That command sequence is much older than Redis: <a href="https:&#x2F;&#x2F;tools.ietf.org&#x2F;html&#x2F;rfc2812#page-37" rel="nofollow">https:&#x2F;&#x2F;tools.ietf.org&#x2F;html&#x2F;rfc2812#page-37</a>