ldns-read-zone: invalid option -- '-' read zone version 1.6.17 (ldns version 1.6.17)

ldns-read-zone: invalid option -- '-' Usage: ldns-read-zone [OPTIONS] <zonefile> Reads the zonefile and prints it. The RR count of the zone is printed to stderr. -b include Bubble Babble encoding of DS's. -0 zeroize timestamps and signature in RRSIG records. -c canonicalize all rrs in the zone. -d only show DNSSEC data from the zone -h show this text -n do not print the SOA record -p prepend SOA serial with spaces so it takes exactly ten characters. -s strip DNSSEC data from the zone -S [[+|-]<number> | YYYYMMDDxx | unixtime ] Set serial number to <number> or, when preceded by a sign, offset the existing number with <number>. With YYYYMMDDxx the serial is formatted as a datecounter, and with unixtime as the number of seconds since 1-1-1970. However, on serial number decrease, +1 is used in stead. (implies -s) -u <rr type> Mark <rr type> for printing in unknown type format. This option may be given multiple times. -u is not meant to be used together with -U. -U <rr type> Mark <rr type> for not printing in unknown type format. This option may be given multiple times. The first occurrence of the -U option marks all RR types for printing in unknown type format except for the given <rr type>. Subsequent -U options will clear the mark for those <rr type>s too, so that only the given <rr type>s will be printed in the presentation format specific for those <rr type>s. -U is not meant to be used together with -u. -v shows the version and exits -z sort the zone (implies -c). if no file is given standard input is read