A **Command-Line Interface (CLI)** is a text-based user interface that allows users to interact directly with a computer’s operating system or software by typing commands. This interaction is facilitated through a command-line interpreter, commonly known as a **shell**, which processes the entered commands and returns the output. **Relationship Between Terminal, Shell, and CLI:** • **Terminal:** Originally referring to physical devices like teletypewriters, in modern computing, a terminal is typically a software application—known as a terminal emulator—that provides a windowed environment for users to interact with the shell. Examples include GNOME Terminal on Linux and Terminal.app on macOS. • **Shell:** The shell is the command-line interpreter that runs within the terminal. It reads the commands entered by the user, interprets them, and communicates with the operating system to execute the commands. Common shells include Bash, Zsh, and PowerShell. • **Command-Line Interface (CLI):** The CLI encompasses the entire environment where the user inputs text commands and receives text-based feedback. It includes both the terminal (as the interface) and the shell (as the interpreter). **Summary:** The **Command-Line Interface (CLI)** is the overarching environment that enables text-based interaction with a computer system. Within this environment, the **terminal** acts as the medium or window through which users input commands, while the **shell** serves as the interpreter that processes these commands and communicates with the operating system to perform the requested actions.