Output hosts advertising ssh via Bonjour/MDNS

bonjour-ssh-hosts.rb

#!/usr/bin/env ruby

def host_name(line='')
  matches = /_ssh._tcp.\s*(.*)$/.match(line)
  matches[1] unless matches.nil? || matches[1].nil?# || !/ /.match(matches[1]).nil?
end

TIMEOUT_SEC = 1

read_results = Thread.new do
  Thread.current[:lines] = []
  discovery = IO.popen('dns-sd -B _ssh._tcp .')
  while line = discovery.readline do
    Thread.current[:lines] << host_name(line)
  end
end

# timer
timer = Thread.new { sleep TIMEOUT_SEC; read_results.kill; puts }

read_results.join
results = read_results[:lines].compact.map { |r| "#{r.gsub(' ', '\ ')}.local" }.uniq

puts results.join(" ")