doccmd

|Build Status| |PyPI|

doccmd

A command line tool for running commands against code blocks in documentation files. This allows you to run linters, formatters, and other tools against the code blocks in your documentation files.

.. contents:: :local:

Installation

With pip ^^^^^^^^^^^^

Requires Python |minimum-python-version|+.

.. code-block:: shell

$ pip install doccmd

With Homebrew (macOS, Linux, WSL) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Requires Homebrew_.

.. code-block:: shell

$ brew tap adamtheturtle/doccmd $ brew install doccmd

.. _Homebrew: https://docs.brew.sh/Installation

With winget (Windows) ^^^^^^^^^^^^^^^^^^^^^

Requires winget_.

.. code-block:: shell

$ winget install --id adamtheturtle.doccmd --source winget --exact

The winget package may not be the latest version.

.. _winget: https://learn.microsoft.com/en-us/windows/package-manager/winget/

Pre-built Linux (x86) binaries ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: console

$ curl --fail -L https://github.com/adamtheturtle/doccmd/releases/download/2026.01.31.3/doccmd-linux -o /usr/local/bin/doccmd && chmod +x /usr/local/bin/doccmd

Pre-built macOS (ARM) binaries ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: console

$ curl --fail -L https://github.com/adamtheturtle/doccmd/releases/download/2026.01.31.3/doccmd-macos -o /usr/local/bin/doccmd && chmod +x /usr/local/bin/doccmd

Pre-built macOS (ARM) binaries ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

.. code-block:: console

$ curl --fail -L https://github.com/adamtheturtle/doccmd/releases/download/2026.01.31.3/doccmd-macos -o /usr/local/bin/doccmd && chmod +x /usr/local/bin/doccmd

You may need to remove the quarantine attribute to run the binary:

.. code-block:: console

$ xattr -d com.apple.quarantine /usr/local/bin/doccmd

Pre-built Windows binaries ^^^^^^^^^^^^^^^^^^^^^^^^^^

Download the Windows executable from the latest release_ and place it in a directory on your PATH.

.. _latest release: https://github.com/adamtheturtle/doccmd/releases/latest

With Docker ^^^^^^^^^^^

.. code-block:: console

$ docker run --rm -v "$(pwd):/workdir" -w /workdir "ghcr.io/adamtheturtle/doccmd" --help

With Nix ^^^^^^^^

Requires Nix_.

.. code-block:: shell

$ nix --extra-experimental-features 'nix-command flakes' run "github:adamtheturtle/doccmd/2026.01.31.3" -- --help

To avoid passing --extra-experimental-features every time, enable flakes_ permanently.

.. _Nix: https://nixos.org/download/ .. _enable flakes: https://wiki.nixos.org/wiki/Flakes#Enabling_flakes_permanently

Or add to your flake inputs:

.. code-block:: nix

{ inputs.doccmd.url = "github:adamtheturtle/doccmd"; }

Using doccmd as a pre-commit hook ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

To run doccmd with pre-commit_, add hooks like the following to your .pre-commit-config.yaml:

.. code-block:: yaml

• repo: https://github.com/adamtheturtle/doccmd-pre-commit rev: v2026.1.31.3 hooks:
  • id: doccmd args: ["--language", "shell", "--command", "shellcheck --shell=bash"] additional_dependencies: ["shellcheck-py"]

.. _pre-commit: https://pre-commit.com

Usage example

.. code-block:: shell

Run mypy against the Python code blocks in README.md and CHANGELOG.rst

$ doccmd --language=python --command="mypy" README.md CHANGELOG.rst

Run gofmt against the Go code blocks in README.md

This will modify the README.md file in place

$ doccmd --language=go --command="gofmt -w" README.md

or type less... and search for files in the docs directory

$ doccmd -l python -c mypy README.md docs/

Run ruff format against the code blocks in a Markdown file

Don't "pad" the code blocks with newlines - the formatter wouldn't like that.

See the documentation about groups for more information.

$ doccmd --language=python --no-pad-file --no-pad-groups --command="ruff format" README.md

Run j2lint against the sphinx-jinja2 code blocks in a MyST file

$ doccmd --sphinx-jinja2 --no-pad-file --command="j2lint" README.md

What does it work on?

• reStructuredText (.rst)

.. code-block:: rst

.. code-block:: shell

  echo "Hello, world!"

.. code:: shell

  echo "Or this Hello, world!"

• Markdown (.md)

By default, .md files are treated as MyST files. To treat them as Markdown, use --myst-extension=. --markdown-extension=.md.

.. code-block:: markdown

echo "Hello, world!"

• MyST (.md with MyST syntax)

.. code-block:: markdown

echo "Hello, world!"

echo "Or this Hello, world!"

echo "Or this code-cell!"

• MDX (.mdx)

.mdx files are supported out of the box. Use --mdx-extension if you need additional suffixes.

.. code-block:: markdown

console.log("Hello, MDX!")

• Djot (.dj)

.dj files are supported out of the box. Use --djot-extension if you need additional suffixes.

.. code-block:: markdown

echo "Hello, Djot!"

• Norg (.norg)

.norg files are supported out of the box. Use --norg-extension if you need additional suffixes.

.. code-block:: text

@code shell echo "Hello, Norg!" @end

• Want more? Open an issue!

Formatters and padding

Running linters with doccmd gives you errors and warnings with line numbers that match the documentation file. It does this by adding padding to the code blocks before running the command.

Some tools do not work well with this padding, and you can choose to obscure the line numbers in order to give the tool the original code block's content without padding, by using the --no-pad-file and --no-pad-groups flag. See using_groups_with_formatters_ for more information.

File names and linter ignores

doccmd creates temporary files for each code block in the documentation file. These files are created in the same directory as the documentation file, and are named with the documentation file name and the line number of the code block. Files are created with a prefix set to the given --temporary-file-name-prefix argument (default doccmd).

You can use this information to ignore files in your linter configuration.

For example, to ignore a rule in all files created by doccmd in a ruff configuration in pyproject.toml:

.. code-block:: toml

[tool.ruff]

lint.per-file-ignores."doccmd_*.py" = [ # Allow hardcoded secrets in documentation. "S105", ]

Running commands in parallel

When doccmd is not writing formatter output back into your documentation files (i.e. you are using --no-write-to-file), you can speed things up by parallelizing both within a document and across documents.

• --example-workers evaluates multiple code blocks from the same document at once.
• --document-workers runs different documents concurrently.

Set either option to 0 to auto-detect a worker count based on the number of CPUs on your machine.

For example, doccmd --no-write-to-file --example-workers 4 --document-workers 2 spreads work across two documents, with up to four blocks active per document. This is handy for CPU-bound linters that only emit diagnostics.

Parallel execution is intentionally disabled whenever --write-to-file is in effect, since doccmd cannot safely merge formatter changes into the original documents out of order. Command output might interleave between example workers and document workers, so stick to the default sequential mode when deterministic stdout/stderr ordering is important.

Skipping code blocks

Code blocks which come just after a comment matching skip doccmd[all]: next are skipped.

To skip multiple code blocks in a row, use skip doccmd[all]: start and skip doccmd[all]: end comments surrounding the code blocks to skip.

Use the --skip-marker option to set a marker for this particular command which will work as well as all. For example, use --skip-marker="type-check" to skip code blocks which come just after a comment matching skip doccmd[type-check]: next.

To skip a code block for each of multiple markers, for example to skip a code block for the type-check and lint markers but not all markers, add multiple skip doccmd comments above the code block.

The skip comment will skip the next code block which would otherwise be run. This means that if you run doccmd with --language=python, the Python code block in the following Markdown or MDX example will be skipped:

.. code-block:: markdown

<-- skip doccmd[all]: next -->

echo "This will not run because the shell language was not selected"

print("This will be skipped!")

Therefore it is not recommended to use skip doccmd[all] and to instead use a more specific marker. For example, if we used doccmd with --language=shell and --skip-marker=echo the following examples show how to skip code blocks in different formats:

• reStructuredText (.rst)

.. code-block:: rst

.. skip doccmd[echo]: next

.. code-block:: shell

  echo "This will be skipped!"

.. code-block:: shell

  echo "This will run"

• Markdown (.md) and MDX (.mdx)

.. code-block:: markdown

<-- skip doccmd[echo]: next -->

echo "This will be skipped!"

echo "This will run"

• MyST (.md with MyST syntax)

.. code-block:: markdown

% skip doccmd[echo]: next

echo "This will be skipped!"

echo "This will run"

Grouping code blocks

Automatic file-level grouping ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

The --group-file option automatically groups all code blocks of the same language within each file, treating them as a single unit for execution. This is useful when code blocks are designed to be executed sequentially, such as in MyST notebooks or tutorial documents where later blocks depend on definitions from earlier ones.

When this option is enabled, you don't need to add explicit group directives - all code blocks in a file are automatically combined.

For example, with --group-file, these blocks work together without any special markup:

.. group doccmd[all]: start

.. code-block:: python

"""Example function which is used in a future code block."""

def my_function() -> None: """Do nothing."""

.. code-block:: python

my_function()

.. group doccmd[all]: end

Manual grouping with directives ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

You might have two code blocks like this:

.. group doccmd[all]: start

.. code-block:: python

"""Example function which is used in a future code block."""

def my_function() -> None: """Do nothing."""

.. code-block:: python

my_function()

.. group doccmd[all]: end

and wish to type check the two code blocks as if they were one. By default, this will error as in the second code block, my_function is not defined.

To treat code blocks as one, use group doccmd[all]: start and group doccmd[all]: end comments surrounding the code blocks to group. Grouped code blocks will not have their contents updated in the documentation file. Error messages for grouped code blocks may include lines which do not match the document, so code formatters will not work on them.

Use the --group-marker option to set a marker for this particular command which will work as well as all. For example, use --group-marker="type-check" to group code blocks which come between comments matching group doccmd[type-check]: start and group doccmd[type-check]: end.

Grouping by MDX attributes ^^^^^^^^^^^^^^^^^^^^^^^^^^^

The --group-mdx-by-attribute option groups MDX code blocks by the value of a specified attribute. Code blocks with the same attribute value are grouped together and executed as a single unit. This is useful for working with MDX files that follow conventions like Docusaurus, where code blocks are grouped using custom attributes.

For example, with --group-mdx-by-attribute=group, these blocks are grouped by their group attribute value:

.. code-block:: markdown

def my_function():
    return "Hello"

def other_function():
    return "World"

result = my_function()

In this example, the first and third code blocks (both with group="example1") are grouped together and executed as one unit, while the second block (with group="example2") is processed separately.

Code blocks without the specified attribute are processed individually as normal.

This option only applies to MDX files.

.. _using_groups_with_formatters:

Using groups with formatters ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

By default, code blocks in groups will be separated by newlines in the temporary file created. This means that line numbers from the original document match the line numbers in the temporary file, and error messages will have correct line numbers. Some tools, such as formatters, may not work well with this separation. To have just one newline between code blocks in a group, use the --no-pad-groups option. If you then want to add extra padding to the code blocks in a group, add invisible code blocks to the document. Make sure that the language of the invisible code block is the same as the --language option given to doccmd.

For example:

• reStructuredText (.rst)

.. code-block:: rst

.. invisible-code-block: java

• Markdown (.md) and MDX (.mdx)

.. code-block:: markdown

Tools which change the code block content cannot change the content of code blocks inside groups. By default this will error. Use the --no-fail-on-group-write option to emit a warning but not error in this case.

Full documentation

See the full documentation <https://adamtheturtle.github.io/doccmd/>__.

.. |Build Status| image:: https://github.com/adamtheturtle/doccmd/actions/workflows/ci.yml/badge.svg?branch=main :target: https://github.com/adamtheturtle/doccmd/actions .. |PyPI| image:: https://badge.fury.io/py/doccmd.svg :target: https://badge.fury.io/py/doccmd .. |minimum-python-version| replace:: 3.10