🌏 Rewrite "greppable" output generated by the `nmap` argument `-oG`

parse-nmap-grep.rb

#!/usr/bin/env ruby
# coding: utf-8
#
# Parse nmap grepable output and display host IP address with open port numbers on each line
#
# Written By:   Derek Callaway [derek.callaway (AT) ioactive {D0T} com]
# ProductName:  Mac OS X 10.13.2 17C88
# Last Updated: Sat Dec 23 15:49:49 PST 2017
#


if ARGV.size < 1
  STDERR.puts("usage: #{$0} FILE")
  STDERR.puts
  STDERR.puts('  FILE  path to file containing NMap grepable output created by nmap(1) -oG')
  STDERR.puts
end

lines = File.readlines(ARGV.first)

lines.each do |l|
  next if !l.include?('/open')

  a = l.split
  h = a[1]
  f = true

  a.each do |b|
    c = b.split(',')

    c.each do |d|
      if d =~ %r{^[0-9]} and d.include?('/') 
        e = d.split('/')
 
        if e[1].eql?('open')
          if f
            print h
            print ' '
            
            f = false
          end

          print e.first
          print ' '
        end
      end
    end
  end

  puts if !f
end

exit 0