queue-ensure.php

<?php

function runCommand ()
{
    $command = 'php artisan queue:work --daemon --env=prod > /dev/null & echo $!';
    $number = exec($command);
    file_put_contents(__DIR__ . '/queue.pid', $number);
}

if (file_exists(__DIR__ . '/queue.pid')) {
    $pid = file_get_contents(__DIR__ . '/queue.pid');
    $result = exec("ps -p {$pid} | awk 'NR>1'");
    if ($result == '') {
        runCommand();
    }
} else {
    runCommand();
}