Some time ago I came across this great command line tool to make http requests: HTTPie. Simple and intuitive API:

http PUT X-API-Token:123 name=Igor

this sends that PUT as JSON. To submit as form (application/x-www-form-urlencoded; charset=utf-8), just set the -f flag.

Now it took me some time to figure out how to send a raw string as body. It turns out you can just write to it’s stdin:

echo '{"name":"Igor"}' | http PUT

Nice API.