Hi,
something like

unless (-e $file) {
        open(FH,">", "$file") or die $!;
}
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is almost always wrong as it's open to race conditions.

So you're better off avoiding file tests:

use Fcntl;
# Open $file for writing unless it already exists
sysopen(FH, $file, O_WRONLY|O_EXCL|O_CREAT) or die $!;
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HTH,
Thomas