title: Difference between /path/to/env/bin/python setup.py and python setup.py in virtualenv
body: <p>This is a silly question but here it goes.</p>
  
  <p>Usually, when I need to install a package in a virtual environment that for some reason is not playing nice with PIP , I activate such environment and then run <code>/path/to/env/bin/python setup.py</code>. This works fine but I have seen that some people just run <code>python setup.py</code>. Is it an omission of the full path? Or maybe, provided the virtual environment is activated, <code>python setup.py</code> installs the package in a virtual environment automatically. I don't know which one is correct.</p>
  
  <p>Note: I don't want to mess up my clean Linux installation testing the hard way, so I thought it would be better to ask here.</p>