- Download the latest release
- Unzip the downloaded .zip file
- Open wifiname.app
You should see the name of the WiFi you're connected to in the Mac status/menu bar. When you switch to a different WiFi the name will be updated automatically.
If you click on the WiFi name displayed it will show you two options: Toggle Visibility or Quit. Toggle Visibility will replace the WiFi name with "_" using as many characters as the currently connected WiFi name.