/usr/bin/mckey: invalid option -- '-'
usage: /usr/bin/mckey
	-m multicast_address
	[-M unmapped_multicast_address]
	 replaces -m and requires -b
	[-s(ender)]
	[-b bind_address]
	[-c connections]
	[-C message_count]
	[-S message_size]
	[-p port_space - 0x111 for UDP (default), 0x2 for IPOIB]
	[-o join as a send-only full-member]
	[-l join without multicast loopback]