Today I learned how to fold/unfold in Vim; it's quite handy.
Unexpectedly, when I exit a file and reenter it, the folds I created are gone (unfolded).
In our company's large project there are quite a lot of sticky (legacy) code blocks which are kind of obsolete but indispensable.
I really need to fold them nearly permanently.
Is there a brief way to tell Vim to save my folding preferences for a file?