Full Listing of Options and Their Descriptions

Options and their Descriptions

--version

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Show Flake8’s version as well as the versions of all plugins installed.

Command-line usage:

flake8 --version

This can not be specified in config files.

-h, --help

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Show a description of how to use Flake8 and its options.

Command-line usage:

flake8 --help
flake8 -h

This can not be specified in config files.

-v, --verbose

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Increase the verbosity of Flake8’s output. Each time you specify it, it will print more and more information.

Command-line example:

flake8 -vv

This can be specified in config files.

Example config file usage:

verbose = 2
-q, --quiet

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Decrease the verbosity of Flake8’s output. Each time you specify it, it will print less and less information.

Command-line example:

flake8 -q

This can be specified in config files.

Example config file usage:

quiet = 1
--count

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Print the total number of errors.

Command-line example:

flake8 --count dir/

This can be specified in config files.

Example config file usage:

count = True
--diff

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Use the unified diff provided on standard in to only check the modified files and report errors included in the diff.

Command-line example:

git diff -u | flake8 --diff

This can not be specified in config files.

--exclude=<patterns>

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Provide a comma-separated list of glob patterns to exclude from checks.

This defaults to: .svn,CVS,.bzr,.hg,.git,__pycache__,.tox

Example patterns:

  • *.pyc will match any file that ends with .pyc
  • __pycache__ will match any path that has __pycache__ in it
  • lib/python will look expand that using os.path.abspath() and look for matching paths

Command-line example:

flake8 --exclude=*.pyc dir/

This can be specified in config files.

Example config file usage:

exclude =
    .tox,
    __pycache__
--filename=<patterns>

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Provide a comma-separate list of glob patterns to include for checks.

This defaults to: *.py

Example patterns:

  • *.py will match any file that ends with .py
  • __pycache__ will match any path that has __pycache__ in it
  • lib/python will look expand that using os.path.abspath() and look for matching paths

Command-line example:

flake8 --filename=*.py dir/

This can be specified in config files.

Example config file usage:

filename =
    example.py,
    another-example*.py
--stdin-display-name=<display_name>

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Provide the name to use to report warnings and errors from code on stdin.

Instead of reporting an error as something like:

stdin:82:73 E501 line too long

You can specify this option to have it report whatever value you want instead of stdin.

This defaults to: stdin

Command-line example:

cat file.py | flake8 --stdin-display-name=file.py -

This can not be specified in config files.

--format=<format>

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Select the formatter used to display errors to the user.

This defaults to: default

By default, there are two formatters available:

  • default
  • pylint

Other formatters can be installed. Refer to their documentation for the name to use to select them. Further, users can specify their own format string. The variables available are:

  • code
  • col
  • path
  • row
  • text

The default formatter has a format string of:

'%(path)s:%(row)d:%(col)d: %(code)s %(text)s'

Command-line example:

flake8 --format=pylint dir/
flake8 --format='%(path)s::%(row)d,%(col)d::%(code)s::%(text)s' dir/

This can be specified in config files.

Example config file usage:

format=pylint
format=%(path)s::%(row)d,%(col)d::%(code)s::%(text)s
--hang-closing

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Toggle whether pycodestyle should enforce matching the indentation of the opening bracket’s line. When you specify this, it will prefer that you hang the closing bracket rather than match the indentation.

Command-line example:

flake8 --hang-closing dir/

This can be specified in config files.

Example config file usage:

hang_closing = True
hang-closing = True
--ignore=<errors>

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Specify a list of codes to ignore. The list is expected to be comma-separated, and does not need to specify an error code exactly. Since Flake8 3.0, this can be combined with --select. See --select for more information.

For example, if you wish to only ignore W234, then you can specify that. But if you want to ignore all codes that start with W23 you need only specify W23 to ignore them. This also works for W2 and W (for example).

This defaults to: E121,E123,E126,E226,E24,E704

Command-line example:

flake8 --ignore=E121,E123 dir/
flake8 --ignore=E24,E704 dir/

This can be specified in config files.

Example config file usage:

ignore =
    E121,
    E123
ignore = E121,E123
--max-line-length=<n>

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Set the maximum length that any line (with some exceptions) may be.

Exceptions include lines that are either strings or comments which are entirely URLs. For example:

# https://some-super-long-domain-name.com/with/some/very/long/path

url = (
    'http://...'
)

This defaults to: 79

Command-line example:

flake8 --max-line-length 99 dir/

This can be specified in config files.

Example config file usage:

max-line-length = 79
--select=<errors>

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Specify the list of error codes you wish Flake8 to report. Similarly to --ignore. You can specify a portion of an error code to get all that start with that string. For example, you can use E, E4, E43, and E431.

This defaults to: E,F,W,C

Command-line example:

flake8 --select=E431,E5,W,F dir/
flake8 --select=E,W dir/

This can also be combined with --ignore:

flake8 --select=E --ignore=E432 dir/

This will report all codes that start with E, but ignore E432 specifically. This is more flexibly than the Flake8 2.x and 1.x used to be.

This can be specified in config files.

Example config file usage:

select =
    E431,
    W,
    F
--disable-noqa

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Report all errors, even if it is on the same line as a # NOQA comment. # NOQA can be used to silence messages on specific lines. Sometimes, users will want to see what errors are being silenced without editing the file. This option allows you to see all the warnings, errors, etc. reported.

Command-line example:

flake8 --disable-noqa dir/

This can be specified in config files.

Example config file usage:

disable_noqa = True
disable-noqa = True
--show-source

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Print the source code generating the error/warning in question.

Command-line example:

flake8 --show-source dir/

This can be specified in config files.

Example config file usage:

show_source = True
show-source = True
--statistics

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Count the number of occurrences of each error/warning code and print a report.

Command-line example:

flake8 --statistics

This can be specified in config files.

Example config file usage:

statistics = True
--enable-extensions=<errors>

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Enable off-by-default extensions.

Plugins to Flake8 have the option of registering themselves as off-by-default. These plugins effectively add themselves to the default ignore list.

Command-line example:

flake8 --enable-extensions=H111 dir/

This can be specified in config files.

Example config file usage:

enable-extensions =
    H111,
    G123
enable_extensions =
    H111,
    G123
--exit-zero

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Force Flake8 to use the exit status code 0 even if there are errors.

By default Flake8 will exit with a non-zero integer if there are errors.

Command-line example:

flake8 --exit-zero dir/

This can not be specified in config files.

--install-hook=VERSION_CONTROL_SYSTEM

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Install a hook for your version control system that is executed before or during commit.

The available options are:

  • git
  • mercurial

Command-line usage:

flake8 --install-hook=git
flake8 --install-hook=mercurial

This can not be specified in config files.

--jobs=<n>

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Specify the number of subprocesses that Flake8 will use to run checks in parallel.

Note

This option is ignored on Windows because multiprocessing does not support Windows across all supported versions of Python.

This defaults to: auto

The default behaviour will use the number of CPUs on your machine as reported by multiprocessing.cpu_count().

Command-line example:

flake8 --jobs=8 dir/

This can be specified in config files.

Example config file usage:

jobs = 8
--output-file=<path>

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Redirect all output to the specified file.

Command-line example:

flake8 --output-file=output.txt dir/
flake8 -vv --output-file=output.txt dir/

This can be specified in config files.

Example config file usage:

output-file = output.txt
output_file = output.txt
--tee

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Also print output to stdout if output-file has been configured.

Command-line example:

flake8 --tee --output-file=output.txt dir/

This can be specified in config files.

Example config file usage:

output-file = output.txt
tee = True
--append-config=<config>

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Provide extra config files to parse in after and in addition to the files that Flake8 found on its own. Since these files are the last ones read into the Configuration Parser, so it has the highest precedence if it provides an option specified in another config file.

Command-line example:

flake8 --append-config=my-extra-config.ini dir/

This can not be specified in config files.

--config=<config>

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Provide a path to a config file that will be the only config file read and used. This will cause Flake8 to ignore all other config files that exist.

Command-line example:

flake8 --config=my-only-config.ini dir/

This can not be specified in config files.

--isolated

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Ignore any config files and use Flake8 as if there were no config files found.

Command-line example:

flake8 --isolated dir/

This can not be specified in config files.

--builtins=<builtins>

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Provide a custom list of builtin functions, objects, names, etc.

This allows you to let pyflakes know about builtins that it may not immediately recognize so it does not report warnings for using an undefined name.

This is registered by the default PyFlakes plugin.

Command-line example:

flake8 --builtins=_,_LE,_LW dir/

This can be specified in config files.

Example config file usage:

builtins =
    _,
    _LE,
    _LW
--doctests

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Enable PyFlakes syntax checking of doctests in docstrings.

This is registered by the default PyFlakes plugin.

Command-line example:

flake8 --doctests dir/

This can be specified in config files.

Example config file usage:

doctests = True
--include-in-doctest=<paths>

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Specify which files are checked by PyFlakes for doctest syntax.

This is registered by the default PyFlakes plugin.

Command-line example:

flake8 --include-in-doctest=dir/subdir/file.py,dir/other/file.py dir/

This can be specified in config files.

Example config file usage:

include-in-doctest =
    dir/subdir/file.py,
    dir/other/file.py
include_in_doctest =
    dir/subdir/file.py,
    dir/other/file.py
--exclude-from-doctest=<paths>

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Specify which files are not to be checked by PyFlakes for doctest syntax.

This is registered by the default PyFlakes plugin.

Command-line example:

flake8 --exclude-in-doctest=dir/subdir/file.py,dir/other/file.py dir/

This can be specified in config files.

Example config file usage:

exclude-in-doctest =
    dir/subdir/file.py,
    dir/other/file.py
exclude_in_doctest =
    dir/subdir/file.py,
    dir/other/file.py
--benchmark

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Collect and print benchmarks for this run of Flake8. This aggregates the total number of:

  • tokens
  • physical lines
  • logical lines
  • files

and the number of elapsed seconds.

Command-line usage:

flake8 --benchmark dir/

This can not be specified in config files.

--bug-report

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Generate information necessary to file a complete bug report for Flake8. This will pretty-print a JSON blob that should be copied and pasted into a bug report for Flake8.

Command-line usage:

flake8 --bug-report

The output should look vaguely like:

{
  "dependencies": [
    {
      "dependency": "setuptools",
      "version": "25.1.1"
    }
  ],
  "platform": {
    "python_implementation": "CPython",
    "python_version": "2.7.12",
    "system": "Darwin"
  },
  "plugins": [
    {
      "plugin": "mccabe",
      "version": "0.5.1"
    },
    {
      "plugin": "pycodestyle",
      "version": "2.0.0"
    },
    {
      "plugin": "pyflakes",
      "version": "1.2.3"
    }
  ],
  "version": "3.1.0.dev0"
}

This can not be specified in config files.

--max-complexity=<n>

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Set the maximum allowed McCabe complexity value for a block of code.

This option is provided by the mccabe dependency’s Flake8 plugin.

Command-line usage:

flake8 --max-complexity 15 dir/

This can be specified in config files.

Example config file usage:

max-complexity = 15