Front Matter

Front matter is a simple YAML-based specification for adding metadata to Jekyll files. You can add it to pages, posts and collections. It goes at the top of the file between two lines containing ---.

There are some standard front matter attributes:

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. However this is overridden if the file is a post/document and has a layout defined in the front matter defaults. Starting from version 3.5.0, using none in a post/document will produce a file without using a layout file regardless of front matter defaults. Using none in a page, however, will cause Jekyll to attempt to use a layout named “none”.
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.
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.
title While not specifically a standard, many templates make use of page/post titles
description While not specifically a standard, many templates make use of page/post descriptions. Start the description value with “> “ to enable multi-line text, indent the multi-line text.

Global Variables

site Site wide information + configuration settings from _config.yml. See below for details.
page Page specific information + the YAML front matter. Custom variables set via the YAML Front Matter will be available here. See below for details.
layout Layout specific information + the YAML front matter. Custom variables set via the YAML Front Matter in layouts will be available here.
content In layout files, the rendered content of the Post or Page being wrapped. Not defined in Post or Page files.
paginator When the paginate configuration option is set, this variable becomes available for use. See Pagination for details.

site.xxxx Variables

site.categories.[CATEGORY] The list of all Posts in category [CATEGORY].
site.collections A list of all the collections.
site.data A list containing the data loaded from the YAML files located in the _data directory.
site.documents An array of all the documents in every collection. Each entry contains the page. properties for the document. To get a list of all collection documents and pages: {{ site.pages | concat: site.documents }}
site.html_files A subset of site.static_files listing those which end in .html.
site.html_pages A subset of site.pages listing those which end in .html.
site.pages An array of all Pages. Each entry contains the page. properties for the page
site.posts A reverse chronological list of all Posts.
site.related_posts If the page being processed is a Post, this contains a list of up to ten related Posts. By default, these are the ten most recent posts. For high quality but slow to compute results, run the jekyll command with the –lsi (latent semantic indexing) option. Also note GitHub Pages does not support the lsi option when generating sites.
site.static_files A list of all static files (i.e. files not processed by Jekyll’s converters or the Liquid renderer). Each file has three properties: path, modified_time and extname.
site.tags.[TAG] The list of all Posts with tag [TAG].
site.time The current time (when you run the jekyll command).
site.url Contains the url of your site as it is configured in the _config.yml. For example, if you have url: http://mysite.com in your configuration file, then it will be accessible in Liquid as site.url. For the development environment there is an exception, if you are running jekyll serve in a development environment site.url will be set to the value of host, port, and SSL-related options. This defaults to url: http://localhost:4000.
site.[CONFIGURATION_DATA] All the variables set via the command line and your _config.yml are available through the site variable. For example, if you have foo: bar in your configuration file, then it will be accessible in Liquid as site.foo. Jekyll does not parse changes to _config.yml in watch mode, you must restart Jekyll to see changes to variables.

site.documents and site.pages

Both of these are arrays of objects. The objects contain the following properties.

categories
collection
comments

page.xxxx Variables

page.content The content of the Page, rendered or un-rendered depending upon what Liquid is being processed and what page is.
page.title The title of the Page (if set)
page.excerpt The un-rendered excerpt of the Page.
page.url The URL of the Post without the domain, but with a leading slash, e.g. /2008/12/14/my-post.html
page.date The Date assigned to the Post. This can be overridden in a Post’s front matter by specifying a new date/time in the format YYYY-MM-DD HH:MM:SS (assuming UTC), or YYYY-MM-DD HH:MM:SS +/-TTTT (to specify a time zone using an offset from UTC. e.g. 2008-12-14 10:30:00 +0900).
page.id An identifier unique to a document in a Collection or a Post (useful in RSS feeds). e.g. /2008/12/14/my-post /my-collection/my-document
page.categories The list of categories to which this post belongs. Categories are derived from the directory structure above the _posts directory. For example, a post at /work/code/_posts/2008-12-24-closures.md would have this field set to [‘work’, ‘code’]. These can also be specified in the YAML Front Matter. Available to collection documents but not to Pages(?).
page.tags The list of tags to which this post belongs. These can be specified in the YAML Front Matter.
page.path The path to the raw post, page or collection document. Example usage: Linking back to the page or post’s source on GitHub. This can be overridden in the YAML Front Matter.
page.next The next post relative to the position of the current post in site.posts. Returns nil for the last entry.
page.previous The previous post relative to the position of the current post in site.posts. Returns nil for the first entry.

These are not described in the Jekyll docs section on Pages but are certainly available

dir - Only available to pages, not to collection documents.
name - Only available to pages, not to collection documents. Source name of document.

Posts

categories
tags
content
date
dir
draft?
excerpt
excerpt_separator
id
next previous
path
title
url

Collection document variables

page.categories
page.collection
page.comments
page.content
page.draft
page.excerpt
page.id
page.layout
page.next
page.output - rendered output of collection document
page.path
page.previous
page.relative_path
url
layout

Collections variables (site.collections.xxxx)

Files

Files can be accessed via site.static_files. They are typically kept in the assets folder.

path - The relative path to the file, e.g. /assets/img/image.jpg
modified_time - The Time the file was last modified, e.g. 2016-04-01 16:35:26 +0200
name - The string name of the file e.g. image.jpg for image.jpg
basename - The string basename of the file e.g. image for image.jpg
extname - The extension name for the file, e.g. .jpg for image.jpg

While front-matter variables can’t be added directly to files, they can be made accessible via the defaults section of _config.yml.

Includes files variable

When using the _includes folder, any include files that allow parameters gain an include object variable.

The object will contain a key for each variable passed as a parameter in the calling page.

Example - in the calling page: {% include note.html content="This is my sample note." %} and in the include page: {{ include.content }}

If you need to send the contents of Jekyll/Liquid variables to the included page, you can do so directly. For example: {% include note.html title=page.title %} - note the lack of quotes.

Github Metadata (site.github.xxxx)

versions object containing version numbers for Jekyll, Ruby and other plugins (e.g. keys: jekyll, kramdown, liquid, maruku, rdiscount, redcarpet, RedCloth, jemoji, jekyll-mentions, jekyll-redirect-from, jekyll-sitemap, github-pages, ruby)
hostname “github.com”

pages_hostname": "github.io",
api_url": "https://api.github.com",
help_url": "https://help.github.com",
environment": "dotcom",
pages_env": "dotcom",
public_repositories": [ Repository Objects ],
organization_members": [ User Objects ],
build_revision": "cbd866ebf142088896cbe71422b949de7f864bce",
project_title": "metadata-example",
project_tagline": "A GitHub Pages site to showcase repository metadata",
owner_name": "github",
owner_url": "https://github.com/github",
owner_gravatar_url": "https://github.com/github.png",
repository_url": "https://github.com/github/metadata-example",
repository_nwo": "github/metadata-example",
repository_name": "metadata-example",
zip_url": "https://github.com/github/metadata-example/zipball/gh-pages",
tar_url": "https://github.com/github/metadata-example/tarball/gh-pages",
clone_url": "https://github.com/github/metadata-example.git",
releases_url": "https://github.com/github/metadata-example/releases",
issues_url": "https://github.com/github/metadata-example/issues",
wiki_url": "https://github.com/github/metadata-example/wiki",
language": null,
is_user_page": false,
is_project_page": true,
show_downloads": true,
url": "http://username.github.io/metadata-example", // (or the CNAME)
baseurl": "/metadata-example",
contributors": [ User Objects ],
releases": [ Release Objects ],
latest_release": [ Release Object ],
private": false,
license":
  key": "mit",
  name": "MIT License",
  spdx_id": "MIT",
  url": "https://api.github.com/licenses/mit"
    ,
source":
  branch": "gh-pages",
  path": "/"

defaults:
  - scope:
      path: "assets/img"
    values:
      image: true