my $fh; open $fh, "testRXD.txt" or die $!; my $i = 0; while (my $line = <$fh>){ chomp $line; system 1, $line; # printf STDERR "task %d '$line' running\n", ++$i; sleep 1 while `tasklist | find "perl.exe" | wc -l` > 100; } close $fh;