I want to run a c prog in background using shell script and once the prog starts running in background my shell script should continue to run without waiting for the c prog to end.
I am using ampersand '&' for the same but it my script still waits for the c prog to end.

Please help.

This is my script.


. /s2.sh

func2 $pid


run_mem_eater_prog() {     
     echo $curr_pid
     return $curr_pid

When I run s1.sh, func1 gets executed then "run_mem_eater_prog" is called which executes ./mem_eater (c executable) and the scripts waits for it to get finished and then calls func2.

How to call func2 without waiting for mem_eater to finish?

  • What is func1 and func2? The pid variable in sh2.sh will be set to the string run_mem_eater_prog, but it will not call the run_mem_eater_prog shell function. Use pid=$(run_mem_eater_prog) for that. – Kusalananda Mar 14 '17 at 8:50
  • sorry for the typo. I am calling it as pid=$(run_mem_eater_prog). – Anamika Lall Mar 14 '17 at 9:56
  • In func2 I have to use the pid returned and write it into sys/fs/cgroups/memory/tasks. ./mem_eater is a c prog which does some malloc and memset in a continuous loop(50 times). Problem is, my script waits for this ./mem_eater to get finished and then runs func2, by the time $pid is passed to func2 as prog already ended i get an error of no such process exists. – Anamika Lall Mar 14 '17 at 10:06
  • It's not that the mem_eater program actually has time to finish and exit before func2 is called? Allocating memory 50 times may be a quick operation. – Kusalananda Mar 14 '17 at 10:08
  • I have added a delay of 1 sec for every loop. – Anamika Lall Mar 14 '17 at 10:14

Try this:

( ./mem_eater & )

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.