Make server port a command-line option.

example/socketio/server.js

@@ -1,3 +1,8 @@
+if (typeof process.argv[2] == 'undefined') {
+  console.error('Usage: node server <port>');
+  return;
+}
+
 var http = require('http');
 var url = require('url');
 var fs = require('fs');
@@ -29,7 +34,7 @@ socketioserver.sockets.on('connection', function(connection) {
   pub.connect('chat');
 });
 
-httpserver.listen(8080, '0.0.0.0');
+httpserver.listen(process.argv[2], '0.0.0.0');
 
 // ==== boring detail
 
@@ -42,7 +47,7 @@ function handler(req, res) {
     fs.readFile(__dirname + '/index.html', function(err, data){
       if (err) return send404(res);
       res.writeHead(200, {'Content-Type': 'text/html'});
-      res.write(data, 'utf8');
+      res.write(data.toString('utf8').replace('{{PORT}}', process.argv[2]), 'utf8');
       res.end();
     });
     break;