How to require a user-installed gem in ruby when system-wide gem with higher version is also available?

Question

I have two versions of a gem installed: system-wide 1.3.2, and user-installed 1.0.0.

I need to use only version 1.0.0, which is installed in my home dir. Is there a way to tell gem to prefer user-installed gems?

Answer 1

You can specify which gem version to use by using the gem command before you require it.

gem 'foo', '1.0.0'
require 'foo'

Answer 2

1. You can specify the GEM_PATH variable, pointing to the gem version 2, GEM_HOME to path to gems for the selected ruby interpreter, and specify PATH to binary folder at the beginning of all PATHs, which contains the gem version.

2. Use rvm, or rbenv apps to control ruby/gem apps per project.