I had a bunch of jekyll posts written in textile with yaml frontmatter I needed to convert to markdown

jekyll-textile2markdown.rb

require 'preamble'
require 'pandoc-ruby'

Dir.glob('*.textile').each do |file|
  front = Preamble.load(file)
  converter = PandocRuby.new(front.content, from: :textile, to: :markdown)
  markdown = converter.convert
  new_file = Preamble.new(front.metadata, markdown)
  new_file.save(file.sub('textile', 'markdown'))
end