$ a
6294  a.exe-out.txt

$ perl pm904757.pl
6281  pm904757.pl-out.txt

$ a
6294  a.exe-out.txt

$ perl pm904757.pl
6325  pm904757.pl-out.txt

$ a
6330  a.exe-out.txt

$ perl pm904757.pl
6323  pm904757.pl-out.txt

$ perl pm904757.pl
6330  pm904757.pl-out.txt