title: passing more than one variables to os.system in python
body: <p>I want to pass two variables to the os.system() for example listing files in different format in specific directory like (ls -l testdirectory) in which both a switch and test directory are variable.
  I know for single variable this one works:</p>
  
  <p><code>option=l
  os.sytem('ls -%s' option)</code></p>
  
  <p>but I dont know how to pass two variables?</p>