Error ping

ping.php

<?php

/**
 * @example Run as `php ping.php`
 *
 * Ping and keep pinging every 5 seconds. 
 *
 * Print out only the errored packets
 */

namespace Maternia\Scripts;

const PING_IP = '8.8.8.8';

while (1) { 
    echo ($p = ping()) ? $p . PHP_EOL : '';
    sleep(2);
}

function ping (string $ip = PING_IP, float $threshold = 500): ?string
{
    $params = PHP_OS === 'Darwin' ? '--apple-time' : '';
    $ping = exec("ping -c 1 $params $ip", $output, $status);

    if ($status !== 0) {
        return date('c').' error '.$status.': '.trim(end($output));
    }

    if (strpos($output[2], 'unreachable') !== false || strpos($output[2], 'timeout') !== false) {
        return date('c').' unreachable/timeout: '.implode(PHP_EOL, $output);
    }

    // string(71) "13:50:07.498883 64 bytes from 8.8.8.8: icmp_seq=0 ttl=56 time=21.692 ms"
    if (!preg_match('/([\d:\.]+).+time=([\d\.]+) ms/', $output[1], $m)) {
        return date('c').': Invalid: '.$output[1];
    }

    if ($m[2] > $threshold) {
        return date('c').': SLOW: '.$output[1];
    }

    return null;
}