use warnings;
use strict;

my $pid = fork();

if ($pid){
    print "parent...\n";
}
else {
    sleep 2;
    system "test.bat";
}

if ($pid){
    print "parent: doing stuff...\n";
}
else {
    print "child: exiting\n";
}

if ($pid){
    print "parent: done doing stuff, waiting...\n";
    wait;
    print "parent: children dead, safe to exit\n";
}

##</code><code>##

parent: doing stuff
parent: done doing stuff, waiting...

"inside batch script"
child: exiting
parent: children dead, safe to exit