Can this be used with update-alternatives?

[lacostenycoder]

I'm trying to use Ruby 2.7.7 on a server which is still running Ubuntu 16.04. I'm able to use ruby-install to install that version, however I can't seem to configure update-alternatives to work in order to have the Ruby version configured system wide. I tried with chruby but that didn't seem to work. Running any rake commands gave error on which version should have been running, it keeps falling back to 2.6.6.

 sudo update-alternatives --list ruby
/usr/bin/ruby2.3
/usr/bin/ruby2.6

I had tried some things that left things in this state. It was probably trying to force this to work with

sudo update-alternatives --install /usr/bin/ruby ruby /opt/rubies/ruby-2.7.7/bin/ruby 100

The errors described above remained so I did

sudo update-alternatives --remove ruby /opt/rubies/ruby-2.7.7/bin/ruby

This is current state of things, but config has been set back to 2.6.6 to not break things for now.

sudo update-alternatives --get-selections | grep ruby
ruby                           manual   /usr/bin/ruby2.6
ruby2.7                        auto     /opt/rubies/ruby-2.7.7
ruby2.7.7                      auto     /etc/alternatives/ruby

I guess I don't have a clear enough understanding of update-alternatives but wondered if anyone here has used it successfully with ruby-install. Using apt install ruby2.7 will only install 2.7.1

[postmodern]

Try running ruby-install --system ruby 2.7.7 which will install it globally into /usr/local. This should then implicitly override /usr/bin/ruby for regular users; because /usr/local/bin comes before /usr/bin in the PATH env variable.

[lacostenycoder]

ok but if I then want to switch to a different ruby version, system wide, how can I do it? can I switch back and forth without reinstalling?