nodemon error on start server

[edusantana]

After instalation of nodemon:

    $ npm install nodemon --save-dev

And updating the start script:

  "scripts": {
    "start": "nodemon -w server.js server.js",

I get this error (ubuntu 16.04 and node v10.14.2):

$ npm start

> [email protected] start /home/eduardo/w/node/pro-mern-stack
> nodemon -w server.js server.js

sh: 1: nodemon: not found
npm ERR! file sh
npm ERR! code ELIFECYCLE
npm ERR! errno ENOENT
npm ERR! syscall spawn
npm ERR! [email protected] start: `nodemon -w server.js server.js`
npm ERR! spawn ENOENT
npm ERR! 
npm ERR! Failed at the [email protected] start script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /home/eduardo/.npm/_logs/2018-12-29T14_00_13_944Z-debug.log

I had to change the nodemon call:

  "scripts": {
    "start": "npx nodemon -w server.js server.js",