Object is the base class of all other classes created in Ruby. It provides the basic set of functions available to all classes, and each function can be explicitly overridden by the user.
This class provides a number of useful methods for all of the classes in Ruby.
Object inherits from BasicObject which allows creating alternate object hierarchies. Methods on object are available to all classes unless explicitly overridden.
In Ruby, everything is an Object including classes and modules. Object and BasicObject are the most low-level class.
ARGF is a stream designed for use in scripts that process files given as command-line arguments or passed in via STDIN.
ARGV contains the command line arguments used to run ruby with the first value containing the name of the executable.
DATA is a File that contains the data section of the executed file. To create a data section use __END__:
ENV is a Hash-like accessor for environment variables.
Holds the original stderr
Holds the original stdin
Holds the original stdout