rumdl - An extremely fast Markdown linter, written in Rust

rumdl is a fast Markdown linter and fixer that helps ensure consistency and best practices in your Markdown files. Built in Rust for exceptional performance.

Features

• Lightning Fast: Built with Rust for exceptional performance
• 50+ lint rules: Comprehensive rule set covering common Markdown issues
• Automatic fixing: Many rules support automatic fixing with --fix
• Highly configurable: Customize rules to match your project's style
• Modern CLI: User-friendly interface with detailed error reporting

Installation

With Cargo:

cargo install rumdl

Usage

Check Markdown files for issues:

# Check a single file
rumdl README.md

# Check multiple files
rumdl doc1.md doc2.md

# Check all Markdown files in a directory (recursive)
rumdl .

# Check and automatically fix issues
rumdl --fix README.md

Command-line Interface

rumdl [options] [file or directory...]

Options

• -c, --config <file>: Use custom configuration file
• -f, --fix: Automatically fix issues where possible
• -l, --list-rules: List all available rules
• -d, --disable <rules>: Disable specific rules (comma-separated)
• -e, --enable <rules>: Enable only specific rules (comma-separated)
• -v, --verbose: Show detailed output

Configuration

rumdl can be configured through command-line options. Support for a rumdl.toml configuration file is planned but not currently implemented.

Current configuration options

• -f, --fix: Automatically fix issues where possible
• -l, --list-rules: List all available rules
• -d, --disable <rules>: Disable specific rules (comma-separated)
• -e, --enable <rules>: Enable only specific rules (comma-separated)
• -v, --verbose: Show detailed output
• -c, --config <file>: Reserved for future custom configuration file support

Output Style

rumdl produces clean, colorized output similar to modern linting tools:

README.md:12:1: [MD022] Headings should be surrounded by blank lines [*]
README.md:24:5: [MD037] Spaces inside emphasis markers: "* incorrect *" [*]
README.md:31:76: [MD013] Line length exceeds 80 characters
README.md:42:3: [MD010] Hard tabs found, use spaces instead [*]

When running with --fix, rumdl shows which issues were fixed:

README.md:12:1: [MD022] Headings should be surrounded by blank lines [fixed]
README.md:24:5: [MD037] Spaces inside emphasis markers: "* incorrect *" [fixed]
README.md:42:3: [MD010] Hard tabs found, use spaces instead [fixed]

Fixed 3 issues in 1 file

For a more detailed view, use the --verbose option:

✓ No issues found in CONTRIBUTING.md
README.md:12:1: [MD022] Headings should be surrounded by blank lines [*]
README.md:24:5: [MD037] Spaces inside emphasis markers: "* incorrect *" [*]
README.md:42:3: [MD010] Hard tabs found, use spaces instead [*]

Found 3 issues in 1 file (2 files checked)
Run with `--fix` to automatically fix issues

Output Format

rumdl uses a consistent output format for all issues:

{file}:{line}:{column}: [{rule*id}] {message} [{fix*indicator}]

The output is colorized by default:

• Filenames appear in blue and underlined
• Line and column numbers appear in cyan
• Rule IDs appear in yellow
• Error messages appear in white
• Fixable issues are marked with [*] in green
• Fixed issues are marked with [fixed] in green

Rules

rumdl implements over 50 lint rules for Markdown files. By default, all rules are enabled except those specifically disabled in your configuration.

For a complete list of rules and their descriptions, run rumdl --list-rules or visit our documentation.

Rules Overview

The following table provides an overview of all supported rules and indicates whether rumdl can detect violations and automatically fix them:

Development

Prerequisites

• Rust 1.70 or higher
• Make (for development commands)

Building

make build

Testing

make test

License

MIT License