sudo 运行 npm或node时，出现找不到命令的情况，运行下面这些命令，
sudo ln -s /usr/local/bin/node /usr/bin/node
sudo ln -s /usr/local/lib/node /usr/lib/node
sudo ln -s /usr/local/bin/npm /usr/bin/npm
sudo ln -s /usr/local/bin/node-waf /usr/bin/node-waf
原文在这边，
https://ask.fedoraproject.org/en/question/23300/npm-command-as-root-user-not-found