ubuntu 12.04 mate(gnome2) desktop installation

edit sources.list:
    sudo nano /etc/apt/sources.list
add mate-desktop repository(visit the website mate-desktop.org for updated repository):
    deb http://repo.mate-desktop.org/ubuntu precise main
update database:
    sudo apt-get update
add mate repository key:
    sudo apt-get install mate-archive-keyring
update database:
    sudo apt-get update
install mate core:
    sudo apt-get install mate-core
install mate desktop:
    sudo apt-get install mate-desktop-environment

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if install mate from ubuntu server 12.04 without desktop environment the do the following below:
    sudo apt-get install xinit
when the server start it will not go directly to the desktop, instead you run command below to start mate. only root user available:
    sudo startx
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