title: GoCD stage to run a script if it exists
body: <p>I have a template that all my pipelines are using.</p>
  
  <p>id like to add the stage to run a contract-tests.sh file.</p>
  
  <p>not all my projects will have this file so there pipelines break. </p>
  
  <p>I do not want to create a new template</p>
  
  <p>I tried the following custom command as a test but it does not actually echo the line to the console.</p>
  
  <p><code>test -f contract-tests.sh &amp;&amp; echo "contract tests file is present"</code></p>