Change Ubuntu 13.10's brightness below minimum

When your laptop brightness is hurting your eyes when you are in a dark place and you want to lower it but cannot because it is already at minimum, this post will hopefully save you.

To lower your Ubuntu 13.10's (or any other versions) brightness below the minimum level follow the following steps.

Open a terminal (with Ctrl + Alt + T) and type the following commands
Step 1:

cd /sys/class/backlight

Step 2:

ls

ls will show you the folders inside the backlight folder
for me it shows intel_backlight, it can be anything for you, depending upon the video driver.

Step 3:

cd ./intel_brightness

Replace intel_brightness with whatever you got from the ls command above.

Step 4:

cat actual_brightness

This will return the current brightness value

Step 5:

echo X | sudo tee brightness

Replace X is the brightness you want to set. For example echo 50 | sudo tee brightness
Enter your sudo password when asked.