Based on the content of your question, I assume your program is running on a Unix system. Considering that any Unix already has a directory specially for the purpose of writing temporary files to, namely /tmp, why would you want to create a directory of your own?

And if you want to make it platform independent, just use:

    my $tmpdir = do {
        require 'File::Spec';
        File::Spec->tmpdir();
    };
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And there are even module that will let you write to a temporary file - but I can't judge from your question whether that will be appropriate for your needs.