The problem:
If you are using mac and install nodejs via pkg file downloaded from the official website, you are likely to encounter this error message when you try to install a npm module globally:
npm ERR! Please try running this command again as root/Administrator.
My solution
DO NOT use sudo command to install the package!
sudo npm install module -g
Some people suggest the above solution on Stack Overflow, but I strongly encourage you not to do package management with sudo. This hack may temporarily solve your problem, but you will encounter more problems later on.
Here is the recommanded way:
Step 1: Find out your username with this command:
whoami
For example, my username is victorleungtw
Step 2: Change ownership of the node modules folder:
sudo chown -R `whoami` /usr/local/lib/node_modules
Then you won’t ever have to use sudo when you install npm packages.
Originally published at victorleungtw.com on February 20, 2015.
Victor Leung 