If I understand your question right, something like this may do what you want:

$your_data =~ /\+Header1(.|\n+)-Header1\n\+Header2(.|\n+)-Header2\n\+H
+eader3(.|\n+)-Header3\n/;
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I wouldn't suggest using that as anything but a starting point, though. There are regex options for changing the . operator to match \n's, and you may want to consider doing a line by line parse (and having boolean--i.e., flag--variables to tell you what section you're in).

The last suggestion might be started like this:

while ($line = <your_file_handle>) {
  if($line =~ /^\+Header1/) { $header1 = 1; next }
   # if +Header1 has its own line use next
  elsif($line =~ /^-Header1/) { next }
  else { $header1 = 0 }
  .
  .
  .
  if($header1) {
    $h1_data[$index++] = $line;
  }
 .
 .
 .
}
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Again, these are just quick things to get you started thinking; you may want to look at this site and search for regex, or look at the perlman pages for more information regarding them.