calculate amount of disk space returned, once all the given files and directories are removed

freespace.rb

#!/usr/bin/env ruby

require 'find'

BLOCK_SIZE = 512 # ブロックサイズは通常 512 バイト

def calculate_freed_space(paths)
  inodes = {}
  total_blocks = 0
  processed_files = {}

  Find.find(*paths) do |file|
    normalized_file = File.expand_path(file)
    next if processed_files.key?(normalized_file)
    processed_files[normalized_file] = true

    if File.exist?(normalized_file)
      stat = File.stat(normalized_file)
      if File.directory?(normalized_file)
        # ディレクトリ自体のサイズを追加
        total_blocks += stat.blocks
      else
        key = [stat.dev, stat.ino]
        inodes[key] ||= { count: 0, blocks: stat.blocks, nlink: stat.nlink }
        inodes[key][:count] += 1
      end
    else
      puts "Warning: #{normalized_file} does not exist and will be skipped."
    end
  end

  inodes.each do |key, info|
    if info[:count] == info[:nlink]
      total_blocks += info[:blocks]
    end
  end

  total_blocks * BLOCK_SIZE
end

if ARGV.empty?
  puts "Usage: ruby free_space_calculator.rb <path1> <path2> ..."
  exit 1
end

paths = ARGV
freed_space = calculate_freed_space(paths)
formatted_size = freed_space.to_s.reverse.scan(/\d{1,3}/).join(',').reverse
puts "Total space that would be freed: #{formatted_size} bytes"