## pseudo code:
my %cache_of_already_read_files;
my $sleep_between = 300;

while (1){
   
      my @xml = &get_xml_files_names; # opendir, system (ls)..
      foreach (@xml) {
         next if exists $cache_of_already_read_files{$_};
         $cache_of_already_read_files{$_} = 'found at'.scalar (localti
+me(time));
         &my_copy_to_destination ($cache_of_already_read_files{$_} );
     }
     sleep $sleep_between;
}
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