Cobra
A Commander for modern Go CLI interactions
...It provides a simple interface for creating powerful CLI interfaces, and will also generate application scaffolding so you can quickly develop your Cobra-based application. This scaffolding includes easy subcommand-based CLIs, fully POSIX-compliant flags, global, local and cascading flags, among many others.
The structure of Cobra is based on commands, flags and arguments. The commands represent actions, the central point of the application; flags modify the behavior of commands; while arguments are things. With these easy-to-use concepts, users will natively understand how to use the application.