diff --git a/04.ls/ls.rb b/04.ls/ls.rb
index 6b1cfd48e4..089cf6517e 100755
--- a/04.ls/ls.rb
+++ b/04.ls/ls.rb
@@ -1,10 +1,38 @@
 #!/usr/bin/env ruby
 # frozen_string_literal: true
 
+require 'optparse'
+require 'etc'
+
 MAX_CHUNK = 3
 TAB_SPACE = 8
 
-file_paths = Dir.entries('.')
+FILE_TYPE = {
+  'fifo' => 'p',
+  'characterSpecial' => 'c',
+  'directory' => 'd',
+  'blockSpecial' => 'b',
+  'file' => '-',
+  'link' => 'l',
+  'socket' => 's'
+}.freeze
+
+FILE_MODE = {
+  '0' => '---',
+  '1' => '--x',
+  '2' => '-w-',
+  '3' => '-wx',
+  '4' => 'r--',
+  '5' => 'r-x',
+  '6' => 'rw-',
+  '7' => 'rwx'
+}.freeze
+
+SPECIAL_MODE = [
+  { bit: 4, index: 2, exec: 's', no_exec: 'S' },
+  { bit: 2, index: 5, exec: 's', no_exec: 'S' },
+  { bit: 1, index: 8, exec: 't', no_exec: 'T' }
+].freeze
 
 def except_hidden_file(file_paths)
   file_paths.reject { |element| element[0] == '.' }
@@ -21,20 +49,95 @@ def transpose_chunks(sliced_paths, num_rows)
   padded_slices.transpose.map(&:compact)
 end
 
-file_paths = file_paths.sort
-file_paths = except_hidden_file(file_paths)
+def convert_file_mode(file_stat)
+  file_mode_octal = file_stat.mode.to_s(8).rjust(6, '0')
+  file_mode = FILE_TYPE[file_stat.ftype].to_s
+  file_permissions = file_mode_octal.slice(3..-1).chars.map { |char| FILE_MODE[char] }.join
+  # 特殊権限の確認　特殊権限は8進数に変換されたファイルモードの3文字目に記載されている　そのためfile_mode_octal[2]を参照する
+  file_permissions = apply_special_modes(file_mode_octal[2].to_i, file_permissions)
+  file_mode + file_permissions
+end
+
+def apply_special_modes(special_modes, permissions)
+  # 0は特殊権限なし、なので最初に弾く（特殊権限は1か2か4であるため）
+  return permissions if special_modes.zero?
 
-num_rows = (file_paths.size.to_f / MAX_CHUNK).ceil
-sliced_paths = chunk_file_paths(file_paths, num_rows)
-shaped_file_paths_array = transpose_chunks(sliced_paths, num_rows)
+  SPECIAL_MODE.each do |mode|
+    next unless (special_modes & mode[:bit]).positive?
+
+    permissions[mode[:index]] = if permissions[mode[:index]] == 'x'
+                                  mode[:exec]
+                                else
+                                  mode[:no_exec]
+                                end
+  end
+  permissions
+end
+
+def format_file_mode(file_path)
+  file_stat = File.lstat(file_path)
+  {
+    file_mode: convert_file_mode(file_stat),
+    nlink: file_stat.nlink.to_s,
+    uid: Etc.getpwuid(file_stat.uid).name,
+    gid: Etc.getgrgid(file_stat.gid).name,
+    size: file_stat.size.to_s,
+    mtime: file_stat.mtime.strftime('%-m %d %H:%M'),
+    file_path:,
+    blocks: file_stat.blocks
+  }
+end
+
+def calclate_max_string_modes(file_modes)
+  {
+    nlink: file_modes.map { |file_mode| file_mode[:nlink].size }.max,
+    uid: file_modes.map { |file_mode| file_mode[:uid].size }.max,
+    gid: file_modes.map { |file_mode| file_mode[:gid].size }.max,
+    size: file_modes.map { |file_mode| file_mode[:size].size }.max,
+    mtime: file_modes.map { |file_mode| file_mode[:mtime].size }.max
+  }
+end
+
+file_paths = Dir.entries('.').sort
+
+opt = OptionParser.new
+options = opt.getopts(ARGV, 'arl')
+
+file_paths = file_paths.reverse if options['r']
+file_paths = except_hidden_file(file_paths) unless options['a']
+
+if options['l']
+  file_modes = file_paths.map { |file_path| format_file_mode(file_path) }
+  total_blocks = file_modes.map { |file_mode| file_mode[:blocks] }.sum
+
+  puts "total #{total_blocks}"
+
+  max_string_modes = calclate_max_string_modes(file_modes)
+  file_modes.each do |file_mode|
+    file_mode_print = [
+      file_mode[:file_mode],
+      file_mode[:nlink].rjust(max_string_modes[:nlink]),
+      file_mode[:uid].ljust(max_string_modes[:uid]),
+      file_mode[:gid].rjust(max_string_modes[:gid] + 1),
+      file_mode[:size].rjust(max_string_modes[:size] + 1),
+      file_mode[:mtime].rjust(max_string_modes[:mtime] + 1),
+      file_mode[:file_path]
+    ].join(' ')
+    puts file_mode_print
+  end
+else
+  num_rows = (file_paths.size.to_f / MAX_CHUNK).ceil
+  sliced_paths = chunk_file_paths(file_paths, num_rows)
+  shaped_file_paths_array = transpose_chunks(sliced_paths, num_rows)
 
-max_string_length = file_paths.map(&:length).max
+  max_string_length = file_paths.map(&:length).max
 
-shaped_file_paths_array.each do |array_element|
-  array_element.each do |element|
-    tab_count = ((max_string_length - element.length) / TAB_SPACE.to_f).ceil + 1 # タブの挿入する回数を計算
-    print element
-    print "\t" * tab_count
+  shaped_file_paths_array.each do |array_element|
+    array_element.each do |element|
+      tab_count = ((max_string_length - element.length) / TAB_SPACE.to_f).ceil + 1 # タブの挿入する回数を計算
+      print element
+      print "\t" * tab_count
+    end
+    puts
   end
-  puts
 end