Developing and testing a CLI program

CLI applications are essential tools in software development, system administration, and automation. When creating CLI applications, interacting with stdin (standard input), stderr (standard error), and stdout (standard output) plays a crucial role in ensuring their effectiveness and user-friendliness.

In this section, we’ll explore why these standard streams are indispensable components of CLI development.

Standard streams

The concept of stdin, stderr, and stdout is deeply rooted in the Unix philosophy of “everything is a file.”(We will explore this more in Chapter 4, File and Directory Operations.) These standardized streams provide a consistent way for CLI applications to communicate with users and other processes. Users have come to expect CLI tools to work in a certain way, and adhering to these conventions enhances the predictability and user-friendliness of your application.

One of the most powerful aspects...