Vi is a full-screen text editor that is available on most Unix systems. It is functionally compatible on all defined terminal types. While advanced users may consider vi a useful tool, it is not straightforward to learn. This article presents a battle plan for getting started using the vi editor. Vi has several commands and capabilities for doing this.
Most keyboards have cursor keys.
If your terminal and the terminal type you are using on the UNIX system are compatible, you should be able to use the cursor keys to position yourself within a file. If your keyboard doesn't have cursor keys, or if they don't work properly with your terminal, vi supports four commands that serve the same function of positioning the cursor. The positioning commands in vi operate only while vi is in command mode, which is the mode in which vi starts. By entering any one of several vi input commands you switch vi to input mode. Once in input mode, any character you type is taken to be text and is added to the file.