Introduction cURL is one of the most powerful tool for testing HTTP requests and responses. Most developers use curl to interact with HTTP APIs or to test a website.
Starting from version 7.43.0 cURL (and libcurl) supports HTTP/2. You can perform a request using the HTTP/2 protocol passing the –http2 flag:
curl -I --http2 https://www.cloudflare.com/ HTTP/2.0 200 server:cloudflare-nginx date:Sun, 24 Jan 2016 21:53:48 GMT content-type:text/html set-cookie:__cfduid=d73309ac5d32f18d2ca9efb414cc0fd111453672428; expires=Mon, 23-Jan-17 21:53:48 GMT; path=/; domain=.