CentOS 8 Detection in PHP

<?php

// checking operating version through rhel
$osVersion = exec("rpm -E %{rhel}");
$lockedvOS = "8";

if (file_exists('/etc/letsencrypt-cpanel.osver8')) {

//let's compare the strings using strcmp()
if ( strcmp($osVersion, $lockedvOS) == 0 ) {
 echo "Both the strings are equal!";
} else {
  echo "Both the strings are not equal!";
}

    // echo "Overriding CentOS 8 's License";
} else {
    // echo "Keep the License of CentOS 7";
}

?>