sub log_tag {
my $tag = shift;
- return if $saved->{tag};
+ return if $saved->{tag} or ! $log;
my $hash = Biblio::RFID::RFID501->to_hash( $rfid->blocks($tag) );
open(my $fh, '>>', $log) || die "$log: $!";
print $fh iso_date,",$tag,", $hash->{content}, "\n";