$ gem install jekyll
ERROR: Could not find a valid gem 'jekyll' (>= 0), here is why:
Unable to download data from https://rubygems.org/ - Errno::ECONNRESET: Connection reset by peer - SSL_connect (https://rubygems.org/latest_specs.4.8.gz)
解决办法
$ gem sources --remove https://rubygems.org/
$ gem sources -a https://ruby.taobao.org/
$ sudo gem update --system
$ sudo gem install jekyll