如下述錯誤訊息，在執行'rails c'後發生。我猜想是在更新homebrew等package management後導致。 /Users/hothero/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/irb/completion.rb:9:in `require': dlopen(/Users/hothero/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/x86_64-darwin11.1.0/readline.bundle, 9): Library