~ : Changes the case of current character
guu : Change current line from upper to lower.
gUU : Change current LINE from lower to upper.
guw : Change to end of current WORD from upper to lower.
guaw : Change all of current WORD to lower.
gUw : Change to end of current WORD from lower to upper.
gUaw : Change all of current WORD to upper.
g~~ : Invert case to entire line
guG : Change to lowercase until the end of document.