markdownlint-cli

What is markdownlint-cli?

The markdownlint-cli package is a command-line interface for the markdownlint library, which is used to lint Markdown files. It helps ensure that Markdown files adhere to a consistent style and are free of common errors.

What are markdownlint-cli's main functionalities?

Linting a single file

This command lints a single Markdown file (README.md) and outputs any issues found according to the default rules.

markdownlint README.md

Linting multiple files

This command lints all Markdown files in the 'docs' directory and its subdirectories, using a glob pattern to match the files.

markdownlint "docs/**/*.md"

Using a custom configuration file

This command lints the README.md file using a custom configuration file (.markdownlint.json) to specify the rules and options.

markdownlint -c .markdownlint.json README.md

Fixing linting issues automatically

This command attempts to automatically fix any linting issues found in the README.md file.

markdownlint --fix README.md

Ignoring specific files or directories

This command lints all Markdown files in the current directory, but ignores the 'node_modules' directory.

markdownlint . --ignore node_modules

Other packages similar to markdownlint-cli

remark-cli

remark-cli is a command-line interface for the remark library, which is a Markdown processor powered by plugins. It can be used to lint, format, and transform Markdown files. Compared to markdownlint-cli, remark-cli offers more flexibility through its plugin system, allowing for a wider range of transformations and customizations.

markdown-it

markdown-it is a Markdown parser that can be extended with plugins to add custom rules and transformations. While it is primarily used for parsing and rendering Markdown, it can also be used for linting with the appropriate plugins. markdown-it is more focused on parsing and rendering, whereas markdownlint-cli is specifically designed for linting.

markdown-lint

markdown-lint is another linter for Markdown files, similar to markdownlint-cli. It provides a set of rules to enforce consistent style and catch common errors. However, markdown-lint is less feature-rich and less actively maintained compared to markdownlint-cli.

README

markdownlint-cli

Command Line Interface for MarkdownLint

Installation

npm install -g markdownlint-cli

On macOS you can install via Homebrew:

brew install markdownlint-cli

Usage

markdownlint --help

  Usage: markdownlint [options] <files|directories|globs>

  MarkdownLint Command Line Interface

  Options:
    -V, --version                              output the version number
    -c, --config <configFile>                  configuration file (JSON, JSONC, JS, YAML, or TOML)
    --configPointer <pointer>                  JSON Pointer to object within configuration file (default: "")
    -d, --dot                                  include files/folders with a dot (for example `.github`)
    -f, --fix                                  fix basic errors (does not work with STDIN)
    -i, --ignore <file|directory|glob>         file(s) to ignore/exclude (default: [])
    -j, --json                                 write issues in json format
    -o, --output <outputFile>                  write issues to file (no console)
    -p, --ignore-path <file>                   path to file with ignore pattern(s)
    -q, --quiet                                do not write issues to STDOUT
    -r, --rules <file|directory|glob|package>  include custom rule files (default: [])
    -s, --stdin                                read from STDIN (does not work with files)
    --enable <rules...>                        Enable certain rules, e.g. --enable MD013 MD041 --
    --disable <rules...>                       Disable certain rules, e.g. --disable MD013 MD041 --
    -h, --help                                 display help for command

Or run using Docker and GitHub Packages:

docker run -v $PWD:/workdir ghcr.io/igorshubovych/markdownlint-cli:latest "*.md"

Note Because --enable and --disable are variadic arguments that accept multiple values, it is necessary to end the list by passing -- before the <files|directories|globs> argument like so: markdownlint --disable MD013 -- README.md.

Globbing

markdownlint-cli supports advanced globbing patterns like **/*.md (more information). With shells like Bash, it may be necessary to quote globs so they are not interpreted by the shell. For example, --ignore *.md would be expanded by Bash to --ignore a.md b.md ... before invoking markdownlint-cli, causing it to ignore only the first file because --ignore takes a single parameter (though it can be used multiple times). Quoting the glob like --ignore '*.md' passes it through unexpanded and ignores the set of files.

Globbing examples

To lint all Markdown files in a Node.js project (excluding dependencies), the following commands might be used:

Windows CMD: markdownlint **/*.md --ignore node_modules

Linux Bash: markdownlint '**/*.md' --ignore node_modules

Ignoring files

If present in the current folder, a .markdownlintignore file will be used to ignore files and/or directories according to the rules for gitignore. If the -p/--ignore-path option is present, the specified file will be used instead of .markdownlintignore.

The order of operations is:

• Enumerate files/directories/globs passed on the command line
• Apply exclusions from -p/--ignore-path (if specified) or .markdownlintignore (if present)
• Apply exclusions from any -i/--ignore option(s) that are specified

Fixing errors

When the --fix option is specified, markdownlint-cli tries to apply all fixes reported by the active rules and reports any errors that remain. Because this option makes changes to the input files, it is good to make a backup first or work with files under source control so any unwanted changes can be undone.

Because not all rules include fix information when reporting errors, fixes may overlap, and not all errors are fixable, --fix will not usually address all errors.

Configuration

markdownlint-cli reuses the rules from markdownlint package.

Configuration is stored in JSON, JSONC, YAML, INI, or TOML files in the same config format.

A sample configuration file:

{
  "default": true,
  "MD003": { "style": "atx_closed" },
  "MD007": { "indent": 4 },
  "no-hard-tabs": false,
  "whitespace": false
}

For more examples, see .markdownlint.jsonc, .markdownlint.yaml, test-config.toml or the style folder.

The CLI argument --config is not required. If it is not provided, markdownlint-cli looks for the file .markdownlint.jsonc/.markdownlint.json/.markdownlint.yaml/.markdownlint.yml in current folder, or for the file .markdownlintrc in the current or all parent folders. The algorithm is described in detail on the rc package page. Note that when relying on the lookup of a file named .markdownlintrc in the current or parent folders, the only syntaxes accepted are INI and JSON, and the file cannot have an extension. If the --config argument is provided, the file must be valid JSON, JSONC, JS, or YAML. JS configuration files contain JavaScript code, must have the .js or .cjs file extension, and must export (via module.exports = ...) a configuration object of the form shown above. If your workspace (project) is ESM-only ("type": "module" set in the root package.json file), then the configuration file should end with .cjs file extension. A JS configuration file may internally require one or more npm packages as a way of reusing configuration across projects.

The --configPointer argument allows the use of JSON Pointer syntax to identify a sub-object within the configuration object (per above). This argument can be used with any configuration file type and makes it possible to nest a configuration object within another file like package.json or pyproject.toml (e.g., via /key or /key/subkey).

--enable and --disable override configuration files; if a configuration file disables MD123 and you pass --enable MD123, it will be enabled. If a rule is passed to both --enable and --disable, it will be disabled.

• JS configuration files must be provided via the --config argument; they are not automatically loaded because running untrusted code is a security concern.
• TOML configuration files must be provided via the --config argument; they are not automatically loaded.

Exit codes

markdownlint-cli returns one of the following exit codes:

• 0: Program ran successfully
• 1: Linting errors
• 2: Unable to write -o/--output output file
• 3: Unable to load -r/--rules custom rule
• 4: Unexpected error (e.g. malformed config)

Use with pre-commit

To run markdownlint-cli as part of a pre-commit workflow, add something like the below to the repos list in the project's .pre-commit-config.yaml:

- repo: https://github.com/igorshubovych/markdownlint-cli
  rev: v0.43.0
  hooks:
  - id: markdownlint

Depending on the environment this workflow runs in, it may be necessary to override the language version of Node.js used by pre-commit.

Related

• markdownlint - API for this module
• markdownlint-cli2 - Alternate CLI implementation
• glob - Pattern matching implementation
• ignore - .markdownlintignore implementation

License

MIT © Igor Shubovych