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Date:Mon Mar 13 04:29:21 2001 
Subject:csh/sh not an issue 
From:Aaron Sloman 
Volume-ID:1010313.02 

ug55aes@cs.bham.ac.uk writes:

> Date: Mon, 12 Mar 2001 14:53:07 +0000 (UTC)
>
> On Mon, Mar 12, 2001 at 02:26:09PM +0000, Stephen Isard wrote:
> > ug55aes@cs.bham.ac.uk wrote:
> >
> > >         echo "Poplog needs either the csh (or tcsh) shell in order to run."
> >
> > Is this true?  Not that I think many people run linux systems without
> > csh, but it seems a funny dependency to have.

There are two sorts of scripts: those for users to set up
environment variables and those to run for rebuilding saved images,
rebuilding indexes, relinking, etc.

1. The user scripts are not *run* but *sourced* (i.e. spliced into
the current shell input stream).

If they were run they would not produce the desired effect in the
user's environment.

Consequently the USER scripts distributed with poplog are provided
in two flavours, (a) suitable for csh/tcsh users and (b) suitable
for sh/bash/ksh users. The latter end in .sh, e.g.

    $usepop/pop/com/popenv
        for csh/tcsh

    $usepop/pop/com/popenv.sh
        for sh/ksh/bash

At Birmingham we make tcsh the default shell for new users, so I've
made only csh/tcsh versions of the default local start scripts (to
make commands like "pop11" find locally grown saved images, e.g.
with rc_graphic, objectclass, and other things precompiled.)
People who use bash can always do this:

    # ... running bash ....

    exec csh
    source ...poplog file....

    exec bash
    # ... running bash ....


2. The poplog SYSTEM scripts use csh and can be used *whatever*
shell the user happens to be using. Moreover csh (or tcsh) is
available on *every* unix/linux system.

So there is no problem about which shell is used for the poplog
scripts: I think this discussion has been based on a
misunderstanding.

> > What is popcd.tar?  I don't have it, so I don't know what I'm missing,
> > but it doesn't appear to be essential for running the poplog in
> > linux1553.tar.gz.  Given its size, why isn't it compressed?

It was a tar file created to go onto a CD to be given to our
students. It contains only gzipped files so further compression
would not achieve anything, as Andrew noted.

It is not worth fetching over the internet unless you have a very
fast connection.

Aaron
====
Aaron Sloman, ( http://www.cs.bham.ac.uk/~axs/ )
School of Computer Science, The University of Birmingham, B15 2TT, UK
EMAIL A.Sloman AT cs.bham.ac.uk   (ReadATas@please !)
PAPERS: http://www.cs.bham.ac.uk/research/cogaff/
FREE TOOLS: http://www.cs.bham.ac.uk/research/poplog/freepoplog.html