Cloning Directories in Ruby

# ln_r
# Copy a directory recursively creating hardlinks for files and real dirs for directories
# Andy Bulka, Reilly Beacom
# version 1.5

require 'fileutils'
require 'optparse'

def ln_r source, target, options = {:verbose => true, :report => true, :countsize => false, options[:deletetarget] => true}

  verbose = options[:verbose]
  puts "ln_r copying and hard linking from #{source} to #{target}" if verbose
  puts "..." if verbose

  raise "source not a directory" if not File.directory?(source)

  # Add trailing slash
  source = File.join(source, "")
  target = File.join(target, "")

  # Ensure target dir exists before we start and delete destination files
  FileUtils.mkdir_p target
  FileUtils.rm_r Dir.glob(File.join(target, '/*')) if options[:deletetarget]

  total_file_sizes = 0
  Dir.glob(File.join(source, '**/*')).each do | source_path |

    target_path = source_path.gsub Regexp.new("^" + source), target
    if File.file? source_path

      FileUtils.mkdir_p File.dirname(target_path)
      FileUtils.ln source_path, target_path
      total_file_sizes += File.size(source_path) if options[:countsize]
      puts "created hard link #{target_path}  (source: #{source_path}" if verbose

    else
      FileUtils.mkdir_p target_path
      puts "created directory " + target_path if verbose
    end
  end
  puts "Done copying/linking." if verbose

  def number_with_delimiter(number, delimiter=",")
    number.to_s.gsub(/(\d)(?=(\d\d\d)+(?!\d))/, "\\1#{delimiter}")
  end
  puts "Bytes saved by linking: #{number_with_delimiter(total_file_sizes/1024000)} Mb" if options[:countsize]

  if options[:report]
    puts
    puts "---- RESULT: SOURCE DIRECTORY"
    puts Dir.glob(File.join(source, '/**/*'))
    puts "---- TARGET DIRECTORY"
    puts Dir.glob(File.join(target, '/**/*'))
    puts "---- RESULT END"
    puts
  end

end



# This hash will hold all of the options
# parsed from the command-line by
# OptionParser.
options = {}

optparse = OptionParser.new do|opts|
  # Set a banner, displayed at the top
  # of the help screen.
  opts.banner = "Usage: ln_r.rb [options] source_dir target_dir"

  # Define the options, and what they do
  options[:verbose] = false
  opts.on( '-v', '--verbose', 'Output more information' ) do
    options[:verbose] = true
  end

  options[:test] = false
  opts.on( '-t', '--test', 'Run test copy on test data dirs - Andy only' ) do
    options[:test] = true
  end

  options[:report] = false
  opts.on( '-r', '--report', 'Display directory of source and target dirs after finish' ) do
    options[:report] = true
  end

  options[:countsize] = false
  opts.on( '-c', '--countsize', 'Display bytes saved by using hard linking' ) do
    options[:countsize] = true
  end

  options[:deletetarget] = true
  opts.on( '-d', '--dontdeletetarget', 'Dont rm -r * target directory first' ) do
    options[:deletetarget] = false
  end

  #options[:logfile] = nil
  #opts.on( '-l', '--logfile FILE', 'Write log to FILE' ) do|file|
  #  options[:logfile] = file
  #end

  # This displays the help screen, all programs are
  # assumed to have this option.
  opts.on( '-h', '--help', 'Display this screen' ) do
    puts opts
    exit
  end
end

# Parse the command-line. Remember there are two forms
# of the parse method. The 'parse' method simply parses
# ARGV, while the 'parse!' method parses ARGV and removes
# any options found there, as well as any parameters for
# the options. What's left is the list of files to resize.
optparse.parse!

puts "Being verbose" if options[:verbose]
#puts "Logging to file #{options[:logfile]}" if options[:logfile]

if options[:test]
  ln_r "LinkTests1/dirA", "LinkTests1/dirB", options
  ln_r "LinkTests2/dirA", "LinkTests2/dirB/MyCopy/Fred", options
  exit
end

if ARGV.length < 2
  puts optparse.help
  exit
end

ln_r ARGV[0], ARGV[1], options