Move all files from source directory to destination, overwriting files only if larger

mv-larger.rb

#!/usr/bin/env ruby

require 'fileutils'

src = ARGV[-2]
dest = ARGV[-1]

unless src and dest and File.directory? src and File.directory? dest
  puts "Usage: mv-larger [-v] [-d] SRC DEST"
  exit false
end

src = File.expand_path src
dest = File.expand_path dest
verbose = ARGV.find_index('-v') ? true : false
dryrun = ARGV.find_index('-d') ? true : false

Dir.foreach src do |file|
  next if file == '.' or file == '..'
  src_file = File.expand_path File.join(src, file)
  dest_file = File.expand_path File.join(dest, file)
  if File.file? dest_file
    src_size = File.size? src_file
    dest_size = File.size? dest_file
    if src_size > dest_size
      FileUtils.mv src_file, dest_file unless dryrun
      puts "\'#{src_file}\' -> \'#{dest_file}\' (larger)" if verbose
    elsif src_size < dest_size
      puts "Kept #{dest_file} (larger)" if verbose
    else
      puts "Kept #{dest_file} (same size)" if verbose
    end
  else
    begin
      FileUtils.mv src_file, dest_file unless dryrun
    rescue StandardError
      puts "Error moving \'#{src_file}\' -> \'#{dest_file}\'"
    end
    puts "\'#{src_file}\' -> \'#{dest_file}\'" if verbose
  end
end