eval { require "$FindBin::Bin/../kohalib.pl" };
}
+use Koha::Script;
+
use Getopt::Long;
use Pod::Usage;
use MARC::Field;
=item B<--unless-exists>
-Will only create the new fields if this field does not exist
+Will only create the new fields if this field does not exist.
+
+For instance, if --field='905$a=0/%Y' and --unless-exists='905$a' are provided, a 905$a will be created unless there is already one.
+If --unless-exists is not passed, a new 905$a will be created in any case.
+
=back