title: Python os module open file above current directory with relative path
body: <p>The documentation for the OS module does not seem to have information about how to open a file that is not in a subdirectory or the current directory that the script is running in without a full path. My directory structure looks like this.</p>
  
  <pre><code>/home/matt/project/dir1/cgi-bin/script.py
  /home/matt/project/fileIwantToOpen.txt
  
  open("../../fileIwantToOpen.txt","r")
  </code></pre>
  
  <p>Gives a file not found error. But if I start up a python interpreter in the cgi-bin directory and try <code>open("../../fileIwantToOpen.txt","r")</code> it works. I don't want to hard code in the full path for obvious portability reasons. Is there a set of methods in the OS module that <em>CAN</em> do this?</p>