This bash script enables GPG, Yubikey and SSH on a nixos live cd for my public key.

enable_gpg.sh

#!/run/current-system/sw/bin/sh

nix-env -iA nixos.git nixos.gnupg nixos.pinentry-curses

gpg --receive-keys DE749C31D060A160
echo "$( \
  gpg --list-keys \
  | grep DE749C31D060A160 -A 1 \
  | head -1 | tr -d '[:space:]' \
):6:" | gpg --import-ownertrust;

echo "pinentry-program $(which pinentry)" > ~/.gnupg/gpg-agent.conf
gpg-connect-agent reloadagent /bye

echo "export SSH_AUTH_SOCK=\$(gpgconf --list-dirs agent-ssh-socket)" >> ~/.bashrc
echo "export PINENTRY_USER_DATA=\"USE_CURSES=1\"" >> ~/.bashrc
echo "export GPG_TTY=\$(tty)" >> ~/.bashrc
source ~/.bashrc
gpg-connect-agent updatestartuptty /bye

echo "DONE."