title: Installing data_files in setup.py with pip install -e
body: <p>I'm trying to provide a bash completion script for my CLI tool that is written in Python. According to the <a href="https://packaging.python.org/guides/distributing-packages-using-setuptools/?highlight=data_files#data-files" rel="noreferrer">Python Packaging Authority</a>, <code>data_files</code> in setup.py is exactly what I need:</p>
  
  <blockquote>
    <p>Although configuring package_data is sufficient for most needs, in some cases you may need to place data files outside of your packages. The data_files directive allows you to do that. It is mostly useful if you need to install files which are used by other programs, which may be unaware of Python packages.</p>
  </blockquote>
  
  <p>So I added the completion file like this:</p>
  
  <pre><code>data_files=[
      ('/usr/share/bash-completion/completions', ['completion/dotenv']),
  ],
  </code></pre>
  
  <p>and try to test it with:</p>
  
  <p><code>pip install -e .</code></p>
  
  <p>In my virtual environment. However, the completion script gets not installed. Did I forgot something or is <code>pip</code> broken? The full project can be found <a href="https://github.com/venthur/dotenv-cli/tree/bash_completion" rel="noreferrer">here</a></p>