The desktop app comes with the command line, but if you want to install only the command line, you are in the right place.
To manually build the binaries, see building from source.
Or are you looking for command line usage?
To install via homebrew:
brew tap keys-pub/tap brew install keys
To install via scoop:
scoop bucket add keys.pub https://github.com/keys-pub/scoop-bucket scoop install keys
Add keys.pub apt repository:
echo "deb https://storage.googleapis.com/aptly.keys.pub current main" \ | sudo tee -a /etc/apt/sources.list.d/keys.list
Add the keys apt signing public key:
wget -qO - https://storage.googleapis.com/aptly.keys.pub/keys.asc | sudo apt-key add -
sudo apt-get update sudo apt-get install keys