opendir(DIR, $some_dir) || die "can't opendir $some_dir: $!";
my @files = grep { /^\./ && -f "$some_dir/$_" } readdir(DIR);
closedir(DIR);
@files = sort {$a <=> $b} @files; # Ascending sort

open my $names, '<', 'newnames.txt' or die "Cannot read newnames.txt: $!\n";
foreach (@files) {
   my $name = <$names>;
   chomp $name;
   rename($_, $name) or warn "rename: $_ : $!";
}