$file = file_get_contents("1.txt");
$file2 = file_get_contents("2.txt");
$pieces = explode("\n", $file);
$pieces2 = explode("\n", $file2);

foreach($pieces as $piece)
{
	foreach($pieces2 as $piece2)
	{
		if(strcmp(trim($piece), trim($piece2)) == 0)
		echo 'yes';
	}
}