Hard links to directories: why not?

[John F. Haugh II]

In article <3724 at auspex.auspex.com> guy at auspex.auspex.com (Guy Harris) writes:
>>My [ second ] favorite question is why doesn't the SunOS ln command
>>permit the use of the -f flag for blasting an existent target flag?
>
>Because the (4.3)BSD "ln" command doesn't seem to, either:

You're missing the entire purpose of the question - the question isn't
what is the behavior, but rather, why isn't the behavior something else.
That two different behaviors exist is obvious - now why hasn't anyone
bothered to add an option to select which one you get?

Another interesting question is why doesn't this work -

Script is typescript, started Sun Jul 22 23:16:41 1990
#rpp386-> pwd
/dev
#rpp386-> ls -l null
crw-rw-rw-   1 sysinfo  sysinfo    4,  2 Jul 22 23:12 null
#rpp386-> mknod barf c 4 2
#rpp386-> mv barf /usr/tmp
#rpp386-> ls -l /usr/tmp/barf
-rw-r--r--   1 root     root           0 Jul 22 23:16 /usr/tmp/barf
#rpp386-> rm /usr/tmp/barf
#rpp386-> exit
Script done Sun Jul 22 23:17:04 1990

My manual says the MV command renames files.  What was so hard about
renaming /dev/barf to /usr/tmp/barf?  And before someone protests that
moving devices around is unusual, it also doesn't work for named pipes.
In fact, the behavior for renaming a named pipe is so far off it's quite
disgusting.
-- 
John F. Haugh II                             UUCP: ...!cs.utexas.edu!rpp386!jfh
Ma Bell: (512) 832-8832                           Domain: jfh at rpp386.cactus.org