$ which jekyll
/home/ubuntu/.rbenv/shims/jekyll
ubuntu@nxtest:~/home-assistant.io$ $(which jekyll) serve -incremental
           WARNING: Error reading configuration. Using defaults (and options).
No parser for 'remental' is available. Use a .toml or .y(a)ml file instead.
            Source: /home/ubuntu/home-assistant.io
       Destination: /home/ubuntu/home-assistant.io/_site
 Incremental build: enabled
      Generating...
     Build Warning: Layout 'post' requested in source/_posts/2014-12-18-website-launched.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2014-12-26-home-control-home-automation-and-the-smart-home.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-01-04-hey-pushbullet-nice-talking-to-you.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-01-11-bootstrapping-your-setup-with-discovery.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-01-13-nest-in-da-house.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-01-24-release-notes.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-02-07-looking-at-the-past.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-02-24-streaming-updates.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-02-28-home-assistant-migrating-to-yaml.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-03-08-new-logo.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-03-11-release-notes.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-03-22-release-notes.markdown does not exist.
     Build Warning: Layout 'post' requested in source/_posts/2015-04-25-release-notes.markdown does not exist.
  Liquid Exception: Liquid syntax error: Unknown tag 'linkable_title' in /home/ubuntu/home-assistant.io/source/_posts/2015-05-09-utc-time-zone-awareness.markdown
jekyll 3.0.0 | Error:  Liquid syntax error: Unknown tag 'linkable_title'