Invoking Flake8¶
Once you have installed Flake8, you can begin using it. Most of the time, you will be able to generically invoke Flake8 like so:
flake8 ...
Where you simply allow the shell running in your terminal to locate Flake8. In some cases, though, you may have installed Flake8 for multiple versions of Python (e.g., Python 2.7 and Python 3.5) and you need to call a specific version. In that case, you will have much better results using:
python2.7 -m flake8
Or
python3.5 -m flake8
Since that will tell the correct version of Python to run Flake8.
Note
Installing Flake8 once will not install it on both Python 2.7 and Python 3.5. It will only install it for the version of Python that is running pip.
It is also possible to specify command-line options directly to Flake8:
flake8 --select E123
Or
python<version> -m flake8 --select E123
Note
This is the last time we will show both versions of an invocation.
From now on, we’ll simply use flake8
and assume that the user
knows they can instead use python<version> -m flake8
instead.
It’s also possible to narrow what Flake8 will try to check by specifying
exactly the paths and directories you want it to check. Let’s assume that
we have a directory with python files and sub-directories which have python
files (and may have more sub-directories) called my_project
. Then if
we only want errors from files found inside my_project
we can do:
flake8 my_project
And if we only want certain errors (e.g., E123
) from files in that
directory we can also do:
flake8 --select E123 my_project
If you want to explore more options that can be passed on the command-line,
you can use the --help
option:
flake8 --help
And you should see something like:
Usage: flake8 [options] file file ...
Options:
--version show program's version number and exit
-h, --help show this help message and exit
-v, --verbose Print more information about what is happening in
flake8. This option is repeatable and will increase
verbosity each time it is repeated.
-q, --quiet Report only file names, or nothing. This option is
repeatable.
--count Print total number of errors and warnings to standard
error and set the exit code to 1 if total is not
empty.
--diff Report changes only within line number ranges in the
unified diff provided on standard in by the user.
--exclude=patterns Comma-separated list of files or directories to
exclude.(Default:
.svn,CVS,.bzr,.hg,.git,__pycache__,.tox)
--filename=patterns Only check for filenames matching the patterns in this
comma-separated list. (Default: *.py)
--format=format Format errors according to the chosen formatter.
--hang-closing Hang closing bracket instead of matching indentation
of opening bracket's line.
--ignore=errors Comma-separated list of errors and warnings to ignore
(or skip). For example, ``--ignore=E4,E51,W234``.
(Default: E121,E123,E126,E226,E24,E704)
--extend-ignore=errors
Comma-separated list of errors and warnings to add to
the list of ignored ones. For example, ``--extend-
ignore=E4,E51,W234``.
--max-line-length=n Maximum allowed line length for the entirety of this
run. (Default: 79)
--select=errors Comma-separated list of errors and warnings to enable.
For example, ``--select=E4,E51,W234``. (Default: )
--disable-noqa Disable the effect of "# noqa". This will report
errors on lines with "# noqa" at the end.
--show-source Show the source generate each error or warning.
--statistics Count errors and warnings.
--enabled-extensions=ENABLED_EXTENSIONS
Enable plugins and extensions that are otherwise
disabled by default
--exit-zero Exit with status code "0" even if there are errors.
-j JOBS, --jobs=JOBS Number of subprocesses to use to run checks in
parallel. This is ignored on Windows. The default,
"auto", will auto-detect the number of processors
available to use. (Default: auto)
--output-file=OUTPUT_FILE
Redirect report to a file.
--tee Write to stdout and output-file.
--append-config=APPEND_CONFIG
Provide extra config files to parse in addition to the
files found by Flake8 by default. These files are the
last ones read and so they take the highest precedence
when multiple files provide the same option.
--config=CONFIG Path to the config file that will be the authoritative
config source. This will cause Flake8 to ignore all
other configuration files.
--isolated Ignore all configuration files.
--builtins=BUILTINS define more built-ins, comma separated
--doctests check syntax of the doctests
--include-in-doctest=INCLUDE_IN_DOCTEST
Run doctests only on these files
--exclude-from-doctest=EXCLUDE_FROM_DOCTEST
Skip these files when running doctests
Installed plugins: pyflakes: 1.0.0, pep8: 1.7.0