Javascript package.json“中的生成脚本出现npm错误”；命令的语法不正确"；

最近，我在学习YouTube教程时尝试设置react应用程序。 我已经阅读了其他文章，但找不到我的语法到底有什么问题

这是我的package.json文件

{
  "name": "reactenv",
  "version": "1.0.0",
  "description": "React Enviroment",
  "main": "index.js",
  "scripts": {
    "start": "npm run build",
    "build": "webpack -d && copy src/index.html dist/index.html && webpack-dev-server --content-base src/ --inline",
    "build:prod": "webpack -p && copy src/index.html dist/index.html"
  },
  "keywords": [
    "reactjs"
  ],
  "author": "Lee Warner",
  "license": "ISC",
  "dependencies": {
    "react": "^16.12.0",
    "react-dom": "^16.12.0"
  },
  "devDependencies": {
    "babel-loader": "^8.0.6",
    "babel-preset-es2016": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "babel-preset-stage-2": "^6.24.1",
    "webpack": "^4.41.2",
    "webpack-cli": "^3.3.10",
    "webpack-dev-server": "^3.9.0"
  }
}

---

一个接一个地运行命令（而不是通过&&&）以了解刚刚发生的错误和复制命令需要的错误，现在出现一个错误，说“找不到指定的文件”我想我需要找到一个新教程-_-这充满了错误，除非每次我想打开项目时都安装webpack，然后安装webpack dev server，然后只在vs代码终端中复制，而不在其他任何地方复制，否则一切都不起作用。然而，当我只运行npm start时，它就不起作用了

{
  "name": "reactenv",
  "version": "1.0.0",
  "description": "React Enviroment",
  "main": "index.js",
  "scripts": {
    "start": "npm run build",
    "build": "webpack -d && copy src/index.html dist/index.html && webpack-dev-server --content-base src/ --inline",
    "build:prod": "webpack -p && copy src/index.html dist/index.html"
  },
  "keywords": [
    "reactjs"
  ],
  "author": "Lee Warner",
  "license": "ISC",
  "dependencies": {
    "react": "^16.12.0",
    "react-dom": "^16.12.0"
  },
  "devDependencies": {
    "babel-loader": "^8.0.6",
    "babel-preset-es2016": "^6.24.1",
    "babel-preset-react": "^6.24.1",
    "babel-preset-stage-2": "^6.24.1",
    "webpack": "^4.41.2",
    "webpack-cli": "^3.3.10",
    "webpack-dev-server": "^3.9.0"
  }
}