-l

ls.rb

@@ -5,6 +5,24 @@ require 'etc'
 
 COLUMNS = 3
 MARGIN = 3
+PERMISSION = {
+  '0' => '---',
+  '1' => '--x',
+  '2' => '-w-',
+  '3' => '-wx',
+  '4' => 'r--',
+  '5' => 'r-x',
+  '6' => 'rw-',
+  '7' => 'rwx'
+}.freeze
+FILETYPE = {
+  '1' => 'p',
+  '2' => 'c',
+  '4' => 'd',
+  '6' => 'b',
+  '10' => '-',
+  '12' => 'l'
+}.freeze
 
 def run
   listed_filenames = list_filenames
@@ -17,9 +35,9 @@ def list_filenames
   params = ARGV.getopts('a', 'r', 'l')
   filenames = params['a'] ? Dir.glob('*', File::FNM_DOTMATCH) : Dir.glob('*')
   filenames = filenames.reverse if params['r']
-  params['l'] ? ownerinfo(filenames) : filenames
-  if params['r']
-    filenames.reverse
+  if params['l']
+    ownerinfo(filenames)
+    exit
   else
     filenames
   end

ls2.rb

@@ -0,0 +1,30 @@
+require 'optparse'
+require 'etc'
+
+NUMBER_OF_COLUMNS = 3
+COLUMN_MARGIN = 3
+SIZE_INDENT = 2
+
+def main
+  files = Dir.glob('*').sort
+  output_ls(files)
+end
+
+def output_ls(files)
+  number_of_row = (files.size / NUMBER_OF_COLUMNS.to_f)
+  max_lengths = make_max_lengths(files, number_of_row)
+
+  (0...number_of_row).each do |row|
+    NUMBER_OF_COLUMNS.times do |column|
+      index = row + column * number_of_row
+      print files[index].ljust(max_lengths[column] + COLUMN_MARGIN) if files[index]
+    end
+    puts
+  end
+end
+
+def make_max_lengths(files, number_of_row)
+  files.each_slice(number_of_row).to_a.map { _1.map(&:length).max }
+end
+
+main