{% if post.author %}

{% assign author = post.author %}

{% elsif page.author %}

{% assign author = page.author %}

{% else %}

{% assign author = site.author %}

{% endif %} {% if author %}

{% if site.googleplus_user %}
  <span class="byline author vcard">by <a href="https://plus.google.com/{{ site.googleplus_user }}?rel=author"><span class="fn">{{ author }}</span></a></span>
{% else %}
  <span class="byline author vcard">by <span class="fn">{{ author }}</span></span>
{% endif %}

{% endif %}