How to display request headers with command line curl

671

votes

Command line curl can display response header by using -D option, but I want to see what request header it is sending. How can I do that?

curl

curl --head http://google.com will do the same as the -I flag :) – Abel Terefe

Note on using --head/-I: not all servers respond exactly the same to HEAD requests (for example, Content-Encoding would be missing if you were attempting to verify that the body would be gzipped) and not all servers support HEAD. -v is usually the safer choice. – cfeduke

possible duplicate of How can I see the request headers made by curl when sending a request to the server? – Jeremy Logan

836

votes

curl's -v or --verbose option shows the HTTP request headers, among other things. Here is some sample output:

$ curl -v http://google.com/
* About to connect() to google.com port 80 (#0)
*   Trying 66.102.7.104... connected
* Connected to google.com (66.102.7.104) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.16.4 (i386-apple-darwin9.0) libcurl/7.16.4 OpenSSL/0.9.7l zlib/1.2.3
> Host: google.com
> Accept: */*
> 
< HTTP/1.1 301 Moved Permanently
< Location: http://www.google.com/
< Content-Type: text/html; charset=UTF-8
< Date: Thu, 15 Jul 2010 06:06:52 GMT
< Expires: Sat, 14 Aug 2010 06:06:52 GMT
< Cache-Control: public, max-age=2592000
< Server: gws
< Content-Length: 219
< X-XSS-Protection: 1; mode=block
< 
<HTML><HEAD><meta http-equiv="content-type" content="text/html;charset=utf-8">
<TITLE>301 Moved</TITLE></HEAD><BODY>
<H1>301 Moved</H1>
The document has moved
<A HREF="http://www.google.com/">here</A>.
</BODY></HTML>
* Connection #0 to host google.com left intact
* Closing connection #0

311

votes

A popular answer for displaying response headers, but OP asked about request headers.

curl -s -D - -o /dev/null http://example.com

-s : Avoid showing progress bar
-D - : Dump headers to a file, but - sends it to stdout
-o /dev/null : Ignore response body

This is better than -I as it doesn't send a HEAD request, which can produce different results.

It's better than -v because you don't need so many hacks to un-verbose it.

111

votes

I believe the command line switch you are looking for to pass to curl is -I.

Example usage:

$ curl -I http://heatmiser.counterhack.com/zone-5-15614E3A-CEA7-4A28-A85A-D688CC418287  
HTTP/1.1 301 Moved Permanently
Date: Sat, 29 Dec 2012 15:22:05 GMT
Server: Apache
Location: http://heatmiser.counterhack.com/zone-5-15614E3A-CEA7-4A28-A85A-D688CC418287/
Content-Type: text/html; charset=iso-8859-1

Additionally, if you encounter a response HTTP status code of 301, you might like to also pass a -L argument switch to tell curl to follow URL redirects, and, in this case, print the headers of all pages (including the URL redirects), illustrated below:

$ curl -I -L http://heatmiser.counterhack.com/zone-5-15614E3A-CEA7-4A28-A85A-D688CC418287
HTTP/1.1 301 Moved Permanently
Date: Sat, 29 Dec 2012 15:22:13 GMT
Server: Apache
Location: http://heatmiser.counterhack.com/zone-5-15614E3A-CEA7-4A28-A85A-D688CC418287/
Content-Type: text/html; charset=iso-8859-1

HTTP/1.1 302 Found
Date: Sat, 29 Dec 2012 15:22:13 GMT
Server: Apache
Set-Cookie: UID=b8c37e33defde51cf91e1e03e51657da
Location: noaccess.php
Content-Type: text/html

HTTP/1.1 200 OK
Date: Sat, 29 Dec 2012 15:22:13 GMT
Server: Apache
Content-Type: text/html

86

votes

The verbose option is handy, but if you want to see everything that curl does (including the HTTP body that is transmitted, and not just the headers), I suggest using one of the below options:

--trace-ascii - # stdout
--trace-ascii output_file.txt # file

64

votes

You get a nice header output with the following command:

 curl -L -v -s -o /dev/null google.de

-L, --location follow redirects
-v, --verbose more output, indicates the direction
-s, --silent don't show a progress bar
-o, --output /dev/null don't show received body

Or the shorter version:

 curl -Lvso /dev/null google.de

Results in:

* Rebuilt URL to: google.de/
*   Trying 2a00:1450:4008:802::2003...
* Connected to google.de (2a00:1450:4008:802::2003) port 80 (#0)
> GET / HTTP/1.1
> Host: google.de
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 301 Moved Permanently
< Location: http://www.google.de/
< Content-Type: text/html; charset=UTF-8
< Date: Fri, 12 Aug 2016 15:45:36 GMT
< Expires: Sun, 11 Sep 2016 15:45:36 GMT
< Cache-Control: public, max-age=2592000
< Server: gws
< Content-Length: 218
< X-XSS-Protection: 1; mode=block
< X-Frame-Options: SAMEORIGIN
<
* Ignoring the response-body
{ [218 bytes data]
* Connection #0 to host google.de left intact
* Issue another request to this URL: 'http://www.google.de/'
*   Trying 2a00:1450:4008:800::2003...
* Connected to www.google.de (2a00:1450:4008:800::2003) port 80 (#1)
> GET / HTTP/1.1
> Host: www.google.de
> User-Agent: curl/7.43.0
> Accept: */*
>
< HTTP/1.1 200 OK
< Date: Fri, 12 Aug 2016 15:45:36 GMT
< Expires: -1
< Cache-Control: private, max-age=0
< Content-Type: text/html; charset=ISO-8859-1
< 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=84=Z0WT_INFoDbf_0FIe_uHqzL9mf3DMSQs0mHyTEDAQOGY2sOrQaKVgN2domEw8frXvo4I3x3QVLqCH340HME3t1-6gNu8R-ArecuaneSURXNxSXYMhW2kBIE8Duty-_w7; expires=Sat, 11-Feb-2017 15:45:36 GMT; path=/; domain=.google.de; HttpOnly
< Accept-Ranges: none
< Vary: Accept-Encoding
< Transfer-Encoding: chunked
<
{ [11080 bytes data]
* Connection #1 to host www.google.de left intact

As you can see curl outputs both the outgoing and the incoming headers and skips the bodydata althought telling you how big the body is.

Additionally for every line the direction is indicated so that it is easy to read. I found it particular useful to trace down long chains of redirects.

15

votes

A command like the one below will show three sections: request headers, response headers and data (separated by CRLF). It avoids technical information and syntactical noise added by curl.

curl -vs www.stackoverflow.com 2>&1 | sed '/^* /d; /bytes data]$/d; s/> //; s/< //'

The command will produce the following output:

GET / HTTP/1.1
Host: www.stackoverflow.com
User-Agent: curl/7.54.0
Accept: */*

HTTP/1.1 301 Moved Permanently
Content-Type: text/html; charset=UTF-8
Location: https://stackoverflow.com/
Content-Length: 149
Accept-Ranges: bytes
Date: Wed, 16 Jan 2019 20:28:56 GMT
Via: 1.1 varnish
Connection: keep-alive
X-Served-By: cache-bma1622-BMA
X-Cache: MISS
X-Cache-Hits: 0
X-Timer: S1547670537.588756,VS0,VE105
Vary: Fastly-SSL
X-DNS-Prefetch-Control: off
Set-Cookie: prov=e4b211f7-ae13-dad3-9720-167742a5dff8; domain=.stackoverflow.com; expires=Fri, 01-Jan-2055 00:00:00 GMT; path=/; HttpOnly

<head><title>Document Moved</title></head>
<body><h1>Object Moved</h1>This document may be found <a HREF="https://stackoverflow.com/">here</a></body>

Description:

-vs - add headers (-v) but remove progress bar (-s)
2>&1 - combine stdout and stderr into single stdout
sed - edit response produced by curl using the commands below
/^* /d - remove lines starting with '* ' (technical info)
/bytes data]$/d - remove lines ending with 'bytes data]' (technical info)
s/> // - remove '> ' prefix
s/< // - remove '< ' prefix

9

votes

I had to overcome this problem myself, when debugging web applications. -v is great, but a little too verbose for my tastes. This is the (bash-only) solution I came up with:

curl -v http://example.com/ 2> >(sed '/^*/d')

This works because the output from -v is sent to stderr, not stdout. By redirecting this to a subshell, we can sed it to remove lines that start with *. Since the real output does not pass through the subshell, it is not affected. Using a subshell is a little heavy-handed, but it's the easiest way to redirect stderr to another command. (As I noted, I'm only using this for testing, so it works fine for me.)

5

votes

the -v option for curl is too verbose in the error output which contains the leading *(status line) or >(request head field) or <(response head field). to get only the request head field:

curl -v -sS www.stackoverflow.com 2>&1 >/dev/null | grep '>' | cut -c1-2 --complement

to get only the request head field:

curl -v -sS www.stackoverflow.com 2>&1 >/dev/null | grep '<' | cut -c1-2 --complement

or to dump it into /tmp/test.txt file with the -D option

curl -D /tmp/test.txt -sS www.stackoverflow.com > /dev/null

in order to filter the -v output, you should direct the error output to terminal and the std output to /dev/null, the -s option is to forbid the progress metering

3

votes

If you want more alternatives, You can try installing a Modern command line HTTP client like httpie which is available for most of the Operating Systems with package managers like brew, apt-get, pip, yum etc

eg:- For OSX

brew install httpie

Then you can use it on command line with various options

http GET https://www.google.com

How to display request headers with command line curl

9 Answers