Definition - What does Command Line mean?
A command line is a horizontal line on an interface that allows the user to type in various commands. Typically, there is a command prompt at the left side of a screen, with a blank line extending to the right where commands are typed.
Techopedia explains Command Line
In the past, command line interfaces were a common type of interface for a personal computer. Now, command line interfaces are more commonly oriented toward high-level users, where personal computers and business workstation operating systems often use a Windows-based approach. In a command-line operating system, the entire screen is a series of command lines. As a user types commands, the field scrolls vertically. This lets the user see past commands and reactions by the computer.
Windows-based operating systems often include a shell or special function that allows the user to bring up a command line interface within a window. This allows for the kinds of functionality that command line interfaces provide. A command line interface is very straightforward in many ways and presents a clear visual record, which is one reason why it is still preferred by some users.