Configure markup

Default handler

In its default configuration, Hugo uses Goldmark to render Markdown to HTML.

{{< code-toggle file=hugo >}} [markup] defaultMarkdownHandler = 'goldmark' {{< /code-toggle >}}

Files with ending with .md, .mdown, or .markdown are processed as Markdown, unless you've explicitly set a different format using the markup field in your front matter.

To use a different renderer for Markdown files, specify one of asciidocext, org, pandoc, or rst in your project configuration.

To use AsciiDoc, Pandoc, or reStructuredText you must install the relevant renderer and update your security policy.

[!note] Unless you need a unique capability provided by one of the alternative Markdown handlers, we strongly recommend that you use the default setting. Goldmark is fast, well maintained, conforms to the CommonMark specification, and is compatible with GitHub Flavored Markdown (GFM).

Goldmark

This is the default configuration for the Goldmark Markdown renderer:

{{< code-toggle config=markup.goldmark />}}

Extensions

The extensions below, excluding Extras and Passthrough, are enabled by default.

Extras

Enable deleted text, inserted text, mark text, subscript, and superscript elements in Markdown.

To avoid a conflict¹, if you enable the "subscript" feature of the Extras extension, you must disable the Strikethrough extension:

{{< code-toggle file=hugo >}} [markup.goldmark.extensions] strikethrough = false

[markup.goldmark.extensions.extras.subscript] enable = true {{< /code-toggle >}}

If you still need to show deleted text after disabling the Strikethrough extension, enable the "deleted text" feature of the Extras extension:

{{< code-toggle file=hugo >}} [markup.goldmark.extensions] strikethrough = false

[markup.goldmark.extensions.extras.delete] enable = true {{< /code-toggle >}}

With this configuration, to format text as deleted, wrap it with double-tildes.

Footnote

Enabled by default, the Footnote extension enables inclusion of footnotes in Markdown.

enable : {{< new-in 0.151.0 />}} : (bool) Whether to enable the Footnotes extension. Default is true.

backlinkHTML : {{< new-in 0.151.0 />}} : (string) The HTML to be displayed at the end of a footnote that links the user back to the corresponding reference in the main text. The default is ↩︎ (a return arrow symbol).

enableAutoIDPrefix : {{< new-in 0.151.0 />}} : (bool) Whether to prepend a unique prefix to footnote IDs, preventing clashes when multiple documents are rendered together. This prefix is unique to each logical path, which means that the prefix is not unique across content dimensions such as language. Default is false.

Passthrough

Enable the Passthrough extension to include mathematical equations and expressions in Markdown using LaTeX markup. See mathematics in Markdown for details.

Typographer

The Typographer extension replaces certain character combinations with HTML entities as specified below:

Goldmark settings explained

Most of the Goldmark settings above are self-explanatory, but some require explanation.

duplicateResourceFiles : (bool) Whether to duplicate shared page resources for each language on multilingual single-host projects. See multilingual page resources for details. Default is false.

[!note] With multilingual single-host projects, setting this parameter to false will enable Hugo's embedded link render hook and embedded image render hook. This is the default configuration for multilingual single-host projects.

parser.wrapStandAloneImageWithinParagraph : (bool) Whether to wrap image elements without adjacent content within a p element when rendered. This is the default Markdown behavior. Set to false when using an image render hook to render standalone images as figure elements. Default is true.

parser.autoDefinitionTermID : {{< new-in 0.144.0 />}} : (bool) Whether to automatically add id attributes to description list terms (i.e., dt elements). When true, the id attribute of each dt element is accessible through the Fragments.Identifiers method on a Page object.

parser.autoHeadingID : (bool) Whether to automatically add id attributes to headings (i.e., h1, h2, h3, h4, h5, and h6 elements).

parser.autoIDType : (string) The strategy used to automatically generate id attributes, one of github, github-ascii or blackfriday. Default is github.

• github: Generate GitHub-compatible id attributes
• github-ascii: Drop any non-ASCII characters after accent normalization
• blackfriday: Generate id attributes compatible with the Blackfriday Markdown renderer

This is also the strategy used by the anchorize template function.

parser.attribute.block : (bool) Whether to enable Markdown attributes for block elements. Default is false.

parser.attribute.title : (bool) Whether to enable Markdown attributes for headings. Default is true.

renderHooks.image.enableDefault : Deprecated in v0.148.0. Use renderHooks.image.useEmbedded instead.

renderHooks.image.useEmbedded : {{< new-in 0.148.0 />}} : (string) When to use the embedded image render hook. One of auto, never, always, or fallback. Default is auto.

• auto: Use the embedded image render hook only for multilingual single-host projects where the duplication of shared page resources feature is disabled. If custom image render hooks are defined by your project, modules, or themes, these will be used instead.
• never: Never use the embedded image render hook. If custom image render hooks are defined by your project, modules, or themes, these will be used instead.
• always: Always use the embedded image render hook, even if custom image render hooks are provided by your project, modules, or themes.
• fallback: Use the embedded image render hook only if custom image render hooks are not provided by your project, modules, or themes. If custom image render hooks exist, these will be used instead.

renderHooks.link.enableDefault : Deprecated in v0.148.0. Use renderHooks.link.useEmbedded instead.

renderHooks.link.useEmbedded : (string) When to use the embedded link render hook. One of auto, never, always, or fallback. Default is auto.

• auto: Use the embedded link render hook only for multilingual single-host projects where the duplication of shared page resources feature is disabled. If custom link render hooks are defined by your project, modules, or themes, these will be used instead.
• never: Never use the embedded link render hook. If custom link render hooks are defined by your project, modules, or themes, these will be used instead.
• always: Always use the embedded link render hook, even if custom link render hooks are provided by your project, modules, or themes.
• fallback: Use the embedded link render hook only if custom link render hooks are not provided by your project, modules, or themes. If custom link render hooks exist, these will be used instead.

renderer.hardWraps : (bool) Whether to replace newline characters within a paragraph with br elements. Default is false.

renderer.unsafe : (bool) Whether to render raw HTML mixed within Markdown. This is unsafe unless the content is under your control. Default is false.

AsciiDoc

This is the default configuration for the AsciiDoc renderer:

{{< code-toggle config=markup.asciidocExt />}}

AsciiDoc settings explained

attributes : (map) A map of key-value pairs, each a document attribute. See Asciidoctor's attributes.

backend : (string) The backend output file format. Default is html5.

extensions : ([]string) An array of enabled extensions, such as asciidoctor-html5s, asciidoctor-bibtex, or asciidoctor-diagram.

[!note] To mitigate security risks, entries in the extension array may not contain forward slashes (/), backslashes (\), or periods. Due to this restriction, extensions must be in Ruby's $LOAD_PATH.

failureLevel : (string) The minimum logging level that triggers a non-zero exit code (failure). Default is fatal.

noHeaderOrFooter : (bool) Whether to output an embeddable document, which excludes the header, the footer, and everything outside the body of the document. Default is true.

preserveTOC : (bool) Whether to preserve the table of contents (TOC) rendered by Asciidoctor. By default, to make the TOC compatible with existing themes, Hugo removes the TOC rendered by Asciidoctor. To render the TOC, use the TableOfContents method on a Page object in your templates. Default is false.

safeMode : (string) The safe mode level, one of unsafe, safe, server, or secure. Default is unsafe.

sectionNumbers : (bool) Whether to number each section title. Default is false.

trace : (bool) Whether to include backtrace information on errors. Default is false.

verbose : (bool) Whether to verbosely print processing information and configuration file checks to stderr. Default is false.

workingFolderCurrent : (bool) Whether to set the working directory to be the same as that of the AsciiDoc file being processed, allowing includes to work with relative paths. Set to true to render diagrams with the asciidoctor-diagram extension. Default is false.

Configuration example

{{< code-toggle file=hugo >}} [markup.asciidocExt] extensions = ['asciidoctor-html5s','asciidoctor-diagram'] workingFolderCurrent = true [markup.asciidocExt.attributes] my-base-url = 'https://example.com/' my-attribute-name = 'my value' {{< /code-toggle >}}

Syntax highlighting

Follow the steps below to enable syntax highlighting.

Step 1 : Set the source-highlighter attribute in your project configuration. For example:

{{< code-toggle file=hugo >}} [markup.asciidocExt.attributes] source-highlighter = 'rouge' {{< /code-toggle >}}

Step 2 : Generate the highlighter CSS. For example:

rougify style monokai.sublime > assets/css/syntax.css

Step 3 : In your base template add a link to the CSS file:

<head>
  ...
  {{ with resources.Get "css/syntax.css" }}
    <link rel="stylesheet" href="{{ .RelPermalink }}" integrity="{{ .Data.Integrity }}" crossorigin="anonymous">
  {{ end }}
  ...
</head>

Step 4 : Add the code to be highlighted to your markup:

[#hello,ruby]
----
require 'sinatra'

get '/hi' do
  "Hello World!"
end
----

Troubleshooting

Run hugo build --logLevel debug to examine Hugo's call to the Asciidoctor executable:

INFO 2019/12/22 09:08:48 Rendering book-as-pdf.adoc with C:\Ruby26-x64\bin\asciidoctor.bat using asciidoc args [--no-header-footer -r asciidoctor-html5s -b html5s -r asciidoctor-diagram --base-dir D:\prototypes\hugo_asciidoc_ddd\docs -a outdir=D:\prototypes\hugo_asciidoc_ddd\build -] ...

Highlight

This is the default configuration.

{{< code-toggle config=markup.highlight />}}

{{% include "/_common/syntax-highlighting-options.md" %}}

Table of contents

This is the default configuration for the table of contents, applicable to Goldmark and Asciidoctor:

{{< code-toggle config=markup.tableOfContents />}}

startLevel : (int) Heading levels less than this value will be excluded from the table of contents. For example, to exclude h1 elements from the table of contents, set this value to 2. Default is 2.

endLevel : (int) Heading levels greater than this value will be excluded from the table of contents. For example, to exclude h4, h5, and h6 elements from the table of contents, set this value to 3. Default is 3.

ordered : (bool) Whether to generates an ordered list instead of an unordered list. Default is false.