nixos/cjdns: prefer 'install' over 'chmod'

            shopt -s lastpipe

            ${pkg}/bin/makekeys | { read private ipv6 public; }

            umask 0077

            echo "CJDNS_PRIVATE_KEY=$private" >> /etc/cjdns.keys

            echo -e "CJDNS_IPV6=$ipv6\nCJDNS_PUBLIC_KEY=$public" > /etc/cjdns.public

            chmod 600 /etc/cjdns.keys

            chmod 444 /etc/cjdns.public

            install -m 600 <(echo "CJDNS_PRIVATE_KEY=$private") /etc/cjdns.keys

            install -m 444 <(echo -e "CJDNS_IPV6=$ipv6\nCJDNS_PUBLIC_KEY=$public") /etc/cjdns.public

        fi

        if [ -z "$CJDNS_ADMIN_PASSWORD" ]; then