non-zero status causes <code>git send-email</code> to abort
before sending any e-mails.</p>
</div>
<div class="paragraph">
<p>The following environment variables are set when executing the hook.</p>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1"><code>GIT_SENDEMAIL_FILE_COUNTER</code></dt>
<dd>
<p>A 1-based counter incremented by one for every file holding an e-mail
to be sent (excluding any FIFOs). This counter does not follow the
patch series counter scheme. It will always start at 1 and will end at
