How to kill all processes that were opened by a shell script upon ctrl + C?

Question

I've got a couple python scripts which I start collectively from a shell script as follows:

#!/bin/bash
python prog1.py &
python prog2.py &
python prog3.py 

Since I am developing I often want to stop these processes. I normally do so by hitting ctrl+C, but unfortuntaly a couple python programs keep (zeromq) sockets open. This means I then have to manually find them (I use lsof -i), and kill them using the PID.

So I'm looking for an easier way of automatically killing those python processes from the shell when I hit ctrl+C. On another thread here on Stackoverflow I found some code which supposedly should do what I need. I just don't understand anything about the code and how I could adjust it to my needs.

Would anybody be so kind to help me out here?

cat >work.py <<'EOF'
import sys, time, signal
signal.signal(signal.SIGINT, signal.SIG_DFL)
for i in range(10):
    time.sleep(1)
    print "Tick from", sys.argv[1]
EOF 
chmod +x work.py

function process {
    python ./work.py $1
}

process one &
wait $!
echo "All done!"

Answer 1

Let the bash script catch SIGINT, and have it kill everything in the current process group:

intexit() {
    # Kill all subprocesses (all processes in the current process group)
    kill -HUP -$$
}

hupexit() {
    # HUP'd (probably by intexit)
    echo
    echo "Interrupted"
    exit
}

trap hupexit HUP
trap intexit INT

python prog1.py &
python prog2.py &
python prog3.py &

wait