What are the potential pitfalls of trying to identify PHP software in a website?

Potential pitfalls of trying to identify PHP software in a website include false positives, where non-PHP software is mistakenly identified as PHP, and false negatives, where PHP software is not detected. To accurately identify PHP software, it is important to use multiple methods of detection and to verify results manually.

// Example code snippet to identify PHP software in a website
$source_code = file_get_contents('http://www.example.com');
$php_detected = strpos($source_code, '<?php') !== false;
if($php_detected) {
    echo 'PHP software detected on the website';
} else {
    echo 'No PHP software detected on the website';
}