unicode_utils gem won't install

Question

I'm getting this error on a bundle install (this is while I am using ruby 1.9.2 (I have tried 1.9.1 as well) and Rails 3.2.11

Installing unicode_utils (1.4.0) /usr/lib/ruby/vendor_ruby/1.8/rubygems/installer.rb:388:in `ensure_required_ruby_version_met': unicode_utils requires Ruby version >= 1.9.1. (Gem::InstallError)
    from /usr/lib/ruby/vendor_ruby/1.8/rubygems/installer.rb:156:in `install'
    from /usr/lib/ruby/vendor_ruby/bundler/source.rb:101:in `install'
    from /usr/lib/ruby/vendor_ruby/bundler/rubygems_integration.rb:78:in `preserve_paths'
    from /usr/lib/ruby/vendor_ruby/bundler/source.rb:91:in `install'
    from /usr/lib/ruby/vendor_ruby/bundler/installer.rb:58:in `run'
    from /usr/lib/ruby/vendor_ruby/bundler/rubygems_integration.rb:93:in `with_build_args'
    from /usr/lib/ruby/vendor_ruby/bundler/installer.rb:57:in `run'
    from /usr/lib/ruby/vendor_ruby/bundler/spec_set.rb:12:in `each'
    from /usr/lib/ruby/vendor_ruby/bundler/spec_set.rb:12:in `each'
    from /usr/lib/ruby/vendor_ruby/bundler/installer.rb:49:in `run'
    from /usr/lib/ruby/vendor_ruby/bundler/installer.rb:8:in `install'
    from /usr/lib/ruby/vendor_ruby/bundler/cli.rb:222:in `install'
    from /usr/lib/ruby/vendor_ruby/bundler/vendor/thor/task.rb:22:in `send'
    from /usr/lib/ruby/vendor_ruby/bundler/vendor/thor/task.rb:22:in `run'
    from /usr/lib/ruby/vendor_ruby/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
    from /usr/lib/ruby/vendor_ruby/bundler/vendor/thor.rb:246:in `dispatch'
    from /usr/lib/ruby/vendor_ruby/bundler/vendor/thor/base.rb:389:in `start'
    from /usr/bin/bundle:13

Answer 1

It's clear in the error message and I'm sure other saw it very clearly: Installing unicode_utils (1.4.0) /usr/lib/ruby/vendor_ruby/1.8/rubygems/installer.rb:388:in `ensure_required_ruby_version_met': unicode_utils requires Ruby version >= 1.9.1. (Gem::InstallError)

You are using a global version of Ruby 1.8. UnicodeUtils works with Ruby 1.9.1 or later

For RVM:

$ rvm --default use 1.9.2

In your Gemfile:

gem 'unicode_utils', '~> 1.4.0'

Installing from terminal works the same.