Save screen brightness on restart in Ubuntu 12.04

Sigh, Ubuntu 12.04 doesn't keep your screen brightness setting, so everytime you log in you need to change it.

There is a way around this, requires editing a file using the terminal.

sudo nano /etc/rc.local

and in the line before the last line which should say "exit 0" add

echo 4 > /sys/class/backlight/acpi_video0/brightness

in other words so it looks like this:

do ctrl+x to save and exit.