copy and paste me when you need something like getopts in ruby.

getopts.rb

require 'optparse'

options = {}
optparse = OptionParser.new do |opts|
  opts.banner = "Usage: #{File.basename($0)} [options]"

  opts.on("-d", "--debug",
    "Enables some helpful debugging output."
  ) { |value| options[:debug] = true }

  opts.on("-f", "--file FILE",
    "The server.xml file you would like to load."
  ) { |value| options[:file] = value }

  opts.on("-o", "--old",
    "Generate using the old formatting."
  ) { |value| options[:old] = true }

  opts.on("-h", "--help", "Display this help message.") do
    puts opts
    exit
  end
end

begin
  optparse.parse!
rescue OptionParser::MissingArgument
  puts "You're missing an argument...\n\n"
  puts optparse
  exit
end