First argument is the UNIX socket to listen on. The next arguments are the command to mask.
For instance, to launch a Minecraft server:
node anyconsole.js /tmp/minecraft java -jar minecraft_server.jar
Now, to access the stdin and out of the process, open a connection to the UNIX socket specified. For instance, using netcat wrapped in readline:
rlwrap nc -U /tmp/minecraft
(For accessing Minecraft servers that are wrapped in anyconsole, I've written lolmc as a front-end to this UNIX socket for Node.js scripts.)
The last 30 lines of output from the command will be shown immediately, and output from the process is line-buffered and sent to the UNIX socket clients on each newline. This is approximately equivalent to
stdbuf -oL java -jar minecraft_server.jar > minecraft.log 2>&1 tail -fn 30 minecraft.log
except, of course, that you have access to the stdin of the process as well.