My condensed version of a cheat sheet for the vi editor.
Quitting
:x Exit, saving changes
:q Exit as long as there have been no changes
ZZ Exit and save changes if any have been made
:q! Exit and ignore any changes
Inserting Text
i Insert before cursor
I Insert before line
a Append after cursor
A Append after line
o Open a new line after current line
O Open a new line before current line
r Replace one character
R Replace many characters
Motion
h Move left
j Move down
k Move up
l Move right
Deleting Text
Almost all deletion commands are performed by typing d followed by a motion.
For example, dw deletes a word.
A few other deletes are:
x Delete character to the right of cursor
X Delete character to the left of cursor
D Delete to the end of the line
dd Delete current line
:d Delete current line