You can put any file type into your `/content` directories, but Hugo uses the `markup` front matter value if set or the file extension (see `Markup identifiers` in the table below) to determine if the markup needs to be processed, e.g.:
| Goldmark | md, markdown, goldmark |Note that you can set the default handler of `md` and `markdown` to something else, see [Configure Markup](/getting-started/configuration-markup/).|
The `markup identifier` is fetched from either the `markup` variable in front matter or from the file extension. For markup-related configuration, see [Configure Markup](/getting-started/configuration-markup/).
Because additional formats are external commands, generation performance will rely heavily on the performance of the external tool you are using. As this feature is still in its infancy, feedback is welcome.
External `asciidoctor` command requires Hugo rendering to _disk_ to a specific destination directory. It is required to run Hugo with the command option `--destination`.
{{% /note %}}
Some [Asciidoctor](https://asciidoctor.org/man/asciidoctor/) parameters can be customized in Hugo:
Parameter | Comment
--- | ---
backend | Don't change this unless you know what you are doing.
doctype | Currently, the only document type supported in Hugo is `article`.
extensions | Possible extensions are `asciidoctor-html5s`, `asciidoctor-bibtex`, `asciidoctor-diagram`, `asciidoctor-interdoc-reftext`, `asciidoctor-katex`, `asciidoctor-latex`, `asciidoctor-mathematical`, `asciidoctor-question`, `asciidoctor-rouge`.
attributes | Variables to be referenced in your AsciiDoc file. This is a list of variable name/value maps. See [Asciidoctor's attributes](https://asciidoctor.org/docs/asciidoc-syntax-quick-reference/#attributes-and-substitutions).
noHeaderOrFooter | Output an embeddable document, which excludes the header, the footer, and everything outside the body of the document. Don't change this unless you know what you are doing.
safeMode | Safe mode level `unsafe`, `safe`, `server` or `secure`. Don't change this unless you know what you are doing.
sectionNumbers | Auto-number section titles.
verbose | Verbosely print processing information and configuration file checks to stderr.
trace | Include backtrace information on errors.
failureLevel | The minimum logging level that triggers a non-zero exit code (failure).
Hugo provides additional settings that don't map directly to Asciidoctor's CLI options:
workingFolderCurrent
: Sets the working directory to be the same as that of the AsciiDoc file being processed, so that [include](https://asciidoctor.org/docs/asciidoc-syntax-quick-reference/#include-files) will work with relative paths. This setting uses the `asciidoctor` cli parameter `--base-dir` and attribute `outdir=`. For rendering diagrams with [asciidoctor-diagram](https://asciidoctor.org/docs/asciidoctor-diagram/), `workingFolderCurrent` must be set to `true`.
preserveTOC
: By default, Hugo removes the table of contents generated by Asciidoctor and provides it through the built-in variable [`.TableOfContents`](/content-management/toc/) to enable further customization and better integration with the various Hugo themes. This option can be set to `true` to preserve Asciidoctor's TOC in the generated page.
Below are all the AsciiDoc related settings in Hugo with their default values:
Notice that for security concerns only extensions that do not have path separators (either `\`, `/` or `.`) are allowed. That means that extensions can only be invoked if they are in one's ruby's `$LOAD_PATH` (ie. most likely, the extension has been installed by the user). Any extension declared relative to the website's path will not be accepted.
