:w - Write (Save)
:wq - Write and quit
:q - Quit, fails if unsaved
:q! - Quit, even if unsaved
ESC - Return to normal mode
i - Insert at cursor position
a - Insert after cursor position
o - Insert on line below cursor
v - Enter visual mode
ctrl+v - Enter visual mode (vertical)
V - Enter visual mode (full lines)
u [in visual mode] - To lowercase
U [in visual mode] - To uppercase
Undo/Redo
u - Undo
ctrl+r - Redo
$ - Jump to end of line
^ - Jump to start of line
h - Move left
j - Move down
k - Move up
l - Move right
H - Move to top of screen
M - Move to middle of screen
L - Move to bottom of screen
gg - Move to start of file
G - Move to end of file
420gg - Move to line 420
w - Jump to start of next word
b - Jump to start of prev word
Search
/something - Search for string
n - Jump to next match
N - Jump to prev match
/something\c - Case insensitive search
y [in visual mode] - Copy highlighted text
yy - Copy the current line
d [in visual mode] - Cut highlighted text
dd - Cut the current line
Ctrl+Shift+V - Paste from external clipboard
:%s/find/replace/g
:s/find/replace/g [in visual mode]
:'<,'>s/find/replace/g [in visual mode]
:%s/address/replace/g
. - Any single character
* - Up to unlimited characters