die "Invalid group\n" if !(defined $num && defined $first && defined $last);
my $arg_first = shift;
if (defined $arg_first) {
- $arg_first =~ /\A\d+\z/ or die $usage;
+ $arg_first =~ /\A[0-9]+\z/ or die $usage;
$first = $arg_first;
} elsif ($mm) {
my $last_article = $mm->meta_accessor('last_article');