A command-line interface (CLI) based calculator is a software application designed for performing arithmetic operations within a text-based terminal or console environment. Rather than a graphical interface with buttons and displays, users interact with it by typing commands and receiving text-based results. A simple example would be entering `5 * 7` and receiving the output `35`.
This type of calculator is valued for its efficiency and adaptability. Its lightweight nature makes it ideal for systems with limited resources, server environments, or situations where a graphical interface is unavailable or impractical. Historically, CLI calculators were among the earliest computational tools available, predating graphical user interfaces, and they continue to be relevant for scripting, automation, and system administration tasks.