Interprocess communication with a Daemon

Question

I want to implement a Unix daemon (let\'s call it myUnixd), and want the user to be able to interact with this daemon via the command line, for example:

Answer 1

One could also use Remote Procedure Call (RPC) for such client-server communication. There are different types of messages (protocols) that can be used together with it, one of them is JSON.

The JSON-RPC protocol is very well accepted for such tasks. You can find different tools and libraries to embed in your software. A quick search on google gives this C library. The advantage of such libraries is that from a JSON specification file, where you define all your remote function calls, it creates client and/or server stubs that you can just use in your code out of the box.

As a listener one can use sockets, as the other responses state, or just an embedded HTTP server like microhttpd (and libcurl for the client). There are plenty of examples out there to just reuse. HTTP allows you also to run your client behind a proxy.