It looks like you are referring to Command Line Interface or shortened CLI.It is, basically, a tool that is used for input and output.
It contains command lines which are put on the screen by a user.
It is only put with a keyboard and is an complete different thing than GUI, which is commands are put in with the mouse, so you have a difference in with what device you put it in.
It is much more powerful than GUI and reliable and is usually self-documenting.
MS-DOS is the most common example of CLI.
I hope I helped a little, let me know in a reply.