1. You need the Pharen language installed.
2. A simple TCP client, netcat on Linux (nc) works great

Compile Reph with:

$ pharen reph.phn

Start the server:

$ php reph.php
Initializing Reph server on 127.0.0.1:10000

Note that this uses .php

Connect to the server with your client and hack away!

$ nc localhost 10000
Initialized Pharen REPL. (map) new worlds!
pharen> (map (* 2) [1 2 3])
[2, 4, 6]
pharen>