gem install mongo

1. gem 安装

    # yum install rubygems -y

  2. gem 源

    # gem sources -l

    # gem sources --remove https://rubygems.org/

    # gem sources -a https://ruby.taobao.org/

  3.ruby >= 1.9.3 安装

    http://tecadmin.net/install-ruby-1-9-3-or-multiple-ruby-verson-on-centos-6-3-using-rvm/

  4.gem  install mongo