If you have an npm application module called say "my-node-app", when running "npm install my-node-app" a link to usr/bin/my-node-app is created. 
i.e. /usr/bin/my-node-app -> /usr/lib/node_modules/my-node-app/my-node-app.js

However devtool does not create this link when packaging the module so it cannot be run as 'my-node-app' and instead it must be started as 
node usr/lib/node_modules/my-node-app/my-node-app.js