Help: Specify multipart MIME data
Protocols: HTTP SMTP IMAP
Mutexed: data head upload-file
For HTTP protocol family, this lets curl emulate a filled-in form in which a
user has pressed the submit button. This causes curl to POST data using the
Content-Type multipart/form-data according to RFC 2388.
For SMTP and IMAP protocols, this is the mean to compose a multipart mail
message to transmit.
This enables uploading of binary files etc. To force the 'content' part to be
a file, prefix the file name with an @ sign. To just get the content part from
a file, prefix the file name with the symbol <. The difference between @ and <
is then that @ makes a file get attached in the post as a file upload, while
the < makes a text field and just get the contents for that text field from a
Tell curl to read content from stdin instead of a file by using - as
filename. This goes for both @ and < constructs. When stdin is used, the
contents is buffered in memory first by curl to determine its size and allow a
possible resend. Defining a part's data from a named non-regular file (such
as a named pipe or similar) is unfortunately not subject to buffering and will
be effectively read at transmission time; since the full size is unknown
before the transfer starts, such data is sent as chunks by HTTP and rejected
Example: send an image to an HTTP server, where \&'profile' is the name of the
form-field to which the file portrait.jpg will be the input:
curl -F email@example.com https://example.com/upload.cgi
Example: send a your name and shoe size in two text fields to the server:
curl -F name=John -F shoesize=11 https://example.com/
Example: send a your essay in a text field to the server. Send it as a plain
text field, but get the contents for it from a local file:
curl -F "story=<hugefile.txt" https://example.com/
You can also tell curl what Content-Type to use by using 'type=', in a manner
curl -F "firstname.lastname@example.org;type=text/html" example.com
curl -F "name=daniel;type=text/foo" example.com
You can also explicitly change the name field of a file upload part by setting
filename=, like this:
curl -F "file=@localfile;filename=nameinpost" example.com
If filename/path contains ',' or ';', it must be quoted by double-quotes like:
curl -F "file=@\\"localfile\\";filename=\\"nameinpost\\"" example.com
curl -F 'file=@"localfile";filename="nameinpost"' example.com
Note that if a filename/path is quoted by double-quotes, any double-quote
or backslash within the filename must be escaped by backslash.
Quoting must also be applied to non-file data if it contains semicolons,
leading/trailing spaces or leading double quotes:
curl -F 'colors="red; green; blue";type=text/x-myapp' example.com
You can add custom headers to the field by setting headers=, like
curl -F "submit=OK;headers=\\"X-submit-type: OK\\"" example.com
curl -F "submit=OK;headers=@headerfile" example.com
The headers= keyword may appear more that once and above notes about quoting
apply. When headers are read from a file, Empty lines and lines starting
with '#' are comments and ignored; each header can be folded by splitting
between two words and starting the continuation line with a space; embedded
carriage-returns and trailing spaces are stripped.
Here is an example of a header file contents:
# This file contain two headers.
X-header-1: this is a header
# The following header is folded.
X-header-2: this is
To support sending multipart mail messages, the syntax is extended as follows:
- name can be omitted: the equal sign is the first character of the argument,
- if data starts with '(', this signals to start a new multipart: it can be
followed by a content type specification.
- a multipart can be terminated with a '=)' argument.
Example: the following command sends an SMTP mime e-mail consisting in an
inline part in two alternative formats: plain text and HTML. It attaches a
curl -F '=(;type=multipart/alternative' \\
-F '=plain text message' \\
-F '= <body>HTML message</body>;type=text/html' \\
-F '=)' -F '=@textfile.txt' ... smtp://example.com
Data can be encoded for transfer using encoder=. Available encodings are
\fIbinary\fP and \fI8bit\fP that do nothing else than adding the corresponding
Content-Transfer-Encoding header, \fI7bit\fP that only rejects 8-bit characters
with a transfer error, \fIquoted-printable\fP and \fIbase64\fP that encodes
data according to the corresponding schemes, limiting lines length to
Example: send multipart mail with a quoted-printable text message and a
base64 attached file:
curl -F '=text message;encoder=quoted-printable' \\
-F '=@localfile;encoder=base64' ... smtp://example.com
See further examples and details in the MANUAL.
This option can be used multiple times.