Build Awesome Command-Line Applications in Ruby 2

Chapter 3Be Helpful

In the previous chapter, we learned how to make an easy-to-use command-line interface. We learned the elements that make a well-formed command-line interface and how to design simple apps and command suites that accept arguments, flags, switches, and commands in an unsurprising^[20] way. What we didn’t talk about was how a user finds out what options and commands such apps provide, what their options mean, and what arguments they accept or require. Without this information, our app might do the job expected of it, but it won’t be very helpful.

Fortunately for us, the standard Ruby library OptionParser and the open source GLI gem give us the power to make our app helpful without a lot of effort. In fact, you’ll see that ...