title: Execute external program in ruby and wait for its execution
body: <p>How do I start an external program (like an excel sheet) from ruby and wait for its execution resp. termination before continuing.</p>
  
  <p>I know I can start the excel sheet with </p>
  
  <pre><code>system 'start excel "my/path/to/the/sheet"' 
  </code></pre>
  
  <p>but using this will only start the sheet and then continues.</p>