gistfile1.txt

function endsWith(str, suffix) {
  return str.indexOf(suffix, str.length - suffix.length) !== -1;
}
var fs = require('fs');
fs.readdir(process.env.PWD, function(err, files) {
  if(err) throw err;
  files.forEach(function(obj) {
    if(endsWith(obj, '.jar')) {
      fs.rename(process.env.PWD + obj, process.env.PWD + obj.substring(obj.length - 4) + process.env.BUILD_NUMBER + '.jar', function(err) {
        if(err) { throw err; }
      });
    }
  });
});