When I try to run the app.js file created by express, I get the following error:
$ node app.js
node.js:134
throw e; // process.nextTick
I installed gulp and when I ran this gulp command in the command line I got a gulp: command not found error. It appeared that it installed gulp in my local folder that is /home/YOURUSERNAME/.node/lib/node_modules and not in the global npm folder.
You can check npm root folder by running this command: npm root -g, which was returning my personal directory /home/YOURUSERNAME/.node/lib/node_modules and not the expected /usr/local/lib/node_modules.
You can fix this by running npm config set prefix /usr/local command.