Extract URL from 856$u in MARC (Ruby)

gistfile1.rb

!/usr/bin/ruby
require 'rubygems'
require 'marc'
require 'optparse'
require 'CSV'

options = {}
OptionParser.new do |opts|
    opts.banner = "Usage: 001-856.rb [options]"

    opts.on("-f", "--format [FORMAT]","Specify format of files to be converted. Currently supported 'marcxml' and 'marc'") do |f|
        options[:format] = f
    end

    opts.on("-s", "--sourcefile [SOURCEFILE]","Specify source file") do |s|
        options[:sourcefile] = s
    end

    opts.on_tail("-h", "--help", "Show this message") do
        puts opts
        exit
    end
end.parse!

sourcefile = options[:sourcefile]
format = options[:format]

# reading records from a batch file
if(format == "marcxml")
	reader = MARC::XMLReader.new(sourcefile)
elsif(format == "marc")
	reader = MARC::Reader.new(sourcefile, :external_encoding => "UTF-8", :invalid => :replace)
else
	puts "Not a recognised format. Currently accept 'marcxml' or 'marc'"
	exit
end

for record in reader
    record.each_by_tag('856') {|field|
        puts record['001'].value.to_s + "," + field['u'].to_s
    }
end