test.sh

#!/bin/bash

function displayPendingTasks() {
    echo "The following machines are still running"
    
    declare -A running

    for i in ${!RUNNING_TASKS[@]}; do 
       if kill -0 $i > /dev/null 2>&1; then
          echo "PID: $i Machine: ${RUNNING_TASKS[$i]}"
          running[$i]="${RUNNING_TASKS[$i]}"
       fi
    done

    read -p "Do you wish to kill these processes and stop waiting? [y/n]: " prompt
    if [ "$prompt" == "y" ]; then
        echo "Stopping processes."
        kill -9 $(echo "${!running[@]}")
        trap - INT
        exit 0
    fi

    wait
}

trap displayPendingTasks INT

declare -a RUNNING_TASKS
for i in `seq 10 20`; do 
    sleep 20 &
    RUNNING_TASKS[$!]="machine-$i"
done

wait