# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/^((?:[0-9A-Fa-f]{2}(?:[:-]?)){7}(?:[0-9A-Fa-f]{2}))$//gm;t' <<< "00:13:a2:00:41:8b:93:7a
0013a200418b937a
AD:12:13:FC:14:EE:FF:FF
ad-12-13-fc-14-ee-ff-ad"
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for SED, please visit: https://www.gnu.org/software/sed/manual/html_node/The-_0022s_0022-Command.html