Remember Vim folding

Key Operation
zO Open all folds recursivley
zo Open one fold
zc Close one fold
zC Close all folds recursivley
za Toggle fold
zA Toggle fold recursivley
zR Open all folds
zM Close all folds

Then i set the following in .vimrc:

" folding
" toggle open fold
nnoremap f zA
" open all
nnoremap F zR
" clos all
nnoremap <C-f> zM