For demo purposes and to be able to check if the messages are coming from the IoT cloud without looking at the screen all the time I created super simple Node-RED flow that receives messages from IBM’s IoT cloud and log them in the debug tab of the Node-RED UI and in parallel it parses JSON format of the messages to obtain value of the „temp“ property which is then passed to OS X say command.
It can be easily modified to pick another property value just by modifying „JSON and parse“ node.