title: oozie create a parameter with today date
body: <p>How can I create a parameter with today date of the format :</p>
  
  <pre><code>yyyy-mm-dd
  </code></pre>
  
  <p>in oozie. I am passing this variable to hive script which is adding the partition for that date, I found the function to create <a href="http://oozie.apache.org/docs/3.2.0-incubating/WorkflowFunctionalSpec.html#a4.2_Expression_Language_Functions" rel="noreferrer">timestamp</a> using : </p>
  
  <pre><code>&lt;param&gt;DATE=${wf:timestamp()}&lt;/param&gt;
  </code></pre>
  
  <p>which should return output in the form :</p>
  
  <pre><code>(YYYY-MM-DDThh:mm:ss.sZ). I.e.: 1997-07-16T19:20:30.45Z
  </code></pre>
  
  <p>but I am getting error :</p>
  
  <pre><code>No function is mapped to the name "wf:timestamp"
  </code></pre>
  
  <p>Also I only want <code>YYYY-MM-DD</code> from the timestamp and there is no substring function also which can give me first 10 chars of the string.</p>