Here's one way. I'm sure others will be along shortly.

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

my @dirs = (qw/dir1 dir2 dir3 dir4/);
my @kids;

for my $i (1..4) {
  my $pid = fork();
  if ($pid) {
    # parent
    push @kids, $pid;
    print "spawned child $pid\n";
  } elsif ($pid == 0) {
    print "I am child $$. \@kids count = $#kids. my dir is $dirs[$#kid
+s+1]\n";
    sleep 5;
    exit(0);
  } else {
    die "couldn.t fork: $! \n";
  }
  print "end loop $i\n";
}
for my $pid (@kids) {
  print "reaping $pid\n";
  waitpid($pid,0);
}
[download]

Output:

I am child 20199. @kids count = -1. my dir is dir1
spawned child 20199
end loop 1
I am child 20200. @kids count = 0. my dir is dir2
spawned child 20200
end loop 2
I am child 20201. @kids count = 1. my dir is dir3
spawned child 20201
end loop 3
I am child 20202. @kids count = 2. my dir is dir4
spawned child 20202
end loop 4
reaping 20199
reaping 20200
reaping 20201
reaping 20202
[download]