This question already has an answer here:
I would like to be able to somehow modify a running command and/or get notified when a running command completes after it has been started.
Normally, when I know a command is going to take a long time, I will preemptively set something up for a notify:
./takes_long_time && touch done
./takes_long_time; touch done
My question is if
./takes_long_time was executed without the
touch, is there a way I can go back and add it without restarting