Node.js 在 npm 中找不到 nodemon

我有一个问题:nodemon没有运行npm脚本(例如npm start)，

$ nodemon server.js
14 Feb 22:59:51 - [nodemon] v1.3.7
14 Feb 22:59:51 - [nodemon] to restart at any time, enter `rs`
14 Feb 22:59:51 - [nodemon] watching: *.*
14 Feb 22:59:51 - [nodemon] starting `node server.js`

在npm脚本中如何调用:

package.json

{
...
  "scripts": {
    "start": "nodemon server.js"
  }
}

运行npm启动脚本时:

$ npm start
> aaa@0.0.1 start /home/akul/Documents/aaa
> nodemon server.js

sh: 1: nodemon: not found

npm ERR! Linux 3.13.0-45-generic
npm ERR! argv "node" "/home/akul/npm-global/bin/npm" "start"
npm ERR! node v0.12.0
npm ERR! npm  v2.5.0
npm ERR! code ELIFECYCLE
npm ERR! aaa@0.0.1 start: `nodemon server.js`
npm ERR! Exit status 127
npm ERR! 
npm ERR! Failed at the aaa@0.0.1 start script 'nodemon server.js'.
npm ERR! This is most likely a problem with the aaa package,
npm ERR! not with npm itself.
npm ERR! Tell the author that this fails on your system:
npm ERR!     nodemon server.js
npm ERR! You can get their info via:
npm ERR!     npm owner ls aaa
npm ERR! There is likely additional logging output above.

npm ERR! Please include the following file with any support request:
npm ERR!     /home/akul/Documents/aaa/npm-debug.log

我一直在寻找解决方案，但还没有找到.