1 Long: header
2 Short: H
3 Arg: <header/@file>
4 Help: Pass custom header(s) to server
5 Protocols: HTTP
6 Category: http
7 ---
8 Extra header to include in the request when sending HTTP to a server. You may
9 specify any number of extra headers. Note that if you should add a custom
10 header that has the same name as one of the internal ones curl would use, your
11 externally set header will be used instead of the internal one. This allows
12 you to make even trickier stuff than curl would normally do. You should not
13 replace internally set headers without knowing perfectly well what you're
14 doing. Remove an internal header by giving a replacement without content on
15 the right side of the colon, as in: -H \&"Host:". If you send the custom
16 header with no-value then its header must be terminated with a semicolon, such
17 as \-H \&"X-Custom-Header;" to send "X-Custom-Header:".
18 
19 curl will make sure that each header you add/replace is sent with the proper
20 end-of-line marker, you should thus \fBnot\fP add that as a part of the header
21 content: do not add newlines or carriage returns, they will only mess things up
22 for you.
23 
24 Starting in 7.55.0, this option can take an argument in @filename style, which
25 then adds a header for each line in the input file. Using @- will make curl
26 read the header file from stdin.
27 
28 See also the --user-agent and --referer options.
29 
30 Starting in 7.37.0, you need --proxy-header to send custom headers intended
31 for a proxy.
32 
33 Example:
34 
35  curl -H "X-First-Name: Joe" http://example.com/
36 
37 \fBWARNING\fP: headers set with this option will be set in all requests - even
38 after redirects are followed, like when told with --location. This can lead to
39 the header being sent to other hosts than the original host, so sensitive
40 headers should be used with caution combined with following redirects.
41 
42 This option can be used multiple times to add/replace/remove multiple headers.
43