finger @@@@@@@@

[Guy Harris]

>In Sun OS 4.0, the null hostname appears to be treated as the
>local host so you see the @@@@ effect.

This appears to be generic to 4.3BSD; the routine "inet_addr" returns 0
when handed a null string.  A null hostname gets passed to
"gethostbyname", which quite reasonably says "no such host"; "finger"
than tries handing it to "inet_addr", which returns 0 rather than -1.

I don't see any reason why "inet_addr" shouldn't reject a null string -
if there isn't at least *one* digit in the string, it's hard to see why
it should be considered a valid Internet address specification.