The default content-type for file uploads is application/octet-stream,
not text/plain as stated in the MANUAL.
If the content-type is not specified, curl will try to guess from the file
extension (it only knows a few), or use the previously specified type (from
an earlier file if several files are specified in a list) or else it will
- using the default type 'text/plain'.
+ use the default type 'application/octet-stream'.
Emulate a fill-in form with -F. Let's say you fill in three fields in a
form. One field is a file name which to post, one field is your name and one