This book assumes you have already read Learning the UNIX Operating System or some other introduction to UNIX. You should already know how to:
Log in and log out
Enter UNIX commands
Change directories
List files in a directory
Create, copy, and remove files
Familiarity with grep (a global search program) and wildcard characters is also helpful.
Although vi can run on almost any terminal, it must know what kind of terminal you are using. The terminal type is usually set in your .profile or .login file. See your system administrator if you are not sure whether your terminal type is defined correctly. This will avoid possible confusion for you when you start experimenting with vi.