Format files in a table like ls

lsformat.rb

require 'io/console'
require 'pp'

files = Dir["*"].sort

MAX_COLUMNS = 9

MAX_COLUMNS.downto(1) do |i|
  columns = files.each_slice(i).map { |x| Array.new(i) { |n| x[n] } }
  rows = columns.transpose
  space = 2
  column_widths = columns.map { |values| values.map(&:to_s).map(&:size).max + space }

  screen_width = $stdin.winsize[1]
  total_width = column_widths.inject(0, :+) # sum

  if total_width < screen_width
    rows.each_with_index do |values, y|
      values.each_with_index do |value, x|
        width = column_widths[x] || 0
        print value.to_s.ljust(width)
      end
      puts
    end
  end

  puts
end