title: PYTHONPATH showing empty in ubuntu 13.04
body: <p>when i do <code>echo $PYTHONPATH</code>  it returns nothing..empty line.</p>
  
  <p>so what does that mean. Im using python and it's working fine ..so whats the use of pythonpath and what should be the value of this in ubuntu 13.04</p>
  
  <p><code>/usr/bin/</code>  </p>
  
  <p>or</p>
  
  <p><code>/usr/lib/</code> </p>
  
  <p>..or something else</p>
  
  <p>and in windows we have python27/source  directory where i could put external sources/drivers , where(or equivalent) it is in ubuntu.</p>
  
  <p>when I do <code>user@user$ dpkg -L python2.7</code> it shows</p>
  
  <pre><code>/.
  /usr
  /usr/lib
  /usr/lib/python2.7
  /usr/lib/python2.7/lib-dynload
  /usr/lib/python2.7/lib2to3
  /usr/lib/python2.7/lib2to3/fixer_util.py
  ....
  /usr/lib/python2.7/lib2to3/Grammar.txt
  /usr/share
  /usr/share/doc
  /usr/share/doc/python2.7
  /usr/share/doc/python2.7/NEWS.gz
  /usr/share/doc/python2.7/README.Debian
  /usr/share/doc/python2.7/ACKS.gz
  /usr/share/doc/python2.7/README.gz
  /usr/share/doc/python2.7/copyright
  /usr/share/lintian
  /usr/share/lintian/overrides
  /usr/share/lintian/overrides/python2.7
  /usr/share/applications
  /usr/share/applications/python2.7.desktop
  /usr/share/menu
  /usr/share/menu/python2.7
  /usr/share/man
  /usr/share/man/man1
  /usr/share/man/man1/2to3-2.7.1.gz
  /usr/share/man/man1/pdb2.7.1.gz
  /usr/share/man/man1/pygettext2.7.1.gz
  /usr/share/man/man1/pydoc2.7.1.gz
  /usr/share/pixmaps
  /usr/share/pixmaps/python2.7.xpm
  /usr/bin
  /usr/bin/2to3-2.7
  /usr/bin/pygettext2.7
  /usr/bin/pydoc2.7
  /usr/share/doc/python2.7/changelog.gz
  /usr/share/doc/python2.7/changelog.Debian.gz
  /usr/bin/pdb2.7
  </code></pre>
  
  <p>I've downloaded chrome driver from this site and put in given directory<code>/usr/bin</code>..but it's not working .where should i put this?
  <a href="https://code.google.com/p/selenium/wiki/ChromeDriver" rel="noreferrer">https://code.google.com/p/selenium/wiki/ChromeDriver</a></p>