I'm far from an expert so you should probably ask someone other than me. But my two cents would be not to paste any code until you have understood it, or unless

I'm far from an expert so you should probably ask someone other than me. But my two cents would be not to paste any code until you have understood it, or unless it's written by a source you trust, or alternatively only paste it somewhere you don't care - when I'm playing around testing stuff I might not fully understand on a linux server I do it on a VPS that's unimportant to me, and that if I mess it up I can very easily restore it back to a clean OS install and I have a bash script ready to reinstall all software I want & all the profile customisations etc.