what i am trying to do is not a multi chat is 2 ppl that talks each other 1 server 1 client

That makes no difference, you just have the first client become the server (in the absence of a server), I'll leave you to figure out why that complicates matters.

if u can explain how to do it ...

You'll be very unlikely to find a more detailed explanation of a line-oriented select-based chat client/server than that. I'm certainly not going to post a complete code example for you... you'll learn exactly nothing.

and not what with.

If you don't know where to start, you'll get nowhere.

-David