An operating system that is directed by entering text commands. DOS is an example of a widely used command line operating system. See DOS and command line.

The Config.sys is the main configuration file used by OS/2, MS-DOS and other operating systems. Config.sys commands loads programs into the memory and sets ups the memory management of the system. The ...

Mac/Unix/Linux Command Line This example from macOS, which is a Unix-based operating system, shows two commands issued after the command line ("terminal window") was launched.