To run this, you can try:
curl -ks https://gist.github.com/bojoer/8613437/raw/uninstall-node.sh | bash
Alternatively,
curl -ksO https://gist.github.com/bojoer/8613437/raw/uninstall-node.sh
chmod +x ./uninstall-node.sh
./uninstall-node.sh
rm uninstall-node.sh
I've tested both methods and can confirm that both ways work except the first method will not run if you did not allow executing of unverified author or untrusted applications and scripts.