ARP for eth0:*

arp.rb

#!/usr/bin/env ruby

# ARPs for all the IPs aliased to this machine.

data = %x[ifconfig -a].split /\n\n/

data.each do |block|
  d = /(eth\d:\d+)\s+/.match(block)
  a = /inet addr:(\d+\.\d+\.\d+\.\d+)/.match(block)

  next if d.nil? or a.nil?

  device  = d[1]
  address = a[1]

  %x[arping -c 3 -I #{device} #{address}]
end