You're entering the command in your debug console, it should be run from the terminal 
Right. Can you please tell me where the terminal is?
I think this user was correct:
It is a application. Go to finder and search terminal.
I don't have a mac myself, but here's a how-to i found using google:
http://www.howtogeek.com/210147/how-to-open-terminal-in-the-current-os-x-finder-location/