Why doesn't validation in PHP?

There is a file users.php:

function user($login, $password){
 $file = file_get_contents(__DIR__ . '/users.txt');
 $users = explode("\n", $file);

 $all = array();
 foreach($users as $str){
 $temp = explode(' ', $str);
 if( $str[1] ) $all[$temp[0]] = $temp[1];
}

 if( $all[$login] == $password ) echo 'ok'; // Check false

 if( $all[$login] && $all[$login] == $password )
 return true;

 return false;
 }

And in the same directory as the file users.txt
admin pass
When I call the function with the Correct username and password returns me false result.
Wanted to know what the problem is, found out that the test does not pass. The screen was put ok but nothing.
When a separate output $all[ $login ] and $password, are identical to both (pass and pass), but the test is still false. Why?