How to fix Python indentation

Use the reindent.py script that you find in the Tools/scripts/ directory of your Python installation:

Change Python (.py) files to use 4-space indents and no hard tab characters. Also trim excess spaces and tabs from ends of lines, and remove empty lines at the end of files. Also ensure the last line ends with a newline.

Have a look at that script for detailed usage instructions.

NOTE: If your linux distro does not have reindent installed by default with Python:

Many linux distros do not have reindent installed by default with python --> one easy way to get reindent is to do pip install reindent.

p.s. An alternative to pip is to use your distros package manager (i.e. apt-get, yum, dnf) but then you need to figure out what package has the command line tool because each distro has the tool in a different package.

I would reach for autopep8 to do this:

$ # see what changes it would make
$ autopep8 path/to/file.py --select=E101,E121 --diff

$ # make these changes
$ autopep8 path/to/file.py --select=E101,E121 --in-place

Note: E101 and E121 are pep8 indentation (I think you can simply pass --select=E1 to fix all indentation related issues - those starting with E1).

You can apply this to your entire project using recursive flag:

$ autopep8 package_dir --recursive --select=E101,E121 --in-place

See also Tool to convert Python code to be PEP8 compliant.