curl websocket

curl.sh

curl --include \
     --no-buffer \
     --header "Connection: Upgrade" \
     --header "Upgrade: websocket" \
     --header "Host: example.com:80" \
     --header "Origin: http://example.com:80" \
     --header "Sec-WebSocket-Key: SGVsbG8sIHdvcmxkIQ==" \
     --header "Sec-WebSocket-Version: 13" \
     http://example.com:80/

The purpose of the key, the one supplied here should work.
The pourpose of that header is to prevent caching of websocket requests.

See https://en.wikipedia.org/wiki/WebSocket#Protocol_handshake