code: function printUsage() {
  	console.log('A little command-line helper to convert from format to another');
  	console.log('\nUsage: node converter.js <operation> <source> <destination>\n');
  	console.log('where <operation> is one of:');
  	_.keys(operations).forEach(function(operationName) {
  		console.log('        ' + operationName);
  	});
  	console.log('\n      <source> is the source file');
  	console.log('\n      <destination> is the destination file');
  
  }
docs: CLI