Catalina Jekyll bad interpreter error

Problem:

When trying to run jekyll in Terminal, I get the following error:

zsh: /usr/local/bin/jekyll: bad interpreter: /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby: no such file or directory

I recently upgraded MacOS.

Before you start:

This how-to assumes you already have knowledge of Terminal and the 'sudo' command, given that you've already installed Jekyll in the past. If not, please proceed at your discretion as 'sudo' command can be harmful if used incorrectly.

Solution:

In Terminal, reinstall jekyll via homebrew:

sudo gem install jekyll

Why this works:

The upgrade to Catalina changed key dependencies of Jekyll. While it is possible to manually link them or add them to your PATH, reinstalling Jekyll should provide an easier and more robust solution. You'll likely also need to reinstall any other gems you need.

Disclaimer:

This solution was verified to work in MacOS 10.15.3 with Jekyll 4.0.0. Your mileage may vary with other versions.

References:

• https://talk.jekyllrb.com/t/cant-run-jekyll-in-mac-os-sierra/1263/2
• https://muffinman.io/macos-catalina-ruby-bad-interpreter-error/ (useful read if you prefer using the Homebrew version)