ruff-formatter

```bash

# Format all files in current directory

ruff format .

# Format specific file(s)

ruff format path/to/file.py

# Check without modifying (CI/pre-commit)

ruff format --check .

# Show diff of what would change

ruff format --diff .

```

When ruff format --check fails:

1. Run ruff format . to auto-fix all formatting
2. Review changes with git diff
3. Commit the formatted code

For import sorting issues, run linter first:

```bash

ruff check --select I --fix . # Sort imports

ruff format . # Then format

```

Disable formatting for specific code:

```python

# fmt: off

matrix = [

[1, 0, 0],

[0, 1, 0],

[0, 0, 1],

]

# fmt: on

x = 1 # fmt: skip

```

In pyproject.toml or ruff.toml:

```toml

[tool.ruff.format]

quote-style = "double" # or "single"

indent-style = "space" # or "tab"

line-length = 88 # default

docstring-code-format = true

```

• 0: Success (files formatted or already formatted)
• 1: With --check: files need formatting
• 2: Error (invalid config, CLI error)