sed script to combine blank lines? (sed + awk solutions)

[Michael Morrell]

/ hpsal2:comp.unix.questions / dave at lsuc.uucp (David Sherman) /  3:49 pm  Oct 16, 1988 /
Some versions of UNIX (including 4.1BSD) include a program
call ssp(1) which does this; it's a bit faster than the
parallel awk script.

Also, if you know your text doesn't contain duplicate lines
(nroff output almost always qualifies, for example), good
old uniq(1) will do it.
----------

I thought the original problem was to replace multiple "blank" lines with
a single newline (\n), where "blank" included lines with only tabs and
formfeeds on them.  ssp and uniq will only help if the lines to be combined
are really blank.