I am trying to get Jekyll running but I have no experience with Ruby.
As far as I can tell the installation of Jekyll has succeeded.
However:
$ jekyll
>
gem uninstall jekyll
sudo gem install jekyll
Open ~/.bash_profile and add this code in the last line,
export PATH=$PATH:/usr/local/lib/ruby/gems/1.9.1/gems/jekyll-2.5.2/bin
Save and close the .bash_profile
Close and reopen the mac terminal, try running jekyll
now, it should work