /Desktop directory, and the icon appears automatically.

Desktop icons in GNOME Standard

If you have only the GNOME Standard environment available, and not GNOME Classic, you must install gnome-shell-extension-desktop-icons.

After the package has been installed, you can switch the desktop icons on or off by using the Tweaks application:

In Red Hat Enterprise Linux 8, sound is handled by the PulseAudio sound server that lets programs output the audio using the Pulseaudio daemon.

For more information on PulseAudio, see the pulseaudio man page.

To handle sound, you can use one of these two graphical applications in GNOME:

System menu is located in the top right corner, and it only enables you to set the intensity of the sound output or sound input through the sound bar. The sound bar for input sound is available only if you are running an application that is supposed to use an iternal microphone (built-in audio), such as some teleconference tools.

Tweaks tool only enables you to configure the Over-Amplification.

GNOME Control Center provides more options to configure sound. You can launch this tool by using one of the approaches described in Launching applications. Moreover, you can also launch it from the System menu by clicking on its icon.

When GNOME Control Center opens, choose Sound from the left vertical bar.

Through GNOME Control Center - Sound, you can configure the following:

The Output and Input menus show only the built-in audio devices unless you connect any external device that can handle sound.

The Output menu enables you to select the required profile from available analog or digital profiles that are displayed depending on available output devices.

The Applications menu shows all currently running applications that can process sound, and allows you to amplify or lower the sound of a particular application.

GNOME Shell provides multiple tools to handle graphics and photography.

You can check the available tools under the Graphics & Photography menu in GNOME Software:

The available tools include:

In GNOME Shell, printing can be set up using the GNOME Control center GUI.

1.10.1. Starting GNOME control center for setting up printing

Procedure

1. Use one of the approaches described in Section 1.5, “Launching applications” to start the GNOME Control center GUI.

   Moreover, you can also start the GNOME Control center from the system menu in the top right corner by clicking on the "Settings" icon.

   
2. When the GNOME Control center GUI appears, go to:

Devices → Printers

Figure 1.1. GNOME Control center configuration tool

1.10.2. Adding a new printer in GNOME Control center

This section describes how to add a new printer using the GNOME Control center GUI.

Prerequisites

To be able to add a new printer using the GNOME Control center GUI, you must click on Unlock, which appears on the right side of the top bar, and authenticate as one of the following users:

• Superuser
• Any user with the administrative access provided by sudo (users listed within /etc/sudoers)
• Any user belonging to the printadmin group in /etc/group

Procedure

1. Open the Add Printer dialog.

   

2. Select one of the available printers (including also network printers), or enter printer IP address or the hostname of a printer server.

   
   

1.10.3. Configuring a printer in GNOME Control center

This section describes how to configure a new printer, and how to maintain a configuration of a printer using the GNOME Control center GUI.

Displaying printer’s settings menu

Procedure

• Click the "settings" button on the right to display a settings menu for the selected printer:

Displaying and modifying printer’s details

Procedure

• Click Printer Details to display and modify selected printer’s settings:

With this menu you can:

• Search for Drivers

  GNOME Control Center communicates with PackageKit that searches for a suitable driver suitable in available repositories.

• Select from Database

  This option enables you to select a suitable driver from databases that have already been installed on the system.

• Install PPD File

  This option enables you to select from a list of available postscript printer description (PPD) files that can be used as a driver for your printer.

Setting the default printer

Procedure

• Click Use Printer by Default to set the selected printer as the default printer:

Removing a printer

Procedure

• Click Remove Printer to remove the selected printer:

Red Hat Enterprise Linux 8 includes the PipeWire media server, which ensures access to multimedia devices and media sharing between applications.

When running a remote desktop session on GNOME Shell on Wayland, PipeWire and the VNC server is used. The functionality of remote desktop session is provided by the gnome-remote-desktop and pipewire packages.

On X.Org, just VNC is needed to run a remote desktop session. This functionality on X.Org is provided by the vino package.

PipeWire is used also with teleconference tools such as BlueJeans when running on GNOME Shell on Wayland. In such case, the pipewire service is activated automatically when you start sharing your screen within the teleconference tool.

To check the status of the pipewire service, run:

~]$ systemctl --user status pipewire

You can customize the GNOME Shell environment for a particular user by using the Tweaks tool.

To open Tweaks, use one of the approaches described in Section 1.5, “Launching applications”.

To choose the required item that you want to customize, use the vertical menu on the left. For example you can choose the applications to start automatically when you log in by using the Statup Applications menu, or you can customize your top bar appearance by using the Top Bar menu.

To be able to configure the GNOME Desktop Environment, you need to understand these basic terms:

dconf has two different meanings.

Firstly, dconf is a key-based Binary Large Object (BLOB) database for storing GNOME configurations. dconf manages user settings such as GDM, application, and proxy settings, and serves as the back end for GSettings.

Secondly, dconf is a command-line utility which is used for reading and writing individual values or entire directories from and to a dconf database.

GSettings is a high-level API for application settings which serves as the front end for dconf.

gsettings is a command-line tool which is used to view and change user settings.

dconf allows system administrators and users several levels of control over GNOME configuration:

Machine-wide default settings can be set by providing a default for a key in a dconf profile. These defaults can be overridden by the user.

Setting a default for a key has two prerequisites:

For example, to set the default background:

When the user profile is created or changed, the user needs to log out and log in again before the changes will be applied.

If you want to avoid creating a user profile, you can use the dconf command-line utility to read and write individual values or entire directories from and to a dconf database. For more information, see the dconf(1) man page.

For dconf to work correctly when using Network File System (NFS) home directories, the dconf keyfile back end must be used.

Note that dconf keyfile back end only works properly if the glib2-fam package is installed. Without this package, notifications on configuration changes made on remote machines are not displayed properly.

With Red Hat Enterprise Linux 8, glib2-fam is available in the BaseOs repository.

To set the dconf keyfile back end:

The dconf keyfile back end takes effect the next time that the user logs in. It polls the keyfile to determine whether updates have been made, so settings may not be updated immediately.

This section describes how to set GSettings keys properties for a single-logged user.

Each GSettings key can have only one value in a dconf database. Setting the same key to a different value at a different place of the dconf database overrides the previous value.

Values of some keys are of array type. For array type, you can specify the value of the key as a list of multiple elements separated by a comma.

To set a GSettings key of array type, follow this syntax:

key=['option1', 'option2']

The following example shows setting of the org.gnome.desktop.input-sources.xkb-options GSettings key whose value is of array type: ⁠

[org/gnome/desktop/input-sources]
# Enable Ctrl-Alt-Backspace for all users
# Set the Right Alt key as the Compose key and enable it
xkb-options=['terminate:ctrl_alt_bksp', 'compose:ralt']

This section focuses on using of the gsettings command to configure, manipulate and manage the GSettings keys. The most frequent use cases that can be resolved by using the gsettings command are shown.

gsettings set SCHEMA [:PATH] KEY

$ gsettings set org.gnome.shell favorite-apps "['firefox.desktop', 'evolution.desktop', 'rhythmbox.desktop', 'shotwell.desktop', 'org.gnome.Nautilus.desktop', 'org.gnome.Software.desktop', 'yelp.desktop', 'org.gnome.Terminal.desktop', 'org.gnome.clocks.desktop']"

gsettings monitor SCHEMA [:PATH] [KEY]

$ gsettings monitor org.gnome.shell favorite-apps

$ gsettings set org.gnome.shell favorite-apps "['firefox.desktop', 'evolution.desktop', 'rhythmbox.desktop', 'shotwell.desktop', 'org.gnome.Nautilus.desktop', 'org.gnome.Software.desktop', 'yelp.desktop', 'org.gnome.Terminal.desktop']"

favorite-apps: ['firefox.desktop', 'evolution.desktop', 'rhythmbox.desktop', 'shotwell.desktop', 'org.gnome.Nautilus.desktop', 'org.gnome.Software.desktop', 'yelp.desktop', 'org.gnome.Terminal.desktop']

gsettings writable SCHEMA [:PATH] KEY

$ gsettings writable org.gnome.shell favorite-apps

gsettings range SCHEMA [:PATH] KEY

$ gsettings range org.gnome.shell remember-mount-password

gsettings describe SCHEMA [:PATH] KEY

$ gsettings describe org.gnome.desktop.screensaver picture-uri

URI to use for the background image. Note that the backend only supports local file:// URIs.

gsettings get SCHEMA [:PATH] KEY VALUE

$ gsettings get org.gnome.shell remember-mount-password

gsettings reset SCHEMA [:PATH] KEY

$ gsettings set org.gnome.desktop.screensaver lock-delay 200

$ gsettings reset org.gnome.desktop.screensaver lock-delay

gsettings reset-recursively SCHEMA [:PATH]

$ gsettings reset-recursively org.gnome.desktop.screensaver

gsettings list-schemas [--print-paths]

$ gsettings list-schemas

org.gnome.rhythmbox.library
org.gnome.shell.overrides
org.gnome.system.proxy.https
org.gnome.clocks
org.gnome.eog.fullscreen
org.gnome.login-screen
org.gnome.eog.view

gsettings list-keys SCHEMA [:PATH]

$ gsettings list-keys org.gnome.shell

enabled-extensions
command-history
remember-mount-password
always-show-log-out
had-bluetooth-devices-setup
looking-glass-history
disable-user-extensions
app-picker-view
disable-extension-version-validation
development-tools
favorite-apps

gsettings list-children SCHEMA [:PATH]

$ gsettings list-children org.gnome.shell

keyboard org.gnome.shell.keyboard
keybindings org.gnome.shell.keybindings

gsettings list-recursively [SCHEMA [:PATH]]

$ gsettings list-recursively

org.gnome.nautilus.desktop network-icon-visible false
org.gnome.nautilus.desktop font ''
org.gnome.nautilus.desktop network-icon-name 'Network Servers'
org.gnome.nautilus.desktop home-icon-name 'Home'
org.gnome.nautilus.desktop volumes-visible true
org.gnome.Vinagre always-enable-listening false
org.gnome.Vinagre always-show-tabs false
org.gnome.Vinagre show-accels false
org.gnome.Vinagre history-size 15
org.gnome.Vinagre shared-flag true

Certain portions of this text first appeared in the GNOME Desktop System Administration Guide. Copyright © 2014 The GNOME Project, Michael Hill, Jim Campbell, Jeremy Bicha, Ekaterina Gerasimova, minnie_eg, Aruna Sankaranarayanan, Sindhu S, Shobha Tyagi, Shaun McCance, David King, and others. Licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

The editors of this Red Hat Enterprise Linux 8 documentation would like to thank the GNOME community members for their valuable contributions to the GNOME Desktop System Administration Guide.

As a system administrator, you can configure the default desktop background, add extra backgrounds, or add multiple backgrounds using the dconf utility.

If the users of the system are not permitted to change background from the defaults, system administrator needs to lock the settings using the locks directory. Otherwise, each user can customize the background according to their preferences.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE wallpapers SYSTEM "gnome-wp-list.dtd">
<wallpapers>
  <wallpaper deleted="false">
    <name>Company Background</name>
    <name xml:lang="de">Firmenhintergrund</name>
    <filename>/usr/local/share/backgrounds/company-wallpaper.jpg</filename>
    <options>zoom</options>
    <shade_type>solid</shade_type>
    <pcolor>#ffffff</pcolor>
    <scolor>#000000</scolor>
  </wallpaper>
</wallpapers>

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE wallpapers SYSTEM "gnome-wp-list.dtd">
<wallpapers>
  <wallpaper deleted="false">
    <name>Company Background</name>
    <name xml:lang="de">Firmenhintergrund</name>
    <filename>/usr/local/share/backgrounds/company-wallpaper.jpg</filename>
    <options>zoom</options>
    <shade_type>solid</shade_type>
    <pcolor>#ffffff</pcolor>
    <scolor>#000000</scolor>
  </wallpaper>
  <wallpaper deleted="false">
    <name>Company Background 2</name>
    <name xml:lang="de">Firmenhintergrund 2</name>
    <filename>/usr/local/share/backgrounds/company-wallpaper-2.jpg</filename>
    <options>zoom</options>
    <shade_type>solid</shade_type>
    <pcolor>#ff0000</pcolor>
    <scolor>#00ffff</scolor>
  </wallpaper>
</wallpapers>

GNOME Shell extensions allow for the customization of the default GNOME Shell interface and its parts, such as window management and application launching.

This section describes how to change the system language using desktop GUI.

The Ctrl+Alt+Backspace shortcut key combination is used for terminating the X.Org display server.

You might want to terminate X.Org especially when:

To enable the Ctrl+Alt+Backspace shortcut to forcibly terminate X.Org by default for all users, you need to set the org.gnome.desktop.input-sources.xkb-options GSettings key.

If the Ctrl+Alt+Backspace key combination is enabled, all users can terminate X.Org , which brings them back to the login prompt.

To disable command-line access for a desktop user, you need to make configuration changes in a number of different contexts:

When closing the lid of your laptop, the computer by default suspends in order to save power. You can prevent the computer from suspending when closing the lid by changing the setting for that behavior.

For more information on the /etc/systemd/logind.conf file, see the logind.conf man page.

When the machine is booted to a graphical login screen or user session, hitting the power button makes the machine suspend by default. This happens both in cases when the user presses the power button physically or when pressing a virtual power button from a remote console. To achieve a different behavior when pressing the power button, set the function of this button with dconf.

For example, if you want the system to shutdown after pressing the power button, use the following procedure:

This configuration initiates a system shutdown after pressing the power button. To configure the system differently, you can set the behavior of particular buttons.

Options for particular buttons:

You can set the default favorite applications for individual users. You can add applications into your favorite list easily using any of the methods mentioned below.

Run the following command to view all the applications that exists in the favorite list:

dconf read /org/gnome/shell/favorite-apps

You can modify system database files using dconf keyfiles to set the same favorites for all users. The following steps edit the dconf profile and then create a keyfile to set default favorite applications for all users in the local configuration database.

You can disable the print dialog from being shown to users. This can be useful if you are giving temporary access to a user or you do not want the user to print to network printers.

To provent applications from printing, lock down the org.gnome.desktop.lockdown.disable-printing key:

Having followed these steps, applications supporting this lockdown key, such as Evolution, Evince, or Gedit, will disable printing.

You can disable the Save and Save As dialogs. This can be useful if you are giving temporary access to a user or you do not want the user to save files to the computer.

To prevent applications from file saving, lock down the org.gnome.desktop.lockdown.disable-save-to-disk key:

Having followed these steps, applications supporting this lockdown key, for example Videos, Image Viewer, Evolution, Document Viewer, or GNOME Shell, will disable their Save As dialogs.

polkit enables you to set permissions for individual operations. For udisks2, the utility for disk management services, the configuration is located at /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy. This file contains a set of actions and default values, which can be overridden by system administrator.

When the user tries to change the disks settings, the following message is returned:

Authentication is required to modify the disks settings.

To prevent the user from logging out, use the folowing procedure.

To lock down user switching, use the following procedure:

The GNOME Display Manager (GDM) is a graphical login program running in the background that runs and manages the X.Org display servers for both local and remote logins.

GDM is a replacement for XDM, the X Display Manager. However, GDM is not derived from XDM and does not contain any original XDM code. In addition, there is no support for a graphical configuration tool in GDM, so editing the /etc/gdm/custom.conf configuration file is necessary to change the GDM settings.

When you make changes to the system configuration such as setting up the login screen banner message, login screen logo, or login screen background, restart GDM for your changes to take effect.

To start an application automatically when the user logs in, create a .desktop file for that application in the /etc/xdg/autostart/ directory. To manage autostart applications for individual users, use the gnome-session-properties application.

As an administrator, you can enable automatic login from the Users panel in GNOME Settings, or you can set up automatic login manually in the GDM custom configuration file, as follows.

Run the follwoing procedure to set up automatic login for a user john.

User sessions that have been idle for a specific period of time can be ended automatically. You can set different behavior based on whether the machine is running from a battery or from mains power by setting the corresponding GSettings key, then locking it.

To set automatic logout for a mains powered machine:

The following GSettings keys are of interest:

If you want to list available values for a key, use the following procedure:

$ gsettings range org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type
enum
'blank'
'suspend'
'shutdown'
'hibernate'
'interactive'
'nothing'
'logout'

This section describes how to:

Configuring the drop in the brightness level

To set the drop in the brightness level when the device has been idle for some time:

Setting brightness level

To set brightness level:

Setting idle time

To set idle time after which the screen is blanked and the default screensaver is displayed:

To enable the screensaver and make the screen lock automatically when the user is idle, follow this procedure:

GNOME Shell features a built-in screencast recorder. The recorder allows users to record desktop or application activity during their session and distribute the recordings as high-resolution video files in the webm format.

To make a screencast:

The Braille display is a device that uses the brltty service to provide tactile output for visually impaired users.

In order that a Braille display works correctly, system administrators must:

braille-device	serial:ttyS0	                # First serial device
braille-device	usb:	                        # First USB device matching braille driver
braille-device	usb:nnnnn	                # Specific USB device by serial number
braille-device	bluetooth:xx:xx:xx:xx:xx:xx	# Specific Bluetooth device by address

serial:ttyUSB0

# dmesg | fgrep ttyUSB0

To activate the Orca screen reader, switch on Always Show Universal Access Menu as described in the following procedure.

Alternatively, you can switch the Orca screen reader on by pressing the Super+Alt+S key combination. As a result, the Universal Access Menu icon is displayed on the top bar.

By default, Orca uses the eSpeak speech synthesizer, but it also supports the Festival Speech Synthesis System (Festival). Both eSpeak and Festival synthesize voice differently. Some users might prefer Festival to the default eSpeak synthesizer.

The libwacom tablet client library needs a definiton file for the tablet that you want to add.

To ensure that the tablet definition file exists, follow this procedure.

To add support for a new tablet into the libwacom tablet information client library, follow this procedure.

Configuration for your Wacom tablet is stored in GSettings in the /org/gnome/settings-daemon/peripherals/wacom/machine-id-device-id key, where machine-id is a D-Bus machine ID, and device-id is a tablet device ID.

The configuration schema for the tablet is org.gnome.settings-daemon.peripherals.wacom.

Stylus configuration is stored in the /org/gnome/settings-daemon/peripherals/wacom/device-id/tool-id key, where tool-id is the identifier for the stylus used for professional ranges. For the consumer ranges with no support for tool-id, a generic identifier is used instead.

The configuration schema for the stylus is org.gnome.settings-daemon.peripherals.wacom.stylus. The configuration schema for the eraser is org.gnome.settings-daemon.peripherals.wacom.eraser.

To get the full list of tablet configuration paths used on a particular machine, use the gsd-list-wacom tool, which is provided by the gnome-settings-daemon package.

Flatpak provides sandbox environment for application building, deployment, distribution, and installation. Applications you run using Flatpak have minimum access to the host system, which protects the system installation against third-party applications. Flatpak provides application stability regardless of your Linux kernel architecture, name, version, or release. Flatpak allows you to install and run multiple versions of the same application simultaneously.

The details of the application packaged with Flatpak are stored in the flatpakref file that uses the .flatpakref extension. Each flatpakref file contains information enabling it to add the remote and install the application. You can access flatpakref files remotely in a remote repository, or you can download and manage them locally on your computer.

Flatpak can be used in combination with third party centralized repositories for applications packaged with Flatpak. Note that Red Hat supports Flatpak as a method of installing applications. Applications from third-party repositories are not supported by Red Hat.

The following section describes how to search for, install, launch, and update Flatpak applications in the graphical interface.

The following section describes how to search for, install, launch, and update Flatpak applications from the command-line.

$ flatpak remote-add --if-not-exists remote-repository path-to-the-remote-repository