underlines.rb

#!/usr/bin/ruby

=begin
Uses MultiMarkdown (must be installed at /usr/local/bin/multimarkdown) to render input, 
then converts `{{text}}` to `<u>text</u>`, providing underlines in the HTML output.
=end

input=STDIN.read

def e_sh(str)
	str.to_s.gsub(/(?=["\\])/, '\\')
end

puts %x{echo "#{e_sh input}"|/usr/local/bin/multimarkdown}.gsub(/\{\{/,"<u>").gsub(/\}\}/,"</u>")