Ubuntu 16.04

$ sudo apt-get update
$ sudo apt-get install ruby ruby-dev make gcc
$ sudo gem install jekyll bundler

Ubuntu 14.04

$ sudo apt-get update
$ sudo apt-get install ruby2.0 ruby2.0-dev
$ sudo gem install bundler
$ sudo gem2.0 install jekyll bundler

How to Start Jekyll

$ jekyll new myblog
$ cd myblog
$ bundle exec jekyll serve

# or simply $ jekyll serve
# with reload and refresh every file changes $ jekyll serve -w
# => Now browse to http://localhost:4000