Changes

Use of global variables is strongly discouraged. The problem with global variables is that, not only are they visible anywhere in the code for a program, they can also be changed from anywhere in the application. This cna can make tracking bugs difficult.

It is useful to know, however, that a number of pre-defined global variables are available to you as a Ruby developer to obtain information about the Ruby enviromentenvironment. A brief summary of each of these variables is contained in the following table.