The article provides a comprehensive guide on building a Command-Line Interface (CLI) application in Python using the argparse library, demonstrated through the creation of a ToDo application. It begins by outlining the setup of the development environment, including installing Python and creating a virtual environment, before detailing the step-by-step process of using argparse to handle command-line arguments and subcommands. The tutorial covers adding tasks, viewing, marking as done, and removing tasks, incorporating error handling, help messages, and advanced features like sorting and filtering tasks based on priority and due dates. By employing argparse's features, such as defining positional and optional arguments and utilizing subcommands, the article illustrates how to create a robust CLI application. The tutorial concludes by highlighting the versatility of the argparse module in enhancing command-line applications, supported by practical examples and code snippets, and is backed by a GitHub repository for further reference.