As it happens, I'm hacking right now on a Unix/Windows QA test script to fork many like processes. It's a bit hacky, but may be of use to you as an example.

use strict;
$|=1;
my $IS_WIN32 = $^O eq 'MSWin32';
my $CAN_FORK = !$IS_WIN32;
my $cmd      = "netstat -na";
my $cmd_exe;
my $SysDir;

if ($IS_WIN32) {
   $SysDir  = "$ENV{SystemRoot}\\system32";
   $cmd_exe = "$SysDir\\netstat.exe";
}

unless ($CAN_FORK) {
   require Win32::Process;
   # save original stdout and stderr
   open(SAVEOUT, ">&STDOUT"); open(SAVEERR, ">&STDERR");
}

my $OutDir = "knob.tmp";
-d $OutDir or (mkdir($OutDir) or die "error: mkdir '$OutDir': $!");

my $nproc = 3;
my @hProc = ();
my @Pids = ();
my $pid;

print "forking $nproc commands (output in dir '$OutDir').\n";

# Fork all the processes ...
for my $i (0 .. $nproc-1) {
   my $Outf = "$OutDir/$i.tmp";
   if ($CAN_FORK) {
      print "$i: cmd='$cmd'\n";
      defined($pid = fork()) or die "error: fork: $!";
      if ($pid == 0) {
         # child
         exec("$cmd >$Outf 2>&1");
         die "error: exec '$cmd': $!";
      }
      # parent continues...
   } else {
      print "$i: cmd_exe='$cmd_exe' cmd='$cmd'\n";
      # redirect stdout and stderr
      open(STDOUT, ">$Outf")   or die "can't redirect stdout";
      open(STDERR, ">&STDOUT") or die "can't dup stdout";
      Win32::Process::Create(my $hProc,               # process object
                             $cmd_exe,                # executable
                             $cmd,                    # command line
                             1,                       # inherit file h
+andles
                             Win32::Process::NORMAL_PRIORITY_CLASS(),
                             ".")                     # working dir
         or die "cannot create process $i: $! ($^E)\n";
      push(@hProc, $hProc);
      $pid = $hProc->GetProcessID();
      # parent continues (redirect back to original) ...
      close(STDOUT);close(STDERR);
      open(STDOUT, ">&SAVEOUT"); open(STDERR, ">&SAVEERR");
   }
   $Pids[$i] = $pid;
   print "$i process started ok (pid=$pid).\n";
}

# Now wait for them to finish ...
for my $i (0 .. $nproc-1) {
   print "$i waiting for process to end...\n";
   my $rc = 0;
   if ($CAN_FORK) {
      $pid = wait();
      $rc = $? >> 8;
      $pid < 0 and die "wait failed: $!";
   } else {
      $pid = $Pids[$i];
      $hProc[$i]->Wait(Win32::Process::INFINITE()) or die "error Wait:
+ $! ($^E)";
      $hProc[$i]->GetExitCode($rc) or die "error GetExitCode: $! ($^E)
+";
   }
   print "i=$i pid=$pid exit code=$rc\n";
}
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