Running multiple Arduino instances on macOS

I'm working on a project with two ESP8266. There is a nicely packaged toolchain available in form of an Arduino core, which I'm using right now. A nice productivity tip when working with multiple interacting controllers is to run a seperate instance of the Arduino IDE for each controller. This allows you to flash and upload with a single click, without changing e.g. the port settings. It also allows you to open a serial console window for each controller and put them right next to each other.

On macOS, you cannot just click on the IDE's icon to run another instance. Instead, the already running instance is activated. Instead, open a shell and run the following command:

open -n /Applications/Arduino.app

A second instance of the IDE will launch, with the same sketch(es) opened as the first. This can be a little confusing. Open the right sketch for the second controller and close all the other windows. Now select the correct port, launch the serial console window and arrange your windows as you want them. There you go, instant productivity boost!