9.1 The vi Editor
9.1.4 Input commands (entry mode)
After you have started vi and specified a file to work with, you will most often use one of the input commands to add text to the file. These commands are entered from command mode and switch vi into entry mode. Once in entry mode, if you want to use one of the other entry mode commands shown, you must first press Escape to return to command mode.

If you are working with vedit or have set showmode on, you will see the mode (append, insert or open) shown in the lower right corner of the screen. If no mode appears, you are not in one of the entry or input modes. The single-letter commands shown in the Figure are case-sensitive and are used to insert or append text.

Note - Only the needed basic Entry mode, Command mode, and Last Line mode commands are covered in this chapter.