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From: tanner@ki4pv.uucp (Dr. T. Andrews)
Newsgroups: comp.unix.wizards
Subject: Re: make importing SHELL
Message-ID: <7046@ki4pv.uucp>
Date: 1 Oct 88 14:08:31 GMT
References: <452@alice.marlow.uucp> <67870@sun.uucp> <67925@sun.uucp> <4147@bsu-cs.UUCP>
Organization: CompuData Inc., DeLand
Lines: 26

In article <4147@bsu-cs.UUCP>, dhesi@bsu-cs.UUCP (Rahul Dhesi) writes:
) I think the problem is that $SHELL exists at all.  It's a poor
) substitute for the #! in 4.3BSD.

The "#!" mechanism and the $SHELL mechanism address different issues.
One is not a substitute for the other.

The first tells the exec(2) family what interpreter should be used
on a "program", since it is not executable.  This causes, eg, "csh"
scripts to be run with "csh".

The second is used by certain applications which wish to spawn a user
shell.  A common case is the "ex" family of editors, which have a "sh"
command to give you a sub-shell without losing your editing session.

Neither of these mechanisms is suitable for determining how commands
should be interepreted in a "Makefile".  It might be clever to start
a Makefile with the line "#! /bin/make SHELL=/bin/sh", and make the
Makefile executable, so that you said "Makefile" instead of "make".

The mistake of importing $SHELL for Makefiles has been made already,
so the clever writer will probably try to include a "SHELL=" line,
not because it is a good thing, but simply for safety.
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