use strict;
use warnings;
$| = 1;
my $cmd = qq{$^X -le "print 'pid=', \$\$"};
for my $i (1..70) {
    print "$i: run $cmd ---------\n";
    my $rc = system(1, $cmd);
    sleep(1);
    print "$i: done (rc=$rc).\n";
    $rc < 0 and print "$i: ($!)\n";
}

##</code><code>##

1: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4600
1: done (rc=384).
2: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3036
2: done (rc=4432).
3: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=7156
3: done (rc=6364).
4: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5604
4: done (rc=4000).
5: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5784
5: done (rc=2820).
6: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=1820
6: done (rc=6592).
7: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6672
7: done (rc=6484).
8: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6452
8: done (rc=4800).
9: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3340
9: done (rc=6652).
10: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4620
10: done (rc=6524).
11: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4240
11: done (rc=224).
12: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3200
12: done (rc=208).
13: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4120
13: done (rc=4112).
14: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5324
14: done (rc=1312).
15: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=7032
15: done (rc=6272).
16: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4164
16: done (rc=6884).
17: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4504
17: done (rc=6404).
18: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6292
18: done (rc=6396).
19: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=748
19: done (rc=416).
20: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6804
20: done (rc=1296).
21: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6696
21: done (rc=5712).
22: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4028
22: done (rc=7148).
23: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3220
23: done (rc=4852).
24: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6788
24: done (rc=92).
25: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6932
25: done (rc=3176).
26: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=960
26: done (rc=5332).
27: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4832
27: done (rc=6928).
28: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=1088
28: done (rc=4500).
29: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3648
29: done (rc=6456).
30: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6756
30: done (rc=3568).
31: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=332
31: done (rc=1484).
32: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5624
32: done (rc=5944).
33: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3612
33: done (rc=6576).
34: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=828
34: done (rc=4408).
35: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=3116
35: done (rc=3172).
36: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4944
36: done (rc=5956).
37: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4752
37: done (rc=3592).
38: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6668
38: done (rc=2780).
39: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6612
39: done (rc=4128).
40: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=2500
40: done (rc=6760).
41: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6808
41: done (rc=4616).
42: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5252
42: done (rc=2640).
43: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4396
43: done (rc=6368).
44: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5088
44: done (rc=2604).
45: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6828
45: done (rc=6664).
46: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6012
46: done (rc=6680).
47: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6136
47: done (rc=2980).
48: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6676
48: done (rc=6556).
49: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5764
49: done (rc=1412).
50: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6720
50: done (rc=3468).
51: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6908
51: done (rc=6156).
52: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=228
52: done (rc=2332).
53: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5204
53: done (rc=4728).
54: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6236
54: done (rc=5952).
55: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6128
55: done (rc=6924).
56: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=5988
56: done (rc=3900).
57: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6656
57: done (rc=6604).
58: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6432
58: done (rc=32).
59: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=432
59: done (rc=6324).
60: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=2376
60: done (rc=7056).
61: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6384
61: done (rc=3432).
62: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=7152
62: done (rc=5652).
63: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=6764
63: done (rc=6480).
64: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
pid=4336
64: done (rc=5028).
65: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
65: done (rc=-1).
65: (Resource temporarily unavailable)
66: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
66: done (rc=-1).
66: (Resource temporarily unavailable)
67: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
67: done (rc=-1).
67: (Resource temporarily unavailable)
68: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
68: done (rc=-1).
68: (Resource temporarily unavailable)
69: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
69: done (rc=-1).
69: (Resource temporarily unavailable)
70: run C:\Strawberry\perl\bin\perl.exe -le "print 'pid=', $$" ---------
70: done (rc=-1).
70: (Resource temporarily unavailable)