Unified diff of strings in Ruby (Two nmap scans)

unified-diff.rb

require 'rubygems'
require 'diff/lcs'
require 'diff/lcs/string'
require 'diff/lcs/hunk'

scan = [
  %x[nmap -nsP -oG - 192.168.1.0/24].split(/\n/).map! { |e| e.chomp },
  %x[nmap -nsP -oG - 192.168.1.0/24].split(/\n/).map! { |e| e.chomp }
]

output = ''
oldhunk = hunk = nil
len = 0

diffs = Diff::LCS.diff scan[0], scan[1]
diffs.each do |diff|
  begin
    hunk = Diff::LCS::Hunk.new(scan[0], scan[1], diff, 1, len)
    len = hunk.file_length_difference
    next unless oldhunk
    
    if hunk.overlaps?(oldhunk) then
      hunk.unshift(oldhunk)
    else
      output << oldhunk.diff(:unified)
    end
  ensure
    oldhunk = hunk
    output << "\n"
  end
end

output << oldhunk.diff(:unified)
output << "\n"
puts output