The Zephyr project includes a swiss-army knife command line tool named west. West’s built-in commands provide a multiple repository management system which allows you to manage and version several git repositories in a single file. This simplifies software configuration. West is also pluggable: you can write your own west “extension commands” which add additional features to west. Zephyr uses this feature to provide conveniences for building applications, flashing and debugging them, and more.
Below is the presentation that Marti Bolivar, Senior Software Engineer at Nordic Semiconductor, gave at the Zephyr Mini-Summit earlier this year.