are repository or the root of the working tree in a non-bare
repository. An exception are hooks triggered during a push (<em>pre-receive</em>,
<em>update</em>, <em>post-receive</em>, <em>post-update</em>, <em>push-to-checkout</em>) which are always
executed in $GIT_DIR.</p>
</div>
<div class="paragraph">
<p>Environment variables, such as <code>GIT_DIR</code>, <code>GIT_WORK_TREE</code>, etc., are exported
so that Git commands run by the hook can correctly locate the repository.  If
your hook needs to invoke