Send error mail if nothing ran the day before

[MichaelCurrin]

As an extension of #5, if no scripts could be executed yesterday because the machine errored on all, was off or was offline, then send a mail today before starting tasks.

Perhaps use the log of the app or create a run file for the app, to see when it last run to completion with at least one successful task.

There is of course the limitation that the script can't watch itself because it might get an error and exit before it can even send the warning. So splitting the warning into a separate script which even runs maybe on a different crontab could help.
Though what watches that? If it is simple enough and robust (independent of the rest of the system) then it will help.
Alternatively, use a script to check yesterday's date appears in the main app's log along with successful end, provided this is logged.

Also ensure there are at least instructions to view the main app log and mainly check runs. This avoids code.