use IPC::Open2

my $outer = "foo";

sub testSub {
    my $inner  = "baz";
    my $forkID = fork();
    if ($forkID == 0) {
        print "outer = $outer\ninner = $inner\n";
    }
    return;
}

testSub();

#!/usr/bin/perl
use strict;
use warnings;

my @outer;
testSub();
print @outer;

sub testSub {
    my ($pid, $inner);
    my $cnt = 0;
    
        for (1 .. 5) {
            if (defined($pid = fork)) {
                if ($pid == 0) {
                    $inner = ++$cnt;
                    push @outer, "Child: $inner\n";
                    exit(0);
                }
                else {
                    print "PID: $pid\n";
                    next;
                }
                    
            }
            else { die "Can't fork $!" }
            
        }
}