I see your point but I'm not sure about this... Everyone already uses an OS for everything by definition... In this case we just want to let the reader know that if he/she usually prefers doing everything via the package manager of the OS that's being used, he/she can also install ruby with it.

What about:
"Infine, se solitamente preferisci usare gli standard del tuo sistema operativo, Ruby è installabile tramite i più comuni sistemi di gestione dei pacchetti"