How do I stop execution of bash script?
SIGINT does not terminate the 'following iteration of the loop'. Rather, when you type ctrl-C, you are sending a SIGINT to the currently running instance of tcpdump, and the loop continues after it terminates. A simple way to avoid this is to trap SIGINT in the shell:
trap 'kill $!; exit' INTuntil [ $n -eq 0 ]do tcpdump -i eth0 -c 1000000 -s 0 -vvv -w /root/nauvoicedump/`date "+%Y-%m-%d-%H-%M"`.pcap& wait n=$(($n-1)) echo $n 'times left'doneNote that you need to run tcpdump in the background (append & to the line that starts it) for this to work. If you have other background jobs running, you may need wait $! rather than just wait.
You should set the starting value of n at least 1 higher than 0. Example:
n=100until [ "$n" -eq 0 ]...It's also a good practice to quote your variables properly.
Also it's probably better if you use a for loop:
for (( n = 100; n--; )); do tcpdump -i eth0 -c 1000000 -s 0 -vvv -w "/root/nauvoicedump/$(date '+%Y-%m-%d-%H-%M').pcap" echo "$n times left"done