GNOME is a flexible display manager. Users can change anything they like. Although this may seem an advantage for the user, for the Linux administrator it certainly is not. If one user changes the desktop settings to a single-click run from a double-click run, it can confuse other users, and make help desk functionatily confusing for the admin. Therefore, as an administrator it is a good idea to manage these settings yourself for your users. There are different ways of doing this. For example, an administrator can set system default settings and allow users to make their own modifications. As an alternative, administrators can also completely lock down the user environment.
To manage desktop settings, GNOME uses the gconfd process, which runs as a daemon. This daemon makes sure that system-wide settings are kept in the directory "/etc/opt/gnome/gconf". Within this directory, you'll find a complete subdirectory structure and many files with the name "%gconf.xml" that contain the actual settings. In addition to the
How to change desktop settings with GNOME
There are two ways of changing these settings. First, it is possible to change the settings from the individual applications. For example, an application like the Nautilus browser allows you to change single-click into double-click. A more generic way of changing these settings is by using the Gconf Editor. You can start this program by using the gconf-editor command from a console or by opening "Computer > More Applications > System > GNOME Configuration Editor".
The GConf Editor allows you to modify generic settings for your system.
Just to show an example of the extensive possibilities offered by Gconf Editor, open the editor and from the left pane, select "Desktop > gnome > file_views". In here, you can see three different options that can be set for file display. One of them is the option "show_hidden_files", which is not selected by default. If you want to show these files all the time, click the selection box. Next, right-click the option. In the quick-menu, you can see that several options are offered. You can select "Set as Default" to make this a default setting, or select "Set as mandatory" to make it a mandatory option. Using these last two options depends on the user account that you are currently using.
As you can probably imagine, only the root user or admin can set options that are mandatory for everyone else. If you are the user root, you want to start creating default settings. From the "File" menu, select "New Defaults Window" and start modifying all settings that you want to change. After saving them, they will automatically be applied the next time a user authenticates. If you want to make these settings mandatory, from the "File" menu in Gnome Config Editor, select "New Mandatory Window" instead of "New Defaults Window". If you want to delete a default or mandatory setting later on, right-click the same setting from Gconf Editor and select "Unset Key".
How to use Desktop Profile Editor
The advantage of Gconf Editor is that it can be used to put settings in place that will be applied for all users. If you want to change settings for a limited amount of users, the Desktop Profile Editor is used instead. To work with the Desktop Profile Editor, you will always follow a two-step procedure. In the first step, you are going to define a profile. In the second step, you assign the profile to a specific user. The following procedure shows how this works.
- Select "Computer > More Applications > System > Desktop Profile Editor". If necessary, enter the password of the user root.
- Click "Add" to add a new profile. Name the profile.
- Select the new profile and click "Edit". This opens a new Gnome session in an xnest window. From this window, configure the desktop as desired.
- From the new window. open the "Edit" menu and select "Changes". This will show you a list of all changes that have been recently applied. Be aware that this can be a rather long list, because the mere move of a window will create a vast amount of changes.
- For each of these changes, select "Ignore" to ignore it, or click the lock icon to lock the change. It will now be saved in this profile.
- Save the profile you have just created by selecting "Profile > Save" and close the Xnest window. The profile files have now been written to the /etc/opt/gnome/desktop-profiles/ directory.
To create a new profile, just change the desktop settings from the Xnest session, opened by the Desktop Profile Editor.
Now that the new profile has been created, you have to assign it to a user. To do this, in User Profile Editor, select one of the available profiles by clicking it. Next, click the "Users" button. This will show you a list of users available on your system. Select the users for which you want to apply this profile, or click "Use this profile for all users" if you want to use it for all users that have been created on your server.
How to lock down the desktop
Up to now, we have discussed how to create profiles and default or mandatory settings. But it is also possible to lock down a desktop, thus limiting the functionality that is available for your users. In the GConf Editor, four options are available to disable functionality for users:
- Disable Command Line
- Disable Print Setup
- Disable Printing
- Disable Save to Disk
You can find them by selecting "Desktop > Gnome > Lockdown" from the left pane. When using any of these, don't forget to set them as mandatory options. Otherwise, users will have an option to avoid them.
Gconf Editor offers four options to lock down the users desktop.
As you've noticed, the options to lock down the desktop from Gconf Editor are rather limited. The Desktop Profile Editor offers far more options. You can access them by selecting the "Lockdown" option from the "Edit" menu in the Xnest Window. This opens a new window from which the lock down options are divided among four different tabs. On the "General" tab, you can disable the command line. On the "Panel" tab, some generic options can be disabled, as well as many applets. Next, the "OpenOffice" tab offers mandatory settings for OpenOffice, like the option to save files in a default format. Next, the "Epiphany Web Browser" tab allows you to limit functionality of the Epiphany Browser.
The Desktop Profile Editor allows you to lock quite a few options for the end-user.
After defining how to lock down your desktop, you have to save the settings in Desktop Profile Editor. To do this, first select "Edit > Changes" and close all the locks. Next, save the settings, and apply them to all the users that have to use them.
In this tip, you have been given an overview of how the GNOME desktop environment can manage desktop settings for end-users, including how to create default settings and how to disable certain functionality for end-users. Hopefully, by centrally administering their desktops, you can increase your end-users' productivity.
About the author: Sander van Vugt is an author and independent technical trainer, specializing in Linux since 1994. Vugt is also a technical consultant for high-availability (HA) clustering and performance optimization, as well as an expert on SLED 10 administration.
This was first published in August 2007