Connecting EV3 to Mac over Bluetooth without Lego Mindstorms software
Bluetooth communication from the Mac to the EV3 is done using RFCOMM. This means that the EV3 appears as a serial port on the Mac. Namely /dev/tty.EV3-SerialPort. To send and receive messages from the EV3, you read and write to this virtual file. Bluetooth will show as "connected" as soon as you open this file. You can find some code examples here.