title: What does {NUMBER} mean in an LDAP filter?
body: <p>I'm maintaining an LDAP filter that looks something like <code>(&amp;(objectClass=person)(sAMAccountName={0}))</code>, and am trying to understand what the <code>{0}</code> means.</p>
  
  <p>I can't seem to find any documentation on this "curly braces with a number" syntax.  I've looked at the <a href="https://tools.ietf.org/search/rfc4515" rel="noreferrer">RFC</a> defining LDAP search strings, at <a href="https://msdn.microsoft.com/en-us/library/aa746475(v=vs.85).aspx" rel="noreferrer">the MSDN docs</a>, and <a href="https://www.centos.org/docs/5/html/CDS/ag/8.0/Finding_Directory_Entries-LDAP_Search_Filters.html" rel="noreferrer">at the centos docs</a>, but none mention this syntax as far as I can tell.</p>
  
  <p>EDIT:</p>
  
  <p>It turns out, this is not part of the LDAP specification.  It is an extension provided by the Jenkins LDAP plugin, and is equal to the username provided by the user when logging in.</p>