-.It Fl 4
-Forces
-.Nm
-to use IPv4 addresses only.
-.It Fl 6
-Forces
-.Nm
-to use IPv6 addresses only.
-.It Fl f Ar file
-Read hosts or
-.Pa addrlist namelist
-pairs from this file, one per line.
-If
-.Pa -
-is supplied instead of a filename,
-.Nm
-will read hosts or
-.Pa addrlist namelist
-pairs from the standard input.
-.It Fl H
-Hash all hostnames and addresses in the output.
-Hashed names may be used normally by
-.Nm ssh
-and
-.Nm sshd ,
-but they do not reveal identifying information should the file's contents
-be disclosed.