What is the name of the large background area of the Windows environment that holds icons for file folders in applications?

1.1. What GNOME 3 is

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.

1.2. GNOME environments, back ends, and display protocols

GNOME 3 provides two user environments:

• GNOME Standard
• GNOME Classic

Both environments can use two different protocols as their graphical back ends:

• The X11 protocol, which uses X.Org as the display server.

• The Wayland protocol, which uses GNOME Shell as the Wayland compositor and display server.

  This solution of display server is further referred as GNOME Shell on Wayland.

The default combination in RHEL 8 is GNOME Standard environment using GNOME Shell on Wayland as the display server. However, due to certain Wayland limitations, you might want to switch the graphics protocol stack to X11. You may also want to switch from GNOME Standard to GNOME Classic.

Additional resources

• For more information about graphics based on the Wayland protocol, see Section 2.6, “Key differences between the Wayland and X11 protocol”.
• For information on how to switch the environments, see Section 2.8, “Selecting GNOME environment and display protocol”.

1.3. Launching applications in GNOME

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

1.4. Managing desktop icons

You can enable the desktop icons functionality and move files to the desktop.

1.5. Disabling the hot corner functionality on GNOME Shell

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 upper-left corner and push the cursor to the screen corner, 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 dconf Editor application
• The gsettings command-line utility
• The No topleft hot corner extension

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 hot corner system-wide, use the No topleft hot corner extension.

1.6. Configuring sound in GNOME

You can configure sound volume and other sound options in GNOME.

1.6.1. Sound configuration tools in GNOME

In RHEL 8, the PulseAudio sound server handles sound output and input. PulseAudio lets programs output the audio using the pulseaudio daemon.

To configure sound, you can use one of the following graphical applications in GNOME:

System menu

The system menu is located in the top-right screen corner. It enables you only 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 using an internal microphone (built-in audio), such as some teleconference tools.

GNOME Control Center

The GNOME Control Center (Settings) application provides other general options to configure sound.

Tweaks

The Tweaks application enables you to configure only volume over-amplification.

Additional resources

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

1.6.3. Sound options in GNOME Control Center

Through the Sound menu in GNOME Control Center, you can configure the following sound options:

Output and Input

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.

Sound Effects The Sound Effects menu sets the volume and theme of system audio alerts. Applications 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.

The Output tab on the sound configuration screen

1.7. Handling graphics and photos

GNOME provides multiple tools to handle graphics and photography.

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

Procedure

1. Open GNOME Software.

   

2. Go to Graphics & Photography.
   

3. Browse the available tools, such as the following:

   Photos For accessing, organizing and sharing your photos. GNU Image Manipulation Program For creating images and editing photographs. Inkspace For creating and editing scalable vector graphics images. XSane For scanning images with a scanner. LibreOffice Draw For create and editing drawings, flow charts, and logos.

1.8. Handling printing

In GNOME, you can set up printing using the Settings application.

1.8.3. Configuring a printer in the Settings application

This section describes how to configure a new printer, and how to maintain a configuration of a printer using the Settings application.

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:

  

  In this menu, you can select the following actions:

  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:

  

1.9. Sharing media between applications

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

1.10. Customizing GNOME Shell environment with the Tweaks tool

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

Procedure

1. Open Tweaks.

   The Tweaks tool

   

2. Select the item that you want to customize in the left side bar.

   For example, you can set applications to start automatically when you log in by using the Startup Applications menu, or you can customize your top bar appearance by using the Top Bar menu.

   Customizing startup applications in Tweaks

   

   Customizing the appearance of your top bar in Tweaks

   

2.1. GNOME environments, back ends, and display protocols

GNOME 3 provides two user environments:

• GNOME Standard
• GNOME Classic

Both environments can use two different protocols as their graphical back ends:

• The X11 protocol, which uses X.Org as the display server.

• The Wayland protocol, which uses GNOME Shell as the Wayland compositor and display server.

  This solution of display server is further referred as GNOME Shell on Wayland.

The default combination in RHEL 8 is GNOME Standard environment using GNOME Shell on Wayland as the display server. However, due to certain Wayland limitations, you might want to switch the graphics protocol stack to X11. You may also want to switch from GNOME Standard to GNOME Classic.

Additional resources

• For more information about graphics based on the Wayland protocol, see Section 2.6, “Key differences between the Wayland and X11 protocol”.
• For information on how to switch the environments, see Section 2.8, “Selecting GNOME environment and display protocol”.

2.2. GNOME Standard

GNOME Standard user interface includes these major components:

Top bar The horizontal bar at the top of the screen provides access to some of the basic functions of GNOME Standard, such as the Activities Overview, clock and calendar, system status icons, and the system menu. System menu

The system menu is located in the top right corner, and enables you:

• Updating settings
• Controlling the sound bar
• Finding information about your Wi-Fi connection
• Switching user
• Logging out
• Turning off the computer

The Activities Overview features windows and applications views that let the user run applications and windows and switch between them.

The search entry at the top allows for searching various items available on the desktop, including applications, documents, files, and configuration tools.

The vertical bar on the left side contains a list of favorite and running applications. You can add or remove applications from the default list of favorites according to your needs.

The workspace list displayed on the right side allows the user to switch between multiple workspaces, or move applications and windows from one workspace to another.

The GNOME 3 Standard Desktop

2.3. GNOME Classic

GNOME Classic represents a mode for users who prefer a more traditional desktop experience that is similar to GNOME 2 environment used with Red Hat Enterprise Linux 6. It is based on GNOME 3 technologies, and at the same time it includes multiple features similar to GNOME 2.

GNOME Classic user interface consists of these major components:

Applications and Places

The Applications menu is displayed at the top left of the screen. It gives the user access to applications organized into categories. If you enable window overview, you can also open the Activities Overview from that menu.

The Places menu is displayed next to the Applications menu on the top bar. It gives the user quick access to important folders, for example Downloads or Pictures.

The taskbar is displayed at the bottom of the screen, and features:

• A window list
• A notification icon displayed next to the window list
• A short identifier for the current workspace and total number of available workspaces displayed next to the notification icon

The system menu is located in the top right corner, and enables the following actions:

• Updating settings
• Controlling the sound bar
• Finding information about your Wi-Fi connection
• Switching user
• Logging out
• Turning off the computer

The GNOME 3 Classic desktop with the Rhythmbox application and the Favorites submenu of the Applications menu

In GNOME Classic, the overview of windows that are open is not available by default. You can see the list of all open windows in the taskbar at the bottom of the screen. However, you can enable the windows overview similar to what is by default available in GNOME Standard by changing the default settings of the GNOME Classic environment as described in Section 2.4, “Enabling window overview in GNOME Classic”.

2.4. Enabling window overview in GNOME Classic

In GNOME Classic, the overview of open windows is not available by default. This procedure enables the window overview for all users on the system.

Enabling the window overview by this procedure is not a permanent change. Each update of the gnome-classic-session package overwrites the configuration file to the default settings, which disable the window overview.

To keep the window overview enabled, apply the procedure after each update of gnome-classic-session.

Procedure

1. Open the /usr/share/gnome-shell/modes/classic.json file as the root user.

2. Find the following line in the file:

   "hasOverview": false

3. Change the line to the following:

   "hasOverview": true

4. Save changes, and close the /usr/share/gnome-shell/modes/classic.json file.
5. Restart the user session.

Verification steps

1. In your GNOME Classic session, open multiple windows.
2. Press the Super key to open the window overview.

3. In the overview, check that:

   • The Dash (the vertical panel on the left side of the screen) is displayed.
   • The bottom panel is not displayed.

   • The workspace switcher is displayed on the right side of the screen.

     Window overview with "hasOverview": true

     

   With the default settings ("hasOverview": false), the overview has the following features:

   • The Dash is not displayed.

   • The bottom panel is displayed. It includes the Window picker button in its left part and the workspace switcher in its right part.

     Window overview with "hasOverview": false

     

2.5. Graphics back ends in RHEL 8

In RHEL 8, you can choose between two protocols to build a graphical user interface:

X11 The X11 protocol uses X.Org as the display server. Displaying graphics based on this protocol works the same way as in RHEL 7, where this was the only option. Wayland The Wayland protocol on RHEL 8 uses GNOME Shell as its compositor and display server, which is further referred as GNOME Shell on Wayland. Displaying graphics based on the Wayland protocol has some differences and limitation compared to X11.

New installations of RHEL 8 automatically select GNOME Shell on Wayland. However, you can switch to X.Org, or select the required combination of GNOME environment and display server as described in Section 2.8, “Selecting GNOME environment and display protocol”.

Note that there are also a few environments where X.Org is preferred over GNOME Shell on Wayland, such as:

• Cirrus graphics used in a VM environment
• Matrox graphics
• Aspeed graphics
• QXL graphics used in a VM environment
• Nvidia graphics when used with the proprietary driver

The Nvidia graphics by default use nouveau, which is an open source driver. nouveau is supported on Wayland, hence you can use Nvidia graphics with nouveau on GNOME Shell on Wayland without any limitations. However, using Nvidia graphics with proprietary Nvidia binary drivers is not supported on GNOME Shell on Wayland. In this case, you need to switch to X.Org as described in Section 2.8, “Selecting GNOME environment and display protocol”.

Additional resources

• You can find the current list of environments for which Wayland is not available in the /usr/lib/udev/rules.d/61-gdm.rules file.
• For additional information on the Wayland project, see Wayland documentation.

2.6. Key differences between the Wayland and X11 protocol

X11 applications

Client applications need to be ported to the Wayland protocol or use a graphical toolkit that has a Wayland backend, such as GTK, to be able to work natively with the compositor and display server based on Wayland.

Legacy X11 applications that cannot be ported to Wayland automatically use Xwayland as a proxy between the X11 legacy clients and the Wayland compositor. Xwayland functions both as an X11 server and a Wayland client. The role of Xwayland is to translate the X11 protocol into the Wayland protocol and reversely, so that X11 legacy applications can work with the display server based on Wayland.

On GNOME Shell on Wayland, Xwayland is started automatically at startup, which ensures that most X11 legacy applications work as expected when using GNOME Shell on Wayland. However, the X11 and Wayland protocols are different, and hence some clients relying on X11-specific features may behave differently under Xwayland. For such specific clients, you can switch to the X.Org display server as described in Section 2.8, “Selecting GNOME environment and display protocol”.

libinput

Red Hat Enterprise Linux 8 uses a new unified input stack, libinput, which manages all common device types, such as mice, touchpads, touchscreens, tablets, trackballs and pointing sticks. This unified stack is used both by the X.Org and by the GNOME Shell on Wayland compositor.

GNOME Shell on Wayland uses libinput directly for all devices, and no switchable driver support is available. Under X.Org, libinput is implemented as the X.Org libinput driver, and driver support is outlined below.

Mice, touchscreens, trackballs, pointing sticks Red Hat Enterprise Linux 8 uses the X.Org libinput driver for these devices. The X.Org evdev driver, which was used in Red Hat Enterprise Linux 7, is available as fallback where required. Touchpads Red Hat Enterprise Linux 8 uses the X.Org libinput driver for touchpads. The X.Org synaptics driver, which was used for touchpads in Red Hat Enterprise Linux 7, is no longer available. Graphics tablets Red Hat Enterprise Linux 8 continues using the X.Org wacom driver, which was used for tablet devices in Red Hat Enterprise Linux 7. However, the X.Org libinput driver is available where required. Other input devices Red Hat Enterprise Linux 7 used the X.Org evdev driver for other input devices that are not included in the above categories. Red Hat Enterprise Linux 8 uses the X.Org libinput driver by default but can fall back to the X.Org evdev driver if a device is incompatible with libinput.

Gestures

GNOME Shell on Wayland supports new touchpad and touchscreen gestures. These gestures include:

• Switching workspaces by dragging up or down with four fingers.
• Opening the Activities overview by bringing three fingers closer together.

2.7. Current Wayland limitations

Nvidia drivers

Proprietary Nvidia binary drivers are not supported with GNOME Shell on Wayland. To avoid any complications while using the Nvidia GPU, GNOME Shell automatically falls back to X.Org, which means that the login screen does not provide any option based on the Wayland protocol.

The nouveau driver is still supported and is the default driver for Nvidia graphics.

Remote desktop

With GNOME Shell on Wayland, VNC support is provided by the gnome-remote-desktop package. Remote access using VNC via gnome-remote-desktop currently requires an already logged in session, and only the primary monitor is accessible. Screen sharing with GNOME Shell on Wayland is possible using the PipeWire media server. For more details on the PipeWire media server, see PipeWire project.

For more advanced VNC usage, you need to switch to X.org, where traditional VNC tools are available. For more information, see Overview of GNOME environments .

X Display Manager

The X Display Manager Control Protocol (XDMCP) is not supported with GNOME Shell on Wayland.

Hence, it is not possible to use the X display manager to start a session on the X.Org display server from the same or another computer.

Additional limitations

The following additional limitations related to the Wayland protocol should be noted:

• X.Org screen manipulation utilities are not available.
• The xrandr utility is not supported because Wayland handles layout, rotations, and resolutions differently.
• GNOME Shell cannot be restarted using the Alt+F2 r shortcut.
• Due to stability issues, using X.org instead of Wayland is recommended in virtual environments. The graphics based on the Wayland protocol are not available for virtual machines that use the qxl driver.
• Wayland does not support the custom or niche input devices that cannot be handled by the libinput driver.

Additional resources

• You can find the current list of environments for which Wayland-based graphics are unavailable in the /usr/lib/udev/rules.d/61-gdm.rules file.

2.8. Selecting GNOME environment and display protocol

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 certain limitations of Wayland, you might want to switch the graphics protocol stack. You might also want to switch from GNOME Standard to GNOME Classic.

Procedure

1. From the login screen (GDM), click the cogwheel next to the Sign In button.

   You cannot access this option from the lock screen. The login screen appears when you first start Red Hat Enterprise Linux 8 or when you log out of your current session.

   

2. From the drop-down menu that appears, select the option that you prefer.

   Note that in the menu that appears on the login screen, the X.Org display server is marked as X11 display server.

The change of GNOME environment and graphics protocol stack resulting from the above procedure is persistent across user logouts, and also when powering off or rebooting the computer.

3.1. The GNOME Software application

GNOME Software is an utility that enables you to install and update applications, software components, and GNOME Shell extensions in a graphical interface.

GNOME Software provides a catalog of graphical applications, which are the applications that include a *.desktop file. The available applications are grouped into multiple categories according to their purpose.

GNOME Software uses the PackageKit and Flatpak technologies as its back ends.

3.2. Installing an application using GNOME Software

This procedure installs a graphical application using the GNOME Software installer.

Procedure

1. Launch the GNOME Software application.

2. Find the application to be installed in the available categories:

   • Audio & Video
   • Communication & News
   • Productivity
   • Graphics & Photography

   • Add-ons

     Add-ons include for example GNOME Shell extensions, codecs, or fonts.

   • Developer Tools
   • Utilities
   

3. Click the selected application.

   

4. Click the Install button.

   

3.3. Installing an application to open a file type

This procedure installs an application that can open a given file type.

Prerequisites

• You can access a file of the required file type in your file system.

Procedure

1. Try opening a file that is associated with an application that is currently not installed on your system.
2. GNOME automatically identifies the suitable application that can open the file, and offers to download the application.

3.4. Installing an RPM package in GNOME

This procedure installs an RPM software package that you manually downloaded as a file.

Procedure

1. Download the required RPM package.

2. In the Files application, open the directory that stores the downloaded RPM package.

   By default, downloaded files are stored in the /home/user/Downloads/ directory.

3. Double-click the icon of the RPM package to install it.

3.5. Installing an application from the application search in GNOME

This procedure installs a graphical application that you find in the GNOME application search.

Procedure

1. Open the Activities Overview screen.

2. Start typing the name of the required application in the search entry.

   

   GNOME automatically finds the application in a repository, and displays the application’s icon.

3. Click the application’s icon to open GNOME Software.

   

4. Click the icon of the application again.

   

5. Click Install to finish the installation in GNOME Software.

3.6. Additional resources

• For installing software on the command line, see Installing software with yum.

4.1. Registering a system using Red Hat account on GNOME

Follow the steps in this procedure to enroll your system with your Red Hat account.

Prerequisites

• A valid account on Red Hat customer portal.

  See the Create a Red Hat Login page for new user registration.

Procedure

1. Go to the system menu, which is accessible from the top-right screen corner and click the Settings icon.
2. In the → section, click Register.
3. Select Registration Server.
4. If you are not using the Red Hat server, enter the server address in the URL field.
5. In the Registration Type menu, select Red Hat Account.

6. Under Registration Details:

   • Enter your Red Hat account user name in the Login field.
   • Enter your Red Hat account password in the Password field.
   • Enter the name of your organization in the Organization field.

7. Click Register.

4.2. Registering a system using an activation key on GNOME

Follow the steps in this procedure to register your system with an activation key. You can get the activation key from your organization administrator.

Prerequisites

• Activation key or keys.

  See the Activation Keys page for creating new activation keys.

Procedure

1. Go to the system menu, which is accessible from the top-right screen corner and click the Settings icon.
2. In the → section, click Register.
3. Select Registration Server.
4. Enter URL to the customized server, if you are not using the Red Hat server.
5. In the Registration Type menu, select Activation Keys.

6. Under Registration Details:

   • Enter Activation Keys.

     Separate multiple keys by a comma (,).

   • Enter the name or ID of your organization in the Organization field.

7. Click Register

4.3. Unregistering the system using GNOME

Follow the steps in this procedure to unregister your system. After unregistering, your system no longer receives software updates.

Procedure

1. Go to the system menu, which is accessible from the top-right screen corner and click the Settings icon.

2. In the → section, click Details.

   The Registration Details screen appears.

3. Click Unregister.

   A warning appears about the impact of unregistering the system.

4. Click Unregister.

4.4. Additional resources

• Registering the system and managing subscription using the command line or web console
• Creating Red Hat Customer Portal Activation Keys
• Understanding Activation Keys
• Registering Systems with Activation keys

5.1. Remote desktop access options

RHEL provides several options for remotely connecting to the desktop. Each option fits a different use case:

Single-user access using GNOME tools

This method enables remote access on the client and the server using graphical GNOME applications. It configures a Virtual Network Computing (VNC) session so that only a single user can connect to the desktop on the server at a given time.

Depending on the session type, this method uses different components to implement screen sharing:

• In an X11 session, it uses the vino component.

• In a Wayland session, it uses the gnome-remote-desktop component.

  This method always uses display number 0. As a consequence, the VNC session always connects to the user who is logged into the server system.

  The VNC client application must support tls_anon connections. For example, you can use the Remote Desktop Viewer (vinagre) application on Linux systems. Before you can connect from Microsoft Windows clients, such as RealVNC, you must disable the VNC encryption on the server.

This method configures a VNC session so that multiple remote clients can connect to the server in parallel. You must first enable the VNC access on the client and the server using command-line tools.

Any VNC client application can connect to a server configured using this method.

This method executes an SSH command on the client that launches an individual graphical on the server. The application window opens on the client.

This method is useful when you do not require a full remote desktop session.

5.2. Remotely accessing the desktop as a single user

You can remotely connect to the desktop on a RHEL server using graphical GNOME applications. Only a single user can connect to the desktop on the server at a given time.

5.3. Remotely accessing the desktop as multiple users

You can remotely connect to the desktop on a RHEL server and open multiple sessions as different users at the same time.

option1=value
option2

session=gnome
alwaysshared
securitytypes=vncauth,tlsvnc
desktop=sandbox
geometry=2000x1200

:number=user

:2=test
:3=vncuser

5.4. Remotely accessing an individual application

You can remotely launch a graphical application on a RHEL server and use it from the remote client.

6.1. Introduction to configuring GNOME

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

• dconf
• GSettings
• gsettings

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.

6.2. Managing user and system GNOME settings

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

• Administrators can define default settings that apply to all users.
• Users can override the defaults with their own settings.
• Administrators can also lock settings to prevent users from overriding them.

6.3. Displaying GSettings values for desktop applications

Viewing and editing of the GSettings values can be achieved with one of the following tools:

• dconf-editor GUI tool
• gsettings command-line utility

The dconf-editor application and gsettings utility have the following in common:

• allow browsing and changing options for system and application preferences
• allow to change preferences
• can be run by regular users, because both tools are intended to browse and modify the current user’s GSettings database

The dconf-editor provides a GUI for browsing the settings and their editing. It presents the hierarchy of settings in a tree-view and also displays additional information about each setting, including the description, type and default value.

The gsettings utility can be used to display and set dconf values. gsettings utility supports Bash completion for commands and settings. This tools also allows you to automate configuration in shell scripts. ⁠

Figure 6.1. dconf-editor showing org.gnome.desktop.background GSettings keys

Prerequisites

• The dconf-editor is not installed on the system by default. To install it, run the following command as the root user:

  # yum install dconf-editor

Procedure

• To list GSettings values in the GUI, open the dconf-editor application.

• To list a specific GSettings value on the command line, use the following command:

  $ gsettings get schema key

  For example:

$ gsettings get org.gnome.desktop.background picture-uri

Additional resources

• For more information on the dconf-editor tool, see the dconf-editor(1) man page and the dconf-editor Project documentation.
• For more information on the gsettings utility, see the gsettings(1) man page.

6.4. Using dconf profiles

The dconf system stores configuration in several different databases. You can configure dconf profiles, which specify the databases that dconf uses.

user-db:user
system-db:local
system-db:site

6.5. Configuring custom default values

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.

Prerequisites

• the user profile exists
• the value for the key was added to a dconf database

Procedure

For example, to set the default background:

1. Create the user profile in /etc/dconf/profile/user:

   user-db:user
   system-db:local

   where local is the name of a dconf database.

2. Create a keyfile for the local database in /etc/dconf/db/local.d/01-background, which contains the following default settings:

   # dconf path
   
   [org/gnome/desktop/background]
   
   # GSettings key names and their corresponding values
   picture-uri='file:///usr/local/share/backgrounds/wallpaper.jpg'
   picture-options='scaled'
   primary-color='000000'
   secondary-color='FFFFFF'

   In the default setting of the keyfile, the following GSettings keys are used:

   Table 6.1. org.gnome.desktop.background schemas GSettings Keys

   Key Name	Possible Values	Description
   picture-options	"none", "wallpaper", "centered", "scaled", "stretched", "zoom", "spanned"	Determines how the image set by wallpaper_filename is rendered.
   picture-uri	filename with the path	URI to use for the background image. Note that the backend only supports local file:// URIs.
   primary-color	default: 000000	Left or Top color when drawing gradients, or the solid color.
   secondary-color	default: FFFFFF	Right or Bottom color when drawing gradients, not used for solid color.

3. Edit the keyfile according to your preferences.

   For more information, see Section 6.3, “Displaying GSettings values for desktop applications”.

4. Update the system databases:

   ~]# dconf update

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

Additional resources

• 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.

6.6. Locking down specific settings

By using the lockdown mode in dconf, you can prevent users from changing specific settings.

Without enforcing the system settings using a lockdown, any settings that users make take precedence over the system settings. User can thus override the system settings with their own.

Procedure

To lock down a GSettings key:

1. Create a locks subdirectory in the keyfile directory such as /etc/dconf/db/local.d/locks/.
2. Add any number of files with keys that you want to lock into this directory.

Example 6.1. Locking the settings for the default wallpaper

1. Set a default wallpaper.
2. Create a new /etc/dconf/db/local.d/locks/ directory.

3. Create a new file in /etc/dconf/db/local.d/locks/00-default-wallpaper with the following contents, listing one key per line:

   # Prevent users from changing values for the following keys:
   /org/gnome/desktop/background/picture-uri
   /org/gnome/desktop/background/picture-options
   /org/gnome/desktop/background/primary-color
   /org/gnome/desktop/background/secondary-color

4. Update the system databases:

   ~]# dconf update

6.7. Storing user settings over NFS

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:

1. Ensure that the glib2-fam package is installed on the system.

   To verify whether the package is installed on the system:

   ~]#  yum list installed

   If glib2-fam is not in the list of installed packages, install it by running:

   ~]# yum install glib2-fam

2. Create or edit the /etc/dconf/profile/user file on every client.

3. At the very beginning of /etc/dconf/profile/user file, add the following line:

   service-db:keyfile/user

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.

6.8. Setting GSettings keys properties

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: ⁠

Example settings of the org.gnome.desktop.input-sources.xkb-options GSettings Key

[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']

6.9. Working with GSettings keys on command line

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

6.10. Acknowledgements

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.

7.1. Multipurpose Internet Mail Extension types

The GNOME desktop uses MIME types to:

• Determine which application should open a specific file format by default.
• Register other applications that can open files of a specific format.
• Set a string describing the type of a file, for example, in a file properties dialog of the files application.
• Set an icon representing a specific file format, for example, in a file properties dialog of the files application.

MIME type names follow a given format:

media-type/subtype-identifier

For example, image/jpeg.

Here image is a media type and jpeg is the subtype identifier.

GNOME follows Multipurpose Internet Mail Extension (MIME) info specification from the Freedesktop.org to determine:

• The machine-wide and user-specific location to store all the MIME type specification files.
• How to register a MIME type so that the desktop environment knows which application you can use to open a specific file format.
• How users can change which applications should open with what file formats.

MIME database

The MIME database is a collection of all the MIME type specification files that GNOME uses to store information about known MIME types.

The most important part of the MIME database from the system administrator’s point of view is the /usr/share/mime/packages/ directory, where the MIME type-related files specifying information on known MIME types are stored. One example of such a file is /usr/share/mime/packages/freedesktop.org.xml, specifying information about the standard MIME types available on the system, by default. The shared-mime-info package provides this file.

Additional resources

• For detailed information describing the MIME type system, see Shared MIME Info specifications on the Freedesktop website.

7.2. Adding a custom MIME type for all users

You must create a new MIME type specification file in the /usr/share/mime/packages/ directory and a .desktop file in the /usr/share/applications/ directory to add a custom MIME type for all the users on the system and register a default application for that MIME type.

Procedure

1. Create the /usr/share/mime/packages/application-x-newtype.xml file with following content:

   <?xml version="1.0" encoding="UTF-8"?>
   
   <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
     <mime-type type="application/x-newtype">
       <comment>new mime type</comment>
       <glob pattern="*.xyz"/>
     </mime-type>
   </mime-info>

   The sample application-x-newtype.xml file here defines a new MIME type application/x-newtype and assigns file names with the .xyz extension to that MIME type.

2. Create a new .desktop file named, for example, myapplication1.desktop in the /usr/share/applications/ with following content:

   [Desktop Entry]
   Type=Application
   MimeType=application/x-newtype
   Name=My Application 1
   Exec=myapplication1

   The sample myapplication1.desktop file here associates the application/x-newtype MIME type with an application named My Application 1. It is run by a command myapplication1.

3. As a root user, update the MIME database for your changes to take effect.

   # update-mime-database /usr/share/mime

4. As a root user, update the application database.

   # update-desktop-database /usr/share/applications

Verification steps

1. To verify that you have successfully associated *.xyz files with the application/x-newtype MIME type, first create an empty file, for example test.xyz and execute the following commands:

   $ touch test.xyz
   
   $ gvfs-info test.xyz | grep "standard::content-type"
     standard::content-type: application/x-newtype

2. To verify myapplication1.desktop is correctly set as the default registered application for the application/x-newtype MIME type, execute following command:

   $ gio mime --query application/x-newtype
   Default application for 'application/x-newtype': myapplication1.desktop
   Registered applications:
   	myapplication1.desktop
   Recommended applications:
   	myapplication1.desktop

7.3. Adding a custom MIME type for individual users

You must create a new MIME type specification file in the ~/.local/share/mime/packages/ directory and a .desktop file in the ~/.local/share/applications/ directory to add a custom MIME type for individual users and register a default application for that MIME type.

Procedure

1. Create the ~/.local/share/mime/packages/application-x-newtype.xml file with following content:

   <?xml version="1.0" encoding="UTF-8"?>
   <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
     <mime-type type="application/x-newtype">
       <comment>new mime type</comment>
       <glob pattern="*.xyz"/>
     </mime-type>
   </mime-info>

   The sample application-x-newtype.xml file here defines a new MIME type application/x-newtype and assigns file names with the .xyz extension to that MIME type.

2. Create a new .desktop file named, for example, myapplication1.desktop, and place it in the ~/.local/share/applications/ directory with following content:

   [Desktop Entry]
   Type=Application
   MimeType=application/x-newtype
   Name=My Application 1
   Exec=myapplication1

   The sample myapplication1.desktop file above associates the application/x-newtype MIME type with an application named My Application 1. It is run by a command myapplication1.

3. Update the MIME database for your changes to take effect:

   $ update-mime-database ~/.local/share/mime

4. Update the application database:

   $ update-desktop-database ~/.local/share/applications

Verification steps

1. To verify that you have successfully associated *.xyz files with the application/x-newtype MIME type, first create an empty file, for example, test.xyz and execute the following commands:

   $ touch test.xyz
   
   $ gvfs-info test.xyz | grep "standard::content-type"
     standard::content-type: application/x-newtype

2. To verify that myapplication1.desktop is correctly set as the default registered application for the application/x-newtype MIME type, execute following command:

   $ gio mime --query application/x-newtype
   Default application for 'application/x-newtype': myapplication1.desktop
   Registered applications:
   	myapplication1.desktop
   Recommended applications:
   	myapplication1.desktop

7.4. Options to override default MIME types

By default, the package-installed /usr/share/applications/mimeapps.list and /usr/share/applications/gnome-mimeapps.list files specify which application is registered to open specific MIME types.

System administrators can create the /etc/xdg/mimeapps.list or /etc/xdg/gnome-mimeapps.list file with a list of MIME types they want to override with the default registered application.

Local users can create the ~/.local/share/applications/mimeapps.list or ~/.local/share/applications/gnome-mimeapps.list file with a list of MIME types for which they want to override the default registered application.

Configurations are applied in the following order:

1. /usr/share/applications/
2. /etc/xdg/
3. ~/.local/share/application/

Within a particular location, the configurations are applied in the following order:

1. mimeapps.list
2. gnome-mimeapps.list

7.5. Overriding default registered application for all the users

As a system administer, you can update the configuration based on the requirements. System administrator’s configuration takes precedence over default package configuration. Within each, the desktop-specific configuration takes precedence over the configuration that does not specify the desktop environment.

Procedure

1. Consult the /usr/share/applications/mimeapps.list file to determine the MIME types for which you want to change the default registered application. For example, the following sample of the mimeapps.list file specifies the default registered application for the text/html and application/xhtml+xml MIME types:

   [Default Applications]
   text/html=firefox.desktop
   application/xhtml+xml=firefox.desktop

   This example above specifies default application (Firefox) by specifying its corresponding .desktop file (firefox.desktop). You can find .desktop files for other applications in the /usr/share/applications/ directory.

2. Create the /etc/xdg/mimeapps.list file and specify the MIME types and their corresponding default registered applications in this file.

   [Default Applications]
   text/html=myapplication1.desktop
   application/xhtml+xml=myapplication2.desktop

   This example above sets the default registered application for the text/html MIME type to myapplication1.desktop and application/xhtml+xml MIME type to myapplication2.desktop.

Verification steps

• For these settings to function correctly, ensure that both the myapplication1.desktop and myapplication2.desktop files are placed in the /usr/share/applications/ directory.

• Execute the gio mime query command to verify that the default registered application is set correctly.

  $ gio mime text/html
  Default application for 'text/html': myapplication1.desktop
  Registered applications:
  	myapplication1.desktop
  	firefox.desktop
  Recommended applications:
  	myapplication1.desktop
  	firefox.desktop

7.6. Overriding default registered application for individual users

Individual users can also update the configuration based on the requirements. This configuration takes precedence over the system administrator’s configuration and the system administrator’s configuration takes precedence over the package configuration. Within each, the desktop-specific configuration takes precedence over the configuration that does not specify the desktop environment.

Procedure

1. Consult the /usr/share/applications/mimeapps.list file to determine the MIME types for which you want to change the default registered application. For example, the following sample of the mimeapps.list file specifies the default registered application for the text/html and application/xhtml+xml MIME types:

   [Default Applications]
   text/html=firefox.desktop
   application/xhtml+xml=firefox.desktop

   This example above specifies default application (Firefox) by specifying its corresponding .desktop file (firefox.desktop). You can find .desktop files for other applications in the /usr/share/applications/ directory.

2. Create the ~/.local/share/applications/mimeapps.list file and specify the MIME types and their corresponding default registered applications in this file.

   [Default Applications]
   text/html=myapplication1.desktop
   application/xhtml+xml=myapplication2.desktop

   This example above sets the default registered application for the text/html MIME type to myapplication1.desktop and application/xhtml+xml MIME type to myapplication2.desktop.

Verification steps

• For these settings to function correctly, ensure that both the myapplication1.desktop and myapplication2.desktop files are placed in the /usr/share/applications/ directory.

• Execute the gio mime query command to verify that the default registered application is set correctly.

  $ gio mime text/html
  Default application for 'text/html': myapplication1.desktop
  Registered applications:
  	myapplication1.desktop
  	firefox.desktop
  Recommended applications:
  	myapplication1.desktop
  	firefox.desktop

8.1. Customizing desktop backgrounds

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.

8.2. Using GNOME Shell extensions to customize desktop environment

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

9.1. Changing the language using desktop GUI

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

Prerequisites

• Required language packages are installed on your system

Procedure

1. Open the GNOME Control Center from the System menu by clicking on its icon.

   

2. In the GNOME Control Center, choose Region & Language from the left vertical bar.

3. Click the Language menu.

   

4. Select the required region and language from the menu.

   

   If your region and language are not listed, scroll down, and click More to select from available regions and languages.

   

5. Click Done.

6. Click Restart for changes to take effect.

   

Some applications do not support certain languages. The text of an application that cannot be translated into the selected language remains in US English.

9.2. Enabling the CTRL+ALT+BACKSPACE shortcut

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:

• A program caused X.Org to stop working.
• You need to switch from your logged-in session quickly.
• You have launched a program that failed.
• You cannot operate in the current session.
• Your screen freezes.

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.

Procedure

1. Create a local database for machine-wide settings in /etc/dconf/db/local.d/00-input-sources:

   [org/gnome/desktop/input-sources]
   # Enable Ctrl-Alt-Backspace for all users
   xkb-options=['terminate:ctrl_alt_bksp']

2. Override the user’s setting, and prevent the user from changing it in /etc/dconf/db/local.d/locks/input-sources:

   # Lock the list of enabled XKB options
   /org/gnome/desktop/input-sources/xkb-options

3. Update the system databases for the changes to take effect:

   # dconf update

4. Users must log out and back in again before the system-wide settings take effect.

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

9.3. Disabling command-line access

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

• Section 9.3.1, “Setting the org.gnome.desktop.lockdown.disable-command-line Key”
• Section 9.3.2, “Disabling virtual terminal switching on X.Org”
• Remove Terminal and any other application that provides access to the terminal from the Applications menu and Activities Overview in GNOME Shell. This is done by removing menu items for those applications.

The following steps do not remove the desktop user’s permissions to access a command line, but rather remove the ways that the desktop user could access command line.

9.4. Preventing the computer from suspending when closing the lid

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.

Some laptops can overheat if they are left running with the lid closed, especially if they are in a confined place. Therefore, consider whether changing the default setting from suspend to an other option is beneficial in your case.

Procedure

1. Open the /etc/systemd/logind.conf file for editing.

2. Find the HandleLidSwitch=suspend line in the file.

   If it is quoted out with the # character at the start, unquote it by removing #.

   If the line is not present in the file, add it.

3. Replace the default suspend parameter with:

   • lock for the screen to lock
   • ignore for nothing to happen
   • poweroff for the computer to switch off

   For example:

   [Login]
   HandleLidSwitch=lock

4. Save your changes, and close the editor.

5. Run the following command so that your changes preserve the next restart of the system:

   # systemctl restart systemd-logind.service

   Restarting the service forcibly interrupts any currently running GNOME session of any desktop user who is logged in. This can result in users losing unsaved data.

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

9.5. Changing behavior when pressing the power button in graphical target mode

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:

Procedure

1. Create a local database for system-wide settings in the /etc/dconf/db/local.d/01-power file:

   [org/gnome/settings-daemon/plugins/power]
   power-button-action='interactive'

2. Override the user’s setting, and prevent the user from changing it in the /etc/dconf/db/local.d/locks/01-power file:

   /org/gnome/settings-daemon/plugins/power/power-button-action

3. Update the system databases:

   # dconf update

4. Log out and back in again before the system-wide settings take effect.

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:

• nothing

  does nothing

• suspend

  suspends the system

• hibernate

  hibernates the system

• interactive

  shows a pop-up query asking the user what to do

  With interactive mode, the system powers off automatically after 60 seconds when hitting the power button. However, you can choose a different behavior from the pop-up query as shown in the figure below.

  Pop-up query for interactive mode

  

10.2. Notifying of the system security classification

You can set up a notification that contains a predefined message in an overlay banner. This is useful for deployments where the user is required to read the security classification of the system before logging in.

Depending on your configuration, the notification can appear at the login screen, after logging in, on the lock screen, or after a longer time with no user activity. You can always dismiss the notification when it appears.

Procedure

1. Install the gnome-shell-extension-heads-up-display package:

   # yum install gnome-shell-extension-heads-up-display

2. Create the 99-hud-message file at either of the following locations:

   • To configure a notification at the login screen, create /etc/dconf/db/gdm.d/99-hud-message.
   • To configure a notification in the user session, create /etc/dconf/db/local.d/99-hud-message.

3. Enter the following configuration in the created file:

   [org/gnome/shell]
   enabled-extensions=['']
   
   [org/gnome/shell/extensions/heads-up-display]
   message-heading="Security classification title"
   message-body="Security classification description"
   # The following options control when the notification appears:
   show-when-locked=true
   show-when-unlocking=true
   show-when-unlocked=true

   Replace the following values with text that describes the security classification of your system:

   Security classification title A short heading that identifies the security classification. Security classification description A longer message that provides additional details, such as references to various guidelines.

   This configuration overrides similar configuration files that also enable an extension, such as Enabling system security classification banners.

   To enable multiple extensions, specify all of them in the enabled-extensions list. For example:

   enabled-extensions=['', '']

4. Update the dconf database:

   # dconf update

5. Reboot the system.

Troubleshooting

• If the notifications are not displayed for an existing user, log in as the user and enable the Heads-up display message extension using the Tweaks application.

11.1. Input methods

Certain scripts, such as Chinese, Japanese, or Korean, require keyboard input to go through an Input Method Engine (IME) to enter native text.

An input method is a set of conversion rules between the text input and the selected script. An IME is a software that performs the input conversion specified by the input method.

To input text in these scripts, you must set up an IME. If you installed the system in your native language and selected your language at the GNOME Initial Setup screen, the input method for your language is enabled by default.

11.2. Available input method engines

The following input method engines (IMEs) are available on RHEL from the listed packages:

Table 11.1. Available input method engines

11.3. Installing input method engines

This procedure installs input method engines (IMEs) that you can use to input Chinese, Japanese, and Korean text.

Procedure

• Install all available input method packages:

  # yum install @input-methods

11.4. Switching the input method in GNOME

This procedure sets up the input method for your script, such as for Chinese, Japanese, or Korean scripts.

Prerequisites

• The input method packages are installed.

Procedure

1. Go to the system menu, which is accessible from the top-right screen corner, and click Settings.
2. Select the Region & Language section.

3. In the Input Sources list, review the currently enabled input methods.

   

4. If your input method is missing:

   1. Click the + button under the Input Sources list.

      

   2. Select your language.

      

      If you cannot find your language in the menu, click the three dots icon (More…) at the end of the menu.

   3. Select the input method that you want to use. A cog wheel icon marks all input methods to distinguish them from simple keyboard layouts.

      

   4. Confirm your selection by clicking Add.

5. Switch the active input method using one of the following ways:

   • Click the input method indicator on the right side of the top panel and select your input method.

     

   • Switch between the enabled input methods using the Super+Space keyboard shortcut.

Verification

1. Open a text editor.
2. Type text in your language.
3. Verify that the text appears in your native script.

12.1. Enabling the Compose key

You can enable the Compose key either for an individual user or for all users.

12.2. Using the Compose key to input characters

This procedure shows how to use the Compose key.

Prerequisites

• The Compose key is enabled on your system.

Procedure

1. Press and release the Compose key.
2. Type the key combination to get the specific symbol. For example, type A E (in capitals) to get Æ, or in lowercase to get æ.

12.3. The Compose key sequences

This section lists some of the Compose key sequences and their resulting characters.

Table 12.1. Common sequences

Additional resources

• For more key sequences, see the X.Org webpage.

13.1. Typing emoji characters in GTK applications

This procedure inserts an emoji character in an application that uses the GTK graphical toolkit, such as in native GNOME applications.

Prerequisites

• Make sure that the application is built on the GTK toolkit.

Procedure

1. Open a GTK application.
2. Make sure that a text field is active.

3. Press Ctrl+..

   The emoji selection menu opens.

4. Browse the emoji characters or type a keyword that identifies the emoji character that you want to insert, such as smile.

   For the full list of keywords associated with emoji characters, see the Other Keywords column on the Emoji List page.

5. Click the selected character, or navigate to it using the cursor keys and press Enter.

Verification

• Check that the intended emoji character now appears at your cursor.

13.2. Typing emoji characters in any applications

This procedure inserts an emoji character in any application, regardless of the graphical toolkit that the application uses.

Procedure

1. Open an application.
2. Make sure that a text field is active.

3. Press Ctrl+Shift+e.

   The underscored letter e appears at your cursor.

4. Type a keyword that identifies the emoji character that you want to insert, such as smile.

   For the full list of keywords associated with emoji characters, see the Other Keywords column on the Emoji List page.

5. Repeatedly press Space to browse the emoji characters that match your keyword.
6. Confirm the selected emoji character by pressing Enter.

Verification

• Check that the intended emoji character now appears at your cursor.

14.1. The GVFS system

This section introduces GVFS and explains how GVFS works.

GVFS provides complete virtual file system infrastructure and handles storage in the GNOME desktop. It uses addresses for full identification based on the Uniform Resource Identifier (URI) standard, syntactically similar to URL addresses in web browsers. These addresses in the form of schema://user@server/path are the key information determining the kind of service.

GVFS helps to mount the resources. These mounts are shared between multiple applications. Resources are tracked globally within the running desktop session, which means that even if you quit an application that triggered the mount, the mount continues to be available for any other application. Multiple applications can access the mount at the same time unless it is limited by a back end. Some protocols by design permit only a single channel.

GVFS mounts removable media in the /run/media/ directory.

14.2. The format of the GVFS URI string

This section explains what the GVFS URI string is and demonstrates how to form one.

You must form a URI string to use back end services. This string is a basic identifier used in GVFS, which carries all necessary information needed for unique identification, such as type of service, back end ID, absolute path, or user name if required. You can see this information in the Files address bar and GTK+ open or save file dialog.

The following example is a very basic form of the URI string, which points to a root directory (/) of the File Transfer Protocol (FTP) server running at the ftp.myserver.net domain:

Example 14.1. A URI string pointing to the root FTP directory

Example 14.2. A URI string pointing to a text file on FTP

ssh:///home/joe/todo.txt

14.3. Mounting a storage volume in GNOME

In virtual file systems, particular resources are set to be mounted automatically, but the most common way is to trigger mounts manually.

Procedure

1. Open the Files application.
2. Click Other Locations in the side bar.
3. Enter the URI string in the Connect to Server field.
4. Press Connect.
5. If the dialog asks you for login credentials, enter your name and password into the relevant entry boxes.
6. When the mounting process finishes, you can start working with the storage volume.

14.4. Unmounting a storage volume in GNOME

You can unmount storage volumes or resources using the following procedure.

Procedure

1. Open the Files application.
2. In the side bar, click the Unmount (⏏) icon next to the chosen mount.
3. Wait until the mount disappears or notification about the safe removal appears.

14.5. Access to GVFS mounts in the file system

This section introduces FUSE, the main daemon for the GVFS virtual file system.

Applications built with the GIO library can access GVFS mounts. In addition, GVFS provides a FUSE daemon which exposes active GVFS mounts. Any application can access active GVFS mounts using the standard POSIX APIs as though mounts were regular file systems.

In certain applications, additional library dependency and new virtual file system (VFS) subsystem specifics might be unsuitable or too complicated. For such reasons and to boost compatibility, GVFS provides a File System in Userspace (FUSE) daemon, which exposes active mounts through its mount for standard Portable Operating System Interface (POSIX) access. This daemon transparently translates incoming requests to imitate a local file system for applications.

You might experience difficulties with certain combinations of applications and GVFS back ends.

The FUSE daemon starts automatically with the main gvfs daemon and mounts volumes either in the /run/user/UID/gvfs/ or ~/.gvfs/ directories as a fallback.

Manual browsing shows individual directories for each GVFS mount. The system passes the transformed path as an argument when you are opening documents from GVFS locations with non-native applications. Note that native GIO applications automatically translate this path back to a native URI.

14.6. Available GIO commands

GIO provides several commands that might be useful for scripting or testing.

Here is a set of POSIX commands counterparts as follows:

Following additional commands provide more control of GIO specifics:

For user convenience, bash completion is provided as a part of the package.

All these commands are native GIO clients, there is no need for the fallback FUSE daemon to be running. Their purpose is not to be drop-in replacements for POSIX commands, in fact, a very little range of switches is supported. In their basic form, these commands take an URI string as an argument instead of a local path.

Additional resources

• The gio(1) man page.

14.7. Sample GIO commands

The following section provides a few examples of the GIO commands usage.

Example 14.3. List all files in the local /tmp directory

Example 14.4. List the content of a text file from a remote system

$ gio cat ssh:///home/joe/todo.txt

Example 14.5. Copy the previous text file to a local /tmp directory

$ gio copy ssh:///home/joe/todo.txt /tmp/

Additional resources

• The gio man page.

14.8. Overview of GVFS metadata

This section provides information on the GVFS metadata and provides instruction on how to view and manipulate them.

The GVFS metadata storage is implemented as a set of key-and-value pairs that bind information to a particular file. Thus, there is a tool for a user or application to save small data designed for runtime information such as icon position, last-played location, position in a document, emblems, notes, and so on.

Whenever you move a file or directory, GVFS moves the metadata accordingly so that metadata stays connected to the respective file. The GVFS stores all metadata privately, so metadata is available only on the machine. However, GVFS tracks mounts and removable media as well.

GVFS mounts removable media in the /run/media/ directory.

To view and manipulate with metadata, you can use:

• the gio info command,
• the gio set command, or
• any other native GIO way of working with attributes.

Additional resources

• The gio man page.

14.9. Setting custom GIO metadata attribute

This procedure describes how to set a custom metadata attribute.

Notice the differences between particular gio info calls and data persistence after a move or rename. Note the gio info command output.

Procedure

1. Create an empty file:

   $ touch /tmp/myfile

2. View the metadata of this file:

   $ gio info -a 'metadata::*' /tmp/myfile
   uri: file:///tmp/myfile
   attributes:

3. Set a string to this file:

   $ gio set -t string /tmp/myfile 'metadata::mynote' 'Please remember to delete this file!'

4. View the metadata:

   $ gio info -a 'metadata::*' /tmp/myfile
   uri: file:///tmp/myfile
   attributes:
     metadata::mynote: Please remember to delete this file!

5. Move this file to a new location:

   $ gio move /tmp/myfile /tmp/newfile

6. View the metadata:

   $ gio info -a 'metadata::*' /tmp/newfile
   uri: file:///tmp/newfile
   attributes:
     metadata::mynote: Please remember to delete this file!

The metadata persists when you move the file using the GIO API.

Additional resources

• The gio man page.

14.10. Password management of GVFS mounts

This section focuses on the GVFS mount authentication.

A typical GVFS mount authenticates on its activation unless the resource allows anonymous authentication or does not require any authentication at all.

In a standard GTK+ dialog, you can choose whether to store the password.

When you select the persistent storage, the password is stored in the user keyring. GNOME Keyring is a central place for secrets storage. The password is encrypted and automatically unlocked on desktop session start using the password provided on login. For protecting it by a different password, you can set the password at the first use.

The Passwords and Keys application helps to manage the stored password and GNOME Keyring. It allows removing individual records or changing passwords.

14.11. GVFS back ends

Back ends in GVFS provide access to a specific type of resource. This section provides a list of available GVFS back ends and their specifications.

Some back ends are packaged separately and not installed by default. For installing additional back ends, use the yum package manager.

Table 14.1. Available back ends

15.1. Troubleshooting access to GVFS locations from non-GIO clients

If you have problems accessing GVFS locations from your application, it might mean that it is not native GIO client. Native GIO clients are typically all GNOME applications using GNOME libraries (glib, gio). The gvfs-fuse service is provided as a fallback for non-GIO clients.

Prerequisite

• The gvfs-fuse package is installed.

  $ yum install gvfs-fuse

Procedure

1. Ensure that gvfs-fuse is running.

   $ ps ax | grep gvfsd-fuse

   If gvfs-fuse is not running, log out and log back in. Red Hat does not recommend starting gvfs-fuse manually.

2. Find the system user ID (UID) for the /run/user/UID/gvfs/ path.

   The gvfsd-fuse daemon requires a path where it can expose its services. When the /run/user/UID/gvfs/ path is unavailable, gvfsd-fuse uses the ~/.gvfs path.

   $ id -u

3. If gvfsd-fuse is still not running, start the gvfsd-fuse daemon:

   $ /usr/libexec/gvfsd-fuse -f /run/user/_UID_/gvfs

   Now, the FUSE mount is available, and you can manually browse for the path in your application.

4. Find the GVFS mounts under the /run/user/UID/gvfs/ or ~/.gvfs locations.

15.2. Troubleshooting an invisible connected USB disk

Under certain circumstances, when you connect a flash drive, the GNOME Desktop might not display it. If your flash drive is not visible in Files, but you can see it in the Disks application, you can attempt to set the Show in user interface option in Disks.

Procedure

1. Open the Disks application.
2. Select the disk in the side bar.
3. Below Volumes, Click → .
4. Click Show in user interface.
5. Confirm by clicking OK.
6. If the flash drive is still not visible, you can try to physically remove the drive and try connecting it again.

15.3. Troubleshooting unknown or unwanted partitions listed in Files

Sometimes, you might see unknown or unwanted partitions when you plug a disk in. For example, when you plug in a flash disk, it is automatically mounted and its volumes are shown in the Files side bar. Some devices have a special partition with backups or help files, which you might not want to see each time you plug in the device.

Procedure

1. Open the Disks application.
2. Select the disk in the side bar.
3. Below Volumes, Click → .
4. Uncheck Show in user interface.
5. Confirm by clicking OK.

15.4. Troubleshooting if a connection to the remote GVFS file system is unavailable

There are number of situations in which the client is unexpectedly and unwillingly disconnected from a virtual file system or a remote disk mount and is not reconnected automatically.

You might see the error messages in such situations. Several causes trigger such situations:

• The connection is interrupted. For example, your laptop is disconnected from the Wi-Fi.
• The user is inactive for some time and is disconnected by the server (idle timeout).
• The computer is resumed from sleep mode.

Procedure

1. Unmount file system.
2. Mount it again.
3. If the connection is getting disabled more often, check the settings in the Network panel in the GNOME Settings.

15.5. Troubleshooting a busy disk in GNOME

If you receive a notification about your disk being busy, determine the programs that are accessing the disk. Then, you can end the programs that are running. You can also use the System Monitor application to kill the programs forcefully.

Prerequisites

• The iotop utility is installed:

  # yum install iotop

Procedure

1. Examine the list of open files.

   • Run the lsof command to get the list of open files.
   • If lsof is not available, run the ps ax command.
   • You can use System Monitor to display the running processes in a GUI.

2. When you have determined the programs, terminate them using any of the following methods:

   • On the command line, execute the kill command.
   • In System Monitor, right-click the line with the program process name, and click End or Kill from the context menu.

Additional resources

• The kill man page.

16.1. Bookmarks in GNOME

Bookmarks integrate into GTK+ and in the GNOME desktop. Every application that presents a standard GTK+ Open and Save dialog (GtkFileChooser) lists bookmarks in the left panel of the dialog. Also, Files and its clones present bookmarks in a sidebar.

Besides bookmarks, GtkFileChooser lists all other available GVFS volumes and mounts in the sidebar.

While activating a bookmark for the first time, the GVFS subsystem looks for existing mounts and tries to mount the location if the mount does not exist yet. This way, you can authenticate even within the Open or Save dialog.

Bookmarks are located in the ~/.config/gtk-3.0/bookmarks file. In the following example, the bookmarked locations are ~/Music, ~/Pictures, ~/Videos, ~/Downloads, and ~/bin, so the content of the ~/.config/gtk-3.0/bookmarks file looks as follows:

file:///home/username/Music
file:///home/username/Pictures
file:///home/username/Videos
file:///home/username/Downloads
file:///home/username/bin

Replace username with the user name you are logged in.

You can use this file to edit bookmarks based on your requirements.

16.2. Adding a bookmark in Files

You can save a reference to a location by bookmarking it.

Procedure

1. Select the folder or file you want to bookmark.

2. Do one of the following:

   • Press Ctrl+D or
   • Drag and drop the file or folder to the sidebar.

16.3. Bookmarks for all GNOME users

System administrators can set a group of bookmarks for all users at once by allowing access to file shares for the users. GNOME stores a list of file-sharing servers in the ~/.config/gtk-3.0/servers file in the XBEL format. XML Bookmark Exchange Language (XBEL) is an XML standard that allows you share URIs (Uniform Resource Identifiers). It is possible to add the list of file-sharing servers to that file to make file-shares easily accessible to multiple users.

In GNOME, XBEL is used to share desktop bookmarks in applications like Files. Here is an example of creating a bookmark titled GNOME FTP with the URI ftp://ftp.gnome.org/ in the ~/.config/gtk-3.0/servers file.

<?xml version="1.0" encoding="UTF-8"?>
<xbel version="1.0"
      xmlns:bookmark="http://www.freedesktop.org/standards/desktop-bookmarks"
      xmlns:mime="http://www.freedesktop.org/standards/shared-mime-info">
   <bookmark href="ftp://ftp.gnome.org/">
      <title>GNOME FTP</title>
   </bookmark>
</xbel>

17.1. Setting different favorite applications for individual users

You can set the default favorite applications for individual users.

Procedure

1. Open the Activities overview by clicking Activities at the top left of the screen.

2. Add applications into your favorite list using any of the following methods:

   • Click the grid button to find the application you want, right-click the application icon, and select Add to Favorites.
   • Click-and-drag the icon into the dash.

3. View all the applications that exists in the favorite list:

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

17.2. Setting the same favorite applications for all users

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.

Procedure

1. Create the key file /etc/dconf/db/local.d/00-favorite-apps to provide information for the local database. /etc/dconf/db/local.d/00-favorite-apps contents:

   # Snippet sets gedit, terminal and nautilus as default favorites for all users
   [org/gnome/shell]
   favorite-apps = ['gedit.desktop', 'gnome-terminal.desktop', 'nautilus.desktop']

2. To prevent users from overriding these settings, create the file /etc/dconf/db/local.d/locks/favorite-apps with the following content:

   # Lock default favorite applications
   /org/gnome/shell/favorite-apps

3. Run the dconf update command to incorporate your changes into the system databases.
4. Logout and login again for system-wide changes to take effect.

18.1. Using enterprise credentials to authenticate in GNOME

You can use your enterprise domain credentials to access your system. This section explains how to log in using enterprise credentials in GNOME, configure enterprise credentials at the GNOME welcome screen, and add an authenticated user with enterprise credentials in GNOME.

18.2. Enabling smart card authentication

You can enable workstations to authenticate using smart cards. In order to do so, you must configure GDM to allow prompting for smart cards and configure operating system to log in using a smart card.

You can use two ways to configure the GDM to allow prompting for smart card authentication with GUI or using the command line.

18.3. Fingerprint authentication

You can use the system-config-authentication tool to enable fingerprint authentication to allow users to login using their enrolled fingerprints. The tool is provided by the authconfig-gtk package.

19.1. Locking down printing

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.

The feature only works in applications which support it. Not all GNOME and third party applications have this feature enabled. The changes do not have effect on applications which do not support this feature.

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

Procedure

1. Create the user profile in /etc/dconf/profile/user unless it already exists:

   user-db:user
   system-db:local

2. Create a local database for machine-wide settings in the etc/dconf/db/local.d/00-lockdown file:

   [org/gnome/desktop/lockdown]
   
   # Prevent applications from printing
   disable-printing=true

3. Override the user’s setting and prevent the user from changing it in the /etc/dconf/db/local.d/locks/lockdown file:

   # List the keys used to configure lockdown
   /org/gnome/desktop/lockdown/disable-printing

4. Update the system databases:

   # dconf update

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

19.2. Locking file saving on disk

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.

The feature only works in applications which support it. Not all GNOME and third party applications have this feature enabled. The changes will have no effect on applications which do not support this feature.

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

Procedure

1. Create the user profile in /etc/dconf/profile/user unless it already exists:

   user-db:user
   system-db:local

2. Create a local database for machine-wide settings in the /etc/dconf/db/local.d/00-lockdown file:

   [org/gnome/desktop/lockdown]
   
   # Prevent the user from saving files on disk
   disable-save-to-disk=true

3. Override the user’s setting and prevent the user from changing it in the /etc/dconf/db/local.d/locks/lockdown file:

   # Lock this key to disable saving files on disk
   /org/gnome/desktop/lockdown/disable-save-to-disk

4. Update the system databases:

   # dconf update

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.

19.3. Locking repartitioning

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.

polkit configuration stored in /etc overrides the configuration shipped by packages in /usr/share/.

Procedure

1. Create a file with the same content as in /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy:

   cp /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy /etc/share/polkit-1/actions/org.freedesktop.udisks2.policy

   Do not change the /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy file, your changes will be overwritten by the next package update.

2. Delete the action you do not need, and add the following lines to the /etc/polkit-1/actions/org.freedesktop.udisks2.policy file:

   <action id="org.freedesktop.udisks2.modify-device">
     <message>Authentication is required to modify the disks settings</message>
        <defaults>
           <allow_any>no</allow_any>
           <allow_inactive>no</allow_inactive>
           <allow_active>yes</allow_active>
         </defaults>
    </action>

   Replace no by auth_admin if you want to ensure only the root user is able to perform the action.

3. Save the changes.

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

Authentication is required to modify the disks settings.

19.4. Locking down user logout and user switching

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

Procedure

1. Create the /etc/dconf/profile/user profile, which contains the following lines:

   user-db:user
   system-db:local

   where local is the name of a dconf database

2. Create the /etc/dconf/db/local.d/ directory if it does not already exist.

3. Create the /etc/dconf/db/local.d/00-logout key file to provide information for the local database:

   [org/gnome/desktop/lockdown]
   # Prevent the user from user switching
   disable-log-out=true

4. Override the user’s setting, and prevent the user from changing it in the /etc/dconf/db/local.d/locks/lockdown file:

   # Lock this key to disable user logout
   /org/gnome/desktop/lockdown/disable-log-out

5. Update the system databases:

   # dconf update

6. Users must log out and back in again before the system-wide settings take effect.

Users can evade the logout lockdown by switching to a different user. To prevent such scenario, lock down user switching as well.

To lock down user switching, use the following procedure:

Procedure

1. Create the /etc/dconf/profile/user profile, which contains the following lines:

   user-db:user
   system-db:local

   where local is the name of a dconf database

2. Create the /etc/dconf/db/local.d/ directory if it does not already exist.

3. Create the /etc/dconf/db/local.d/00-user-switching key file to provide information for the local database:

   # Prevent the user from user switching
   [org/gnome/desktop/lockdown]
   disable-user-switching=true
   
   [org/gnome/desktop/screensaver]
   user-switch-enabled=false

4. Override the user’s setting, and prevent the user from changing it in the /etc/dconf/db/local.d/locks/lockdown file:

   # Lock this key to disable user switching
   /org/gnome/desktop/lockdown/disable-user-switching
   /org/gnome/desktop/screensaver/user-switch-enabled

5. Update the system databases:

   # dconf update

6. Users must log out and back in again before the system-wide settings take effect.

20.1. Single-application mode

Single-application mode is a modified GNOME session that reconfigures the Mutter window manager into an interactive kiosk. This session locks down certain behavior to make the standard desktop more restrictive. The user can interact only with a single application selected by the administrator.

You can set up single-application mode in a number of fields, from communication to entertainment or education, and use it as a self-serve machine, an event manager, a registration point, and so on.

The single-application mode configuration is available from the gnome-session-kiosk-session package.

20.2. Enabling single-application mode

This procedure installs and enables single-application mode, which restricts the GNOME session to a single application.

Procedure

1. Install the gnome-session-kiosk-session package:

   # yum install gnome-session-kiosk-session

2. As the user that will open the single-application session, create the /home/user/.local/bin/redhat-kiosk file:

   [user]$ mkdir -p ~/.local/bin
   
   [user]$ touch ~/.local/bin/redhat-kiosk

3. Edit the /home/user/.local/bin/redhat-kiosk file and enter the executable name of the application that you want to launch in single-application mode.

   For example, to launch the Firefox browser in single-application mode, enter the following content:

   #!/bin/sh
   
   while true; do
       firefox --kiosk https://example.org
   done

   The while true loop ensures that the application restarts if it terminates for any reason.

4. Make the file executable:

   [user]$ chmod +x ~/.local/bin/redhat-kiosk

5. If you created the file or its containing directories as a different user than the single-application user, such as root, ensure that the file has the correct permissions:

   # chown -R user:group ~user/.local

6. At the GNOME login screen, select the Kiosk session from the cogwheel button menu and log in as the single-application user.

21.1. What GDM is

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.

21.2. Restarting GDM

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.

Restarting the service forcibly interrupts any currently running GNOME session of any desktop user who is logged in. This can result in users losing unsaved data.

Procedure

• To restart the GDM service, run the following command:

  # systemctl restart gdm.service

Procedure

• To display results of the GDM configuration, run the following command:

  $ DCONF_PROFILE=gdm gsettings list-recursively org.gnome.login-screen

21.3. Adding an autostart application for all users

You can set application to start automatically when any user logs into the GNOME environment.

Procedure

1. Create a .desktop file in the /etc/xdg/autostart/ directory, such as /etc/xdg/autostart/nautilus.desktop. Enter the following content in the file:

   [Desktop Entry]
   Type=Application
   Name=Files
   Exec=/usr/bin/nautilus -n
   OnlyShowIn=GNOME;
   X-GNOME-Autostart-enabled=true

   • Replace Files with the name of the application.
   • Replace /usr/bin/nautilus -n with the command that starts the application. Use the full file path.

2. Optionally, configure the application to start only when a selected GSettings key is enabled. GNOME then runs the application automatically if the key’s value is true. If the key’s value changes in the running session, GNOME starts or stops the application to match the new value.

   Add the following line in the .desktop file:

   AutostartCondition=GSettings org.gnome.desktop.background show-desktop-icons

   • Replace org.gnome.desktop.background show-desktop-icons with the GSettings schema and key that the automatic start depends on.

Additional resources

• You can also configure an autostart application for a specific user. Use the Tweaks application, which is available from the gnome-tweaks package.

21.4. Configuring automatic login

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 following procedure to set up automatic login for a user john.

Procedure

• Edit the /etc/gdm/custom.conf file, and make sure that the [daemon] section in the file specifies the following:

  [daemon]
  AutomaticLoginEnable=True
  AutomaticLogin=john

  Replace john with the user that you want to be automatically logged in.

21.5. Configuring automatic logout

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.

Users can potentially lose unsaved data if an idle session is automatically ended.

To set automatic logout for a mains powered machine:

Procedure

1. Create a local database for machine-wide settings in the /etc/dconf/db/local.d/00-autologout file:

   [org/gnome/settings-daemon/plugins/power]
   # Set the timeout to 900 seconds when on mains power
   sleep-inactive-ac-timeout=900
   # Set action after timeout to be logout when on mains power
   sleep-inactive-ac-type='logout'

2. Override the user’s setting, and prevent the user from changing it in the /etc/dconf/db/local.d/locks/autologout file:

   # Lock automatic logout settings
   /org/gnome/settings-daemon/plugins/power/sleep-inactive-ac-timeout
   /org/gnome/settings-daemon/plugins/power/sleep-inactive-ac-type

3. Update the system databases:

   # dconf update

4. Users must log out and back in again before the system-wide settings take effect.

The following GSettings keys are of interest:

• org.gnome.settings-daemon.plugins.power.sleep-inactive-ac-timeout

  The number of seconds that the computer needs to be inactive before it goes to sleep if it is running from AC power.

• org.gnome.settings-daemon.plugins.power.sleep-inactive-ac-type

  What should happen when the timeout has passed if the computer is running from AC power.

• org.gnome.settings-daemon.plugins.power.sleep-inactive-battery-timeout

  The number of seconds that the computer needs to be inactive before it goes to sleep if it is running from power.

• org.gnome.settings-daemon.plugins.power.sleep-inactive-battery-type

  What should happen when the timeout has passed if the computer is running from battery power.

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

Procedure

• Run the gsettings range command on the required key. For example:

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

21.6. Setting a default desktop session for all users

You can configure a default desktop session that is preselected for all users that have not logged in yet.

If a user logs in using a different session than the default, their selection persists to their next login.

Procedure

1. Copy the configuration file template:

   # cp /usr/share/accountsservice/user-templates/standard \
        /etc/accountsservice/user-templates/standard

2. Edit the new /etc/accountsservice/user-templates/standard file. On the Session=gnome line, replace gnome with the session that you want to set as the default.

3. Optional: To configure an exception to the default session for a certain user, follow these steps:

   1. Copy the template file to /var/lib/AccountsService/users/user-name:

      # cp /usr/share/accountsservice/user-templates/standard \
           /var/lib/AccountsService/users/user-name

   2. In the new file, replace variables such as ${USER} and ${ID} with the user values.
   3. Edit the Session value.

21.7. Setting screen brightness and idle time

This section describes how to:

• Configure the drop in the brightness level
• Set brightness level
• Set idle time

Configuring the drop in the brightness level

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

Procedure

1. Create a local database for machine-wide settings in the /etc/dconf/db/local.d/00-power file including these lines:

   [org/gnome/settings-daemon/plugins/power]
   idle-dim=true

2. Update the system databases:

   # dconf update

3. Users must log out and back in again before the system-wide settings take effect.

Setting brightness level

To set brightness level:

Procedure

1. Create a local database for machine-wide settings in the /etc/dconf/db/local.d/00-power file, as in the following example:

   [org/gnome/settings-daemon/plugins/power]
   idle-brightness=30

   Replace 30 with the integer value you want to use.

2. Update the system databases:

   # dconf update

3. Users must log out and back in again before the system-wide settings take effect.

Setting idle time

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

Procedure

1. Create a local database for machine-wide settings in /etc/dconf/db/local.d/00-session, as in the following example:

   [org/gnome/desktop/session]
   idle-delay=uint32 900

   Replace 900 with the integer value you want to use.

   You must include the uint32 along with the integer value as shown.

2. Update the system databases:

   # dconf update

3. Users must log out and back in again before the system-wide settings take effect.

21.8. Locking the screen when the user is idle

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

Procedure

1. Create a local database for system-wide settings in the etc/dconf/db/local.d/00-screensaver file:

   [org/gnome/desktop/session]
   # Set the lock time out to 180 seconds before the session is considered idle
   idle-delay=uint32 180
   [org/gnome/desktop/screensaver]
   # Set this to true to lock the screen when the screensaver activates
   lock-enabled=true
   # Set the lock timeout to 180 seconds after the screensaver has been activated
   lock-delay=uint32 180

   You must include the uint32 along with the integer key values as shown.

2. Override the user’s setting, and prevent the user from changing it in the /etc/dconf/db/local.d/locks/screensaver file:

   # Lock desktop screensaver settings
   /org/gnome/desktop/session/idle-delay
   /org/gnome/desktop/screensaver/lock-enabled
   /org/gnome/desktop/screensaver/lock-delay

3. Update the system databases:

   # dconf update

4. Users must log out and back in again before the system-wide settings take effect.

21.9. Screencast recording

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:

Procedure

1. To start the recording, press the Ctrl+Alt+Shift+R shortcut.

   When the recorder is capturing the screen activity, it displays a red circle in the top-right corner of the screen.

2. To stop the recording, press the Ctrl+Alt+Shift+R shortcut.

   The red circle in the top-right corner of the screen disappears.

3. Navigate to the ~/Videos directory where you can find the recorded video with a file name that starts with Screencast and includes the date and time of the recording.

The built-in recorder always captures the entire screen, including all monitors in multi-monitor setups.

22.1. Configuring the screen rotation for a single user

This procedure sets screen rotation for the current user.

Procedure

1. Go to the system menu, which is accessible from the top-right screen corner, and click the Settings icon.
2. In the → section, choose Displays.
3. Configure the rotation using the Orientation field.
4. Confirm your choice by clicking Apply.
5. If you are satisfied with the new setup preview, click on Keep changes.

The setting persists to your next login.

22.2. Configuring the screen rotation for all users

This procedure sets a default screen rotation for all users on a system and is suitable for mass deployment of homogenized display configuration.

Procedure

1. Prepare the preferable setup for a single user as in Configuring the screen rotation for a single user.

2. Copy the transform section of the ~/.config/monitors.xml configuration file, which configures the screen rotation. An example portrait orientation:

   <?xml version="1.0" encoding="UTF-8"?>
   
   <transform>
     <rotation>left</rotation>
     <flipped>no</flipped>
   </transform>

3. Paste the content in the /etc/xdg/monitors.xml file that stores system-wide configuration.
4. Save the changes.

The new setup takes effect for all the users the next time they log in in the system.

23.1. Components that provide accessibility features

Accessibility for users with a visual impairment is ensured by the Orca screen reader on the Red Hat Enterprise Linux 8 desktop. Orca is included in the default RHEL installation.

Orca reads information from the screen and communicates it to you using the following components:

Speech synthesizer Provides a speech output. The default speech synthesizer on RHEL 8 is eSpeak-NG. Braille display Provides a tactile output. The BRLTTY service enables this functionality.

23.2. Configuring the brltty service

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

In order for the Braille display to work correctly, perform the following procedures.

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

serial:ttyUSB0

# dmesg | fgrep ttyUSB0

24.1. Preparing a tablet definition file

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

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

Prerequisites

• List all local devices recognized by libwacom:

  $ libwacom-list-local-devices

  Make sure that your device is recognized in the output.

  If your device is not listed, the device is missing from the libwacom database. However, the device might still be visible as an event device in the kernel under /proc/bus/input/devices, and if you use the X.Org display server, in the X11 session on the xinput list.

Procedure

1. Install the package that provides tablet definition files:

   # yum install libwacom-data

   The package installs tablet definitions in the /usr/share/libwacom/ directory.

2. Check whether the definition file is available in the /usr/share/libwacom/ directory.

   To use the screen mapping correctly, support for your tablet must be included in the libwacom database and in the udev rules file.

   A common indicator that a device is not supported by libwacom is that it works normally in a GNOME session, but the device is not correctly mapped to the screen.

3. If the definition file for your device is not available in /usr/share/libwacom/, you have these options:

   • The required definition file may already be available in the linuxwacom/libwacom upstream repository. You can try to find the definition file there. If you find your tablet model in the list, copy the file to the local machine.

   • You can create a new tablet definition file. Use the data/wacom.example file below, and edit particular lines based on the characteristics of your device.

     Example 24.1. Example model file description for a tablet

     [Device]
     
     # The product is the product name announced by the kernel
     Product=Intuos 4 WL 6x9
     
     # Vendor name of this tablet
     Vendor=Wacom
     
     # DeviceMatch includes the bus (usb, serial), the vendor ID and the actual
     # product ID
     DeviceMatch=usb:056a:00bc
     
     # Class of the tablet. Valid classes include Intuos3, Intuos4, Graphire, Bamboo, Cintiq
     Class=Intuos4
     
     # Exact model of the tablet, not including the size.
     Model=Intuos 4 Wireless
     
     # Width in inches, as advertised by the manufacturer
     Width=9
     
     # Height in inches, as advertised by the manufacturer
     Height=6
     
     # Optional features that this tablet supports
     # Some features are dependent on the actual tool used, e.g. not all styli
     # have an eraser and some styli have additional custom axes (e.g. the
     # airbrush pen). These features describe those available on the tablet.
     #
     # Features not set in a file default to false/0
     
     [Features]
     # This tablet supports styli (and erasers, if present on the actual stylus)
     Stylus=true
     
     # This tablet supports touch.
     Touch=false
     
     # This tablet has a touch ring (Intuos4 and Cintiq 24HD)
     Ring=true
     # This tablet has a second touch ring (Cintiq 24HD)
     Ring2=false
     
     # This tablet has a vertical/horizontal scroll strip
     VStrip=false
     HStrip=false
     
     # Number of buttons on the tablet
     Buttons=9
     
     # This tablet is built-in (most serial tablets, Cintiqs)
     BuiltIn=false

24.2. Adding support for a new tablet

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

Prerequisites

• The definition file for the tablet that you want to add exists.

  For more information on ensuring that the definition file exists, see Section 24.1, “Preparing a tablet definition file”.

Procedure

1. Add and install the definition file with the .tablet suffix:

   # cp the-new-file.tablet /usr/share/libwacom/

   Once installed, the tablet is part of the libwacom database. The tablet is then available through libwacom-list-local-devices.

2. Create a new /etc/udev/rules/99-libwacom-override.rules file with the following content so that your settings are not overwritten:

   ACTION!="add|change", GOTO="libwacom_end"
   KERNEL!="event[0-9]*", GOTO="libwacom_end"
   
   [new tablet match entries go here]
   
   LABEL="libwacom_end"

3. Reboot your system.

24.3. Where is the Wacom tablet configuration stored

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.

24.4. Listing available Wacom tablet configuration paths

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.

Prerequisites

• Make sure that the gnome-settings-daemon package is installed on your system.

  # yum install gnome-settings-daemon

Procedure

• To get the full list of tablet configuration paths used on your machine, run the following command:

  $ /usr/libexec/gsd-list-wacom

Using machine-id, device-id, and tool-id in configuration paths allows for shared home directories with independent tablet configuration per machine. However, when sharing home directories between Machines, the Wacom settings apply only to one machine.

This is because the machine-id for your Wacom tablet is included in the configuration path of the /org/gnome/settings-daemon/peripherals/wacom/machine-id-device-id GSettings key, which stores your tablet settings.

25.1. The Flatpak technology

Flatpak provides a sandbox environment for application building, deployment, distribution, and installation.

Applications that you launch using Flatpak have minimum access to the host system, which protects the system installation against third-party applications. Flatpak provides application stability regardless of the versions of libraries installed on the host system.

Flatpak applications are distributed from repositories called remotes. Red Hat provides a remote with RHEL applications. Additionally, third-party remotes are available as well. Red Hat does not support applications from third-party remotes.

25.2. Setting up Flatpak

This procedure installs the Flatpak package manager.

Procedure

• Install the flatpak package:

  # yum install flatpak

25.3. Enabling the Red Hat Flatpak remote

This procedure configures the Red Hat Container Catalog as a Flatpak remote on your system.

Prerequisites

• You have an account on the Red Hat Customer Portal.

  For large-scale deployments where the users do not have Customer Portal accounts, Red Hat recommends using registry service accounts. For details, see Registry Service Accounts.

Procedure

1. Enable the rhel Flatpak remote:

   $ flatpak remote-add \
             --if-not-exists \
             rhel \
             https://flatpaks.redhat.io/rhel.flatpakrepo

2. Log into the Red Hat Container Catalog:

   $ podman login registry.redhat.io
   
   Username: your-user-name
   Password: your-password

   Provide the credentials to your Red Hat Customer Portal account or your registry service account tokens.

   By default, Podman saves the credentials only until you log out.

3. Optional: Save your credentials permanently. Use one of the following options:

   • Save the credentials for the current user:

     $ cp $XDG_RUNTIME_DIR/containers/auth.json \
          $HOME/.config/flatpak/oci-auth.json

   • Save the credentials system-wide:

     # cp $XDG_RUNTIME_DIR/containers/auth.json \
          /etc/flatpak/oci-auth.json

     For best practices, Red Hat recommends that you log into the Red Hat Container Catalog using registry account tokens when installing credentials system-wide.

Verification

• List the enabled Flatpak remotes:

  $ flatpak remotes
  
  Name    Options
  rhel    system,oci,no-gpg-verify

25.4. Searching for Flatpak applications

This procedure searches for an application in the enabled Flatpak remotes on the command line. The search uses the application name and description.

Prerequisites

• Flatpak is installed.
• The Red Hat Flatpak repository is enabled.

Procedure

• Search for an application by name:

  $ flatpak search application-name

  For example, to search for the LibreOffice application, use:

  $ flatpak search LibreOffice

  The search results include the ID of the application:

  Application ID               Version  Branch  Remotes  Description
  
  org.libreoffice.LibreOffice           stable  rhel     The LibreOffice productivity suite

25.5. Installing Flatpak applications

This procedure installs a selected application from the enabled Flatpak remotes on the command line.

Prerequisites

• Flatpak is installed.
• The Red Hat Flatpak remote is enabled.

Procedure

• Install an application from the rhel remote:

  $ flatpak install rhel application-id

  Replace application-id with the ID of the application. For example:

  $ flatpak install rhel org.libreoffice.LibreOffice

25.6. Launching Flatpak applications

This procedure launches an installed Flatpak application from the command line.

Prerequisites

• Flatpak is installed.
• The selected Flatpak application is installed.

Procedure

• Launch the application:

  $ flatpak run application-id

  Replace application-id with the ID of the application. For example:

  $ flatpak run org.libreoffice.LibreOffice

25.7. Updating Flatpak applications

This procedure updates one or more installed Flatpak applications to the most recent version in the corresponding Flatpak remote.

Prerequisites

• Flatpak is installed.
• A Flatpak remote is enabled.

Procedure

• Update one or more Flatpak applications:

  • To update a specific Flatpak application, specify the application ID:

    $ flatpak update application-id

  • To update all Flatpak applications, specify no application ID:

    $ flatpak update

25.8. Installing Flatpak applications in the graphical interface

This procedure searches for Flatpak applications using the Software application.

Prerequisites

• Flatpak is installed.
• The Red Hat Flatpak remote is enabled.

Procedure

1. Open the Software application.
2. Make sure that the Explore tab is active.
3. Click the search button in the upper-left corner of the window.
4. In the input box, type the name of the application that you want to install, such as LibreOffice.

5. Select the correct application in the search results.

   If the application is listed several times, select the version where the Source field in the Details section reports flatpaks.redhat.io.

6. Click the Install button.
7. If Software asks you to log in, enter your Customer Portal credentials or your registry service account tokens.
8. Wait for the installation process to complete.
9. Optional: Click the Launch button to launch the application.

25.9. Updating Flatpak applications in the graphical interface

This procedure updates one or more installed Flatpak applications using the Software application.

Prerequisites

• Flatpak is installed.
• A Flatpak remote is enabled.

Procedure

1. Open the Software application.
2. Select the Updates tab.
3. In the Application Updates section, you can find all available updates to Flatpak applications.

4. Update one or more applications:

   • To apply all available updates, click the Update All button.
   • To update only a specific application, click the Update button next to the application item.

5. Optional: Enable automatic application updates.

   1. Click the menu button in the upper-right corner of the window.
   2. Select Update Preferences.

   3. Enable Automatic Updates.

      Flatpak applications now update automatically.