title: Should I manually install all my system wide packages after upgrading to Python 3?
body: <p>I have some systemwide packages I've installed and I'm unclear whether I'm supposed to install another copy of them all for Python3 or if there is some way to 'point' Python3 at them. I'm on a Mac. </p>
  
  <p>I still have Python 2.7.9 which has all the packages (most installed with either brew or pip and maybe one or two manually like pyqt). Do I basically have to redo the installation process for every single package again? Or is there some way to simply have Python3 'inherit' everything I've installed so far under 2.7.9?</p>
  
  <p>Also, from what I understand, to install under Python3 with pip I would use pip3 install, is that correct? How would I do the same with ones installed with Homebrew? Is there a brew3 command? Or does Homebrew install to all versions of Python?</p>