Open Source

GConf makes Linux administration a little more like Windows

Get a look at the Linux Configuration Editor and how it mimics the Windows Registry as a configuration tool.

It was only a matter of time before a tool came along and made the configuration of Linux a bit more like Windows. Now before you look away, this is a good thing. Actually, it’s a very good thing because the Linux community has taken a very complex tool (the Windows Registry Editor), applied it to Linux configurations, and made it simpler.

With that in mind, let me introduce you to the Linux Configuration Editor. First, I will show you just what this tool is capable of, and then I'll give you a brief walk-through of the tool.

The GConf tool
The Linux Configuration Editor (also called GConf) is a configuration data storage mechanism that was released with GNOME 2.0. This tool stores all configuration data in XML-format text files, but also allows a Registry Editor-like binary database back end and/or an SQL type back end. Even the look and feel of the Configuration Editor resembles that of the Windows Registry Editor, which is shown in Figure A.

Figure A
Remember: Always back up your registry before working with the GConf tool.

As you can see in Figure B, the opening screen is very similar to the Windows Registry Editor’s layout.

Figure B
There are four types of configurations to choose from in the left pane.

If you click on one of the right arrows in the left pane (see Figure C), the tree menu will expand, revealing a list of configurable apps.

Figure C
The pink circle highlights where you will click to expand the tree menu of the Configuration Editor.

While the left pane lists the editable applications available to the Configuration Editor, the upper right pane is dedicated to the actual configuration of the applications (or system, or desktop, or schema). Each instance will be different in that there may (or may not) be check boxes, text areas to enter, or descriptions to fill in. The bottom right pane is there to hold information pertaining to a particular configuration option.

From the drop-down menus, there are a number of interesting options. One is the ability to create a bookmark within the tool. If there are options that you find yourself frequently visiting, you can simply create a bookmark to that option so you only have to select it from a drop-down list as opposed to navigating through a seemingly endless list of options. As you can see, in Figure D, I have created a bookmark for the options selection under gnome-session.

Figure D
Bookmarks can only be deleted from the Edit Bookmarks menu item from the Bookmarks drop-down list.

Note that, like Windows Registry editing, the Configuration Editor names each option/entry as a Key. So, as you can see in Figure D, in the Key Documentation pane, each entry has a Key Name (the name of the option) and a Key Owner (the app, system, or schema to which the option belongs).

Calling the Configuration Editor can be done in two ways. In Red Hat 8.0, you will find a menu entry (called Configuration Editor) under Main Menu | Applications | System Tools. If you do not find that entry, open up a terminal window and enter the command gconf-editor.

Working with the application
Now that you know your way around the tool, it's time to see it in action. What I am going to do is to configure a few Keys in the options section under gnome-session. Once you navigate to this section and open the gnome-session tree, you will see the options folder (see Figure E). Clicking on this options folder reveals five configurable items:
  • splash_image
  • show_splash_image
  • auto_save_session
  • logout_prompt
  • allow_tcp_connections

Figure E
By default, the splash_image is configured and the show_splash_scren and logout_prompt options are enabled.

What files does this tool affect?
If you happen to improperly configure an option and make your desktop unusable, you can, through text mode, change to the /etc/gconf/gconf.xml.defaults/ directory. In my example below, I could change (with the cd command) to the /etc/gconf/gconf.xml.defaults/apps/gnome-session/options directory. Each of the applicable files uses the %gconf.xml name.

The first thing I am going to do is edit the splash image that the users see when they log on to their desktops. Instead of using the default /usr/share/pixmaps/splash/gnome-splash.png, I'll edit this to use something like /data/pics/company_splash.png (of course this image doesn't really exist; it is only being used for demonstration). To do this, double click on the splash_image entry that will change the Value to a text entry field. Erase the current value, enter the new value of /data/pics/company_splash.png, and click Enter to finalize the configuration. To check to see if this configuration works, select Quit from the File drop-down menu, and log out of X. When you log back into X, you should see your newly-configured splash screen.

The next configuration I will do is to enable the auto_save_session by simply checking the check box to the right of this option. Once this is done, you won't be asked to save the X session each time you log out. It’s that simple.

Next, let's look at configuring the systemwide terminal. When a systemwide terminal is configured, any time a terminal is needed, the configured terminal will be used as opposed to the default. Since I am fond of a less CPU-intensive terminal (rather than that of the gnome-terminal),I tend to useaterm. Within the Desktop | Gnome | Applications directory, you will find the terminal entry. Double click on the exec Value and enter the command that you call your favorite terminal window. For my example, I use aterm -tr -tint magenta -fg green -bg blue +sb to call a purple-tinted aterm with green text, blue highlighting, and no scroll bar. After the text is typed, hit enter and close the Configuration Editor. Your systemwide terminal is now configured.

The Linux-ification of the Registry Editor
The Linux Configuration Editor can be just as useful as Microsoft's Registry Editor, even though the GConf is not as crucial to the stability of the system. Not only can the Configuration Editor be as useful, it will not bring down your system if a Key entry is incorrectly entered. Remember, these Key values (as configured in the Configuration Editor) simply consist of edited XML files within a certain directory (/etc/gconf/gconf.xml.defaults/)—and should you botch an entry, you can drop into text mode (if you render the graphical mode unusable) and correct it.


About Jack Wallen

Jack Wallen is an award-winning writer for TechRepublic and He’s an avid promoter of open source and the voice of The Android Expert. For more news about Jack Wallen, visit his website

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