title: Append value to Hashfield
body: <p>Redis <a href="http://redis.io/commands/append" rel="nofollow noreferrer">is able to append</a> a string to the value of a <code>key</code>. Instead of a normal key, I need to append to the value of a <code>Hashfield</code>. I am currently solving it the obvious way:</p>
  <pre><code>redis.HGET('hash', 'field2append', function(err, reply){
      redis.HSET('hash', 'field2append', reply + appendString);
  });
  </code></pre>
  <p>Since the setup involves clusters in multiple physical (node.js) servers, the above could cause data loss due to the time taken between node receiving the value and setting it again (in case another server is updating the same field at the same time).</p>
  <p>Is there a safer way to <code>append</code> a string to the <code>value</code> of a <code>hashfield</code>?</p>