old_contents: """
      ydf/cli
      ~~~~~~~
  
      Defines the command-line interface.
  """
  
  import click
  import sys
  
  from ydf import templating, yaml_ext
  
  
  @click.command('ydf')
  @click.argument('yaml',
                  type=click.File('r'))
  @click.option('-t', '--template',
                type=str,
                default=templating.DEFAULT_TEMPLATE_NAME,
                help='Name of Jinja2 template used to build Dockerfile')
  @click.option('-s', '--search-path',
                type=click.Path(file_okay=False),
                default=templating.DEFAULT_TEMPLATE_PATH,
                help='File system paths to search for templates')
  @click.option('-o', '--output',
                type=click.File('w'),
                help='Dockerfile generated from translation',
                default=sys.stdout)
  def main(yaml, template, search_path, output):
      """
      YAML to Dockerfile
      """
      yaml = yaml_ext.load(yaml.read())
      env = templating.environ(search_path)
      rendered = env.get_template(template).render(templating.render_vars(yaml))
      output.write(rendered)
  
  
  if __name__ == '__main__':
      main()
  
new_contents: """
      ydf/cli
      ~~~~~~~
  
      Defines the command-line interface.
  """
  
  import click
  import sys
  
  from ydf import templating, yaml_ext
  
  
  @click.command('ydf')
  @click.argument('yaml',
                  type=click.File('r'))
  @click.option('-v', '--variables',
                type=click.Path(dir_okay=False),
                help='YAML file containing variables to be exposed to YAML file and template during rendering')
  @click.option('-t', '--template',
                type=str,
                default=templating.DEFAULT_TEMPLATE_NAME,
                help='Name of Jinja2 template used to build Dockerfile')
  @click.option('-s', '--search-path',
                type=click.Path(file_okay=False),
                default=templating.DEFAULT_TEMPLATE_PATH,
                help='File system paths to search for templates')
  @click.option('-o', '--output',
                type=click.File('w'),
                help='Dockerfile generated from translation',
                default=sys.stdout)
  def main(yaml, variables, template, search_path, output):
      """
      YAML to Dockerfile
      """
      yaml = yaml_ext.load(yaml.read())
      env = templating.environ(search_path)
      rendered = env.get_template(template).render(templating.render_vars(yaml))
      output.write(rendered)
  
  
  if __name__ == '__main__':
      main()
  
subject: Add -v/--variables CLI option.