title: PYTHONPATH is not working for multiple path
body: <p>I want to set pythonpath, but it doesnt work for other directory.</p>
  
  <p>My bashrc:</p>
  
  <p><strong>export PYTHONPATH=/usr/lib/python2.7<br/>
  export PYTHONPATH=$PYTHONPATH/plat-linux2:$PYTHONPATH/lib-dynload:$PYTHONPATH/dist-packages:$PYTHONPATH/lib-tk:$PYTHONPATH</strong></p>
  
  <p>If I keep only first line(single directory) <br/>
  <strong>export PYTHONPATH=/usr/lib/python2.7</strong><br/>
  then, my bash shell takes me to the /usr/lib/python2.7 directory.</p>
  
  <p>But when I include multiple directory - <br/>
  <strong>export PYTHONPATH=$PYTHONPATH/plat-linux2:$PYTHONPATH/lib-dynload:$PYTHONPATH/dist-packages:$PYTHONPATH/lib-tk:$PYTHONPATH</strong><br/>
  It throws error like 
  bash: cd: /usr/lib/python2.7/plat-linux2:/usr/lib/python2.7/lib-dynload:/usr/lib/python2.7/dist-packages:/usr/lib/python2.7/lib-tk:/usr/lib/python2.7: No such file or directory</p>