cidr.rb

require "ipaddr"

text = ARGF.read
cidrs = []
while (match = text.match(%r[(\d+\.\d+\.\d+\.\d+/\d+)]))
  cur = IPAddr.new(match[1])
  cur_addrs = cur.to_range.to_a
  cidrs.each do |cidr|
    puts "overlap: #{cur} x #{cidr}" if cur_addrs.any?{|cur_addr| cidr.to_range.cover?(cur_addr) }
  end
  cidrs << cur
  cidrs.uniq!
  text = match.post_match
end