rndc-confgen: invalid argument --
Usage:
 rndc-confgen [-a] [-b bits] [-c keyfile] [-k keyname] [-p port] [-s addr] [-t chrootdir] [-u user]
  -a:		 generate just the key clause and write it to keyfile (/etc/bind/rndc.key)
  -A alg:	 algorithm (default hmac-sha256)
  -b bits:	 from 1 through 512, default 256; total length of the secret
  -c keyfile:	 specify an alternate key file (requires -a)
  -k keyname:	 the name as it will be used  in named.conf and rndc.conf
  -p port:	 the port named will listen on and rndc will connect to
  -q:		 suppress printing written key path
  -s addr:	 the address to which rndc should connect
  -t chrootdir:	 write a keyfile in chrootdir as well (requires -a)
  -u user:	 set the keyfile owner to "user" (requires -a)