Once you have installed Flake8, you can begin using it. Most of the time, you will be able to generically invoke Flake8 like so:
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 3.8 and Python 3.9) and you need to call a specific version. In that case, you will have much better results using:
python3.8 -m flake8
python3.9 -m flake8
Since that will tell the correct version of Python to run Flake8.
Installing Flake8 once will not install it on both Python 3.8 and Python 3.9. 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
python<version> -m flake8 --select E123
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:
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
And you should see something like:
Usage: flake8 [options] file file ...
--version show program's version number and exit
-h, --help show this help message and exit