Selecting Alternate Desktops in RHEL 6 with GDM

The developers of Gnome have been shedding functionality in an attempt to make Gnome simpler. One of the things that has gone missing is the ability of GDM to select a different desktop. How this is a good thing is beyond me, but regardless, it's the way it is and it needs a workaround. At my job, we install CentOS onto commodity machines along with our software and ship them to our customers' sites. We have one application that runs without any window manager at all via the /home/username/.Xclients script. When we moved to CentOS 6.0, this suddenly stopped working. After I determined that the .Xclients script wasn't being run, a big of googling found this page which has a very elegant workaround. This script allows an individual user's .Xclients script to override the default selection of Gnome, but doesn't force other users to use .Xclients in order to get Gnome. Everyone wins! At least until the next time Gnome get stupider, er, simpler.

Formatting Source Code for Blogging

When pasting source code into a blog, it is nice to have the formatting preserved. There is now a site that makes this easy: formatmysourcecode.blogspot.com

3D Acceleration in VirtualBox

When adding the VirtualBox Guest Extensions to a VM running Linux, make sure that you have 3D acceleration enabled in the VM's settings before you install them. If you do not, the extensions will be compiled without the acceleration and you won't get the benefit thereof. I was pleasantly surprised to see that recent Linux distributions will dynamically size their desktops to the window size of the VM once the extensions are properly installed.

How to Change the GDM 2 Background

In the past, Gnome GDM's appearance could be changed with themes. This was changed when GDM was rewritten for Gnome 2. GDM now uses gconf and the keys are documented in the Gnome Library. At first I was having little luck with these as I was naively running gconftool-2 as root. You have to run the gconftool-2 as gdm:

sudo -u gdm gconftool-2 -t str -s /desktop/gnome/background/picture_filename /full/path/to/your/background.png

How to Restore Control-Alt-Backspace in Red Hat Derived Distros

The disabling of Ctrl-Alt-Backspace has finally made it into Red Hat Enterprise and derived distributions as of RHEL 6.0. To restore it without having to resort to GUI clikery, add this to /etc/X11/xinit/xinitrc-common:

setxkbmap -option terminate:ctrl_alt_bksp