desc "Stop agents from running background tasks"
  task :stop do
    if File.exist?( pidfile )
      pid = File.read( pidfile ).to_i
      if pid > 0
        puts "Stopping agents (process #{pid})."
        Process.kill('INT', pid.to_i ) rescue nil
      end
      `rm #{pidfile}`
    else
      puts "No agents are currently running."
    end
  end