title: What is an EOFError in Ruby file I/O?
body: <p>The <a href="http://www.ruby-doc.org/core/classes/EOFError.html" rel="noreferrer">official documentation</a> doesn't specify.  I understand EOFError means "End of file error", but what exactly does that mean? If a file reader reaches the end of a file, that doesn't sound like an error to me.</p>