php value format on unix code example

Example 1: php start of day epoch

$beginOfDay = strtotime("today", $timestamp);
$endOfDay   = strtotime("tomorrow", $beginOfDay) - 1;

Example 2: php date

$dateTime = new \DateTime();
/**
 * You can get the string by using format
 */
$dateTime->format('Y-m-d H:i:s');