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From: mwp@munnari.oz (Michael W. Paddon)
Newsgroups: comp.unix.wizards
Subject: Re: Symbolic Links
Message-ID: <1817@munnari.oz>
Date: Wed, 9-Sep-87 02:12:51 EDT
Article-I.D.: munnari.1817
Posted: Wed Sep  9 02:12:51 1987
Date-Received: Fri, 11-Sep-87 00:58:47 EDT
References: <2931@ulysses.homer.nj.att.com>
Organization: Comp Sci, Melbourne Uni, Australia
Lines: 44

in article <2931@ulysses.homer.nj.att.com>, ekrell@hector..UUCP (Eduardo Krell) says:

> The original question was about removing a symbolic link, and how
> could you tell the difference between removing the symbolic link and
> the directory it points to.

The point is that your implementation requires *more* sophistication
form the average user than the BSD one. How many casual users know
what lstat(2) does off the top of their heads?

> Your example above is different (I'm assuming "somepath" is the symlink).
> I can also come with an example as simple as yours that's hard to explain
> to a naive user:

Explaining the BSD semantics requires only the model of a global jump
to another part of the tree. Explaining situations which your semantics
lead to requires detailed knowledge of symlinks and the way context can
affect path names.

> /foo has 2 subdirectories: /foo/d1 and /foo/d2. /foo/d1 is empty.
> /foo/d2 is really a symbolic link.
> 
> 	cd /foo/d2
> 	rmdir ../d1
> 
> This never works under BSD semantics.

But with the idea of global jumps, this example is meaningless.

It seems to me that you are suggesting a change to the kernel because
the semantics of "cd .." don't please you under the BSD system. Your
proposal certainly fixes this behaviour. There seem to be other ramifications
of the scheme that far outweigh the proposed advantages, as has
been pointed out by numerous examples.

I am not wholly against your ideas -- "cd .." really irks me on occasion.
However, jumping in and changing the kernel may not be the best solution.

					mwp
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