Ivan says to 電訊台
One line OpenSSL digest generation bash echo -n 'MAC Address' | xxd -r -p | openssl dgst -sha1 -mac HMAC -macopt hexkey:8544E3B47ECA58F9583043F8 | awk '{print $2}' | cut -c 1-24 | sed 's/.\{4\}/& /g'