Starting KDE
The following is from the svn-20080121 version of the BLFS book. (http://lfs-matrix.org/blfs/view/svn/kde/config.html)
Configuring
Back up your existing ~/.xinitrc file and create a new .xinitrc file to start KDE:
echo "exec startkde" > ~/.xinitrc
If you have D-BUS installed, you can start the D-BUS session daemon here as well. Starting the session daemon here has the added bonus that it will exit when you log out of your KDE session. If you wish to start the daemon here, use the following command instead of the one shown above:
echo "exec dbus-launch --exit-with-session startkde" >> ~/.xinitrc
Note
Check the ~/.xinitrc file and ensure you have no other window managers or other X applications mentioned before KDE.
If you installed the Desktop-file-utils package, ensure the XDG_DATA_DIRS and XDG_CONFIG_DIRS environment variables are configured properly as explained in that package and update the MIME-type application database (as root):
update-desktop-database
Ensure all libraries can be found with (as root):
ldconfig
At this point you can bring up KDE with:
startx