Ruby is well known as a language that is easy to use from the surface but is very deep and complex underneath. That’s what we know and love about it as a language. Its standard library has a similar design and as such it contains many hidden gems. One of the gems I’ve learned about recently is un. It’s designed to be a command line utility executed directly from ruby. This is its usage description:
Most of the commands have pretty limited utility. They just seem to be portable UNIX utilities for use when Ruby is present but a UNIX environment is not. In fact, the description of the package is “Utilities to replace common UNIX commands in Makefiles etc.”. Perhaps they’re useful in embedded systems (it’s my understanding that Ruby is commonly used for embedded systems in Japan).