Command line interface
A command line interface or CLI is a method of interacting with a computer by giving it lines of text commands in written form either from keyboard input or from a script. The computer then generally responds with text output to the display or to a file. It contrasts with graphical user interfaces (GUIs).
Examples of programs which use command line interfaces include the Unix shell, VMS DCL, and related follow-on designs like /A> and MS-DOS's command.com. These programs are often called command line interpreters.
There are other programs which use CLIs as well. The CAD program AutoCAD has one. In some computing environments like Oberon or Smalltalk, most of the text which appears on the screen may be used for giving commands.
The commands given on a command line interface often are of the form
doSomething how toAFileor
doSomething how toAnInputFile > outputFiledoSomething corresponds to a verb, how to an adverb (it describes how the command should be performend) and toAFile to a direct object.
Advantages of a command line interface
Even though new users seem to learn GUIs more quickly to perform common operations, carefully developed CLIs have several advantages: