This is in regards to this line on the gamepedia server config walkthrough:
"To become or add an operator (op), type /op <player> into the server console or gui." Where do I find this server console/gui?
I'm on a Mac. I have the folder with server.jar, the start command document, eula.txt, the logs folder, and server.properties, as attached below.
Post the contents of your startup script.