Tags

You can assign one or multiple tags to pages using the tags variable. Tags allows to group content in interesting ways.

For example, in a blog site you may want to group post of different categories:

---
title: The history of the static site generators
tags:
  - post
  - ssg
---

This post have two tags, one to identify the type of page (post) and other with the topic (ssg). To collect all pages tagged as post in the layouts, use the search object:

<ul>
  {% for post in search.pages("post") %}
  <li>{{ post.data.title }}</li>
  {% endfor %}
</ul>

And to get all pages tagged as post and ssg add the two tags names separated with a space:

<ul>
  {% for post in search.pages("post ssg") %}
  <li>{{ post.data.title }}</li>
  {% endfor %}
</ul>

Tags in _data

Unlikely other values, when you define tags in a _data.* file and in the front matter of the pages, the value is not overrided, but aggregated. In other words: the page will have all tags defined in _data.* and in the front matter. In the previous example, instead of assigning the "post" tag to all pages manually, you could define it in a _data.* file in the directory where all posts are stored and use the front matter to assign the other tags individually.