Mencari String dan nomor baris menggunakan php

Code di bawah digunakan untuk mencari text/value string pada sebuah file , jika value ditemukan maka akan mereturn line number pada value tersebut ..

 <?php

    function find_line_number_by_string($filename, $search,$case_sensitive = false)
        {
            $line_number = "";
            if ($file_handler = fopen($filename, "r")) {
                $i = 0;
                while ($line = fgets($file_handler)) {
                    $i++;
                    //case sensitive is false by default
                    if ($case_sensitive == false) {
                        $search = strtolower($search); //convert file and search string
                        $line = strtolower($line); //to lowercase
                    }
                    //find the string and store it in an array
                    if (strpos($line, $search) !== false) {
                        $line_number .= $i . ",";
                    }
                }
                fclose($file_handler);
            } else {
                return "File not exists, Please check the file path or filename";
            }
            //if no match found
            if (count($line_number)) {
                return substr($line_number, 0, -1);
            } else {
                return "No match found";
            }
        }
        
        
  	//use function
        $output = find_line_number_by_string('example.html', 'materials');

        print "String(s) found in ".$output;