how to get the ID of a process executed via setsid

Question

I\'m planning to control some programs (like a media player and a shell) via a webapp, since the webpage die everytime the user visits it, I decided that the webapp will ope

Answer 1

Only somewhat intricate methods using strace come to my mind.

If you can do without redirecting standard error:

read _ _ sid < <(2>&1 strace -esetsid setsid bash -i <fifoin >fifoout)
echo $sid

If you need to redirect standard error:

strace -o/tmp/filename -esetsid setsid bash -i <fifoin >fifoout 2>&1 &
sleep 1 # Hope 1 s is long enough
read _ _ sid </tmp/filename
echo $sid

Answer 2

You still need to background the process with &, otherwise it'll be running in the foreground blocking the following lines from even attempting to execute.

setsid bash -i <fifoin >fifoout 2>&1 &
kill $!