title: Jekyll version questions
body: <p>If I run <code>jekyll -v</code> in terminal, I got this:</p>
  <pre><code>/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/universal-darwin19/rbconfig.rb:229: warning: Insecure world writable dir /usr/local/opt in PATH, mode 040777
  jekyll 4.1.0
  </code></pre>
  <p>But if I run <code>gem list jekyll</code>, it says I have another version of jekyll:</p>
  <pre><code>*** LOCAL GEMS ***
  
  jekyll (2.4.0)
  jekyll-coffeescript (1.2.2)
  jekyll-gist (1.5.0)
  jekyll-paginate (1.1.0)
  jekyll-sass-converter (1.5.2)
  jekyll-watch (1.5.1)
  </code></pre>
  <p>Does it mean I have two different versions of Jekyll installed? and how can I choose to use the old version 2.4.0? and is it possible to uninstall the 4.1.0?</p>
  <p>Thanks</p>