因為主機環境不能聯外網，悲哀，所以只能想辦法下載包，上傳到主機來安裝
環境：el6.x86_64
1. gem 安裝[http://centos.ustc.edu.cn/centos/6/os/x86_64/Packages/]
Ruby 1.9.2版本默認已安裝Ruby Gem，如果你的版本低於這個？那就往下看吧
安裝gem 需要ruby的版本在 1.8.7 以上
# rpm -qa |grep ruby
rubygems-1.3.7-5.el6.noarch
ruby-1.8.7.374-4.el6_6.x86_64
ruby-irb-1.8.7.374-4.el6_6.x86_64
ruby-libs-1.8.7.374-4.el6_6.x86_64
ruby-rdoc-1.8.7.374-4.el6_6.x86_64
ruby-devel-1.8.7.374-4.el6_6.x86_64
rubygems-devel-1.3.7-5.el6.noarch
2. redis-stat [gem install 默認下載的安裝包路徑：/usr/local/share/gems/cache]
gem install --local redis-3.0.7.gem
Successfully installed redis-3.0.7
1 gem installed
Installing ri documentation for redis-3.0.7...
Installing RDoc documentation for redis-3.0.7...
# gem install --local redis-stat-0.4.13.gem
Successfully installed redis-stat-0.4.13
1 gem installed
Installing ri documentation for redis-stat-0.4.13...
Installing RDoc documentation for redis-stat-0.4.13...
# gem query --local