title: String interpolation to bash inside python code
body: <p>I need interpolate python variable to bash command something like that:</p>
  
  <pre><code>var = foo
  cmd = '/etc/openvpn/easy-rsa/pkitool --server  %s' % var
  </code></pre>
  
  <p>UPDATED: I eronneously posted this question. It seemed to me it doesn't work properly but then I saw code does what it should. Question closed. Anyway it shows people how to interpolate string into bash and thus is useful.</p>