while you can specify that a substitution take place on
many lines (1,3s/// for lines 1-3, .,$s/// for lines "here"
to end of file, or %s/// for lines "all") VI is based on
EX which is a line editor.
there may be some advanced voodoo mumbo-jumbo that will allow
VIM (or ELVIS, another enhanced VI) to munge the double \n\n
the way you want it to...
but there's probably a better tool.
try "man wml" for example ("apt-get install wml" if you don't
have it)...
just one suggestion, there are plenty of others (including
perl and/or xml)...
