HackNet

The best hacking game ever, Its a modern super immersive terminal-driven hacking game with a fully internally-consistent network simulation and an interface so real you shouldn't play it in an airport. It follows the story of recently deceased hacker "Bit", whose death may not be the 'accident' the media reports. You stand in for no one, as most games have you do - play for yourself, make your own decisions, and see the world react - if you're leaving a trace that is.
Hacknet has no protagonist, other than the person using it. Don't be reckless though - it's more real than you think. You also sometimes get hacked by other hackers. Example: Naix. There's also an expansion DLC - Hacknet Labyrinths

When someone is talking smart (ie. Hacking, ddosing, dosing) when they don't know anything and should learn from the hacking simulator Hacknet. Hacknet is a hacking simulator released to Steam on August 12, 2015.