What command line shall i use to know about the random IP address being changed by hackers?

I wonder if any hackers could change my IP address if it is set random but not fixed with router, and what command line i shall use to know about the IP address being changed or control or connected with someone else's PC...

What is a VPN?

VPN is (Virtual Private Network) were first used by companies to enable their employees to securely access internal systems such as email remotely (e.g. from home or while on business trips). Today they are increasingly being used for personal use by individuals to protect their privacy while online in public places (e.g. when using the wi-fi connection in a cafe) or in a country where the internet is censored / blocked (e.g. China, Saudi Arabia��).