It's not continuous at any point. As I mentioned, the image of any open interval is ##\mathbb R##. As a consequence, we take ##\varepsilon =1##, for example, and for any ##a\in\mathbb R## and ##\delta >0##, we find an ##x\in (a-\delta,a+\delta)## such that ##|f(x)-f(a)| \geqslant 1##.