php post如何换行 php post换行的方法

<?php $str=$_POST['name1'].'-'.$_POST['phone1'].'-'.$_POST['address'].'-'.$_POST['express'];

echo $str."
";

$fp=fopen("b.txt","a+");

fwrite($fp,$str);//写入

fclose($fp);//关闭

?>

$str=$_POST['name1'].'-'.$_POST['phone1'].'-'.$_POST['address'].'-'.$_POST['express']."rn";