1. To open an existing file for editing:
vi intro
This opens the file intro for editing. This file already exists in the current directory.
2. To create a file to edit:
vi part2
This command starts vi with a new file named part2. This file does not exist in the current directory until it is written to using the write command.
3. To simply start vi:
vi
This command places you in vi. You can then enter and edit text and write it to a file.