When we have an ACS Server up and running we also need a tool that can be used to make HTTP requests to the server. The ReST API is accessed via HTTP and returns responses in JSON. We could use a Web Browser for all API calls that require HTTP GET, but lots of API calls will need a client that can execute HTTP POST and HTTP PUT operations.
So it is best to start working with a tool that can make HTTP GET, POST, and PUT calls.
One such tool is cURL and it is commonly available on most Linux based systems. Check if you have it by doing:
$ curl curl: try 'curl --help' or 'curl --manual' for more information
If you don’t have curl installed you can find it here: https://curl.haxx.se/