c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
SPDX-License-Identifier: curl
Short: b
Long: cookie
Arg: <data|filename>
Protocols: HTTP
Help: Send cookies from string/file
Category: http
Example: -b cookiefile $URL
Example: -b cookiefile -c cookiefile $URL
See-also: cookie-jar junk-session-cookies
Added: 4.9
Multi: append
---
Pass the data to the HTTP server in the Cookie header. It is supposedly the
data previously received from the server in a "Set-Cookie:" line. The data
should be in the format "NAME1=VALUE1; NAME2=VALUE2". This makes curl use the
cookie header with this content explicitly in all outgoing request(s). If
multiple requests are done due to authentication, followed redirects or
similar, they will all get this cookie passed on.

If no '=' symbol is used in the argument, it is instead treated as a filename
to read previously stored cookie from. This option also activates the cookie
engine which will make curl record incoming cookies, which may be handy if
you are using this in combination with the --location option or do multiple URL
transfers on the same invoke. If the file name is exactly a minus ("-"), curl
will instead read the contents from stdin.

The file format of the file to read cookies from should be plain HTTP headers
(Set-Cookie style) or the Netscape/Mozilla cookie file format.

The file specified with --cookie is only used as input. No cookies will be
written to the file. To store cookies, use the --cookie-jar option.

If you use the Set-Cookie file format and do not specify a domain then the
cookie is not sent since the domain will never match. To address this, set a
domain in Set-Cookie line (doing that will include sub-domains) or preferably:
use the Netscape format.

Users often want to both read cookies from a file and write updated cookies
back to a file, so using both --cookie and --cookie-jar in the same command
line is common.
