# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/-[^-]*$|:[^:\n]*$//gm;t' <<< "ABCDEF
FEDCBA:XA
AA-BB-CCCC-01
AA-BB-CCCC-21:ABC
ABCDEFGH-IJK-1X"
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