/rc.local （ran as root)
https://unix.stackexchange.com/questions/210939/what-user-runs-the-commands-defined-in-etc-rc-local
crontab -e (ran as login user)
https://askubuntu.com/questions/814/how-to-run-scripts-on-start-up
https://serverfault.com/questions/449651/why-is-my-crontab-not-working-and-how-can-i-troubleshoot-it