问题描述
我想知道使用Ubuntu的网站的HTTP状态。为此，我使用了curl和wget命令。但是问题是这些命令下载了完整的网站页面，然后搜索标题并将其显示在屏幕上。例如：
$ curl -I trafficinviter.com
HTTP/1.1 200 OK
Date: Mon, 02 Jan 2017 14:13:14 GMT
Server: Apache
X-Pingback: http://trafficinviter.com/xmlrpc.php
Link: <http://trafficinviter.com/>; rel=shortlink
Set-Cookie: wpfront-notification-bar-landingpage=1
Content-Type: text/html; charset=UTF-8
Wget命令也会发生同样的事情，在该命令中，整个页面正在下载并且不必要地占用了我的带宽。
我要寻找的是：如何在不实际下载任何页面的情况下获取HTTP状态代码，从而节省带宽消耗。我曾尝试使用curl，但不确定是要下载完整页面还是仅下载系统标题以获取状态代码。
最佳方法
curl -I仅获取HTTP标头；它不会下载整个页面。从man curl：
-I, --head
(HTTP/FTP/FILE) Fetch the HTTP-header only! HTTP-servers feature
the command HEAD which this uses to get nothing but the header
of a document. When used on an FTP or FILE file, curl displays
the file size and last modification time only.
另一种选择是安装lynx并使用lynx -head -dump。
HEAD请求由HTTP 1.1协议(RFC 2616)指定：
9.4 HEAD
The HEAD method is identical to GET except that the server MUST NOT
return a message-body in the response. The metainformation contained
in the HTTP headers in response to a HEAD request SHOULD be identical
to the information sent in response to a GET request. This method can
be used for obtaining metainformation about the entity implied by the
request without transferring the entity-body itself. This method is
often used for testing hypertext links for validity, accessibility,
and recent modification.
次佳方法
对于wget，您需要使用--spider选项发送诸如curl的HEAD请求：
$ wget -S --spider https://google.com
Spider mode enabled. Check if remote file exists.
--2017-01-03 00:08:38-- https://google.com/
Resolving google.com (google.com)... 216.58.197.174
Connecting to google.com (google.com)|216.58.197.174|:443... connected.
HTTP request sent, awaiting response...
HTTP/1.1 302 Found
Cache-Control: private
Content-Type: text/html; charset=UTF-8
Location: https://www.google.co.jp/?gfe_rd=cr&ei=...
Content-Length: 262
Date: Mon, 02 Jan 2017 15:08:38 GMT
Alt-Svc: quic=":443"; ma=2592000; v="35,34"
Location: https://www.google.co.jp/?gfe_rd=cr&ei=... [following]
Spider mode enabled. Check if remote file exists.
--2017-01-03 00:08:38-- https://www.google.co.jp/?gfe_rd=cr&ei=...
Resolving www.google.co.jp (www.google.co.jp)... 210.139.253.109, 210.139.253.93, 210.139.253.123, ...
Connecting to www.google.co.jp (www.google.co.jp)|210.139.253.109|:443... connected.
HTTP request sent, awaiting response...
HTTP/1.1 200 OK
Date: Mon, 02 Jan 2017 15:08:38 GMT
Expires: -1
Cache-Control: private, max-age=0
Content-Type: text/html; charset=Shift_JIS
P3P: CP="This is not a P3P policy! See https://www.google.com/support/accounts/answer/151657?hl=en for more info."
Server: gws
X-XSS-Protection: 1; mode=block
X-Frame-Options: SAMEORIGIN
Set-Cookie: NID=...; expires=Tue, 04-Jul-2017 15:08:38 GMT; path=/; domain=.google.co.jp; HttpOnly
Alt-Svc: quic=":443"; ma=2592000; v="35,34"
Transfer-Encoding: chunked
Accept-Ranges: none
Vary: Accept-Encoding
Length: unspecified [text/html]
Remote file exists and could contain further links,
but recursion is disabled -- not retrieving.