vim folding - how to copy unfolded lines

Question

I would like to copy/delete all the lines except the folded lines and vice-versa. How do I do that? It is ok if I have to use a plugin for that as well. But, I would love to have that functionality.

Answer 1

:folddoopen y W

yanks every non-folded line into register w. W is used to append to register w.

:folddoopen d

deletes every non-folded line.

There's of course a mirror command, :folddoclose that acts on every folded line.