I think object oriented programming is overrated, however I want to learn this paradigm. I have been trying to do this in PHP 5 and C++ with QT 4. Unfortunately, I tend to program in structured way, I do not use much of inheritance nor multiple instances. I think I have to learn a pure object oriented language that force me to use above features.
I think the best option is probably to learn Ruby. Could You confirm or name better alternative?
I work mainly on a x86-64 Linux.
Object-oriented programming isn’t about syntax. It a programming paradigm.
A language can force you to use objects (if everything is an object, for example) but using one of those languages isn’t going to “force” you to learn object-oriented programming.
You have to learn when and why you use these techniques (data abstraction, encapsulation, polymorphism, and inheritance) to think in objects. Get a good reference in object-oriented programming and use whatever language (that supports OOP) you are most comfortable with to apply those techniques.