Password Generator written in Ruby

pass

#!/usr/bin/env ruby

num = 12
num_times = 1

if ARGV[0]
  num_times = ARGV[0].to_i
end

if ARGV[1]
  num = ARGV[1].to_i
end

list = ('a'..'z').to_a + ('A'..'Z').to_a + ('1'..'9').to_a
list.delete_if{|s| ['l','o','I','O','1'].include? s }

num_times.times{
  begin
    pass = ''
    num.times{
      rand_num = rand(list.size)
      pass += "#{list[rand_num]}"
  }
  end until pass =~ /\d/
  puts pass
}