config.nix

{
  # The script uses either the CLI or GUI program depending on being in a shell or not.
  environment.interactiveShellInit = "export PINENTRY_USER_DATA=$TTY";
}

pinentry

#!/usr/bin/env bash

# http://unix.stackexchange.com/questions/236746/change-pinentry-program-temporarily-with-gpg-agent
# https://github.com/keybase/keybase-issues/issues/1099#issuecomment-59313502
if [[ -z $PINENTRY_USER_DATA ]]; then
  exec pinentry-gtk-2 "$@"
else
  exec pinentry-curses --ttyname "$PINENTRY_USER_DATA" "$@"
fi