无法在 NODE.JS 中重新启动服务器。 Nodemon 命令不起作用，不会重新启动

Question

我今天刚接触 NODE JS，这是我第一天使用它，但我似乎无法使用 node mon server 命令重新启动服务器。但是每次我把它放在终端上时我都会得到这个，[![在终端输入这个时会显示这个][1]][1]

https://i.stack.imgur.com/yR2qD.png 请查看此图片，打开此链接，这是我尝试重新启动服务器时得到的

`

const express = require('express');
    const cors = require('cors');
    const mongoose = require('mongoose');
    
    require('dotenv').config();
    
    const app = express();
    const port = process.env.PORT || 5000;
    
    app.use(cors());
    app.use(express.json()); //parse json
    
    const uri = process.env.ATLAS_URI;//setting env variables
    mongoose.connect(uri, { useNewUrlParser: true, useCreateIndex: true }
    );
    
    
    const connection = mongoose.connection;
    connection.once('open', () => {
      console.log("MongoDB database connection established successfully");
    })
    
    const exercisesRouter = require('./routes/exercises');
    const usersRouter = require('./routes/users');
    
    app.use('/exercises', exercisesRouter);
    app.use('/users', usersRouter);
    
    app.listen(port, () => {
        console.log(`Server is running on port: ${port}`);
    });