I'm writing some scripts to automate common things like changing the language/keyboard layour or installing legacy tools like browser, passwordsafe and so on. This is designed for an Antergos installation, which itself is based on Arch Linux. My first task is changing the default keyboard layout. Altough I selected German in the installation process, I got a English layout after installation.

Using the GUI, it's done like described here: http://mixeduperic.com/linux/how-to-enable-multiple-language-keyboard-layouts-in-gnome3.html

How can I set this layout programatically? I'm looking for some kind of configuration file, where I can replace the English one by German in some case.