# black > A Python auto code formatter. > More information: . - Auto-format a file or entire directory: `black {{path/to/file_or_directory}}` - Format the code passed in as a string: `black -c "{{code}}"` - Output the changes that would be applied for each file: `black --diff {{path/to/file_or_directory}}` - Perform a dry run (print what would be done without actually doing it): `black --check {{path/to/file_or_directory}}` - Auto-format a file or directory emitting exclusively error messages to stderr: `black --quiet {{path/to/file_or_directory}}` - Auto-format a file or directory without replacing single quotes with double quotes (adoption helper, avoid using this for new projects): `black --skip-string-normalization {{path/to/file_or_directory}}`