HOWTO: Use Jekyll on macOS via MacPorts

a) Install latest Ruby and RubyGems from MacPorts

sudo port install rubyXY rb-rubygems

b) Set latest RubyXY as default

port select --list ruby
sudo port select --set  ruby rubyXY

c) Update RubyGems

sudo gem update --system

d) Install Bundler, Jekyll, plugins

sudo gem install -n /opt/local/bin bundler jekyll jekyll-docs jekyll-maps

e) Update Jekyll

bundle update && bundle install OR
sudo bundle update jekyll

f) Build and view website locally

bundle exec jekyll serve

g) Recover from unresolved specs during Gem specification reset

gem list
sudo gem cleanup <package_name>  # for multiple versions of given packages