strtotime to get Unix timestamp

echo strtotime('now');

1788972887

Comparing two dates

$dt1='25-12-2015'; // First Date one in a variable
$dt2='01-07-2016'; // Second Date in a variable

$dt11=strtotime($dt1); // Converting first date to timestamp
$dt22=strtotime($dt2); // Converting second date to timestamp

if($dt11 > $dt22){
$dt=$dt1;
}else{
$dt=$dt2;
}
echo "Highest  Date : $dt ";

Highest Date : 01-07-2016

echo date('D',strtotime('now'))

$pub_date='2024-02-11T15:36:25Z'
$my_date=date('d-M-Y h:i:s', strtotime($pub_date));

Other ways to get Unix Timestamp