bug

#!/usr/bin/ruby
#
# Batch URL generator
#
# Copyright 2012 Kareem Khazem
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 2.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

require 'optparse'

# Default options
options = {}
options[:base_url] = "http://www.google.co.uk/"
options[:lead_zeroes] = true
options[:start] = 0
options[:end]   = 9

# Get command line options
parser = OptionParser.new do |opts|
  prog_name = File.basename($PROGRAM_NAME)
  opts.banner = <<END_BANNER

Batch URL Generator
```````````````````
Usage: #{prog_name} [options]
END_BANNER
  opts.on("-u URL", "--base-url",
          "The non-changing part of the URL") do |url|
    options[:base_url] = url
  end
  opts.on("--[no-]lead-zeroes",
          "Whether the ID should be padded with 0s") do |lead|
    options[:lead_zeroes] = lead
  end
  opts.on("-s NUM", "--start-id",
          "The lowest ID number to generate") do |num|
    options[:start] = num.to_i
  end
  opts.on("-e NUM", "--end-id",
          "The highest ID number to generate") do |num|
    options[:end] = num.to_i
  end
end
parser.parse!

# generate urls
#
# find the length of the id. '-1' means that it will not be padded.
id_length = -1
if options[:lead_zeroes]
  high_string = options[:end].to_s
  length = high_string.length
end
for i in options[:start] .. options[:end] do
  url = sprintf "%s", options[:base_url]
  if options[:lead_zeroes]
    url += sprintf "%0#{length}d", i
  else
    url += sprintf "%d", i
  end
  puts url
end