Configuration
Jekyll allows you to concoct your sites in any way you can dream up, and it’s
thanks to the powerful and flexible configuration options that this is possible.
These options can either be specified in a _config.yml
file placed in your
site’s root directory, or can be specified as flags for the jekyll
executable
in the terminal.
Configuration Settings
Global Configuration
The table below lists the available settings for Jekyll, and the various options
(specified in the configuration file) and flags
(specified on the command-line) that control them.
Setting | Options and Flags |
---|---|
Site Source Change the directory where Jekyll will read files |
|
Site Destination Change the directory where Jekyll will write files |
|
Safe |
|
Exclude Exclude directories and/or files from the conversion. These exclusions are relative to the site's source directory and cannot be outside the source directory. |
|
Include
Force inclusion of directories and/or files in the conversion.
|
|
Keep files
When clobbering the site destination, keep the selected files.
Useful for files that are not generated by jekyll; e.g. files or
assets that are generated by your build tool.
The paths are relative to the |
|
Time Zone
Set the time zone for site generation. This sets the |
|
Encoding
Set the encoding of files by name. Only available for Ruby
1.9 or later).
The default value is |
|
Defaults Set defaults for YAML Front Matter variables. |
see below |
Destination folders are cleaned on site builds
The contents of <destination>
are automatically
cleaned, by default, when the site is built. Files or folders that are not
created by your site will be removed. Some files could be retained
by specifying them within the <keep_files>
configuration directive.
Do not use an important location for <destination>
; instead, use it as
a staging area and copy files from there to your web server.
Build Command Options
Setting | Options and Flags |
---|---|
Regeneration Enable auto-regeneration of the site when files are modified. |
|
Configuration Specify config files instead of using |
|
Drafts Process and render draft posts. |
|
Environment Use a specific environment value in the build. |
|
Future Publish posts with a future date. |
|
LSI Produce an index for related posts. |
|
Limit Posts Limit the number of posts to parse and publish. |
|
Force polling Force watch to use polling. |
|
Verbose output Print verbose output. |
|
Silence Output Silence the normal output from Jekyll during a build |
|
Incremental build Enable the experimental incremental build feature. Incremental build only re-builds posts and pages that have changed, resulting in significant performance improvements for large sites, but may also break site generation in certain cases. |
|
Serve Command Options
In addition to the options below, the serve
sub-command can accept any of the options
for the build
sub-command, which are then applied to the site build which occurs right
before your site is served.
Setting | Options and Flags |
---|---|
Local Server Port Listen on the given port. |
|
Local Server Hostname Listen at the given hostname. |
|
Base URL Serve the website from the given base URL |
|
Detach Detach the server from the terminal |
|
Skips the initial site build. Skips the initial site build which occurs before the server is started. |
|
X.509 (SSL) Private Key SSL Private Key. |
|
X.509 (SSL) Certificate SSL Public certificate. |
|
Do not use tabs in configuration files
This will either lead to parsing errors, or Jekyll will revert to the default settings. Use spaces instead.
Custom WEBRick Headers
You can provide custom headers for your site by adding them to _config.yml
Defaults
We only provide on default and that’s a Content-Type header that disables caching in development so that you don’t have to fight with Chrome’s aggressive caching when you are in development mode.
Specifying a Jekyll environment at build time
In the build (or serve) arguments, you can specify a Jekyll environment and value. The build will then apply this value in any conditional statements in your content.
For example, suppose you set this conditional statement in your code:
When you build your Jekyll site, the content inside the if
statement won’t be run unless you also specify a production
environment in the build command, like this:
Specifying an environment value allows you to make certain content available only within specific environments.
The default value for JEKYLL_ENV
is development
. Therefore if you omit JEKYLL_ENV
from the build arguments, the default value will be JEKYLL_ENV=development
. Any content inside {% if jekyll.environment == "development" %}
tags will automatically appear in the build.
Your environment values can be anything you want (not just development
or production
). Some elements you might want to hide in development environments include Disqus comment forms or Google Analytics. Conversely, you might want to expose an “Edit me in GitHub” button in a development environment but not include it in production environments.
By specifying the option in the build command, you avoid having to change values in your configuration files when moving from one environment to another.
Front Matter defaults
Using YAML Front Matter is one way that you can specify configuration in the pages and posts for your site. Setting things like a default layout, or customizing the title, or specifying a more precise date/time for the post can all be added to your page or post front matter.
Often times, you will find that you are repeating a lot of configuration options. Setting the same layout in each file, adding the same category - or categories - to a post, etc. You can even add custom variables like author names, which might be the same for the majority of posts on your blog.
Instead of repeating this configuration each time you create a new post or page, Jekyll provides a way to set these defaults in the site configuration. To do this, you can specify site-wide defaults using the defaults
key in the _config.yml
file in your projects root directory.
The defaults
key holds an array of scope/values pairs that define what defaults should be set for a particular file path, and optionally, a file type in that path.
Let’s say that you want to add a default layout to all pages and posts in your site. You would add this to your _config.yml
file:
Here, we are scoping the values
to any file that exists in the scopes path. Since the path is set as an empty string, it will apply to all files in your project. You probably don’t want to set a layout on every file in your project - like css files, for example - so you can also specify a type
value under the scope
key.
Now, this will only set the layout for files where the type is posts
.
The different types that are available to you are pages
, posts
, drafts
or any collection in your site. While type
is optional, you must specify a value for path
when creating a scope/values
pair.
As mentioned earlier, you can set multiple scope/values pairs for defaults
.
With these defaults, all posts would use the my-site
layout. Any html files that exist in the projects/
folder will use the project
layout, if it exists. Those files will also have the page.author
liquid variable set to Mr. Hyde
as well as have the category for the page set to project
.
In this example the layout
is set to default
inside the collection with the name my_collection
.
Precedence
Jekyll will apply all of the configuration settings you specify in the defaults
section of your _config.yml
file. However, you can choose to override settings from other scope/values pair by specifying a more specific path for the scope.
You can see that in the last example above. First, we set the default layout to my-site
. Then, using a more specific path, we set the default layout for files in the projects/
path to project
. This can be done with any value that you would set in the page or post front matter.
Finally, if you set defaults in the site configuration by adding a defaults
section to your _config.yml
file, you can override those settings in a post or page file. All you need to do is specify the settings in the post or page front matter. For example:
The projects/foo_project.md
would have the layout
set to foobar
instead
of project
and the author
set to John Smith
instead of Mr. Hyde
when
the site is built.
Default Configuration
Jekyll runs with the following configuration options by default. Alternative settings for these options can be explicitly specified in the configuration file or on the command-line.
There are two unsupported kramdown options
Please note that both remove_block_html_tags
and
remove_span_html_tags
are currently unsupported in Jekyll due
to the fact that they are not included within the kramdown HTML converter.
Markdown Options
The various Markdown renderers supported by Jekyll sometimes have extra options available.
Redcarpet
Redcarpet can be configured by providing an extensions
sub-setting, whose
value should be an array of strings. Each string should be the name of one of
the Redcarpet::Markdown
class’s extensions; if present in the array, it will
set the corresponding extension to true
.
Jekyll handles two special Redcarpet extensions:
no_fenced_code_blocks
— By default, Jekyll sets thefenced_code_blocks
extension (for delimiting code blocks with triple tildes or triple backticks) totrue
, probably because GitHub’s eager adoption of them is starting to make them inescapable. Redcarpet’s normalfenced_code_blocks
extension is inert when used with Jekyll; instead, you can use this inverted version of the extension for disabling fenced code.
Note that you can also specify a language for highlighting after the first delimiter:
```ruby
# ...ruby code
```
With both fenced code blocks and highlighter enabled, this will statically
highlight the code; without any syntax highlighter, it will add a
class="LANGUAGE"
attribute to the <code>
element, which can be used as a
hint by various JavaScript code highlighting libraries.
smart
— This pseudo-extension turns on SmartyPants, which converts straight quotes to curly quotes and runs of hyphens to em (---
) and en (--
) dashes.
All other extensions retain their usual names from Redcarpet, and no renderer
options aside from smart
can be specified in Jekyll. A list of available
extensions can be found in the Redcarpet README file.
Make sure you’re looking at the README for the right version of
Redcarpet: Jekyll currently uses v3.2.x. The most commonly used
extensions are:
tables
no_intra_emphasis
autolink
Kramdown
In addition to the defaults mentioned above, you can also turn on recognition
of GitHub Flavored Markdown by passing an input
option with a value of “GFM”.
For example, in your _config.yml
:
kramdown:
input: GFM
Custom Markdown Processors
If you’re interested in creating a custom markdown processor, you’re in luck! Create a new class in the Jekyll::Converters::Markdown
namespace:
Once you’ve created your class and have it properly set up either as a plugin
in the _plugins
folder or as a gem, specify it in your _config.yml
:
Incremental Regeneration
Incremental regeneration is still an experimental feature
While incremental regeneration will work for the most common cases, it will not work correctly in every scenario. Please be extremely cautious when using the feature, and report any problems not listed below by opening an issue on GitHub.
Incremental regeneration helps shorten build times by only generating documents
and pages that were updated since the previous build. It does this by keeping
track of both file modification times and inter-document dependencies in the
.jekyll-metadata
file.
Under the current implementation, incremental regeneration will only generate a
document or page if either it, or one of its dependencies, is modified. Currently,
the only types of dependencies tracked are includes (using the
{% include %}
tag) and layouts. This means that plain
references to other documents (for example, the common case of iterating over
site.posts
in a post listings page) will not be detected as a dependency.
To remedy some of these shortfalls, putting regenerate: true
in the front-matter
of a document will force Jekyll to regenerate it regardless of whether it has been
modified. Note that this will generate the specified document only; references
to other documents’ contents will not work since they won’t be re-rendered.
Incremental regeneration can be enabled via the --incremental
flag (-I
for
short) from the command-line or by setting incremental: true
in your
configuration file.