A user interface to a computer's operating system or application in which a user types a command on a specified line in response to a prompt. The system responds to the command, and the user can then enter another command, and so on.
Generally, this is a textual environment that, while usually more cryptic and less user-friendly, provides a user with a fast method of inputting options to an application. Due to the textual method of input, command-line applications can often have their use automated. The primary alternative to a Command-Line Interface is the GUI.
This is a text-based interface that launches and configures an application from the command line. An example is the McAfee® Command Line Scanner, scan.exe, which takes various parameters, including which files to scan.