Getting only response header from HTTP POST using cURL

One can request only the headers using HTTP HEAD, as option -I in curl(1).

$ curl -I / 

Lengthy HTML response bodies are a pain to get in command-line, so I'd like to get only the header as feedback for my POST requests. However, HEAD and POST are two different methods.

How do I get cURL to display only response headers to a POST request?

8 Answers

-D, --dump-header <file> Write the protocol headers to the specified file. This option is handy to use when you want to store the headers that a HTTP site sends to you. Cookies from the headers could then be read in a second curl invocation by using the -b, --cookie option! The -c, --cookie-jar option is however a better way to store cookies. 

and

-S, --show-error When used with -s, --silent, it makes curl show an error message if it fails. 

and

-L/--location (HTTP/HTTPS) If the server reports that the requested page has moved to a different location (indicated with a Location: header and a 3XX response code), this option will make curl redo the request on the new place. If used together with -i/--include or -I/--head, headers from all requested pages will be shown. When authentication is used, curl only sends its credentials to the initial host. If a redirect takes curl to a different host, it won’t be able to intercept the user+password. See also --location-trusted on how to change this. You can limit the amount of redirects to follow by using the --max-redirs option. When curl follows a redirect and the request is not a plain GET (for example POST or PUT), it will do the following request with a GET if the HTTP response was 301, 302, or 303. If the response code was any other 3xx code, curl will re-send the following request using the same unmodified method. 

from the man page. so

curl -sSL -D - -o /dev/null 

follows redirects, dumps the headers to stdout and sends the data to /dev/null (that's a GET, not a POST, but you can do the same thing with a POST - just add whatever option you're already using for POSTing data)

note the - after the -D which indicates that the output "file" is stdout.

The other answers require the response body to be downloaded. But there's a way to make a POST request that will only fetch the header:

curl -s -I -X POST 

An -I by itself performs a HEAD request which can be overridden by -X POST to perform a POST (or any other) request and still only get the header data.

The Following command displays extra informations

curl -X POST -v > /dev/null 

You can ask server to send just HEAD, instead of full response

curl -X HEAD -I 

Note: In some cases, server may send different headers for POST and HEAD. But in almost all cases headers are same.

For long response bodies (and various other similar situations), the solution I use is always to pipe to less, so

curl -i | less 

or

curl -s -D - | less 

will do the job.

Maybe it is little bit of an extreme, but I am using this super short version:

curl -svo. <URL> 

Explanation:

-v print debug information (which does include headers)

-o. send web page data (which we want to ignore) to a certain file, . in this case, which is a directory and is an invalid destination and makes the output to be ignored.

-s no progress bar, no error information (otherwise you would see Warning: Failed to create the file .: Is a directory)

warning: result always fails (in terms of error code, if reachable or not). Do not use in, say, conditional statements in shell scripting...

Much easier – this also follows links.

curl -IL 

While the other answers have not worked for me in all situations, the best solution I could find (working with POST as well), taken from here:

curl -vs ' 1> /dev/null

headcurl.cmd (windows version)

curl -sSkv -o NUL %* 2>&1 

• I don't want a progress bar -s,
• but I do want errors -S,
• not bothering about valid https certificates -k,
• getting high verbosity -v (this is about troubleshooting, is it?),
• no output (in a clean way).
• oh, and I want to forward stderr to stdout, so I can grep against the whole thing (since most or all output comes in stderr)
• %* means [pass on all parameters to this script] (well(), well usually that's just one parameter: the url you are testing

real-world example (on troubleshooting proxy issues):

C:\depot>headcurl google.ch | grep -i -e http -e cache 

Hostname was NOT found in DNS cache GET HTTP/1.1 HTTP/1.1 301 Moved Permanently Location: Cache-Control: public, max-age=2592000 X-Cache: HIT from company.somewhere.ch X-Cache-Lookup: HIT from company.somewhere.ch:1234 

Linux version

for your .bash_aliases / .bash_rc:

alias headcurl='curl -sSkv -o /dev/null $@ 2>&1'