Here, I’m posting my solution for ruby / jekyll issue after MacOS update. I use jekyll for my website and few days back when I tried to update my website blog and executed bundle exec jekyll serve, I faced this issue. I don’t have the exact error messages. So please decide for yourself.

The error message suggested to execute bundle install. However, this spiralled to other errors related to unf_ext, commonmarker and other packages suggesting gem pristine installs. On trying the suggested solutions, I eventually got a message about not having the right permissions. These are the links which I went through during my search:

• Ruby on Mac
• Install Jekyll on Mac

Finally, this is what I did:

• Check which ruby and which gem
  • If it’s system’s ruby (/usr/bin/…), then you can simply install a local ruby with your choice of version.
• Run brew doctor
  • It should return Your system is ready to brew. If any warnings are shown, first try to resolve them. In my case, I uninstalled homebrew completey using this LINK and reinstalled using this LINK.
  • Please follow the steps as described (1. prepare your mac, 2. Install Homebrew) Read the tutorials thoroughly as it requires update in .zshrc and .zshprofile files.
  • Once this is done, check again brew doctor and verify that it returns Your system is ready to brew.
• Now, run brew install [email protected] or the version you prefer. If you run brew install ruby, then it installs [email protected] and eventually this will cause tainted object compatibility errors with jekyll theme.
  • Pay attention to the messages displayed during installation. You will have to set paths as indicated in the messages. For instance, echo 'export PATH="/opt/homebrew/opt/[email protected]/bin:$PATH"' >> ~/.zshrc, export LDFLAGS="-L/opt/homebrew/opt/[email protected]/lib" and export CPPFLAGS="-I/opt/homebrew/opt/[email protected]/include"
• Check which ruby and which gem
  • Now, you should see (/usr/local/….). If you still get paths such as /usr/bin/…, in that case, you have not set the paths in the above step.
  • At the end, you may also see a warning about sassc . Pay attention to this warning and accordingly add gem 'sassc-rails' in the gemfile in local repo
• gem install jekyll
• gem install bundler
• Move to your local repo path, and run bundle update and bundle
• Finally, bundle exec jekyll serve

Hope it was helpful.