I want keep private my main wallet.
Why? If you really want privacy, you can send all your funds through a mixer and have a new private wallet. I will remove my negative trust if you share the transaction and I can verify the dates and other things. Or let me guess, you scammed someone before and don't want us knowing?
How check private keys on vps?
vps is very generic and doesn't help to what wallet your using. If your using bitcoin core, one of the commands you can use is dumpprivkey [insert address here].