code: function exec (command, options) {
    let start
    let end
    const lang = options.hash && options.hash.lang
    switch (lang) {
      case 'raw':
        start = end = ''
        break
      case 'inline':
        start = end = '`'
        break
      default:
        const fenceLanguage = lang || ''
        start = '```' + fenceLanguage + '\n'
        end = '\n```'
    }
    const output = cp.execSync(command, {
      encoding: 'utf8',
      cwd: options.hash && options.hash.cwd
    })
    return start + output.trim() + end
  }
docs: Execute a command and include the output in a fenced code-block.
  
  @param {string} command the command, passed to `child-process#execSync()`
  @param {object} options optional arguments and Handlebars internal args.
  @param {string} options.hash.lang the language tag that should be attached to the fence
  (like `js` or `bash`). If this is set to `raw`, the output is included as-is, without fences.
  @param {string} options.hash.cwd the current working directory of the example process
  @returns {string} the output of `execSync`, enclosed in fences.
  @access public
  @memberOf helpers