How to make a specific gem version as default?

Question

I have two versions of ruby gem.

json (default: 2.0.2, 1.8.6) 

Here, the latest version is set to default; however I need json 1.8.6 to be set as default. Is there anyway to make the older versions of the gem as default? cos I am unable to uninstall the default json version. Need a switch between available gem versions.

Answer 1

Check what you have with:

gem list json 

Set the one you want:

gem install --default -v1.8.6 json 

This is most useful for things like "bundler"!!! For other things, using bundler and a Gemfile is probably a better choice.

Answer 2

Add

gem 'json', '1.8.6' 

to your Gemfile or execute

gem install 'json' -v 1.8.6 # may require sudo if you use system ruby 

from terminal.