title: Changing default python to another version
body: <p>Currently when I use "python" command, it points to python2.6. I have installed python3.1 and I want the "python" command point to python3.1. How it is possible?</p>
  
  <pre><code>mahmood@mpc:~$ which python 
  /usr/bin/python
  mahmood@mpc:~$ ls -l /usr/bin/python
  lrwxrwxrwx 1 root root 9 2010-11-24 16:14 /usr/bin/python -&gt; python2.6
  mahmood@mpc:~$ uname -a
  Linux orca 2.6.32-24-server #39-Ubuntu SMP Wed Jul 28 06:21:40 UTC 2010 x86_64 GNU/Linux
  </code></pre>