ill continue

my @files=@{finder()}; 

sub finder{ 
  use File::Find;
  my $lpre=length($prefix); 
  my $lext=length($ext); 
  my $mustbesize=$lpre+$count+$lext; 

  my @txts; 

  find(sub { 
            my $name=substr($File::Find::name,2); # kill the ./ ; 
            return unless (length($name)==$mustbesize); 
            return unless (substr($name,0,$lpre) eq $prefix); 
            return unless (substr($name,-1,$lext) eq $ext); 
            return unless (substr($name,$lpre,$count)=~m/^\d+$/); 
            push @txts,$name;
           }
      , '.');

  return \@txts ; 

}  # finder
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Edit, opps, added the digits test, hope i did it right with substr as an lvalue