Preprocessing HTML doesn't work on my mac

[purushottamjha]

I tried this command preprocess index.html > index1.html

and my html looks like this

<!-- Bootstrap -->
<link rel="stylesheet" href="bower_components/bootstrap/dist/css/bootstrap.min.css">
<!-- End Bootstrap -->

<!-- @if NODE_ENV='production' -->
<script src="some/production/lib/like/analytics.js"></script>
<!-- @endif -->

<!-- @exclude -->
<header>You're on dev!</header>
<!-- @endexclude -->

However, after preprocessing I don't see any change in the generated file.