Basic vi Commands

Linux
i or insert to insert text
ii ir insert insert to replace (overwrite)
arrow keys to navigate
esc :q! to exit with out changes
esc :wq to save and exit
my fave
esc shift^ZZ to save and exit.

*BSD
same as above but no arrow keys and sometimes no insert i(only)
esc takes you to command mode and you can navigate
.with keys
x =delete
h,j,k,l = arrows
etc...
just the very basics
Almost forgot that *BSD has an editor ee I like alot when you're done editing
esc and you get a little menu