Change Screen Brightness in Ubuntu Terminal

I had a problem in my HP pavilion G6 Laptop with brightness change. I could not change the brightness using my function keys. Though I could change brightness by the Brightness & Lock settings, lowest brightness level was too bright for me. So I used following method to reduce the brightness.

sudo -s
nano /sys/class/backlight/intel_backlight/brightness

(In my case it was intel_backlight. This may change from computer to computer.) Edit the value of the file. In my case, the value was about 4000. So I reduced it to 800 and saved. Then the brightness was reduces. You can reduce the brightness into any level by just editing this file.

If you want to reduce the brightness at every startup, include following command in /etc/rc/local file.( /etc/rc.local file is executed at the end of every startup. If you put a command there, you can run that command at every startup)

echo 800 > /sys/class/backlight/intel_backlight/brightness

Restart your computer and you'll see your command is effective.

A little more fun : 
       I created a small shell script (.sh) to reduce my brightness to any amount at any time easily. But for this script I would have changed the brightness using the entire command given above. This shell script made it easy. I just needed to execute the shell script and pass brightness value as a command line parameter as follows.

./brightness 600

Here is my shell script:
    
#!/bin/sh
echo $1 > /sys/class/backlight/intel_backlight/brightness

echo "[+] Brightness set to $1\n"