Administering the system using the GNOME desktop environment

Procedure

1. Launch the GNOME Software application.

2. Find the application that you want to install using any of the following methods:

   • Click the search button in the upper-left corner of the window and type the name of the application.

     

   • Browse the application categories in the Explore tab.

     

3. Click the selected application.

4. Click Install.

   

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.

Procedure

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

   Note

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

2. Double-click the RPM package file to install it.

Procedure

1. Open the Activities Overview screen.

2. Type the name of the required application in the search entry.

   

   The search results display the application’s icon, name, and description.

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

   

4. Click Install to finish the installation in Software.

Procedure

1. Enable the rhel Flatpak remote:

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

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2. Log into the Red Hat Container Catalog:

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

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   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

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   • Save the credentials system-wide:

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

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

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 Thunderbird.

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.

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.

Procedure

1. Open the system menu, which is accessible from the upper-right screen corner, and click Settings.

   

2. Go to About → Subscription.

3. If you are not using the Red Hat server:

   1. In the Registration Server section, select Custom Address.
   2. Enter the server address in the URL field.
4. In the Registration Type section, select Activation Keys.

5. Under Registration Details:

   • Enter your activation keys in the Activation Keys field.

     Separate your keys by a comma (,).

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

Procedure

1. Open the system menu, which is accessible from the upper-right screen corner, and click Settings.

   

2. Go to About → Subscription.

   The Registration Details screen appears.

3. Click Unregister.

   A warning appears about the impact of unregistering the system.

4. Click Unregister.

Procedure

1. Edit the /etc/systemd/logind.conf configuration file and set the HandlePowerKey=poweroff variable to one of the following options:

   poweroff

   Shut down the computer.

   reboot

   Reboot the system.

   halt

   Initiate a system halt.

   kexec

   Initiate a kexec reboot.

   suspend

   Suspend the system.

   hibernate

   Initiate system hibernation.

   ignore

   Do nothing.

   For example, to reboot the system upon pressing the power button, use this setting:

   HandlePowerKey=reboot

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Procedure

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

   [org/gnome/settings-daemon/plugins/power]
   power-button-action=<value>

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   Replace <value> with one of the following power button actions:

   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 pressing the power button. However, you can choose a different behavior from the pop-up query.

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

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

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3. Update the system databases:

   # dconf update

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

Procedure

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

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

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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)'

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   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']

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4. Update the dconf database:

   # dconf update

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5. Reboot the system.

Procedure

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

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

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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

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   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']

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4. Update the dconf database:

   # dconf update

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5. Reboot the system.

Procedure

1. Use one of the approaches described in Launching applications to start the Settings application.

   Moreover, you can also start the Settings application from the system menu in the upper right corner by clicking on the "Settings" icon.

   

2. When the Settings application GUI appears, go to Printers.

   Figure 9.1. GNOME Control center configuration tool

   

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Procedure

1. Open the Printers dialog.

   

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2. Click on Unlock and authenticate.

   

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

   

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4. Confirm your selection by clicking Add in the top right corner.

   

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Procedure

1. Click the settings (⚙️) button on the right to display a settings menu for the selected printer:

   

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2. Click Printing Options → Test Page.

Procedure

1. Click the settings (⚙️) button on the right to display a settings menu for the selected printer:

   

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

   

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   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.

   

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Procedure

1. Click the settings (⚙️) button on the right to display a settings menu for the selected printer:

   

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

   

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Procedure

1. Click the settings (⚙️) button on the right to display a settings menu for the selected printer:

   

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2. Click Printing Options.

Procedure

1. Click the settings (⚙️) button on the right to display a settings menu for the selected printer:

   

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2. Click Remove Printer to remove the selected printer:

   

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Procedure

1. Open the Files application.

2. Click Other Locations in the side bar.

   The window lists all connected storage volumes and all network shares that are publicly available on your local area network.

   If you can see the volume or network share in this list, mount it by clicking the item.

   If you want to connect to a different network share, use the following steps.

3. Enter the GVFS URI string to the network share 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 fields.
6. When the mounting process finishes, you can browse the files on the volume or network share.

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 from the side bar or a notification about the safe removal appears.

Procedure

1. Open the Files application.

2. Click Other Locations in the side bar.

   The window lists all connected storage volumes and all network shares that are publicly available on your local area network.

   If you can see the volume or network share in this list, mount it by clicking the item.

   If you want to connect to a different network share, use the following steps.

3. Enter the GVFS URI string to the network share 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 fields.
6. When the mounting process finishes, you can browse the files on the volume or network share.

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 from the side bar or a notification about the safe removal appears.

Procedure

1. Create an empty file:

   $ touch /tmp/myfile

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2. View the metadata of this file:

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

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3. Set a string to this file:

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

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4. View the metadata:

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

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5. Move this file to a new location:

   $ gio move /tmp/myfile /tmp/newfile

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6. View the metadata:

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

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Procedure

1. Ensure that gvfs-fuse is running.

   $ ps ax | grep gvfsd-fuse

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   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

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

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

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   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.

Procedure

1. Open the Disks application.
2. Select the disk in the side bar.
3. Below Volumes, click Additional partition options > Edit Mount Options
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.

Procedure

1. Open the Disks application.
2. Select the disk in the side bar.
3. Below Volumes, click Additional partition options > Edit Mount Options
4. Deselect Show in user interface.
5. Confirm by clicking OK.

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.

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.

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>

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   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 field_code

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   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.

   Based on how myapplication1 gets started, choose one respective field code from Desktop Entry Specification. For example, for an application capable of opening multiple files, use:

   Exec=myapplication1 %F

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

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

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

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

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Verification

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

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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

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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>

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   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 field_code

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   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.

   Based on how myapplication1 gets started, choose one respective field code from Desktop Entry Specification. For example, for an application capable of opening multiple files, use:

   Exec=myapplication1 %F

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

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

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4. Update the application database:

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

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Verification

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

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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

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

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

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

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   This example above specifies default application (Mozilla 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

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   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.

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

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   This example above specifies default application (Mozilla 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

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   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.