Eric Zhong

$ gem install jekyll
ERROR:  Could not find a valid gem 'jekyll' (>= 0), here is why:
          Unable to download data from http://ruby.sdutlinux.org/ - server did not return a valid file (http://ruby.sdutlinux.org/latest_specs.4.8.gz)

# 安装 RVM (Ruby Version Manager)
$ \curl -L https://get.rvm.io | bash -s stable

# 根据提示操作 (Load RVM into a shell session *as a function*)
$ echo "source ~/.profile" >> /Users/xxx/.bash_profile

# 更新
$ rvm get stable --autolibs=enable
$ rvm reload                             # 也可以关闭终端后重新开

# 安装最新版 Ruby
$ rvm list known
$ rvm install ruby-2.4
$ ruby -v
ruby 2.4.0p0 (2016-12-24 revision 57164) [x86_64-darwin16]

# 更新 gem
$ gem -v
2.6.10

$ gem update --system
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    server did not return a valid file (http://ruby.sdutlinux.org/specs.4.8.gz)

$ gem install jekyll
ERROR:  Could not find a valid gem 'jekyll' (>= 0), here is why:
          Unable to download data from http://ruby.sdutlinux.org/ - server did not return a valid file (http://ruby.sdutlinux.org/specs.4.8.gz)

$ export http_proxy=127.0.0.1:64000
$ export https_proxy=127.0.0.1:64000

$ ping ruby.sdutlinux.org
PING sdutlinux.org (69.39.236.56): 56 data bytes
64 bytes from 69.39.236.56: icmp_seq=0 ttl=43 time=262.186 ms

$ gem update --system
ERROR:  While executing gem ... (Gem::RemoteFetcher::FetchError)
    too many connection resets (http://ruby.sdutlinux.org/specs.4.8.gz)

$ unset export http_proxy
$ unset export https_proxy

$ gem sources --remove http://ruby.sdutlinux.org/
$ gem sources -a https://ruby.taobao.org/
$ gem sources -l
*** CURRENT SOURCES ***
https://ruby.taobao.org/

$ gem update --system
Latest version currently installed. Aborting.

$ gem install jekyll

$ jekyll serve
Configuration file: /Users/xxx/xxx/ericzhong.github.io/_config.yml
       Deprecation: Auto-regeneration can no longer be set from your configuration file(s). Use the --[no-]watch/-w command-line option instead.
       Deprecation: The 'pygments' configuration option has been renamed to 'highlighter'. Please update your config file accordingly. The allowed values are 'rouge', 'pygments' or null.
Configuration file: /Users/zwj/working/ericzhong.github.io/_config.yml
       Deprecation: Auto-regeneration can no longer be set from your configuration file(s). Use the --[no-]watch/-w command-line option instead.
       Deprecation: The 'pygments' configuration option has been renamed to 'highlighter'. Please update your config file accordingly. The allowed values are 'rouge', 'pygments' or null.
             Theme: value of 'theme' in config should be String to use gem-based themes, but got Hash
            Source: /Users/xxx/xxx/ericzhong.github.io
       Destination: /Users/xxx/xxx/ericzhong.github.io/_site
 Incremental build: disabled. Enable with --incremental
      Generating... 
  Dependency Error: Yikes! It looks like you don't have rdiscount or one of its dependencies installed. In order to use Jekyll as currently configured, you'll need to install this gem. The full error message from Ruby is: 'cannot load such file -- rdiscount' If you run into trouble, you can find helpful resources at https://jekyllrb.com/help/! 
  Conversion error: Jekyll::Converters::Markdown encountered an error while converting '_posts/2013-09-04-install-openstack-from-source.md':
                    rdiscount
             ERROR: YOUR SITE COULD NOT BE BUILT:
                    ------------------------------------
                    rdiscount

$ gem install rdiscount
$ jekyll serve