`chmod +x` then just `./build.js compress` and you're off

build.js

#!/usr/local/bin/node

var minify = require('uglify-js').minify;
var fs = require('fs');

var tasks = {
  //tasks go here. here's an example Uglify:
  compress: function() {
    var minified = minify('input.js');
    fs.writeFile('example.js', minified.code, function(err) {
      if (err) throw err;
      console.log('Minified example.js');
      runNextTask(); //as long as the task calls runNextTask() at the end, chaining works
    });
  },
};

var commands = process.argv.slice(2);

function runNextTask() {
  var task = commands.shift();
  if (typeof(task) !== 'undefined') {
    tasks[task]();
  }
}

runNextTask();