irb.1: useless option [ci skip]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55984 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
irb.1: useless option [ci skip]
[ruby-dev:49767] [Bug #12692]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55984 b2dd03c8-39d4-4d8f-98ff-823fe69b080e