Working with Unix-based operating systems, most users is more or less familiar with vi editor. The vi editor is available on almost Unix systems where it uses the standard alphabetic keys for commands. Therefore, we can start it from any type of terminal, console or shell.
vi (pronounced “vee-eye”) is short for “vi”sual editor. It displays a window into the file being edited that shows 24 lines of text. vi is a text editor, not a “what you see is what you get” word processor. vi lets you add, change, and delete text, but does not provide such formatting capabilities as centering lines or indenting paragraphs.