Linux command to set the screen size

Hi all,
today I will teacher how to set the screen size using xrandr Linux command.

To find out what sizes are available, run:
$ xrandr -q
SZ: Pixels Physical Refresh
*0 1024 x 768 ( 271mm x 203mm ) *75 70 60
1 800 x 600 ( 271mm x 203mm ) 75 72 60 56

To set the screen size to an available size, run:
$ xrandr -s 800x600

Thanks,
God bless you ... [:P]