Posted: Oct 17, 2017 8:36 pm
by Cito di Pense
I'm trying to understand what your 'single keystroke' approach seeks to accomplish, but it sounds like you don't just want to suspend your current session, and you don't want to log all the way out. The mac-related threads at "ask different" (SA) have a number of recommendations, mainly involving getting hold of an app that puts a menu in your menu bar that allows you to activate a script with a key combo, for fast user switching or something like that.

For anyone else with less complicated ambitions, the CTRL-SHIFT-EJECT combination immediately sleeps your display. If you've set your user security to do so, it will request your user password when you wake the display. But then, so does mousing (swiping or whatever you do on the trackpad) to the proper hot corner to activate your screen-saver.