markdownlint-cli/README.md

# markdownlint-cli

[![GitHub Actions Build Status][actions-badge]][actions-url]

> Command Line Interface for [MarkdownLint][markdownlint]

## Installation

```bash
npm install -g markdownlint-cli
```

On macOS you can install via [Homebrew](https://brew.sh/):

```bash
brew install markdownlint-cli
```

## Usage

```bash
markdownlint --help

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

  MarkdownLint Command Line Interface

  Options:

    -h, --help                                  output usage information
    -V, --version                               output the version number
    -c, --config [configFile]                   configuration file (JSON, JSONC, JS, or YAML)
    -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
    -o, --output [outputFile]                   write issues to file (no console)
    -p, --ignore-path [file]                    path to file with ignore pattern(s)
    -r, --rules  [file|directory|glob|package]  custom rule files
    -s, --stdin                                 read from STDIN (does not work with files)
```

### Globbing

`markdownlint-cli` supports advanced globbing patterns like `**/*.md` ([more information][globprimer]).
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][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][rules] from `markdownlint` package.

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

A sample configuration file:

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

For more examples, see [.markdownlint.jsonc][markdownlint-jsonc], [.markdownlint.yaml][markdownlint-yaml], or the [style folder][style-folder].

The CLI argument `--config` is not required.
If it is not provided, `markdownlint-cli` looks for the file `.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][rc-standards].
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` extension, and must export (via `module.exports = ...`) a configuration object of the form shown above.
A JS configuration file may internally `require` one or more npm packages as a way of reusing configuration across projects.

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

## Exit codes

`markdownlint-cli` returns one of the following exit codes:

- `0`: Program ran successfully
- `1`: Linting errors / bad parameter
- `2`: Unable to write `-o`/`--output` output file
- `3`: Unable to load `-r`/`--rules` custom rule

## Use with pre-commit

To run `markdownlint-cli` as part of a [pre-commit](https://pre-commit.com/) workflow, add something like the below to the `repos` list in the project's `.pre-commit-config.yaml`:

```yaml
- repo: https://github.com/igorshubovych/markdownlint-cli
  rev: v0.27.0
  hooks:
  - id: markdownlint
```

## Related

- [markdownlint][markdownlint] - API for this module
- [glob][glob] - Pattern matching implementation
- [ignore][ignore] - `.markdownlintignore` implementation

## License

MIT © Igor Shubovych

[actions-badge]: https://github.com/igorshubovych/markdownlint-cli/workflows/CI/badge.svg?branch=master
[actions-url]: https://github.com/igorshubovych/markdownlint-cli/actions?query=workflow%3ACI
[markdownlint]: https://github.com/DavidAnson/markdownlint
[markdownlint-jsonc]: https://github.com/DavidAnson/markdownlint/blob/main/schema/.markdownlint.jsonc
[markdownlint-yaml]: https://github.com/DavidAnson/markdownlint/blob/main/schema/.markdownlint.yaml
[rules]: https://github.com/DavidAnson/markdownlint/blob/main/doc/Rules.md
[config]: https://github.com/DavidAnson/markdownlint#optionsconfig
[style-folder]: https://github.com/DavidAnson/markdownlint/tree/main/style
[rc-standards]: https://www.npmjs.com/package/rc#standards
[glob]: https://github.com/isaacs/node-glob
[globprimer]: https://github.com/isaacs/node-glob/blob/master/README.md#glob-primer
[ignore]: https://github.com/kaelzhang/node-ignore
[gitignore]: https://git-scm.com/docs/gitignore