How to determine if I’m in powershell or cmd?

All credit goes to PetSerAl, this had to be posted as an aswer:

(dir 2>&1 *`|echo CMD);&<# rem #>echo PowerShell

Within Win32-OpenSSH this command also works, and outputs CMD.

NB : Win32-OpenSSH seems a bit limited, cd is not recognized on my system.