ftp -V (return code: -15)
ftp: version: Name or service not known
ftp>
ftp -h (return code: 0)
Usage: { ftp | pftp } [-46pinegvtd] [hostname]
-4: use IPv4 addresses only
-6: use IPv6, nothing else
-p: enable passive mode (default for pftp)
-i: turn off prompting during mget
-n: inhibit auto-login
-e: disable readline support, if present
-g: disable filename globbing
-v: verbose mode
-t: enable packet tracing [nonfunctional]
-d: enable debugging