Ruby: How to install a specific version of a ruby gem?

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

Solution 1:

Use the -v flag:

$ gem install fog -v 1.8

Solution 2:

Use the --version parameter (shortcut -v):

$ gem install rails -v 0.14.1
…
Successfully installed rails-0.14.1

You can also use version comparators like >= or ~>

$ gem install rails -v '~> 0.14.0'
…
Successfully installed rails-0.14.4

With newer versions of rubygems you can tighten up your requirements:

$ gem install rails -v '~> 0.14.0, < 0.14.4'
…
Successfully installed rails-0.14.3

Since some time now you can also specify versions of multiple gems:

$ gem install rails:0.14.4 rubyzip:'< 1'
…
Successfully installed rails-0.14.4
Successfully installed rubyzip-0.9.9

But this doesn't work for more than one comparator per gem (yet).

Solution 3:

For installing gem install gemname -v versionnumber

For uninstall gem uninstall gemname -v versionnumber

Solution 4:

for Ruby 1.9+ use colon.

gem install sinatra:1.4.4 prawn:0.13.0