'vue' 不是内部或外部命令，也不是可运行的程序 或批处理文件。安装vue无效

• • 问题
  • 重新安装vue仍然失败
  • 解决

问题

当我用vue创建项目的时候，出现问题，排查后如下：

C:\WINDOWS\system32>vue -v
'vue' 不是内部或外部命令，也不是可运行的程序
或批处理文件。

即win10未识别vue。

重新安装vue仍然失败

于是

C:\WINDOWS\system32>npm install vue -g
+ vue@2.6.14
updated 1 package in 2.265s

明明已经安装成功了。
但是，在 C:\Users\xxxx\AppData\Roaming\npm目录下，找不到 vue.cmd!!!

这就导致就算我配置了环境变量，系统仍然识别不了 vue 命令

解决

各种百度，各种搜索都不能解决，我都快要卸载node重新安装了。

这时突然灵光一闪，想起安装 vue-cli 的时候的报错信息：

C:\WINDOWS\system32>npm install -g  @vue/cli
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated @hapi/joi@15.1.1: Switch to 'npm install joi'
npm WARN deprecated @hapi/address@2.1.4: Moved to 'npm install @sideway/address'
npm WARN deprecated @hapi/bourne@1.3.2: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated @hapi/hoek@8.5.1: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated @hapi/topo@3.1.6: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated har-validator@5.1.5: this library is no longer supported
npm WARN deprecated uuid@3.4.0: Please upgrade  to version 7 or higher.  Older versions may use Math.random() in certain circumstances, which is known to be problematic.  See https://v8.dev/blog/math-random for details.
npm ERR! Unexpected end of JSON input while parsing near '...t":"7.12.1","eslint-f'

npm ERR! A complete log of this run can be found in:
npm ERR!     C:\Users\xxxx\AppData\Roaming\npm-cache\_logs\2021-06-30T15_19_25_551Z-debug.log

这个报错是npm版本不对，于是升级npm

C:\WINDOWS\system32>npm install npm -g
C:\Users\xxxx\AppData\Roaming\npm\npx -> C:\Users\xxxx\AppData\Roaming\npm\node_modules\npm\bin\npx-cli.js
C:\Users\xxxx\AppData\Roaming\npm\npm -> C:\Users\xxxx\AppData\Roaming\npm\node_modules\npm\bin\npm-cli.js
+ npm@7.19.0
added 256 packages from 146 contributors in 18.008s

再安装 vue-cli

C:\WINDOWS\system32>npm install -g  @vue/cli
npm WARN deprecated urix@0.1.0: Please see https://github.com/lydell/urix#deprecated
npm WARN deprecated resolve-url@0.2.1: https://github.com/lydell/resolve-url#deprecated
npm WARN deprecated har-validator@5.1.5: this library is no longer supported
npm WARN deprecated uuid@3.4.0: Please upgrade  to version 7 or higher.  Older versions may use Math.random() in certain circumstances, which is known to be problematic.  See https://v8.dev/blog/math-random for details.
npm WARN deprecated @hapi/topo@3.1.6: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated @hapi/bourne@1.3.2: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated @hapi/address@2.1.4: Moved to 'npm install @sideway/address'
npm WARN deprecated request@2.88.2: request has been deprecated, see https://github.com/request/request/issues/3142
npm WARN deprecated @hapi/hoek@8.5.1: This version has been deprecated and is no longer supported or maintained
npm WARN deprecated uuid@3.4.0: Please upgrade  to version 7 or higher.  Older versions may use Math.random() in certain circumstances, which is known to be problematic.  See https://v8.dev/blog/math-random for details.
npm WARN deprecated @hapi/joi@15.1.1: Switch to 'npm install joi'

added 938 packages, and audited 939 packages in 3m

59 packages are looking for funding
  run `npm fund` for details

8 vulnerabilities (4 moderate, 4 high)

Some issues need review, and may require choosing
a different dependency.

Run `npm audit` for details.

这时候，vue.cmd终于下载成功了！

vue也能正常使用了

C:\WINDOWS\system32>vue --version
@vue/cli 4.5.13