require 'optparse' class Parser # attr_accessor attr_reader :options def initialize @options = {:tag1 => nil, :tag2 => nil} parser = OptionParser.new { |opts| opts.banner = 'Usage: changelog_generator.rb [tag1 tag2] [options]' opts.on('-h', '--help', 'Displays Help') do puts opts exit end opts.on('-v', '--[no-]verbose', 'Run verbosely') do |v| @options[:verbose] = v end } parser.parse! #udefined case with 1 parameter: if ARGV[0] && !ARGV[1] puts parser.banner exit end if ARGV[1] @options[:tag1] = ARGV[0] @options[:tag2] = ARGV[1] end end end