A simple Ruby gem example for testing its usage in an IRB console

gem build sample_gem.gemspec
gem install ./sample_gem-0.1.0.gem
irb

In the IRB session, require your gem:

require 'sample_gem'

Now, you can create an instance of SampleGem and call its methods:

gem_instance = SampleGem.new
gem_instance.greet

You should see the output:

SampleGem instance created!
Hello from SampleGem!