PHP 获取服务器运行时间（system uptime）

如题，PHP 获取 VPS 服务器运行时间（system uptime），在 WordPress 模板中使用显示出来。

代码提取自雅黑探针，PHP7 下测试通过。

if ( !function_exists( 'sys_uptime' ) ) {
	function sys_uptime() {
		$output='';
		if (false === ($str = @file("/proc/uptime"))) return false;
		$str = explode(" ", implode("", $str));
		$str = trim($str[0]);
		$min = $str / 60;
		$hours = $min / 60;
		$days = floor($hours / 24);
		$hours = floor($hours - ($days * 24));
		$min = floor($min - ($days * 60 * 24) - ($hours * 60));
		if ($days !== 0) $output .= $days."天";
		if ($hours !== 0) $output .= $hours."小时";
		if ($min !== 0) $output .= $min."分钟";
		return $output;
	}
}

其它代码：How to display system uptime in php?

$str   = @file_get_contents('/proc/uptime');
$num   = floatval($str);
$secs  = fmod($num, 60); $num = (int)($num / 60);
$mins  = $num % 60;      $num = (int)($num / 60);
$hours = $num % 24;      $num = (int)($num / 24);
$days  = $num;

#Or, with intdiv (PHP7):

$str   = @file_get_contents('/proc/uptime');
$num   = floatval($str);
$secs  = fmod($num, 60); $num = intdiv($num, 60);
$mins  = $num % 60;      $num = intdiv($num, 60);
$hours = $num % 24;      $num = intdiv($num, 24);
$days  = $num;