...
<entry>
  <type>Post</type>
  <url>URL</url>
  <title>The title</title>
  <content>The blog post goes here</content>
</entry>
<entry>
  <type>Comment</type>
  <in-reference-to>URL</in-reference-to>
  <title>The title of the comment</title>
  <content>The content itself</content>
</entry>
...

##</code><code>##

my $tmpComments = File::Temp->new(SUFFIX=>'.txt') or die "File::Temp: $!\n";
foreach (#Go through the whole xml file) {
  if ($type eq 'Comment') {
  # Parse the xml and save the parts as variables
  print $tmpComments "$posturl~~~$date~~~$author~~~$content\n";
  # $posturl holds the <in-reference-to> url
  }
}

##</code><code>##

foreach (#Loop through the xml file again) {
  print "$title\n";
  print "$content\n";
  ...
 
  seek $tmpComments, 0, 0 or die "Seek $tmpComments failed: $!\n"; #Rewind temporary comments file
  while (my $line = <$tmpComments>) {
    # Split each line, store url as $commentID
    my @process_comment = split(/~~~/, $line);
    my $commentID = $process_comment[0];

    # If the urls match, add it to the comments variable
    if ($commentID eq $posturl) {
      my $commentDate = $process_comment[1];
      my $commentAuthor = $process_comment[2];
      my $commentBody = $process_comment[3];
      $comments.= "$commentDate | $commentAuthor | $commentBody";
    }
  }
  print $comments;
}