Проблема с запуском в Джекилле. Монтаж

Я установил Ruby, RubyGems, а затем Jekyll, но когда я запускаю Jekyll, я получаю эту ошибку.

$ jekyll serve
/var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:365:in `require_program': program version required (Commander::Runner::CommandError)
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:364:in `each'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:364:in `require_program'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:52:in `run!'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/delegates.rb:7:in `run!'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/import.rb:10
    from /usr/local/bin/jekyll:19
/usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require': no such file to load -- json (LoadError)
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/jekyll-1.3.0/bin/../lib/jekyll/filters.rb:2
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/jekyll-1.3.0/bin/../lib/jekyll.rb:43
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/jekyll-1.3.0/bin/jekyll:7
    from /usr/local/bin/jekyll:19:in `load'
    from /usr/local/bin/jekyll:19
somasundaram@somasundaram-Inspiron-3521:~/allfiles/msomu/msomu.github.io$ ^C
somasundaram@somasundaram-Inspiron-3521:~/allfiles/msomu/msomu.github.io$ jekyll/var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:365:in `require_program': program version required (Commander::Runner::CommandError)
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:364:in `each'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:364:in `require_program'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/runner.rb:52:in `run!'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/delegates.rb:7:in `run!'
    from /var/lib/gems/1.8/gems/commander-4.1.5/lib/commander/import.rb:10
    from /usr/local/bin/jekyll:19
/usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require': no such file to load -- json (LoadError)
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/jekyll-1.3.0/bin/../lib/jekyll/filters.rb:2
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/jekyll-1.3.0/bin/../lib/jekyll.rb:43
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require'
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from /var/lib/gems/1.8/gems/jekyll-1.3.0/bin/jekyll:7
    from /usr/local/bin/jekyll:19:in `load'
    from /usr/local/bin/jekyll:19

Также, если нет способа исправить это, пожалуйста, помогите мне, если кто-то скажет мне, как полностью удалить Ruby, RubyGems Jekyll и заново установить его или исправить эту ошибку.