. 用法

"HTTP/1.1 302 Object moved 
Cache-Control: no-cache 
Pragma: No-Cache 
Content-Length: 107 
Content-Type: text/html; 
Charset=utf-8 
Expires: Wed, 12 Sep 2018 04:58:42 GMT 
Location: login.asp 
Server: Microsoft-IIS/7.5 
Set-Cookie: ASPSESSIONIDQSADRQQS=CKINDEPAENCKEIBKDMDGIACN; 
path=/ X-Powered-By: ASP.NET 
Date: Thu, 13 Sep 2018 04:58:43 GMT 
Connection: close "

匹配时间
// . 不会匹配换行符
preg_match('/Date: (.*)$/mi',$resp,$matches);