Linux will continue to have nasty security holes, but again: the sky isn't falling. Your Linux system is still far more secure than the average Windows desktop. Attackers are more interested in targeting the larger Windows install base. And Linux does have a great security architecture Windows lacks, too--simply getting most of your programs from a centralized software repository instead of a gaggle of websites helps a lot.
No, you don't need to start running antivirus software on your Linux system, but be aware: You're not perfectly safe on Linux, or any other system.
Like all those Windows and Mac systems out there, your Linux system is full of security holes. We just haven't found them all yet. Be humble when talking about Linux's security or you may find yourself with egg on your face when the next Shellshock bug blows up.
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