diff --git a/cal.rb b/cal.rb
old mode 100644
new mode 100755
index 94c0c1e..0ba865e
--- a/cal.rb
+++ b/cal.rb
@@ -1,32 +1,29 @@
+#!/usr/bin/ruby
+
 require 'date'
+require 'optparse'
 
-time = Time.now.localtime
-year = time.year.to_i
-month = time.month.to_i
-currentday = time.day  # 現在日
-startwday = Date.new(year,month,1).wday # その月の最初の曜日
-endmonth = Date.new(year,month,-1) # その月の日数
-endwday = time.wday # その月の最後の曜日
+optmonth = ARGV.getopts('m:')
+optyear = ARGV.getopts('y:')
 
+# opt = OptionParser.new
+# opt.on('-m')
+# opt.on('-y')
+# opt.parse!
 
-a = Date.new(2024, 3, 6)
-puts  "\t#{a.month}月\s#{a.year}"
-b = %w(日 月 火 水 木 金 土)
-b.each do |week|
-  print "\s#{week}"
+year = Date.today.year
+month = Date.today.month
+startwday = Date.new(year, month, 1).wday # その月の最初の曜日
+enddate = Date.new(year, month, -1).day # その月の最後の曜日
+week = %w[日 月 火 水 木 金 土]
+
+puts "\t#{month}月 #{year}"
+puts week.join(' ')
+print '   ' * startwday
+
+days = startwday
+(1..enddate).each do |day|
+  print day.to_s.rjust(2) + ' '
+  days += 1
+  print "\n" if days % 7 == 0
 end
-days = (1..31).to_a
-days.each do |day|
-  if day == 1
-    print "\n\s\s#{day}"
-  elsif day % 7 == 0 && day != 7
-    print "\s#{day}\n"
-  elsif day == 7
-    print "\s\s#{day}\n"
-  elsif day >= 10
-    print "\s#{day}"
-  else
-    print "\s\s#{day}"
-  end
-end
-