title: pyenv installs multiple pythons, but recognizes only some
body: <p>I am trying to get pyenv up and running (Mac OS X), so I can use tox/detox to test code vs. multiple python environments. I was able to install multiple python3 versions, and then I used <code>pyenv global</code> on all the versions. After doing that, <code>pyenv versions</code> returns this list:</p>
  
  <pre><code>  system
  * 3.2.6 (set by /Users/Workspace/.pyenv/version)
    3.3.6
    3.4.6
    3.5.3
    3.6.1
  </code></pre>
  
  <p>However, only 3.4 and 3.5 are recognized (along with 2.7.8, which I believe is 'system'):</p>
  
  <pre><code>Geoffreys-MBP:pydnmr-tox Workspace$ python --version
  Python 2.7.8
  Geoffreys-MBP:pydnmr-tox Workspace$ python3.2 --version
  -bash: python3.2: command not found
  Geoffreys-MBP:pydnmr-tox Workspace$ python3.3 --version
  -bash: python3.3: command not found
  Geoffreys-MBP:pydnmr-tox Workspace$ python3.4 --version
  Python 3.4.3
  Geoffreys-MBP:pydnmr-tox Workspace$ python3.5 --version
  Python 3.5.2
  Geoffreys-MBP:pydnmr-tox Workspace$ python3.6 --version
  -bash: python3.6: command not found
  </code></pre>
  
  <p>Any ideas what is causing this behavior? tox/detox similarly cannot find any Python version besides 3.4/3.5.</p>
  
  <p>Edit: it seems that pyenv has installed all the environments, but <code>python3.x</code> commands weren't finding them. <code>python3.4</code> and <code>python3.5</code> were working because they found previous top-level installations. Results for <code>pyenv which python3.x.y</code> vs. <code>python3.x [--version]</code> shown below.</p>
  
  <pre><code>$ pyenv which python3.2
  /Users/Workspace/.pyenv/versions/3.2.6/bin/python3.2
  $ python3.2 --version
  -bash: python3.2: command not found
  $ python3.2
  -bash: python3.2: command not found
  pyenv which python3.3
  /Users/Workspace/.pyenv/versions/3.3.6/bin/python3.3
  $ python3.3 --version
  -bash: python3.3: command not found
  $ pyenv which python3.4
  /usr/local/bin/python3.4  # old install
  $ python3.4 --version
  Python 3.4.3              # not 3.4.6 installed by pyenv
  $ pyenv which python3.4.6
  pyenv: python3.4.6: command not found
  $ python3.4.6 --version
  -bash: python3.4.6: command not found
  $ pyenv which python3.5
  /Users/Workspace/.pyenv/versions/3.5.3/bin/python3.5
  $ python3.5 --version
  Python 3.5.2  #Linked to my old 3.5.2 install instead of pyenv 3.5.3 install
  $ pyenv which python3.6
  /Users/Workspace/.pyenv/versions/3.6.1/bin/python3.6
  $ python3.6 --version
  -bash: python3.6: command not found
  </code></pre>
  
  <p>However, installing tox-pyenv as suggested in the answers below allowed tox to find and use all of these environments!</p>