ruff

Check current directory

$ ruff check

$ ruff check [file.py] [other.py]

$ ruff check --fix

$ ruff format

$ ruff check --show-fixes

$ ruff check --watch

$ ruff check --select [E,F,W]

$ ruff check --ignore [E501]

ruff [check] [format] [--fix] [--select rules] [options] [paths]

ruff is an extremely fast Python linter written in Rust. It implements rules from Flake8, isort, pyupgrade, and other tools.
Speed is the primary advantage. Ruff is 10-100x faster than traditional Python linters. This enables real-time feedback and CI integration without delays.
Rule selection controls which checks run. Categories include E (pycodestyle errors), F (Pyflakes), W (warnings), I (isort), UP (pyupgrade), and many more.
The formatter is Black-compatible, providing consistent code style. It integrates with the linter for a unified toolchain.
Configuration in pyproject.toml or ruff.toml customizes behavior. Per-file ignores and extends support complex project needs.
Fix mode modifies files automatically. Unsafe fixes may change behavior and require separate opt-in.

check

Run linting.

Format code.

Auto-fix violations.

Apply unsafe fixes.

Rules to enable.

Rules to ignore.

Additional rules.

Configuration file.

Show available fixes.

Watch for changes.

Output format (text, json, etc.).

Show statistics.

Show diff for fixes.

Rust-based - requires separate installation from Python. Not all Flake8 plugins are implemented. Rapidly evolving.

Ruff was created by Charlie Marsh in 2022. It achieved immediate popularity due to its speed, replacing multiple Python tools with a single fast alternative.

flake8(1), black(1), pylint(1), isort(1)