what about skipping the directory entries?

my $dir = '/Path/to/a/data/directory';

opendir my $DH, $dir or die "Cannot open '$dir' $!";

my %hash;
while ( my $file = readdir $DH ) {

    next if $file =~ /~$/;
    next if -d "$dir/$file";                       # should also skip 
+'.' and '..' entries

    # read and process file
}
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update: fix path issue "$dir/$file"