I have bought a Lenovo Ideapad S10-3 Netbook and installed Ubuntu 9.04 on it. I want to control the brightness of the scree using terminal. I tried

sudo echo 60 > /proc/acpi/video/IGD0/DD01/brightness
It executed, but the brightness of screen remained same. I dont have a LCD folder inside
. I only have IGD0 folder.

My screen brightness changes by using Fn key and Brightness applet but not from terminal. what could be the cause of problem