how to designate the port no. in the server?

[luckypoem]

hi.

root@AR:~/node-http-tunnel# ./server events.js:160 throw er; // Unhandled 'error' event ^

Error: listen EADDRINUSE :::80 at Object.exports._errnoException (util.js:896:11) at exports._exceptionWithHostPort (util.js:919:20) at Server._listen2 (net.js:1246:14) at listen (net.js:1282:10) at Server.listen (net.js:1378:5) at t.listen (/root/node-http-tunnel/lib/request_tunnel.js:221:18) at Object. (/root/node-http-tunnel/server:19:3) at Module._compile (module.js:541:32) at Object.Module._extensions..js (module.js:550:10) at Module.load (module.js:456:32) root@AR:~/node-http-tunnel#

in my server,port 80 is occupied,how to designate the port no. for the server binary?