>>54
> It fails to execute "require 'rubygems/defaults/operating_system'"
Humm....
Ignoring this exception is no problem?

> >‎ Exception `NoMethodError' at c:/ruby/lib/ruby/1.8/rational.rb:78
> >‎ - undefined method `gcd' for Rational(1, 2):Rational
> You might execute a code like Rational(1, 2).gcd,
> but the Rational class does not have a method named gcd.
I found "Rational::gcd" in rational.rb ...
But, the error has occurred. This is why?

sample code is here.
----cut here----
#!ruby -Ku
puts "hello"
----cut here----
Run command "ruby -d foobar.rb" to confirm.