nbd-client version 3.27.1
Usage: nbd-client -name|-N name host [port] nbd_device
	[-block-size|-b block size] [-timeout|-t timeout] [-swap|-s]
	[-persist|-p] [-nofork|-n] [-systemd-mark|-m] [-i ident|-nonetlink|-L]
	[-readonly|-R] [-size|-B bytes] [-preinit|-P]
Or   : nbd-client -u (with same arguments as above)
Or   : nbd-client nbdX
Or   : nbd-client -d nbd_device
Or   : nbd-client -c nbd_device
Or   : nbd-client -h|--help
Or   : nbd-client -l|--list host
Or   : nbd-client -V|--version
All commands that connect to a host also take:
	[-F|-certfile certfile] [-K|-keyfile keyfile]
	[-A|-cacertfile cacertfile] [-H|-tlshostname hostname] [-x|-enable-tls]
	[-y|-priority gnutls-priority-string]
Default value for blocksize is 512
Allowed values for blocksize are 512,1024,2048,4096
Note, that kernel 2.4.2 and older ones do not work correctly with
blocksizes other than 1024 without patches
Default value for port is 10809. Note that port must always be numeric
Bug reports and general discussion should go to nbd@other.debian.org