From a CLI you run into issues with `nc` and the like supporting https. You can get close with `curl` since it has a -H option that allows you to provide headers in a file.

    curl -v -H @request1.txt neverssl.com

With a request1.txt header file

    X-Header: mine
    User-Agent: bob

Will generate a request of

    > GET / HTTP/1.1
    > Host: neverssl.com
    > Accept: */*
    > X-Header: mine
    > User-Agent: bob

You end up needing to know 3 options. -X <METHOD> to specify the HTTP method, -d @<file> if you want to send a request body, and -H.