How to undo fill-paragraph in emacs?

I have a text file that is pretty long. Any easy way to "undo" a M-q (fill-paragraph) on a file that was written and saved a while ago?

For example, I want to change this:

They're coming to take me away, ha-haaa!!
They're coming to take me away, ho-ho, hee-hee, ha-haaa

To the funny farm. Where life is beautiful all the time and I'll
be happy to see those nice young men in their clean white
coats and they're coming to take me away, ha-haaa!!!!!

To this:

They're coming to take me away, ha-haaa!! They're coming to take me away, ho-ho, hee-hee, ha-haaa

To the funny farm. Where life is beautiful all the time and I'll be happy to see those nice young men in their clean white coats and they're coming to take me away, ha-haaa!!!!!

Solution

You can set fill-columnn to a really large number, and fill.

C-u 10000 C-x f M-x fill-individual-paragraphs

Or you can use a little custom function:

(defun refill-paragraphs-to-be-one-line ()
  "fill individual paragraphs with large fill column"
  (interactive)
  (let ((fill-column 100000))
    (fill-individual-paragraphs (point-min) (point-max))))