title: Generating v5 UUID. What is name and namespace?
body: <p>I've read the <code>man</code> page, but I do not understand what <code>name</code> and <code>namespace</code> are for.</p>
  <blockquote>
  <p>For version 3 and version 5 UUIDs the additional command line
  arguments namespace and name have to be given. The namespace is either
  a UUID in string representation or an
  identifier for internally pre-defined namespace UUIDs (currently known are &quot;ns:DNS&quot;, &quot;ns:URL&quot;, &quot;ns:OID&quot;, and &quot;ns:X500&quot;). The
  name is a string of arbitrary length.</p>
  </blockquote>
  <p>The namespace:</p>
  <blockquote>
  <p>The namespace is either a UUID in string representation or an</p>
  </blockquote>
  <p>Does it mean that I need to store it (UUID v4) somewhere in relation to the generated UUID v5? In either case, why is this not done automatically?</p>
  <blockquote>
  <p>The name is a string of arbitrary length.</p>
  </blockquote>
  <p><code>name</code> a completely random string? What is the purpose of it then? Can it be decoded from the UUID v5?</p>