如何grep cURL的输出？

70

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

但是，当通过grep结果管道输出结果时，屏幕上显示的信息并不是更少，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

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，并非所有在此通过识别grep作为存在stdout和因此通过向终端传递。但是，我能找到的与此最接近的东西man curl （永远不要用谷歌搜索！）是：

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.

我怎样才能expiry使curl输出中的行呢？此外，我应该阅读什么才能更好地了解情况？

似乎对于“ stdmeta”文件描述符来说，这将是一个很好的用例。

bash  command-line  curl 
— 多坦科恩
source
@EladKarako：谢谢。这是一个很好的答案，但不适用于这种情况。也许Windows Shell没有单独的输出文件处理程序的概念，但这在Linux Shell中是不同的情况。
— dotancohen
1
我感到不得不对风和谷歌人的卷发小心谨慎。我敢肯定那一定会返回一些有价值的结果。
— JeremyCanfield

Answers:

105

curl将输出写入stderr，因此将其重定向并抑制进度：

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

curl将信息写入stderr 的原因是您可以这样做：在
curl <url> | someprgram没有该信息的情况下，someprogram

— 安通
source
2
-v做冗长的技巧..谢谢
— astroanu
2
不需要，-v您将通过管道传输大量文本。.特别是在多重重定向和SSL握手以及证书交换方面！！您应该--include只将标头添加到响应的正文中，或者最好使用--head，并且，\r如果打算将值存储在变量中，甚至以后再将其发送到输出，则最好在最后将其删除（请参阅上面带有Content-Length示例的评论）
19

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

$ curl -v --silent https://google.com/ --stderr - | grep expire
*    expire date: 2015-09-01 00:00:00 GMT
— 亚历山大大帝
source
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