Look before you paste from a website to terminal 9 years ago
or you could just copy the code-snippet by placing the mouse next to character 'l' of 'ls' and mark it with shift+right arrow key.
Each selected character and of course white space gets highlighted. When you highlighted the white space next to 'ls' on the right next highlighted character should be '-' but i keeps on marking seemingly forever. If you paste that you'll see that every single character of 'invisible' code gets marked.