I was having the same issue when tried with the syntax "ng new " and solved that simply by updating the existing node version from 5.x.x to 8.x.x. After successful updation of node, the syntax worked perfectly for me. Please update the existing version of node. As it is clearly mentioned in angular documentation that these commands require the node version >= 6.9.x. For reference please check https://angular.io/guide/quickstart. It clearly states "Verify that you are running at least node 6.9.x and npm 3.x.x by running node -v and npm -v in a terminal/console window. Older versions produce errors, but newer versions are fine".

打开cmd，输入npm install -g @angular/cli 在环境变量中，在用户变量或系统变量中添加“Path”value=C:\Users\your-user\.npm-packages\node_modules\.bin 打开cmd: c:\>cd your-new-project-path .．.\project-path\> ng new my-app 或者ng all-ng-commands

安装x32版本的nodejs而不是x64版本(即使在64位windows机器上)。

我必须将npm路径添加到user path环境变量中。你可以以管理员身份运行以下PowerShell脚本:

$path = npm config get prefix    
$userPath = [Environment]::GetEnvironmentVariable("Path", "User")

if (($userPath -split ';') -notcontains $path) 
{
    [Environment]::SetEnvironmentVariable("PATH", ('{0};{1}' -f $userPath, $path), "User")
}

与其使用内置的命令提示符，不如开始使用NodeJS安装版本的命令提示符。然后它将完美地工作，没有任何问题。

在尝试更新Windows 7 (x64)上的PATH变量之前，运行CMD控制台AS ADMINISTRATOR和ng命令对我有用，这也适用于VISUAL STUDIO CODE控制台。

它为我工作在CMD控制台/ VS CODE