deleting some empty lines with sed

[Peter Andersen]

I have some source-files that I produce documentation from.

I use sed to make a few changes to the text. I have figured
most of it out, but I have one problem remaining:
If two or more blank lines appear, I want to remove all but
one of these.

I have tried the following sed script

    s^ *$//p
1,$ N
    s/\(\n\n\)\n*/\1/gp

but it didn't work.

Does anyone have a way of doing this, perhaps using something
else but sed. I'm not a perl-guru, but if its possible in perl
I'd like to hear about that too.

Peter