'ng' is not recognized as an internal or external command, operable program or batch file

You can also try:

 > npm run ng <command>

This error is simply telling you that Angular CLI is either not installed or not added to the PATH. To solve this error, first, make sure you’re running Node 6.9 or higher. A lot of errors can be resolved by simply upgrading your Node to the latest stable version.

Open up the Terminal on macOS/Linux or Command Prompt on Windows and run the following command to find out the version of Node you are running:

I had the same issue on Windows7. I resolved it setting correct path.

1. First find ng.cmd file on your System. It will usually at:

   E:\Users\<USERNAME>\AppData\Roaming\npm
   

2. Set PATH to this location.

3. Close existing command window and open new one

4. Type

   ng version
   

Also remember to install angular with -g command.

npm install -g @angular/cli