rumdl

rumdl [OPTIONS] COMMAND [PATHS...]

rumdl is a native Markdown linter and formatter. The name is Ru(st) MarkDown Linter. It is modeled on ruff: one fast binary covers linting, formatting, caching, editor integration, and CI output.It implements 84 rules, largely aligned with markdownlint (including the `MD###` IDs). Existing `.markdownlint.json`, `.markdownlint.yaml`, and related files are discovered automatically, so a first run can compare results without rewriting config. `rumdl import` converts those files to `.rumdl.toml` when you are ready to switch.Built-in flavors (standard/GFM, MkDocs, MDX, Quarto, Pandoc, Obsidian, kramdown, Azure DevOps, MyST, Hugo, and others) adjust rules for dialect-specific syntax. When no flavor is set, rumdl infers one from the filename (`.mdx`, `.qmd` / `.Rmd`, and so on).check is the CI/pre-commit path: non-zero exit when violations remain. fmt is the editor/format-on-save path: it rewrites files and exits 0 even if some issues cannot be auto-fixed. Files that contain Git conflict markers are left unchanged.Exit codes: 0 success, 1 Markdown violations, 2 tool or configuration error (with --deny-config-warnings, unknown rules and similar config problems also exit 2).

check [PATHS...]

Lint Markdown files and print diagnostics. Paths override include patterns from config.

With check: apply safe fixes in place. Exit 0 if everything was fixed, 1 if violations remain.

Format files in place. Same fixes as check --fix, but always exits 0 after a successful format (formatter-style codes).

Show what would change instead of writing files.

With fmt: exit 1 if formatting would change anything, without writing files.

Re-run whenever files change.

Disable rules (comma-separated IDs, or `all`).

Enable only these rules.

Skip files matching comma-separated globs.

Limit the run to matching files.

Honor `.gitignore` when scanning directories (default on). Does not apply to paths given on the command line.

Ignore exclude patterns from the config file.

Read Markdown from stdin. fmt --silent - writes only formatted Markdown to stdout.

Filename used for stdin diagnostics, config, and relative links.

Diagnostic format: `text` (default), `full`, `concise`, `grouped`, `json`, `json-lines`, `sarif`, `junit`, `github`, `gitlab`, `azure`, `pylint`.

Print diagnostics, suppress summaries.

Suppress diagnostics and summaries (use with fmt when stdout must be pure Markdown).

Config file path, or an inline `KEY = VALUE` override (repeatable).

Ignore discovered config files and use built-in defaults.

`auto` (default), `always`, or `never`.

Write a default `.rumdl.toml`. --pyproject writes `[tool.rumdl]` instead. --preset NAME selects `default`, `google`, or `relaxed`.

Convert a markdownlint JSON/JSONC/YAML config to rumdl format.

List rules, or print one rule's documentation (ID or alias).

Print the merged effective configuration. get KEY queries one setting; file prints the loaded config path.

Start the Language Server Protocol server on stdio.

Install or update the rumdl VS Code extension.

Print a completion script (`bash`, `zsh`, `fish`, `powershell`, `elvish`).

Print version information.

Discovery walks up from the working directory and stops at `.git` or a depth limit. First match wins: `.rumdl.toml`, `rumdl.toml`, `.config/rumdl.toml`, then `pyproject.toml` `[tool.rumdl]`. Subdirectory configs apply to files under that directory. With no project file, rumdl falls back to markdownlint configs, then a user file under `~/.config/rumdl/` (or `$XDGCONFIGHOME/rumdl/`) and finally `~/.rumdl.toml`.

$ # .rumdl.toml
[global]
line-length = 100
exclude = ["node_modules", "build", "dist"]
respect-gitignore = true
flavor = "mkdocs"
disable = ["MD013", "MD033"]

[per-file-flavor]
"**/*.mdx" = "mdx"

[MD007]
indent = 2

[MD013]
line-length = 100
code-blocks = false
reflow = true

Still beta pending a 1.0 compatibility policy. The CLI, config model, and core rules are intended for production use, but details can still change.markdownlint compatibility is broad, not bit-identical. Some historic rule numbers are intentionally absent (for example MD002, MD006) to match upstream markdownlint.fmt and check --fix do not share exit-code semantics. Using the wrong one in CI will either fail a clean format or hide remaining violations.`--respect-gitignore` does not apply to paths you pass explicitly. A file listed on the command line is checked even if gitignored.

rumdl was created by Ruben J. Jongejan (rvben) and first published in February 2025 (MIT, Rust). It is positioned as a Ruff-style toolchain for Markdown: one native binary instead of a Node markdownlint install. The project later added flavor support, an LSP, editor extensions, and package availability on crates.io, PyPI, Homebrew, pacman, and Nix.

markdownlint(1), prettier(1), vale(1), ruff(1), biome(1)

Source code · Homepage · Documentation