title: Virtualenv with only Python3
body: <p>I have two different Ubuntu VMs first 14.04 second 16.04. On the first one when I create virtualenv with pyhton3 for some reason python27 is also gets installed </p>
  
  <pre><code>user@ubuntu:~/venv$ virtualenv  --python=python3 --no-site-packages py3-venv
  Already using interpreter /usr/bin/python3
  Using base prefix '/usr'
  New python executable in /home/user/venv/py3-venv/bin/python3
  Also creating executable in /home/user/venv/py3-venv/bin/python
  Installing setuptools, pip, wheel...done.
  user@ubuntu:~/venv$ source py3-venv/bin/activate
  (py3-venv) user@ubuntu:~/venv$ python -V
  Python 2.7.12
  </code></pre>
  
  <p>Same thing done on the second VM works as intended</p>
  
  <pre><code>user@my-box:~/venv$ virtualenv -p /usr/bin/python3 py3-venv
  Already using interpreter /usr/bin/python3
  Using base prefix '/usr'
  New python executable in /home/user/venv/py3-venv/bin/python3
  Also creating executable in /home/user/venv/py3-venv/bin/python
  Installing setuptools, pip, wheel...done.
  user@my-box:~/venv$ source py3-venv/bin/activate
  (py3-venv) user@my-box:~/venv$ which python
  /home/user/venv/py3-venv/bin/python
  (py3-venv) user@my-box:~/venv$ python -V
  Python 3.5.2
  </code></pre>
  
  <p>I need the virtualenv to run python3 even though I type python command. Any ideas how to do it? </p>
  
  <p>[UPDATE]</p>
  
  <p>This is the strangest thing I have ever seen</p>
  
  <pre><code>(py3-venv) user@ubuntu:~/venv$ which python
  /home/user/venv/py3-venv/bin/python
  (py3-venv) user@ubuntu:~/venv$ python -V
  Python 2.7.12
  (py3-venv) user@ubuntu:~/venv$ ./py3-venv/bin/python -V
  Python 3.4.3
  </code></pre>
  
  <p>[UPDATE 2]</p>
  
  <p>I am completely lost... Even <code>strace python</code> command points to the correct file </p>
  
  <pre><code>(py3-venv) user@ubuntu:~/venv$ strace python
  execve("/home/user/venv/py3-venv/bin/python", ["python"], [/* 24 vars */]) = 0
  brk(0)                                  = 0x204f000
  </code></pre>
  
  <p>[UPDATE 3]</p>
  
  <p>If I remove everything other than <code>/home/user/venv/py3-venv/bin</code> from the <code>PATH</code> python command fails to execute... Please help!!</p>
  
  <pre><code>(py3-venv) user@ubuntu:~$ export PATH=/home/user/venv/py3-venv/bin
  (py3-venv) user@ubuntu:~$ echo $PATH
  /home/user/venv/py3-venv/bin
  (py3-venv) user@ubuntu:~$ python -V
  Command 'python2.7' is available in the following places
   * /usr/bin/python2.7
   * /usr/local/bin/python2.7
  The command could not be located because '/usr/bin:/usr/local/bin' is not included in the PATH environment variable.
  python2.7: command not found
  </code></pre>