OK ... what is hindering you? :)

update

you are already using a regex to match empty lines, time to understand what they do

perlre#Metacharacters

  ^   Match the beginning of the string            Not in []
       (or line, if /m is used)
...
  $   Match the end of the string                  Not in [], but can

...

  *   Matches the preceding element 0 or more      Not in []
              times
[download]

update

and look again into marshall's code ;-)