Vu 	Lowercase line
VU 	Uppercase line
g~~ 	Invert case
vEU 	Switch word to uppercase
vE~ 	Modify word case
ggguG 	Set all text to lowercase
gggUG 	Set all text to uppercase
:set ignorecase 	Ignore case in searches
:set smartcase 	Ignore case in searches excepted if an uppercase letter is used
:%s/\<./\u&/g 	Sets first letter of each word to uppercase
:%s/\<./\l&/g 	Sets first letter of each word to lowercase
:%s/.*/\u& 	Sets first letter of each line to uppercase
:%s/.*/\l& 	Sets first letter of each line to lowercase