I am wondering if that "mkdir" is actually re-creating the sub-directories
Not really. Try it: 
mkdir 'XXX';
open my $FH, '>', 'XXX/1';
close $FH; 
mkdir "XXX" or warn $!;
open my $FH, '<', 'XXX/1' or die $!;
close $FH;

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In reply to Re^3: File APPEND/OVERWRITE by choroba
in thread File APPEND/OVERWRITE by he204035

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