Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!uflorida!haven!ncifcrf!nlm-mcs!adm!smoke!gwyn
From: gwyn@smoke.ARPA (Doug Gwyn )
Newsgroups: comp.unix.questions
Subject: Re: Bourne Shell Comments Problem
Keywords: Bourne Shell UNIX Problem
Message-ID: <8608@smoke.ARPA>
Date: 3 Oct 88 06:48:21 GMT
References: <292@dsacng1.UUCP> <375@stiatl.UUCP> <8567@smoke.ARPA> <1628@ficc.uu.net>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 25

In article <1628@ficc.uu.net> peter@ficc.uu.net (Peter da Silva) writes:
>In article <8567@smoke.ARPA>, gwyn@smoke.ARPA (Doug Gwyn ) writes:
>> Nearly all Bourne shell scripts I have encountered in the past
>> several years start with #.
>You must not have used systems with the csh available then, since csh (not
>sh) uses the first character to determine whether to pass the script off onto
>the bourne shell.

Csh on old BSD systems did this, since # was not a general comment
character in the really old version of the Bourne shell that they used.
Later a hack was added to permit a limited form of # comments in Bourne
shell scripts on BSD systems.  UNIX System V has always had general #
comments in Bourne shell scripts, and most scripts start with comments
describing what the script is for, etc.

However, a port of csh to UNIX System V should NOT "exec" scripts using
csh, and a Bourne shell even on BSD should never do this.  On BSD systems,
the #! kludge can be used to force the right interpreter; on UNIX System V
this is not usually supported, and since csh is not standard on UNIX
System V in that environment shell scripts should always be executed by a
Bourne shell (except for explicit "csh <foo" or "csh foo", of course).

I notice that few porters of csh to a UNIX System V environment seem to
be familiar enough with the UNIX System V environment to fix such
incompatibilities when they do the port.