sneltoetsen/basics: http://www.dummies.com/computers/macs/mac-operating-systems/how-to-use-basic-unix-commands-to-work-in-terminal-on-your-mac/
10 basic terminal commands: https://computers.tutsplus.com/tutorials/10-terminal-commands-that-every-mac-user-should-know–mac-4825
open Finder meteen van in huidige map in Terminal: http://osxdaily.com/2009/11/30/open-current-folder-in-finder-from-the-terminal/