ERROR: Could not find a valid gem ‘rdiscount‘ (>= 0), here is why:
Unable to download data from https://rubygems.org/ - Errno::ETIMEDOUT: Operation timed out - connect(2) (https://rubygems.org/latest_specs.4.8.gz)
图片如下：
$ gem sources
删除ruby官网镜像源：
$ gem sources --remove http://rubygems.org/
添加淘宝镜像源：
$ gem sources --a http://ruby.taobao.org/
原文：http://www.cnblogs.com/ayseeing/p/4103814.html