If you regularly do command line JSON requests, I'm a big fan of HTTPie. It's so much easier to use correctly. https://httpie.io/docs/cli/examples

For example, here's a JSONy POST request with cURL:

curl -s -H "Content-Type: application/json" -X POST https://api.ctl.io/v2/authentication/login --data '{"username":"YOUR.USERNAME","password":"YOUR.PASSWORD"}'

Here's that same request with HTTPie:

http POST https://api.ctl.io/v2/authentication/login username=YOUR.USERNAME password=YOUR.PASSWORD