# If you'd like to omit non-matching lines from the result; add ';d' to the end of the expression.
sed -E 's/^VIR\s+RECU\s+(\d+)\nDE:\s+([\s\S]*?)(\nMOTIF:\s+(.*))?$//g;t' <<< "VIR RECU 998721687978
DE: Mrs PAUL SMITH
564
MOTIF: ANY REASON"
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