Commands

$ rattle COMMAND [OPTIONS] ...

The following runtime options are available on commands that lint code, autofix code, or materialize lint configuration.

--debug, --quiet / -q

Raise or lower the level of output and logging.

--config-file / -c PATH

Override the normal hierarchical configuration and use the configuration from the specified path, ignoring all other configuration files entirely.

--exclude PATTERN

Override configured file exclusions with a glob pattern. This option may be passed more than once. Like Ruff’s --exclude, direct path arguments are also excluded when they match the pattern.

$ rattle lint . --exclude "generated/**"

--extend-exclude PATTERN

Add a glob pattern to the configured file exclusions. This option may be passed more than once. Direct path arguments are still checked unless they are excluded by configuration with force-exclude.

$ rattle lint . --extend-exclude "docs/_build/**"

--tags / -t TAGS

Select or filter the set of lint rules to apply based on their tags.

This takes a comma-separated list of tag names, optionally prefixed with !, ^, or -. Tags without one of those prefixes are treated as include tags. Tags with one of those prefixes are treated as exclude tags.

Lint rules are enabled if and only if they have at least one tag in the include list and no tags in the exclude list.

For example:

$ rattle lint --tags "hello,world,^cats" ...

The command above filters the enabled lint rules to ones that have either the hello or world tag, and excludes any rules with the cats tag, even if they would otherwise have been selected.

--rules / -r RULES

Override the configured set of lint rules entirely.

This takes a comma-separated list of rule selectors, with the same accepted forms as enable and disable:

• import selectors such as rattle.rules.fixit_extra:use-f-string

• built-in rule collections such as blank-lines, fixit, or fixit-extra

• exact built-in rule names such as use-f-string

For example:

$ rattle lint --rules "use-f-string" path/to/file.py
$ rattle lint --rules "fixit,fixit-extra" path/to/file.py

--output-format / -o FORMAT_TYPE

Override how Rattle prints violations to the terminal.

See output-format for available formats.

--output-template TEMPLATE

Override the Python formatting template used with output-format = "custom".

lint

Lint one or more paths and print a list of lint errors. If - is given as the first path, then the second path is used for configuration lookup and error messages, and the input is read from standard input.

$ rattle lint [OPTIONS] [--brief] [--diff] [--stats] [PATH ...]

--brief / -b

Print each diagnostic on one line, without source snippets or help text.

--diff / -d

Show suggested fixes, in unified diff format, when available.

--stats

Print violation counts grouped by containing directory.

fix

Lint one or more paths and apply suggested fixes. If - is given as the first path, then the second path is used for configuration lookup, the input is read from standard input, and the fixed output is printed to standard output, ignoring --interactive.

$ rattle fix [OPTIONS] [--interactive | --automatic] [--brief] [--diff] [PATH ...]

--interactive / -i

Interactively prompt the user to apply or decline each available autofix. Press y to apply, n to skip, or q to stop prompting and leave the remaining fixes unapplied.

--automatic / -a

Automatically apply suggested fixes for all lint errors when available. This is the default behavior.

--brief / -b

Print each diagnostic on one line, without source snippets or help text.

--diff / -d

Show applied fixes in unified diff format when applied automatically.

lsp

Start the language server providing IDE features over LSP. This command is only available if Rattle is installed with the lsp extras, for example pip install "rattle-lint[lsp]". See IDE for more details.

$ rattle lsp [--no-stdio] [--tcp PORT | --ws PORT]

--no-stdio / -n

Disable the default stdio transport when serving over TCP or WebSocket.

--tcp

Serve LSP over TCP on PORT.

--ws / -w

Serve LSP over WebSocket on PORT.

--debounce-interval / -d

Delay in seconds for server-side debounce. Default: 0.5.

rules

Display the lint rules enabled for the current configuration. Pass paths to see the rules resolved for those files or directories.

$ rattle rules [PATH ...]

--test

Test enabled lint rules using their VALID and INVALID test cases. Use --rules to select the rules to test.

Rule selectors use the same forms as enable and disable.

Example:

$ rattle rules --test -r .examples.teambread.rules
test_INVALID_0 (rattle.testing.hollywood-name-rule) ... ok
test_INVALID_1 (rattle.testing.hollywood-name-rule) ... ok
test_VALID_0 (rattle.testing.hollywood-name-rule) ... ok
test_VALID_1 (rattle.testing.hollywood-name-rule) ... ok

----------------------------------------------------------------------
Ran 4 tests in 0.024s

OK

$ rattle rules --test -r use-f-string

validate

Validate config. When no path is provided, Rattle validates pyproject.toml from the current directory.

$ rattle validate
$ rattle validate pyproject.toml