title: How can I run a Ruby gem from the shell?
body: <p>Say I have a gem that transforms from Celsius to Fahrenheit. So, from within my IRB, and after the gem is installed, I can do:</p>
  
  <pre><code>Temperature.convert_to_celsius(80)
  </code></pre>
  
  <p>My question is, how do you modify a gem in order for it to be able to be run from the shell? I  have seen some gems that have a bin folder, but I am not sure how to proceed. What is the proper way of doing so?</p>