2. Command Line Interface

A Command Line Interface allows the user to interact directly with the computer system by typing in commands (instructions) into a screen which looks similar to the one below:

You cannot just type in any kind of instruction of course, because the computer will only react to a definite set of words.

These commands are very specific, for example in DOS you could type in:

copy c:\item.txt   d:\

That tells the machine to copy the file 'item.txt' that resides in the root directory of drive C: into the root directory of drive D:\

Many commands have what are called 'switches'. These are extra parameters or flags which add extra functionality to the command. For example:

Before Windows was developed, this type of user interface was what most people used to get the computer to follow instructions.

It is still around though, for example a technician setting up a server in a data centre might use a command line interface or a mainframe administrator setting up a configuration file.

The main disadvantage of a command line interface is that the person must have detailed knowledge of the command that can be used.