How to Install GNOME 3 (GNOME-Shell) in ubuntu 9.10Karmic Koala

GNOME (GNU Network Object Model Environment) is a desktop environment created for the operating system GNU / Linux Desktop Environment is recognized as the official GNU project. With the announcement of version 3.0 was introduced GNOME-Shell, which integrates various functions into a 'single window.  The desktop area is divided into several parts depending on the activities and workspaces is dynamic: you can add or remove workspaces and you can move any applications in different areas of work, as already happens with Compiz.

Now you can see How  to install GNOME on Ubuntu 9.10-Shell Karmic Koala.

     First  you have to install all the dependencies needed to successfully build and run gnome-shell.

     $ sudo apt-get build-dep gnome-shell

   After installing all the packages necessary steps for installing veritable gnome-shell

     $ sudo apt-get install gnome-shell

 Once installed, you can start GNOME-Shell by typing the following command in a terminal:

     $ gnome-shell --replace

GNOME-Shell is still under development and therefore very unstable.
Try it in your Test machine or in a Virtual machine.

How-To: Change Default Display Manager in Ubuntu 8.04

A display manager is a program that gives a graphical login screen and starts an X server session. Desktop environment KDE comes with Display manager kdm(KDM) and GNOME come with display manager gdm (GNOME).

Some time a user installs two or more desktop environments like kdm and gdm as display managers, and sometimes it's possible for the user to change default display manager . This can be done easily by using the command dpkg-reconfigure .

For example, if you installed KDE then GNOME, and the default display manager remained GDM, if you want change it use the following command : sudo dpkg-reconfigure kdm

The following commands can use for other display managers

dpkg-reconfigure gdm
dpkg-reconfigure xdm

If only one display manager is installed, the command will not respond.