This script adds an icon to turn off iMac display on Linux (iMac doesn't have a physical key to turn off display without sleeping)
Tested on iMac Mid 2011 Fedora 27
git clone https://github.com/mpodshivalin/imac-display-off.git
cd imac-display-off
sh install.sh
Icon made by Pixel perfect from www.flaticon.com is licensed by CC 3.0 BY