Makes the fetching more verbose/talkative. Mostly useful for debugging. A line starting with '>'
means "header data" sent by curl, '<' means "header data" received by curl that is hidden in
normal cases, and a line starting with '*' means additional info provided by curl.
-H, --header <header>
(HTTP) Extra header to use when getting a web page. You may specify any number of extra headers.
Note that if you should add a custom header that has the same name as one of the internal ones
curl would use, your externally set header will be used instead of the internal one. This allows
you to make even trickier stuff than curl would normally do. You should not replace internally set
headers without knowing perfectly well what you're doing. Remove an internal header by giving a
replacement without content on the right side of the colon, as in: -H "Host:".
curl will make sure that each header you add/replace is sent with the proper end-of-line marker,
you should thus not add that as a part of the header content: do not add newlines or carriage
returns, they will only mess things up for you.
See also the -A, --user-agent and -e, --referer options.
This option can be used multiple times to add/replace/remove multiple headers.