-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.
і
-S, --show-error
When used with -s, --silent, it makes curl show an error message if it fails.
і
-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.
зі сторінки man. тому
curl -sSL -D - www.acooke.org -o /dev/null
слід переспрямувати, скидає заголовки до stdout та надсилає дані в / dev / null (це GET, а не POST, але ви можете зробити те ж саме з POST - просто додайте будь-який варіант, який ви вже використовуєте для POSTing даних)
зауважте -
після цього, -D
який вказує на те, що вихідний "файл" є stdout.
curl -s -D - http://yahoo.com -o nul