Jekyll broken after upgrading Ubuntu/Ruby

upgrade ruby 16.04 jekyll

I had the same issue. It's caused by ruby update in new Ubuntu. Just uninstall jekyll and install it again:

gem uninstall jekyll
gem install jekyll

In addition to the answer by @Piotr, I also had to uninstall and reinstall the gem bundler. That is, I ran,

gem uninstall bundler
gem install bundler
bundle

Only after this did bundle exec jekyll serve start to work again after my upgrade from ubuntu 18.04 to 20.04.

Related

Will updating software with a 'deb' file remove the previous version?
unity-control-center not working in i3wm on Ubuntu 16.04
I want shotwell to open all .cr2 files in a folder and all its subfolders, what command line do I use?
Gnome Shell extensions: Attempt to postMessage on disconnected port
How to make tab completion append slash for directory symlinks?
what does 'y' stand for in apt-get install? [duplicate]
Headphone not working on Ubuntu 17.04 - Dell XPS 15
Does installing kernel 4.13 on Ubuntu 12.04 change the update policy?
Skype is not opening after entering the loging credentials in ubuntu 16.04 LTS
Where exactly is all the source code on Launchpad browseable?
Use case where script filenames have leading numbers to determine execution order
How to identify whether an app is a snap or a flatpak or a native app on my computer?