(error) ERR unknown command 'redis-cli'

We have installed the redis client.

When we type the following command inside C:\Program Files\Redis\redis-cli.exe:

redis-cli -h redis-server.example.com -p 6390 ping

It throws the following error:

(error) ERR unknown command 'redis-cli'

And the same command when fired inside inside C:\Windows\System32\cmd.exe throws the following error:

'redis-cli' is not recognized as an internal or external command, operable program or batch file.

Notice that Path is set to C:\Program Files\Redis\redis-cli.exe

What is the problem?

via Student