ect name stored in the ref,
<code>&lt;new-oid&gt;</code> is the new object name to be stored in the ref and
<code>&lt;ref-name&gt;</code> is the full name of the ref.
When creating a new ref, <code>&lt;old-oid&gt;</code> is the all-zeroes object name.</p>
</div>
<div class="paragraph">
<p>If the hook exits with non-zero status, none of the refs will be
updated. If the hook exits with zero, updating of individual refs can
still be prevented by the <a href="#update"><em>update</em></a> hook.</p>
</div>
<div c