The folks at 4chan are well-known for their malicious pranks, with this being one of the newest. The image claims that all post-2009 Macs come with a Bitcoin miner built-in, and that it simply needs to be unlocked by typing a certain string in Terminal. First of all, it’s never a wise idea to type random stuff in Terminal/Command Prompt unless you know what you’re doing. This particular command simply reformats your hard drive.
This isn’t the first time that 4chan trolls have tried to trick people into destroying their devices. A recent prank caused Xbox One users to brick their devices in the hopes of attaining backwards compatibility with Xbox 360 games.
Another prank was designed to trick iPhone users into dropping their phones in water.
So in short, if something seems too good to be true, it usually is. Macs do not come with Bitcoin miners built in. But if you do want to mine on a Mac, DiabloMiner is one of the best.