fork + exec + caller should not wait for child

Question

I have two scripts script_a and script_b. script_a calls script_b. script_b forks two processes. As shown below.

script_a waits for both the parent and child of script_b

Answer 1

`` backticks in perl wait for the command to complete. So if you don't want parent process to wait put in sytem(command &) in background.

Answer 2

Instead of using `` in script_a. We have redirected the STDOUT and STDERR in script_a. Something like

script_a

system("script_b.pl > /var/tmp/out_file 2>&1");

script_b

#! /usr/local/bin/perl

$f_id = fork();

if (! $f_id) {
    exec("sleep 10; echo 'i am child'");
}

if ($f_id) {
    print "i am parent\n";
}

This way the caller didnot wait for the child in exec to complete.

Thanks for the help here.