Shell command operations for Linux

1. At the command terminal to get root user rights

In the terminal, enter:
sudo passwd root
Enter new UNIX Password: (enter your password here)
Retype new UNIX Password: (Determine the password you entered)
Passwd:password updated successfully

Later, if you want to get root privileges, just do the following:
Su Root
Password: (Enter the password you set above here)

If you want to disable the root account again,

Then you can execute sudo passwd-l root

2. Installing KDE

After you have configured the source for Ubuntu, use the following command to install KDE3.
sudo apt-get install Kubuntu-desktop

If you want to use KDE4, use the following command
sudo apt-get install Kubuntu-kde4-deskto

3. Temporarily modify host name

hostname [NewName]

4. Adjust the screen brightness

　　Ubuntu default screen brightness for the largest, looking very dazzling, so I want to lower a bit, but no matter how the tune is not changed, it seems that everyone has encountered this problem, so there are many solutions, below I write a personal think relatively simple solution:

Terminal Input Code:

1	sudogedit /etc/default/grub

found in open filegrub_cmdline_linux= ""Change intogrub_cmdline_linux= "Acpi_backlight=vendor"you can save it after you change it.then upgrade grub:

1	sudoupdate-grub

re-start the ... Press FN to adjust. used to set the brightness initial value:Terminal Input Code:

1	sudogedit /etc/rc.local

add a sentence in the Open file (add before exit 0)Code:echo >/sys/class/backlight/intel_backlight/brightnessthen save it After the above method, you can adjust the screen brightness, and restart will not change the brightness value you set, the eyes no longer have to endure the pain of light thorn in the night.