#! -- reconsideration?

Eric Vought adfh at qlue.com
Wed May 10 13:54:42 PDT 2000

That may or may not be why /usr exists, but it is now used for more than
that. For many administrators, the primary difference between programs in
/bin and /sbin and programs in /usr/bin and /usr/sbin is that the the /
programs are statically linked and local if the system has any local disk
at all. The programs in / are the bare minimum to get the system up and
perform maintenance- even maintenance on the shared libraries. /usr is
often shared between systems and may very well be read-only.

/usr/local is then used for non-static, non-maintenance programs that
are unique to the local system and is almost always mounted
read-write. IBM has come up with some bizarre conventions for /usr/local-
it is often a link into the DFS (distributed file system) tree- the exact
opposite of its intended use and very counter-intuitive. Many vendors
don't have a /usr/local as shipped, but many admins create it anyway.

It is certainly possible to remove /usr and come up with new conventions
that accomplish this, but there should be a good reason.

After all that, I agree with you that the POSIX standard should not
require /usr to exist. It is acceptable for the linux filesystem standard
to require these various directpries, but POSIX deals with too many
different types of systems.

On Wed, 10 May 2000, Mark Kettenis wrote:

>    From: Daniel Quinlan <quinlan at transmeta.com>
>    Date: 09 May 2000 14:31:24 -0700
>    Dan Kegel <dank at alumni.caltech.edu> writes:
>    > Now that you've explained your objection to /bin/posixsh, can you
>    > comment on /usr/posix/bin/sh?
>    If it's necessary to use a name other than /bin/sh, I would prefer a
>    file in /bin.  "posixsh" is okay.
>    I don't really like /usr/posix/bin/sh.  I would prefer to avoid a new
>    hard-coded pathname under /usr and I definitely object to a new
>    top-level directory under /usr just for POSIX programs.  I think it
>    would be confusing and it's usage would be very inconsistent in
>    practice.
> I don't like a hardcoded path under /usr either, the primary reason
> being that the Hurd (you known, the GNU "kernel") won't have /usr.
> I've been told that in the past /usr was introduced in UNIX only
> because all utilities didn't fit on one disk anymore.  Nowadays, there
> are much more elegant methods to solve that problem, and /usr just
> means another entry in the root directory.  It would be a pity if we
> needed /usr just to be POSIX conformant.
> Mark

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