my $regex = {
    'txt'  => qr{.*txt$}i,
    'conf' => qr{.*conf$}i
    # ... and so on
};

opendir DH, '.';

while(my$file=readdir(DH)){
  for (keys %$regex){
    if ($file =~ /$regex->{$_}/){
      print "$file has ", uc$_, " ext\n"
    }
  }
}
[download]