spawn.js

var sys   = require('sys'),
    spawn  = require('child_process').spawn,
    http  = require('http');

http.createServer(function (request, response) {
  response.writeHead(200, {'Content-Type': 'text/plain'});
  var cat = spawn('tail', ['-f', '/var/log/system.log']);
  cat.stdout.on('data', function(data) {
    response.write(data);    
  });
}).listen(8124);