如何grep cURL的输出？

Question

如何grep cURL的输出？

我需要检索 SSL 证书的到期日期。该curl应用程序确实提供了以下信息：

$ curl -v https://google.com/
* Hostname was NOT found in DNS cache
*   Trying 212.179.180.121...
* Connected to google.com (212.179.180.121) port 443 (#0)
* successfully set certificate verify locations:
*   CAfile: none
  CApath: /etc/ssl/certs
* SSLv3, TLS handshake, Client hello (1):
* SSLv3, TLS handshake, Server hello (2):
* SSLv3, TLS handshake, CERT (11):
* SSLv3, TLS handshake, Server key exchange (12):
* SSLv3, TLS handshake, Server finished (14):
* SSLv3, TLS handshake, Client key exchange (16):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSLv3, TLS change cipher, Client hello (1):
* SSLv3, TLS handshake, Finished (20):
* SSL connection using ECDHE-ECDSA-AES128-GCM-SHA256
* Server certificate:
*        subject: C=US; ST=California; L=Mountain View; O=Google Inc; CN=*.google.com
*        start date: 2014-10-22 13:04:07 GMT
*        expire date: 2015-01-20 00:00:00 GMT
*        subjectAltName: google.com matched
*        issuer: C=US; O=Google Inc; CN=Google Internet Authority G2
*        SSL certificate verify ok.
> GET / HTTP/1.1
> User-Agent: curl/7.35.0
> Host: google.com
> Accept: */*
> 
< HTTP/1.1 302 Found
< Cache-Control: private
< Content-Type: text/html; charset=UTF-8
< Location: https://www.google.co.il/?gfe_rd=cr&ei=HkxbVMzCM-WkiAbU6YCoCg
< Content-Length: 262
< Date: Thu, 06 Nov 2014 10:23:26 GMT
* Server GFE/2.0 is not blacklisted
< Server: GFE/2.0
< 
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>302 Moved</TITLE></HEAD><BODY>
<H1>302 Moved</H1>
The document has moved
<A HREF="https://www.google.co.il/?gfe_rd=cr&amp;ei=HkxbVMzCM-WkiAbU6YCoCg">here</A>.
</BODY></HTML>
* Connection #0 to host google.com left intact

Run Code Online (Sandbox Code Playgroud)

然而，当通过grep结果管道输出时，屏幕上的信息不是更少，而是更多：

$ curl -v https://google.com/ | grep expire
* Hostname was NOT found in DNS cache
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0*   Trying 212.179.180.84...
* Connected to google.com (212.179.180.84) port 443 (#0)
* successfully set certificate verify locations:
*   CAfile: none
  CApath: /etc/ssl/certs
* SSLv3, TLS handshake, Client hello (1):
} [data not shown]
* SSLv3, TLS handshake, Server hello (2):
{ [data not shown]
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0* SSLv3, TLS handshake, CERT (11):
{ [data not shown]
* SSLv3, TLS handshake, Server key exchange (12):
{ [data not shown]
* SSLv3, TLS handshake, Server finished (14):
{ [data not shown]
* SSLv3, TLS handshake, Client key exchange (16):
} [data not shown]
* SSLv3, TLS change cipher, Client hello (1):
} [data not shown]
* SSLv3, TLS handshake, Finished (20):
} [data not shown]
* SSLv3, TLS change cipher, Client hello (1):
{ [data not shown]
* SSLv3, TLS handshake, Finished (20):
{ [data not shown]
* SSL connection using ECDHE-ECDSA-AES128-GCM-SHA256
* Server certificate:
*        subject: C=US; ST=California; L=Mountain View; O=Google Inc; CN=*.google.com
*        start date: 2014-10-22 13:04:07 GMT
*        expire date: 2015-01-20 00:00:00 GMT
*        subjectAltName: google.com matched
*        issuer: C=US; O=Google Inc; CN=Google Internet Authority G2
*        SSL certificate verify ok.
> GET / HTTP/1.1
> User-Agent: curl/7.35.0
> Host: google.com
> Accept: */*
> 
< HTTP/1.1 302 Found
< Cache-Control: private
< Content-Type: text/html; charset=UTF-8
< Location: https://www.google.co.il/?gfe_rd=cr&ei=IkxbVMy4K4OBbKuDgKgF
< Content-Length: 260
< Date: Thu, 06 Nov 2014 10:23:30 GMT
* Server GFE/2.0 is not blacklisted
< Server: GFE/2.0
< 
{ [data not shown]
100   260  100   260    0     0    714      0 --:--:-- --:--:-- --:--:--   714
* Connection #0 to host google.com left intact

Run Code Online (Sandbox Code Playgroud)

我怀疑其curl检测到它在不打印到终端，并因此给出了不同的输出，而不是其全部通过公认的grep作为stdout和因此通过向终端传递。然而，我能找到的最接近的东西man curl （永远不要用谷歌搜索！）是这样的：

PROGRESS METER
   curl  normally  displays  a  progress meter during operations, indicating the amount of transferred data, transfer speeds and estimated time
   left, etc.

   curl displays this data to the terminal by default, so if you invoke curl to do an operation and it is about to write data to the  terminal,
   it disables the progress meter as otherwise it would mess up the output mixing progress meter and response data.

   If you want a progress meter for HTTP POST or PUT requests, you need to redirect the response output to a file, using shell redirect (>), -o
   [file] or similar.

   It is not the same case for FTP upload as that operation does not spit out any response data to the terminal.

   If you prefer a progress "bar" instead of the regular meter, -# is your friend.

Run Code Online (Sandbox Code Playgroud)

我怎样才能expiry从curl输出中取出一行？此外，我应该阅读什么才能更好地了解情况？

似乎这将是“stdmeta”文件描述符的一个很好的用例。

Answer 1

Ant*_*hon 133

curl 将输出写入 stderr，因此重定向它并抑制进度：

curl -v --silent https://google.com/ 2>&1 | grep expire

Run Code Online (Sandbox Code Playgroud)

curl将信息写入 stderr的原因是您可以这样做：
curl <url> | someprgram没有该信息破坏输入someprogram

不需要`-v`，您将通过管道传输大量文本..尤其是在多次重定向、SSL 握手和证书交换中！！您应该使用 `--include` 将标头添加到响应的正文中，或者最好使用 `--head`，此外，如果您打算存储值，最好在末尾删除 `\r`在变量中，甚至稍后将其发送到输出（请参阅我上面的“内容长度”示例评论） (3认同)
-v 做了冗长的技巧..谢谢 (2认同)

Answer 2

小智 24

可以--stderr -用作参数，将输出从 stderr（默认）重定向到 stdout。使用此选项，您还应该使用--silent来抑制进度条。

$ curl -v --silent https://google.com/ --stderr - | grep expire
*    expire date: 2015-09-01 00:00:00 GMT

Run Code Online (Sandbox Code Playgroud)

归档时间：	10 年，12 月前
查看次数：	198239 次
最近记录：	7 年前