From that link, it would appear that’s not a valid Raspbian command. :
I’ve looked into the launchpad method too but I’m unable to run the
sudo add-apt-repository ppa:gridcoin/gridcoin-stable
I get this error
sudo: add-apt-repository: command not found
This is on a Raspberry Pi 3 running Raspbian.
scalextrix55 · 4 months ago
You will need to flash your SD card with Ubuntu for the launchpad to work I think, I never used it myself.