php中的正则表达式失败[关闭]

I am trying to fetch this from a file:

BEGIN_SEREFERRALS 2 google 13 15 search 2 2 END_SEREFERRALS

I use this function:

     function getTextBetweenSEO($file)
{
    $pattern = "/BEGIN_SEREFERRALS\s(.*)\sEND_SEREFERRALS/i";
    preg_match_all($pattern, $file, $matches);
    print_r($matches);
    exit();
    return $matches[1];

}

What I have printed is this:

Array ( [0] => Array ( ) [1] => Array ( ) )

why does the regular expression fails

you can try with this regex :

$pattern = "^BEGIN_SEREFERRALS(.*)END_SEREFERRALS^";

Array
(
    [0] => Array
        (
            [0] => BEGIN_SEREFERRALS 2 google 13 15 search 2 2 END_SEREFERRALS
        )

    [1] => Array
        (
            [0] =>  2 google 13 15 search 2 2 
        )
)

FIX For pattern on blob text data:

$pattern = "/BEGIN_SEREFERRALS(.*)END_SEREFERRALS/";

getTextBetweenSEO("jsdfhksdjhskjfdsjfhsdkjfhBEGIN_SEREFERRALS 2 google 13 15 search 2 2 END_SEREFERRALSjklajdakldjaslkdjakldjalkdjalksdj")

Array
(
    [0] => Array
        (
            [0] => BEGIN_SEREFERRALS 2 google 13 15 search 2 2 END_SEREFERRALS
        )

    [1] => Array
        (
            [0] =>  2 google 13 15 search 2 2 
        )
)