macOS script which executes the command line, and when the command finishes posts a macOS notification that the command has finished, it's time(1) info, and the exit code.

exec-notify.sh

#!/bin/sh -e

TIMEFILE=`mktemp -t exec-notify` || exit 1

EXIT_CODE=0
/usr/bin/time -o "${TIMEFILE}" "$@" || EXIT_CODE=$?

cat "${TIMEFILE}"
echo exit=$EXIT_CODE

MESSAGE="exec “$1 …”\ntime: `cat ${TIMEFILE}`\nexited: $EXIT_CODE"                

rm "${TIMEFILE}"

osascript -e "display notification \"$MESSAGE\" with title \"Terminal.app\""

exit $EXIT_CODE

Example:

% exec-notify.sh some very long command
… output of `some very long command`…
      100.20 real        31.88 user        25.83 sys
exit=0