Service bots

>>59772392
Do you mean using the API?

You're going to need to program for that, I believe there is a third party tool that could interface the programming for you but not sure on functionality.

And you could use websockets or streaming sockets with most modern languages.

Twitter you could probably do with Grease Monkey in Firefox.
I've made some cool stuff using Grease Monkey that's really hit Firefox hard (it doesn't like getting told to open a hundred tabs, perform string changes and submit them).

>>59772470
In particular, I wonder if there is a way to do so without using a browser, in an environment without GUI.

>>59772586
Yep I suggest twitter4j

Supports mostly everything, can link you an example I did if you want

>>59772392
Literally Google for what you want to read and write to, pick one of the libraries that confess up, and read their tutorial. It will be right in there.

Also, trivial.