Enable/Disable Screen Sharing on Mac

# Enable Screen Sharing
sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.screensharing.plist

# Disable Screen Sharing
sudo launchctl unload -w /System/Library/LaunchDaemons/com.apple.screensharing.plist 

with thanks to: https://gist.github.com/stefanschmidt/2432503