Read Instructions Carefully
Technically Flux is a Night Shift Mode for Mac & Windows
Flux on Mac does essentially the same thing as what Night Shift does on iOS. Flux determines your location and when the sun starts to set, it changes the colors of your display to be more conducive to a setting without natural lighting.
sudo add-apt-repository ppa:kilian/f.lux sudo apt-get update sudo apt-get install fluxgui