Express command not found

With the release of Express 4.0.0 it looks like you need to do sudo npm install -g express-generator.

You need to run:

npm install -gd express-generator

The original express with cli, now the cli split into separate express-generator package. Originally generated by the project is running express node app.js, because httpserver relevant code in app.js, and now this part of the code to the project directory bin/www below, app.js retain only achieve app logic code, you need to run the bin/www. Just a very simple application and refinement package dependency version changes.