A very important global object is process. process represent the current running node program.
console is also a global object. console.log is the most common method to print debug code. This is similar to System.out.println() in java
Demo for globals using console.log
var util = require( 'util' );
console.log( 'Version: ' + process.version );
console.log( 'Prefix: ' + process.installPrefix );
console.log( 'This process is pid ' + process.pid );
console.log( 'This platform is ' + process.platform);
console.log( util.inspect( process.memoryUsage()));
console.log( __filename );
console.log( __dirname );