Customizing the GNOME desktop environment

Procedure

1. Open the Extensions application.

2. Enable the Desktop Icons extension.

   

Procedure

1. Open Tweaks. For more details see Launching applications in GNOME.

2. Select Startup Applications in the left side bar.

   

3. Click the plus sign button (+).

   

4. Select an application from the list of available applications and click Add.

   

Verification

1. Open Tweaks.
2. Select Startup Applications in the left side bar.

3. List of applications launched at start will be present in the center section.

   

Procedure

1. Locate the .desktop file in the /usr/share/applications/ directory that corresponds to the application you want to start automatically.

2. As the root user, copy the .desktop file to the /home/<targetuser>/.config/autostart/ directory:

   # cp /usr/share/applications/<yourapp>.desktop /home/<targetuser>/.config/autostart/

   Replace <yourapp> with the name of your application. Replace <targetuser> with the username.

3. Ensure that the .desktop file is owned by the target user and has the correct permissions:

   # chown <targetuser>:<targetuser> /home/<targetuser>/.config/autostart/<yourapp>.desktop
   # chmod 644 /home/<targetuser>/.config/autostart/<yourapp>.desktop

   Replace <targetuser> with the username. Replace <yourapp>.desktop with the .desktop file you copied.

Procedure

1. Locate the .desktop file in the /usr/share/applications/ directory that corresponds to the application you want to start automatically.

2. As the root user, copy the .desktop file to the /etc/xdg/autostart/ directory:

   # cp /usr/share/applications/<yourapp>.desktop /etc/xdg/autostart/

   Replace <yourapp> with the name of your application.

3. Ensure that the .desktop file has the correct permissions to be read by all users:

   # chmod 644 /etc/xdg/autostart/<yourapp>.desktop

   Replace <yourapp>.desktop with the .desktop file you copied.

Procedure

1. Create the /etc/dconf/db/gdm.d/01-override-logo configuration file with the following content:

   [org/gnome/login-screen]
   logo='/path/to/logo.png'

   Replace /path/to/logo.png with the full path to the image file that you want to use as the login screen logo.

2. Update the system databases:

   # dconf update

Verification

1. Log out or otherwise switch to the login screen.
2. Check if it displays the logo that you selected.

3. If the logo does not update, restart GDM:

   # systemctl restart gdm

   Warning

   Restarting the gdm service terminates all currently running GNOME sessions of all desktop users who are logged in. This might result in users losing unsaved data.

Procedure

1. Create a plain text /etc/dconf/db/local.d/00-logout keyfile in the /etc/dconf/db/local.d/ directory with the following content:

   [org/gnome/desktop/lockdown]
   # Disable user logut
   disable-log-out=true
   
   # Disable user switching
   disable-user-switching=true

2. Create a new file under the /etc/dconf/db/local.d/locks/ directory and list the keys or subpaths you want to lock down:

   # Lock user logout
   /org/gnome/desktop/lockdown/disable-log-out
   
   # Lock user switching
   /org/gnome/desktop/lockdown/disable-user-switching

3. Apply the changes to the system databases:

   # dconf update

Procedure

1. Create a plain text /etc/dconf/db/local.d/00-printing keyfile in the /etc/dconf/db/local.d/ directory with the following content:

   [org/gnome/desktop/lockdown]
   # Disable printing
   disable-printing=true

2. Create a new file under the /etc/dconf/db/local.d/locks/ directory and list the keys or subpaths you want to lock down:

   # Lock printing
   /org/gnome/desktop/lockdown/disable-printing

3. Apply the changes to the system databases:

   # dconf update

Procedure

1. Create a plain text /etc/dconf/db/local.d/00-filesaving keyfile in the /etc/dconf/db/local.d/ directory with the following content:

   [org/gnome/desktop/lockdown]
   # Disable saving files on disk
   disable-save-to-disk=true

2. Create a new file under the /etc/dconf/db/local.d/locks/ directory and list the keys or subpaths you want to lock down:

   # Lock file saving
   /org/gnome/desktop/lockdown/disable-save-to-disk

3. Apply the changes to the system databases:

   # dconf update

Procedure

1. Create a plain text /etc/dconf/db/local.d/00-lockdown keyfile in the /etc/dconf/db/local.d/ directory with the following content:

   [org/gnome/desktop/lockdown]
   
   # Disable command prompt
   disable-command-line=true

2. Create a new file under the /etc/dconf/db/local.d/locks/ directory and list the keys or subpaths you want to lock down:

   # Lock command prompt
   /org/gnome/desktop/lockdown/disable-command-line

3. Apply the changes to the system databases:

   # dconf update

4. For this settings to take effect, users needs to log out and log back in.

Procedure

1. Copy the /usr/share/polkit-1/actions/org.freedesktop.udisks2.policy file under the /etc/share/polkit-1/actions/ directory:

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

2. In the /etc/polkit-1/actions/org.freedesktop.udisks2.policy file, delete any actions that you do not need and add the following lines:

   <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>

   If you want to restrict access only to the root user, replace <allow_any>no</allow_any> with <allow_any>auth_admin</allow_any>.

Procedure

1. Install the GNOME Kiosk packages:

   # dnf install gnome-kiosk gnome-kiosk-search-appliance

2. At the GNOME login screen, select Search Appliance Session from the gear button menu and log in as the single-application user.
3. The Mozilla Firefox browser opens as a full-screen window in its kiosk mode. It shows the Google search page.

Procedure

1. Install the GNOME Kiosk packages:

   # dnf install gnome-kiosk gnome-kiosk-script-session

2. At the GNOME login screen, select Kiosk Script Session from the gear button menu and log in as the single-application user.

3. The gedit text editor opens as a full-screen window. It shows the shell script that configures which application runs in your single-application session.

   Edit the shell script and enter the application that you want to start in the single-application session.

   For example, to start the Mozilla Firefox browser, enter the following content:

   #!/usr/bin/sh
   
   firefox --kiosk https://example.org

4. Save the script file.

5. Close the gedit window.

   The session terminates and restarts with your selected application.

6. The next time you log into the single-application session, your selected application runs.

1. Launch Settings.

   You can use one of the approaches described in Launching applications in GNOME. Alternatively, you can also launch it from the system menu by clicking on its icon.

   

2. In Settings, choose Sound from the left vertical bar.

Procedure

1. Install the gnome-shell-extension-classification-banner package:

   # dnf install gnome-shell-extension-classification-banner

2. Create the 99-class-banner file at either of the following locations:

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

3. Enter the following configuration in the created file:

   [org/gnome/shell]
   enabled-extensions=['classification-banner@gnome-shell-extensions.gcampax.github.com']
   
   [org/gnome/shell/extensions/classification-banner]
   background-color='rgba(200,16,46,0.75)'
   message='TOP SECRET'
   top-banner=true
   bottom-banner=true
   system-info=true
   color='rgb(255,255,255)'

   Warning

   This configuration overrides similar configuration files that also enable an extension, such as Notifying of the system security classification.

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

   enabled-extensions=['heads-up-display@gnome-shell-extensions.gcampax.github.com', 'classification-banner@gnome-shell-extensions.gcampax.github.com']

4. Update the dconf database:

   # dconf update

5. Reboot the system.

Procedure

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

   # dnf 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=['heads-up-display@gnome-shell-extensions.gcampax.github.com']
   
   [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.

   Warning

   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=['heads-up-display@gnome-shell-extensions.gcampax.github.com', 'classification-banner@gnome-shell-extensions.gcampax.github.com']

4. Update the dconf database:

   # dconf update

5. Reboot the system.

Procedure

1. Open the Settings application.
2. Select Accessibility.

3. Enable the Always Show Accessibility Menu item.

   Enabling the Accessibility menu in Settings

   

Verification

1. Open an application with text content.
2. Check that the screen reader reads the text in the application.

Procedure

1. Click on the Activities button in the upper-left corner of the screen.
2. Type Settings and click on the Settings icon to open the Settings application.
3. In the Settings window, click on Keyboard in the left sidebar.
4. Scroll down and select the Compose Key option.
5. Toggle the slider to enable the Compose Key.
6. Select the key you want to use as the Compose Key.
7. Once you have selected the Compose Key, close the Settings window.

Procedure

1. Allow all clients to connect to the X server:

   # xhost +

2. Run the following command to set the Compose Key:

   # su - <username> -c "gsettings set org.gnome.desktop.input-sources xkb-options \"['compose:<compose_key>']\""

   Replace <username> with the username of the user for whom you want to enable the Compose Key. Replace <compose_key> with the key you want to use as the Compose Key. You can use the ralt option to designate the right Alt key as the Compose Key.

   To see other Compose Key options that you can use to set up a Compose Key on your keyboard, use:

   $ grep compose /usr/share/X11/xkb/rules/evdev.lst

3. Resets the access control:

   # xhost -

Procedure

1. Create the /etc/dconf/db/local.d/00-compose-key configuration file with the following content:

   [org/gnome/desktop/input-sources]
   xkb-options=['compose:<compose_key>']

   Replace <compose_key> with the key you want to use as the Compose Key. You can use the ralt option to designate the right Alt key as the Compose Key.

   To see other Compose Key options that you can use to set up a Compose Key on your keyboard, use:

   $ grep compose /usr/share/X11/xkb/rules/evdev.lst

2. Update the dconf database with the new configuration:

   # dconf update

3. Restart your system or log out and log back in to your GNOME session for the changes to take effect.

Procedure

1. Download the extension archive from the GNOME Extensions website.

2. Extract the archive into the /usr/share/gnome-shell/extensions/ directory:

   # unzip -q <extension-file.zip> -d /usr/share/gnome-shell/extensions/

   Replace <extension-file.zip> with the name of the extension zip file.

3. Adjust the permissions to ensure that the extension files are readable and executable by everyone:

   # chmod -R 755 /usr/share/gnome-shell/extensions/<extension-directory>/

   Replace <extension-directory> with the name of the extension directory.

4. Create a new /etc/dconf/db/local.d/00-extensions file with the following content:

   [org/gnome/shell]
   enabled-extensions=['myextension1@myname.example.com', 'myextension2@myname.example.com']

   Replace the UUIDs (myextension1@myname.example.com, myextension2@myname.example.com) with the ones you want to enable. You can find the UUID of an extension on its GNOME Shell Extensions website page.

5. Apply the changes to the system databases:

   # dconf update

Procedure

1. Create a new /etc/dconf/db/local.d/00-extensions file with the following content:

   [org/gnome/shell]
   enabled-extensions=['myextension1@myname.example.com', 'myextension2@myname.example.com']
   development-tools=false

   Replace the UUIDs (myextension1@myname.example.com, myextension2@myname.example.com) with the ones you want to enable. You can find the UUID of an extension on its GNOME Shell Extensions website page.

2. To prevent users from changing these settings, create a new /etc/dconf/db/local.d/locks/extensions file with the following content:

   /org/gnome/shell/enabled-extensions
   /org/gnome/shell/development-tools

3. Apply the changes to the system databases:

   # dconf update