Clint : Clint is a python module filled with a set of awesome tools for developing commandline applications.
testify : Go code (golang) set of packages that provide many tools for testifying that your code will behave as you intend.
cliff : Command Line Interface Formulation Framework. cliff is a framework for building command line programs. It uses plugins to define sub-commands, output ...
viper : Viper is a complete configuration solution for Go applications including 12-Factor apps. It is designed to work within an application, and can handle ...
docopt : Command-line interface description language. docopt helps you define interface for your command-line app, and automatically generate parser for it.
Cobra is a library providing a simple interface to create powerful modern CLI interfaces similar to git & go tools.
Cobra is also an application that will generate your application scaffolding to rapidly develop a Cobra-based application.