title: Bash one liner - Test if a file exists and source if it does other exit with error
body: <p>In other words I want to make this into a one-liner:</p>
  
  <pre><code>    test -e ${MY_HOME}/setup-env.sh || { echo "ERROR: MY_HOME not defined or does not contain srtup-env.sh" 1&gt;&amp;2 ; exit 1; }
  
      . ${MY_HOME}/setup-env.sh
  </code></pre>