What is a CLI (Command Line Interface)?

With the familiar Graphical User Interface (GUI), you interact using text, icons, and pictures in multiple windows. A Command Line Interface (CLI) is more basic. It has no icons or pictures, and often is so simple that even a mouse will not work — it relies on the keyboard.

CLIs are used:

• To communicate basic commands to a device, for example, before an operating system starts.
• To communicate with a device that doesn't support complex features such as GUIs.
• To control devices where strict, lock-step, "statements and responses" are preferred. A great advantage to a CLI is that you can always see what you did — whereas with a GUI, if you aren't paying attention when your hand slips, you may never know what happened.

See an example of a CLI by typing Start > Run > command. (In Windows 2000 or Windows XP, Start > Run > cmd). Notice there are no menus, but only a blinking cursor after the prompt (the prompt usually ends with a greater than sign ">"). Type dir in the window, and press Enter.

The first screenshot command, instead of just a basic "dir" command, limits results to those starting with "w". The asterisk (*) means that you don't care what comes after the "w".

This same trick can be used to change directories (the cd command), which is useful when the whole pathname is longer than you want to type. For example, to change directories from C:\ to C:\Program Files\NETGEAR\SC101 Manager Utility\, you might type:

cd prog*
cd net*
cd s*

When you're finished with a CLI, type exit then RETURN. (Some programs that use CLIs use quit or bye instead of exit).

It's possible to cut-and-paste in a CLI that is inside a window, but the commands aren't the same as a word processor. To make a record of what you've done, it's probably easiest to take a screenshot or two.

N101518.asp Aug. 16, 2005