Error: Curl with Elasticsearch 6

I'm trying to do

curl -X PUT -d @'/home/cuckoo/.cuckoo/elasticsearch/template.json' 'http://localhost:9200/_template/cuckoo'

but, I have this error:

{"error":"Content-Type header [application/x-www-form-urlencoded] is not supported","status":406}

Can you help me, please.

Regards
EBO

I think you need to include this in your curl https://www.elastic.co/guide/en/elasticsearch/reference/6.3/common-options.html#_content_type_requirements

Thanks for your answer; but, what would be the correct way to include it?

Any idea?

A lot of the examples in the docs allow you to copy them as valid curl commands, so you could look there.