How to install a gem to the current folder

Question

I want to use a Ruby gem locally (not install it for the entire machine) for use in a single script. I know how to install gems with Bundler with a Gemfile and bundle install . But for a simple script, this seems overkill to set up bundler.

Is there a way to install a gem to a subfolder of my script and use it, similar to the way npm installs Node.js packages in node_modules ?

Here's what I have tried so far.

gem install -i ruby plist installs the plist gem in ruby/gems/plist-3.1.0

I tried to require it in my script extract.rb by doing require './ruby/gems/plist-3.1.0/lib/plist but that fails with require: cannot load such file: plist/generator ( plist/generator.rb is required by lib/plist.rb ).

Ruby 2.0 on OSX

Answer 1

You can bundle install to a different location with the --path option, for example:

bundle install --path vendor/bundle

Also see http://bundler.io/v1.1/bundle_install.html

Answer 2

If you don't want to involve Bundler, just install your gems locally as in your example and then set the GEM_PATH env in your script before your require, eg:

#!/usr/bin/env ruby

ROOT = File.expand_path('..', __FILE__)
ENV['GEM_PATH'] = File.join(ROOT, 'ruby')
# or to just append to
# ENV['GEM_PATH'] += ":#{ File.join(ROOT, 'ruby') }"

require 'plist'

assuming your script is in the same folder as the ruby folder (otherwise adjust the filepath accordingly).

Answer 3

You can do it by creating gemset for particular application. follow these steps for that -

$ rvm gemset create <gemset_name>

It will create a gemset for currently selected ruby version. you can check currently selected ruby version by this command -

$ rvm list

Then navigate to your app directory by cd into it.

now execute this command -

$ rvm use @<gemset_name>

Now whenever you install any gem it will be installed in current gemset which is being used not for the entire machine.

Make sure - you run gem install bundler in newly created gemset so it will not raise error when you will run bundle install .