Vi: Start-up, Modes, Save and Quit

To enter Vi type:

 vi FILENAME

Vi has two modes: Normal (command) mode and edit mode.

 Switch to normal mode:     <ESC>
 Switch to edit mode:       i or a

Getting out of Vi (change to normal mode <ESC>):

 Exit Vi:                       :q
 Exit Vi (ignore changes):      :q!
 Save:                          :w
 Save and Exit:                 :wq

Switch to (edit) an other file:

:edit FILENAME

Getting help:

:help topic