http://www-rohan.sdsu.edu/doc/debian/ch-editor.html
http://www.washington.edu/computing/unix/vi.html
http://hubpages.com/hub/Vi-Unix-Editor-How-to-use-Vi-Editor-and-Common-Problems
http://thomer.com/vi/vi.html
http://unix.t-a-y-l-o-r.com/Vi.html
http://forum.codecall.net/linux-tutorials-guides-tips/23785-how-use-vi-key-bindings-bash.html
http://acms.ucsd.edu/info/vi_tutorial.shtml
http://staff.washington.edu/rells/R110/
http://www.builderau.com.au/program/unix/soa/Use-vi-to-edit-files-in-a-UNIX-environment/0,339024638,339160224,00.htm