#!/bin/bash USERNAME=$1 AUTHSTRING=00:00:00:00:00:00:00:00:00:00:00:66:74:69:2f for (( i=0; i<${#USERNAME}; i++ )); do HEXCHAR=$(echo -n ${USERNAME:$i:1} | od -An -txC | xargs) AUTHSTRING=${AUTHSTRING}:${HEXCHAR} done echo ${AUTHSTRING}