host.rb

require 'net/ssh'

class Host
  def initialize(host, user, options={})
    @ssh = Net::SSH.start(host, user, options)
  end
  
  def close
    @ssh.close
  end
  
  def run_chef(chef_command="sudo chef-client")
    @ssh.exec! chef_command
  end
  
  def installed_packages
    @packages ||= @ssh.exec! 'dpkg --get-selections'
    @packages.split("\n").collect {|pkg| pkg.split(" ")[0] }
  end
  
  def users
    @users ||= @ssh.exec! 'cat /etc/passwd'
    @users.split("\n").collect {|u| u.split(":")[0] }
  end
end