simplify kill line

pgrep returns the PID as default output. the `-f` flag has it search the full command line, not just the 15 chars present in /proc/pid/stat's process name field
if you *really* feel the need to pipe grep into awk, try searching using awk instead like so:
    ps -ef | awk '/rabbit/ {print $8}';
to be really, really simple about it, the line could be
    pkill -SIGKILL -f rabbit