ポートスキャンするスクリプトをRubyで書くとこんな感じ

gistfile1.txt

// install net-ping
gem install net-ping


// script
#!/usr/local/bin/ruby
require 'rubygems'
require 'net/ping'

def portscan(ip = IPAddr.new('127.0.0.1'), ports = 1..65536)
  ports.each { |p|
    ping_tcp = Net::Ping::TCP.new(ip, p)
    puts "#{ip} \t[#{p}]" if ping_tcp.ping?
  }
end


# -----------------------------------
# main
# -----------------------------------
@input_file = ARGV[0] || "./pinglist.txt"
@ports = [
  'http',
  'https',
  'ssh',
  'ftp',
  'telnet',
  3389  #RDP
]

File::open( @input_file ) { |f|
  f.each { |line|
    portscan(line.chomp, @ports)
    puts "-------------------------------"
  }
}


// etc

for i in 1..254
  portscan("192.168.0.#{i}", 1..65536)
end