/usr/bin/ruby ruby is an interpreted scripting language for quick and easy object-oriented programming. It has many features to process text files and to do system management tasks (like in Perl).
/System/Library/Frameworks/Ruby.framework/Ruby Ruby framework contains interfaces for the Ruby scripting language.
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby Ruby is an interpreted scripting language for quick and easy object-oriented programming. It has many features to process text files and to do system management tasks (like in Perl). It is simple, straight-forward, and extensible. If you want a language for easy object-oriented programming, or you don't like the Perl ugliness, or you do like the concept of LISP, but don't like too many parentheses, Ruby might be your language of choice.
The binary is a part of Ruby public framework.