一但重開機，要執行npm，就要執行底下

nvm use stable

應該是自己那沒設好

http://learn.bevry.me/node/install/

git clone git://github.com/creationix/nvm.git ~/.nvm
printf “\n\n# NVM\nif [ -s /.nvm/nvm.sh ]; then\n\tNVM_DIR=/.nvm\n\tsource ~/.nvm/nvm.sh\nfi” » /.bashrc
NVM_DIR=/.nvm
source ~/.nvm/nvm.sh

nvm use stable

nvm list