Stuck on old Ruby version (macOS)

Question

I keep trying to get ruby on my system from v 2.3.7 to v 2.7.1 but no matter what command I enter (update, install, rbenv global etc) it stays with the old version. I think it's an old installation that doesn't get overwritten when I install a new version, but whenever I try to run something with the "ruby" command it only uses the 2.3.7 install.

Here's an example of what I'm talking about. This was after was trying to uninstall everything I could to do a full reinstall, but I can't even figure out how to uninstall it. I then tried to upgrade the ruby version that the system was telling me was there, but brew couldn't find it.

$ ruby -v

ruby 2.3.7p456 (2018-03-28 revision 63024) [universal.x86_64-darwin18]

$ brew upgrade ruby

Updating Homebrew...

Error: ruby not installed

Answer 1

brew upgrade ruby upgrades the ruby installed by Homebrew . "Error: ruby not installed" says you don't have Ruby installed by Homebrew. Homebrew will not upgrade the Ruby that comes with MacOS.

Instead, brew install ruby . This will leave your MacOS Ruby alone and install its own.