+substitutions. The
+.I flags
+consist of zero or more of the following characters:
+.RB ` 4 '
+looks up the
+.IR host 's
+IPv4 address(es);
+.RB ` 6 '
+looks up the
+.IR host 's
+IPv6 address(es);
+and
+.RB ` * '
+returns all of the found addresses, separated by spaces, rather than
+just the first one. If neither address family is requested, then
+.RB ` 46 '
+is assumed. IPv6 address lookup of names, rather than address literals,
+depends on the external
+.BR adnshost (1)
+program; if it is not present then only IPv4 lookups will be performed.