The part of the operating system that receives and executes operating system commands. Every operating system has a command processor. When the command prompt is displayed, the command processor is waiting for a command. After you enter a command, the command processor analyzes the syntax to make sure the command is valid, and then either executes the command or issues an error warning. For operating systems with a graphical user interface, the command processor interprets mouse operations and executes the appropriate command.
Another term for command processor is command line interpreter.