open my $fh, "source-data.txt"
    or die "opening source-data.txt: $!";
  print "<blockquote>\n";
  while ( my $line = <$fh> )
  {
      # protect against most egregious HTML violations
      $line =~ s/&/&amp;/g;
      $line =~ s/</&lt;/g;
      $line =~ s/>/&gt;/g;

      # mark upper-case words as italic.  not locale-safe.
      $line =~ s!\b([A-Z])+\b!<i>$1</i>!g;

      # output the result
      print $fh $line;
  }
  print $fh "</blockquote>\n";
  close $fh
    or die "closing source-data.txt: $!";