compare.rb

require 'pathname'

directories = Pathname.name('.').children.select(&:directory?)

file_paths = {}

directories.each do |directory|
  directory.children.each do |file_path|
    basename = file_path.basename
    file_paths[basename] ||= []
    file_paths[basename] << file_path
  end
end

file_paths.each do |basename, file_paths|
  next if file_paths.size <= 1

  puts "Duplicate #{basename}: #{file_paths.join(', ')}"
end