x.c

#include <stdio.h>                       
#include <unistd.h>                      
                                         
const int S2uS = 1000000;                
                                         
                                         
int                                      
main() {                                 
  for (int i = 0; i < 5; i++) {          
    fprintf(stdout, "HELLO - %d\r\n", i);
    usleep(1 * S2uS);                    
  }                                      
                                         
  return 0;                              
}

x.coffee

{ spawn } = require 'child_process'

child = spawn "./x"
child.stdout.pipe process.stdout

x.js

// Generated by CoffeeScript 1.4.0
var child, spawn;

spawn = require('child_process').spawn;

child = spawn("./x");

child.stdout.pipe(process.stdout);