Ruby ping scan

expanded.rb

finished = []
ips = []
range = 1..254

range.each do |i| 
  ip_address = "192.168.111.#{i}"
  Thread.new do
    `ping -q -c1 -W1 #{ip_address}`.split(/\n+/)[2].split(/,\s*/)[1].to_i > 0 and ips << ip_address
    finished << i
  end
end

until finished.count == range.count
  print "\r%#{(finished.count/range.count.to_f * 100).round}"
  sleep 0.1
end

print "\r          \r"
puts ips.sort do |a, b|
  a.split(?.)[-1].to_i <=> b.split(?.)[-1].to_i
end

one-liner.rb

finished = []; ips = []; range = 1..254; range.each { |i| ip_address = "192.168.111.#{i}"; Thread.new { `ping -q -c1 -W1 #{ip_address}`.split(/\n+/)[2].split(/,\s*/)[1].to_i > 0 and ips << ip_address; finished << i } }; until finished.count == range.count; print "\r%#{(finished.count/range.count.to_f * 100).round}"; sleep 0.1; end; print "\r          \r"; puts ips.sort { |a, b| a.split(?.)[-1].to_i <=> b.split(?.)[-1].to_i }

This was tested only on MRI Ruby 1.9.3-p194. You may need to tweak the timeout or counts, depending on the nature and quality of the network you're testing.