No automatic backlight, please!
If an external display is in use in mirror mode, even if automatic brightness adjustment is set to off, when you close the lid and open it again, internal display's brightness is automatically set to a non-zero value. This is extremely annoying and there's no option to turn internal display off completely when using external one.
Imagine a magic script that monitors your lid state, and when lid is open, it dims internal display.
Here it is!
Put the executable file nobacklight to ~/.bin directory. Then put nobacklight.plist to ~/Library/LaunchAgents.
So this is basically the installation script:
brew install brightness
git clone --depth 1 https://github.com/pirj/nobacklight
cd nobacklight
mkdir -p ~/.bin
cp nobacklight ~/.bin
cp nobacklight.plist ~/Library/LaunchAgents
launchctl load ~/Library/LaunchAgents/nobacklight.plist
It periodically checks if lid is open. Nothing fancy, it uses command line tools that come with OSX, specifically ioreg and brightness from homebrew.
Author: Phil Pirozhkov
License: MIT