I am away from my machine for an extended period. Before I left, I quit the KM engine. I now realize that I want it to be running to execute some tasks that were previously configured with Time triggers. I am able to ssh into my machine. Is there a way to start the KM engine from the command line?
You actually don't even need to know where it's installed. You can use either:
open -a 'Keyboard Maestro Engine'
open -b com.stairways.keyboardmaestro.engine
and macOS will launch it wherever it is.
This is helpful if you don't know where an app is -- which is often true now if you are trying to launch one of Apple's own apps which look like they are in /Applications/ or /Applications/Utilities/ but aren't really, or if you are looking for an app like 'Screen Sharing.app' or 'Archive Utility' which has never been in an easy-to-find/remember folder.
That being said, @gglick's suggestion has one advantage: if there are multiple versions of Keyboard Maestro installed (for example, if you have a clone of your boot drive attached) the open command can get confused sometimes, so using the specific path as they recommended would ensure that you are opening the one you'd expect.
Just to cover all bases, here's an AppleScript solution for those that might prefer it:
tell application "Keyboard Maestro Engine" to activate
If you save this from Script Editor into your ~/Library/Scripts folder, then you can run it from the Scripts menu in the Apple Menu bar. Using http://www.red-sweater.com/fastscripts/, you can assign a hotkey to it if you like.