You can also use a here document to replace all those prints. You just tell it what you want to be printed plus it'll also interpolate variables (e.g. turn $dog_name into "Fido")

As an example, instead of

  print "  <HR>\n";
  print "  <TABLE border=0 width=100% bgcolor=\"\#005533\">\n";
  print "   <TR><TD>\n";
  print "$username\n";
[download]

you can write

print <<END;
  <HR>
  <TABLE border=0 width=100% bgcolor="#005533">
    <TR><TD>
   $username
END
[download]

Instead of END, it can be any word and that word must appear alone to end the here document.