convert between timezones

timeconverter.rb

#!/usr/bin/env ruby -w
# input may be given as "2:00 PM"  or "14:00"
# timeconverter.rb "2:00 PM" "5:00 PM"
# timeconverter.rb --from="America/Denver" "2:00 PM"
# http://tzinfo.rubyforge.org/doc/files/README.html
require 'rubygems'
require 'tzinfo'
require 'time'
require 'choice'


module Choice
  def get_unparsed_args(args)
    flat=Choice.choices.to_a.flatten
    args.delete_if { |a| a[0].chr == '-' || a[0,1] == '--' || flat.include?(a) }
    args
  end
end

PROGRAM_VERSION = 0.1

Choice.options do
  header ''
  header 'Specific options:'

  #option :from, :required => true do
  option :from do
    short '-f'
    long '--from=timezone'
    desc 'The timezone of the time you are giving as argument. Default America/New_York'
    default 'America/New_York'
  end
  ## Added since this lib does not ARGV.shift
  #option :time, :required => true do
  option :time do
    short '-t'
    long '--time=time'
    desc 'The time of the place, to be converted. e.g. 12:00 PM or 23:34'
  end

  option :countries do
    long '--countries=[PATTERN]'
    desc 'List all countries, or those matching a pattern'
    action do |value|
      if value == true
        puts TZInfo::Country.all.sort
      else
        patt= value
        puts TZInfo::Country.all.sort.find_all{|item| item.name =~ /#{patt}/;  }
      end
      exit
    end
  end
  option :countrycodes do
    short '-c'
    long '--countrycodes'
    desc 'List all country codes'
    action do
      puts TZInfo::Country.all_codes.sort
      exit
    end
  end
  option :listtimezones do
    long '--listtimezones=COUNTRY_CODE'
    desc 'List timezones for given country code. Use -c to fetch codes.'
    action do |value|
      patt= value
      cc = TZInfo::Country.get(patt)
      timezones = cc.zone_identifiers;
      puts timezones;
      exit
    end
  end

  separator ''
  separator 'Common options: '

  option :help do
    long '--help'
    desc 'Show this message'
  end

  option :version do
    short '-v'
    long '--version'
    desc 'Show version'
    action do
      puts "timeconverter.rb v#{PROGRAM_VERSION}"
      exit
    end
  end
end

### I am unable to get the balance arguments in ARGV since the options have not been shifted. 
puts "ARGS:" , Choice.args
puts "END ARGS"
unparsed=Choice.get_unparsed_args(ARGV)

#timestr=Choice.choices[:time]
tz = TZInfo::Timezone.get(Choice.choices[:from])
tz1 = TZInfo::Timezone.get('Asia/Calcutta')
#local = tz.utc_to_local(Time.utc(2008,9,4,14,00,0))
unparsed.each {|timestr|
  puts timestr
  local = tz.local_to_utc(Time.parse(timestr))
  puts tz1.utc_to_local(local)
}