Detailed package info for CentOS 5.6

packages.rb

require 'rubygems'
require 'nokogiri'
require 'open-uri'

@xml = Nokogiri open 'http://vault.centos.org/5.6/os/x86_64/repodata/comps.xml'

def printGroups(default = true)
  puts "=== #{'Non' unless default}Default Groups ==="
  @xml.xpath("//default[text()='#{default}']/..").each_with_index do |group, ix|
    puts "#{ix + 1}.) #{group.at_xpath('name').text}"
    
    printPackages group, 'mandatory'
    printPackages group, 'default'
    printPackages group, 'optional'
  end
end

def printPackages(group, type)
  puts "    * #{type} packages *"
  group.xpath(".//packagereq[@type='#{type}']").to_a.sort_by!(&:text).each do |req|
    puts "      - #{req.text}"
  end
end

printGroups
# printGroups(false)