Shellscript + PHP file for automatically ending looped Database query

long-running-query.php

<?php

require 'some-bootstrap.php'; // perhaps wp-load.php
global $db; // perhaps $wpdb

$count = $db->query("DELETE FROM sometable WHERE somefield = 'somevalue' LIMIT 100"); // should return affected rows count

die($count);

long-running-query.sh

#!/usr/bin/env bash
while ! php long-running-query.php ; do sleep 1; echo -n .; done