Consider the following simplified example:
my_prog|awk '...' > output.csv &
my_pid="$!" #Gives the PID for awk instead of for my_prog
sleep 10
kill $my_pid #my_prog still has data in its buffer that awk never saw. Data is lost!
In bash, $my_pid points to the PID for awk. However, I need the PID for my_prog. If I kill awk, my_prog does not know to flush it's output buffer and data is lost. So, how would one obtain the PID for my_prog? Note that ps aux|grep my_prog will not work since there may be several my_prog's going.
NOTE: changed cat to awk '...' to help clarify what I need.