If you'll try to run curl
with --http2
flag with curl
shipped with macOS by default (as of macOS 10.12) you'll get the following error:
curl -I --http2 https://http2.akamai.com/
curl: (1) Unsupported protocol
To fix that you can reinstall curl
using brew with --with-nghttp2
flag and replace the standard curl
with newly installed:
brew install curl --with-nghttp2
brew link curl --force
and after you restart your terminal:
curl -I --http2 https://http2.akamai.com/
HTTP/2 200
server: Apache
...