Ruby ID name and variable scope

Ruby identifiers are used to point to constants, variables, methods, classes, and modules. The first letter of the identifiers helps us determine the scope of the content that the identifiers direct.

Ruby is case sensitive.

Ruby uses a convention to help it differentiate the usage of a name:

A) the first character before the name indicates the usage of the name.

B). The local variables, method parameters, and method names should start with a lowercase letter or an underline.

C) The global variable uses the dollar sign as the prefix $.

D) instance variables start.

E). class variables start.

F). The class name, Module name, and constant should start with an uppercase letter.

The first letter can be followed by any combination of letters, numbers, and underscores;

@ Cannot be followed by numbers directly.