How to Remap the Touchbar Screenshot icon on your external keyboard using Karabiner on MacOS

I have been using a MacBook pro with a TouchBar for 3 years and one the Touchbar’s feature that I mostly use is the possibility to quickly take a screenshot.

Photo by Nikolay Tarashchenko on Unsplash

Today I have started (again) to use my MacBook connected to an external display with an external keyboard and so it is a bit uncomfortable to use the TouchBar.
Anyway, I tried for a couple of times to use the Touch bar to take a screenshot and then I decided to find another solution.
I knew that in macOS is possible to take a screenshot with a keyboard shortcut but I wanted the same GUI that is provided using the screenshot Icon on the TouchBar.
I started to search for a solution and I found an application called Karabiner that allows remapping the keyboard keys on macOS.

I downloaded Karabiner and I tried to assign to the “print screen” key of my external keyboard the same Screenshot feature but it was impossible.
Then I realised that the GUI that is launched using the icon on the touchbar to take a screenshot is a real macOS Application called “Screenshot” and I decided to assign to the “print screen” key a script to launch this app.
To do this I decided to use Karabiner but not through the GUI.
For this advanced mapping, it is necessary to write a rule in the Karabiner’s config file.
The Karabiner’s config file is in the following path:

cd ~/.config/karabiner

The file is called “Karabiner.json”, to launch a specific application using a certain key on your keyboard you can paste the following code in the “rules” section.