tcpdump-all-ints.sh

# When this exits, exit all background processes:
trap 'kill $(jobs -p) &> /dev/null && sleep 0.2 &&  echo ' EXIT

# Create one tcpdump output per interface and add an identifier to the beginning of each line:
if [[ $@ =~ -i[[:space:]]?[^[:space:]]+ ]]; then
    tcpdump -l $@ | sed 's/^/[Interface:'"${BASH_REMATCH[0]:2}"'] /' &
else
    for interface in $(ifconfig | grep '^[a-z0-9]' | awk '{print $1}'i | sed "/:[0-9]/d")
    do
       tcpdump -l -i $interface -nn $@ | sed 's/^/[Interface:'"$interface"'] /' 2>/dev/null &
    done
fi
  # wait .. until CTRL+C
wait