title: Permission denied when installing Tensorflow with pip
body: <p>When I try to install Tensorflow with <code>pip install tensorflow</code>, I get this exception:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 215, in main
      status = self.run(options, args)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/commands/install.py", line 342, in run
      prefix=options.prefix_path,
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_set.py", line 784, in install
      **kwargs
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_install.py", line 851, in install
      self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_install.py", line 1064, in move_wheel_files
      isolated=self.isolated,
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/wheel.py", line 345, in move_wheel_files
      clobber(source, lib_dir, True)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/wheel.py", line 323, in clobber
      shutil.copyfile(srcfile, destfile)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 83, in copyfile
      with open(dst, 'wb') as fdst:
  IOError: [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/protobuf-3.5.2-py2.7-nspkg.pth'
  </code></pre>
  
  <p>What does it mean? How can I install the <code>tensorflow</code> package?</p>
  
  <p>When I use: <code>sudo pip install tensorflow</code> I now get this exception:</p>
  
  <pre><code>Traceback (most recent call last):
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 215, in main
      status = self.run(options, args)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/commands/install.py", line 342, in run
      prefix=options.prefix_path,
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_set.py", line 778, in install
      requirement.uninstall(auto_confirm=True)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_install.py", line 754, in uninstall
      paths_to_remove.remove(auto_confirm)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_uninstall.py", line 115, in remove
      renames(path, new_path)
    File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/utils/__init__.py", line 267, in renames
      shutil.move(old, new)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 302, in move
      copy2(src, real_dst)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 131, in copy2
      copystat(src, dst)
    File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 103, in copystat
      os.chflags(dst, st.st_flags)
  OSError: [Errno 1] Operation not permitted: '/var/folders/n6/bfff99yn3nnc46h_gh5tc7fm0000gn/T/pip-TI9hQ_-uninstall/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/six-1.4.1-py2.7.egg-info'
  </code></pre>
  
  <p>Instead of saying denied it says Operation not permitted</p>