Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!umd5!brl-adm!adm!rbj@ICST-CMR.ARPA
From: rbj@ICST-CMR.ARPA (Root Boy Jim)
Newsgroups: comp.unix.wizards
Subject: Magic symlink syntax
Message-ID: <16184@brl-adm.ARPA>
Date: 15 Jun 88 21:43:58 GMT
Sender: news@brl-adm.ARPA
Lines: 53

? From: David Elliott <dce@mips.com>

? We are in the process of considering a system modification that systems
? folks lovingly refer to as the "nami hack" (or "namei hack" for BSD folks).
? This is the modification that allows one to put a variable inside of
? a symbolic link target so that people can choose default execution
? "universes" or "modes" or "system types".

? I believe that the Apollo Domain/IX syntax was '($name)' or '$(name)'.
? I'd like to get a list of those currently available, as well as the
? pros and cons of each syntax.
? 
? Also, if other people have come up with functionally similar systems
? that use a different mechanism, I'd like to hear about those as well.

Sequent and Pyramid have `conditional symbolic links'. While not as
general as the scheme you describe, they look like:

   2 lrwxr-xr-x  1 root     wheel           4 Jan 11 16:10 /bin -> ucb=.bin att=/usr/att/bin

and are made like:

LN(1)               DYNIX Programmer's Manual               LN(1)

NAME
     ln - make links

SYNOPSIS
     ln [ -s ] name1 [ name2 ]
     ln [ -s ] name ... directory
     ln [ -f ] name ... directory
     ln -c att=name1 ucb=name2 name3

DESCRIPTION

     ...

     The -c option causes ln to create symbolic links.  The
     values for the conditional symbolic link must be given,
     preceded by the corresponding universe identifier (`att=' or
     `ucb=').  The values may be given in either order.

Hope this helps. I see no reason why the names should be restricted to
`ucb' and `att'. Of course then wd'd need a `default=' clause or return
an untranslatable error or use the first as a default.

? David Elliott		dce@mips.com  or  {ames,prls,pyramid,decwrl}!mips!dce
 
	(Root Boy) Jim Cottrell	<rbj@icst-cmr.arpa>
	National Bureau of Standards
	Flamer's Hotline: (301) 975-5688
	The opinions expressed are solely my own
	and do not reflect NBS policy or agreement
	My name is in /usr/dict/words. Is yours?