Command line tool to render a mustache template with a json context file

mustache.js

#!/usr/bin/env node

var 
  mu = require('Mu'),
  fs = require('fs');

var 
  usage = ''
    + '\n'
    + ' Usage: mustache.js [context] [template]\n'
    + '\n'
    + ' Arguments:\n'
    + '   context     context file in json format\n'
    + '   template    template file\n'
    ;

// verify arguments exist before continuing
if(!process.argv[2] || !process.argv[3]) {
  console.log(usage);
  process.exit(0);
}

var
  contextFileName = process.argv[2],
  templateFileName = process.argv[3],
  context = {};
  template = "",
  partials = {},
  compiled = {};

// read the template context from a json file
fs.readFile(contextFileName, 'ascii', function(err, buffer) {

  if(err) {
    console.error("Error reading from context file: "+contextFileName);
    console.error(err.stack);
    process.exit(1);
  }
  
  context = JSON.parse(buffer);

  // read the mustache template from a file
  fs.readFile(templateFileName, 'ascii', function(err, buffer) {
    
    if(err) {
      console.error("Error reading from template file: "+templateFileName);
      console.error(err.stack);
      process.exit(1);
    }

    template = buffer;

    // compile the template 
    compiled = mu.compileText(template, partials);

    // write the rendered template to stdout
    compiled(context).addListener('data', function( results  ) { 
      process.stdout.write(results);
    });

  });

});