vi and vim are the most commonly available editors in the Linux
environment.  If you’re proficient with vi you can use it on
almost any UNIX or UNIX-like computer.  It is installed by default
in all versions of RedHat Linux, FreeBSD, Solaris, NetBSD, SCO UNIX,
IRIX, and many other UNIX operating systems.  It does have a major
drawback in the fact that there is no online help, no GUI, no menus,
nothing that will help you once you start the editor.  In this
fashion it is most like the old DOS editor, edlin.  There are so
many excellent references to vi on the internet and in press that
rewriting those resources here would be an injustice.  Instead,
read through some of these articles



https://engineering.purdue.edu/ECN/Resources/KnowledgeBase/Docs/20020202121609

http://unix.t-a-y-l-o-r.com/Vi.html

and of course

http://www.vim.org



O’Reilly and Associates also has several excellent books:

Learning the Vi editor - http://www.oreilly.com/catalog/vi6/index.html

vi Editor Pocket Reference - http://www.oreilly.com/catalog/vipr/