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Ubuntu: init 3
sudo service lightdm stop
sudo service lightdm start

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root 方式save:
gksudo nvidia-settings

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Disable nouveau

Run sudoedit /etc/modprobe.d/nvidia-graphics-drivers.conf and fill it with this:

# This file was installed by nvidia-current-updates
# Do not edit this file manually

blacklist nouveau
blacklist lbm-nouveau
alias nouveau off
alias lbm-nouveau off

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Enable root account login on Ubuntu 12.04
 -------------------------------------------------------

To get started, press Ctrl – Alt – T on your keyboard to open Terminal.
When it opens, run the commands below to create a new root password.

(1)
1.open Terminal
2.create a new password for the root user. ==>sudo passwd root
3.unlock the root account.==>sudo passwd -u root
4.sudo sh -c 'echo "greeter-show-manual-login=true" >> /etc/lightdm/lightdm.conf'

Restart your computer and choose to login as root.

(2)
Vi /etc/lightdm/lightdm.conf
autologin-user:root

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右鍵 Terminal
sudo apt-get install nautilus-open-terminal

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Screen saver:
sudo apt-get purge gnome-screensaver
sudo apt-get install xscreensaver xscreensaver-gl-extra xscreensaver-data-extra

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sudo 免密碼:
chmod 740 /etc/sudoers
gedit /etc/sudors  (Vi非常難用,怪)
account ALL=(ALL) NOPASSWD: ALL (RHEL是用群組,這邊要用account)
chmod 440 /etc/sudoers

or

echo 密碼 | sudo  -S shutdown -r now