This verbfile adds some basic logging and changes the dest directory to `book/`. (if you don't use a verbfile, verb-cli will just process templates in the `docs` directory by default.)

verbfile-with-logging.js

var file = require('fs-utils');

module.exports = function(verb) {
  verb.log.subhead('building', 'My Book');

  // Process templates
  file.writeFileSync('book/', verb.read('src/*.tmpl.md', {
    data: 'chapters/*.json' // custom metadata for templates
  }));

  verb.log.success('  Done');
};