while ( <$fh> )
  {
      # protect against most egregious HTML violations
      s/&/&amp;/g; s/</&lt;/g; s/>/&gt;/g;

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

      # output the result
      print $fh $_;
  }