title: pip on OSX Yosemite 10.10 gives bad command
body: <p>I run OSX Yosemite on a macbook air.  I have python3 installed, as well as the apple developer package.  I am trying to install modules like ones I have installed already including matplotlib.  Basically when I try to install scientific python packages like SciPy, Ginga, AstroPy, iPython, etc, I get this in the terminal after attempting a pip install:</p>
  
  <pre><code>-bash: pip: command not found
  </code></pre>
  
  <p>So I attempt at downloading the tarball if provided and I follow the instructions to install that way as guided by the website and the README files, and I still get errors.  For instance, in this astropy tarball, it states to run python setup.py install from the directory and this is what happens:</p>
  
  <pre><code>jesses-Air:astropy-1.0 jessehanowell$ python setup.py install
  running install
  Checking .pth file support in /Library/Python/2.7/site-packages/
  error: can't create or remove files in install directory
  
  The following error occurred while trying to add or remove files in the
  installation directory:
  
  [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/test-easy-
  
  install-632.pth'
  
  The installation directory you specified (via --install-dir, --prefix, or
  the distutils default setting) was:
  
  /Library/Python/2.7/site-packages/
  
  Perhaps your account does not have write access to this directory?  If the
  installation directory is a system-owned directory, you may need to sign in
  as the administrator or "root" account.  If you do not have administrative
  access to this machine, you may wish to choose a different installation
  directory, preferably one that is listed in your PYTHONPATH environment
  variable.
  
  For information on other options, you may wish to consult the
  documentation at:
  
  https://pythonhosted.org/setuptools/easy_install.html
  
  Please make the appropriate changes for your system and try again.
  </code></pre>
  
  <p>It says the same thing for a "python3 setup.py install" command as well.  Keep in mind I have python3 installed and Yosemite still runs on python v2.4.7, and I am running the terminal from the downloads directory, where the files are located.  Maybe I have to change the file unzipped files to a new location?  But basically I am disappointed because I really want to learn to use these packages.  I know if my friend was able to install matplotlib that I should be able to install these.  </p>
  
  <p>So is there a way to restore pip to my computer and install that way?  Or can someone point out the obvious thing I am doing incorrectly?  Thanks for the assistance folks!  </p>