I love providing you with links to great code examples; but it’s time to shake things up.
I have found, for you, a link to the worst piece code example I have seen in some time. The code itself is great, but what it actually does is so bad that I can’t get into describing it here.
Without further delay, check out letting complete strangers run shell commands on your server.
In fairness to the author, he does put a disclaimer that basically says you should never ever use this code. But it’s too good of an opportunity for me to pass up: a chance to remind everyone that code can be incredibly dangerous.