UP

Any file that contains a YAML front matter block will be processed by Jekyll as a special file.

The front matter must be the first thing in the file and must take the form of valid YAML set between triple-dashed lines.

Here is a basic example:

---
layout: post
title: Blogging Like a Hacker
---

Between these triple-dashed lines, you can set predefined variables or even create custom ones of your own. These variables will then be available for you to access using Liquid tags both further down in the file and also in any layouts or includes that the page or post in question relies on.

Predefined Variables

Predefined Global Variables

There are a number of predefined global variables that you can set in the front matter of a page or post.

  • layout: If set, this specifies the layout file to use. Use the layout file name without the file extension. Layout files must be placed in the _layouts directory. Using null will produce a file without using a layout file. This is overridden if the file is a post/document and has a layout defined in the front matter defaults.
  • permalink: If you need your processed blog post URLs to be something other than the site-wide style (default /year/month/day/title.html), then you can set this variable, and it will be used as the final URL.
  • published: Set to false if you don’t want a specific post to show up when the site is generated.

Render Posts Marked As Unpublished
To preview unpublished pages, run jekyll serve or jekyll build with the --unpublished switch.

Jekyll also has a handy drafts feature tailored specifically for blog posts.

Predefined Variables for Posts

These are available out-of-the-box to be used in the front matter for a post.

  • date: A date here overrides the date from the name of the post. This can be used to ensure correct sorting of posts. A date is specified in the format YYYY-MM-DD HH:MM:SS +/-TTTT; hours, minutes, seconds, and timezone offset are optional.
  • category/categories: Instead of placing posts inside of folders, you can specify one or more categories that the post belongs to. When the site is generated the post will act as though it had been set with these categories normally. Categories (plural key) can be specified as a YAML list or a space-separated string.
  • tags: Similar to categories, one or multiple tags can be added to a post. Also like categories, tags can be specified as a YAML list or a space-separated string.

Custom Variables

You can also set your own front matter variables you can access in Liquid.

For instance, if you set a variable called food, you can use that in your page:

---
food: Pizza
---

<h1>{{ page.food }}</h1>

Don’t repeat yourself

If you don’t want to repeat your frequently used front matter variables over and over,
define defaults for them and only override them where necessary (or not at all).
This works both for predefined and custom variables.

References