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Re: lynx-dev Re: who owns what

From: Bela Lubkin
Subject: Re: lynx-dev Re: who owns what
Date: Sun, 11 Oct 1998 02:34:03 -0700

David Combs wrote:

> Symlinks to not-yet-created files have several important uses.  So do
> symlinks to not-owned files.  Removing those abilities would be both
> difficult and damaging to the normal operation of the system.
> Just for general knowledge for us all, please detail some of
> those uses.  thanks!

Many systems provide default user startup files which are symlinks to a
system copy.  For instance, if your shell is csh, your account may have
been created with .cshrc being a symlink to /etc/default.cshrc.  This is
of course a symlink to a not-owned file.  If the administrator wants to
change something in csh startup, he changes it there.  If you are an
"advanced" user you'll probably have replaced that with your own
version, in which case you must also take responsibility for
occasionally checking what he's changed, deciding whether you want to
incorporate it.

Likewise, you might be using some program that another user (joe)
installed in his account.  Call it foo.  It has a .foorc file which is
rarely changed.  You trust joe, and you know that he occasionally
updates his .foorc to add new useful capabilities.  So you make a link
from his to yours (ln -s ~joe/.foorc ~/.foorc).

Symlinks to nonexistent files exist any time the target of a symlink is
deleted.  If joe deletes .foorc, your symlink still exists (but you get
"file not found" if you try to access it).  As I said before, it would
not be practical for the system to delete such links when the linked-to
file disappears, since it doesn't have an index of all symlinks (and
maintaining such an index would add way too much overhead).  Also, what
if joe deleted his .foorc and then created a new one -- you would want
your link to still point to the new one.  In fact, some editors update a
file by removing the old one, then creating a new one, in which case
your link would break any time joe changed the file!

I can't think of a specific example right now of a deliberately created
link to a nonexistent file, but I know I've seen them before and they
were necessary.


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