The code that replaces
    tag: a b c d b
with
    tag: [[a => a]] [[b => b]] [[c => c]] [[d => d]]
could be written

  new_content << 'tag:'
  line.split[1..-1].uniq.each { | tag | new_content << " [[#{tag} => #{tag}]]" }

Jim
-- 
Jim Menard, jim.menard / gmail.com, jimm / io.com
http://www.io.com/~jimm