CLI Applications

A user interface is like a joke. If you have to explain it, it’s not that good.

– Martin LeBlanc

In this chapter, we are going to learn how to create Command-Line Interface (CLI) applications, also known as Command-Line Applications, in Python. A CLI is a user interface where users type commands into a console or terminal. Notable examples include the Bash and Zsh shells on macOS, Linux, and other UNIX-based operating systems, and the Windows Command Prompt and PowerShell. A CLI application is an application that is primarily used in such a command-line shell environment. One executes a CLI application by typing a command, possibly followed by some arguments, into the shell.

Although Graphical User Interfaces (GUIs) and web applications are far more popular, CLI applications still have their place. They are especially popular among developers, system administrators, network administrators, and other technical users. There are...