Killall doesn't work if I call it from a bash script

Question

I'm starting a tcpdump inside a script and I also kill it from the same script. So I'm currently using the killall command for this: The script gets executed from an udev rule: This is the section, which should terminate the tcpdump : In addition I also use -s SIDKILL , because I've read that this could also help.

What is the problem that killall doesn't terminate the tcpdump . When I start the script manually it is all working properly.

 if [[ "$pid1" != "" ]];then
          sudo killall -s SIGKILL tcpdump
          sh /tmp/scripts/autoumount.sh &
          sudo kill -9 $$
          echo "autodump stopped"

Answer 1

Since you're starting tcpdump from the same script, there's no need for killall .

If you're running multiple background processes, use an array, like so:

pids=( )                 # initialize empty array
tcpdump & pids+=( "$!" ) # extend said array

...later on, you can kill those PIDs:

kill "${pids[@]}"