# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/\b[a-zA-Z]{1,2}\d{3,5}[a-zA-Z]?\b//gm;t' <<< "M394
,MP4245)
TD493!
X4958A
V49534@
U394U
A5909.
TED492
R32
R4!3
U394UU
A5909AA
5349A"
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