Editing with vi
vi is ubiquitous: you will find it even in the
smallest distributions. It is much easier to use than
its original forms, ed and ex.
vi has two main modes: move and insert. A variety
of commands in vi will put you into insert
mode, but ESC is the way to get out!
As mentioned in on page 168 of your text, spell
(or ispell, an interactive version) are usually
used outside of vi.
Summary of vi commands
A summary of vi commands is here.
Editing with emacs
emacs is a far more ambitious program
emacs is derived from teco, an even more cryptic
editor than ed; the
history of emacs is far more detailed than
that of ed.
emacs in action
emacs has a distinctive look:
A summary of emacs commands is here.
emacs and ispell
Unlike vi, it is very easy and convenient to run ispell interactively within emacs.