Christian Bäuerlein stellt das Thema vor
The Lost Art of Single File Ruby Programs
A loose collection of Ruby fun facts and examples to organize your code in a single file.
Ruby is a very concise language and offers some nice features if you want to put all your functionality in one file, which is especially useful if you use Ruby for scripting.
I want to present some fun and/or practical examples that you might or might not know.