Modes of Operation
The vi editor supports three modes of operation: command mode, in which keys are interpreted as commands; insert mode, in which keys are interpreted as input to the file; and last-line mode, in which ex commands can be entered.
As indicated earlier, upon entering vi, the editor is in command mode. This means that you can enter any of the vi command mode commands. The typical new user complaint is that no prompt exists in command mode. In fact, this is true for two of the three vi modes. We can whine about it, or accept it and move on. Basically, the editor accepts any characters typed while in command mode as commands. The commands usually are one-letter commands. They do not echo when typed, and the editor does ...