Ruby – Install Specific Version of a Ruby Gem

rubyrubygems

Using the command-line gem tool, how can I install a specific version of a gem?

Use the -v flag:

$ gem install fog -v 1.8

If your problem is to run binaries of a certain version, then:

rails --version # => the latest version
rails _2.3.10_ --version # => Rails 2.3.10

This pattern (gem-binary _gem-version_) works for any gem binary.