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From: jik@athena.mit.edu (Jonathan I. Kamens)
Newsgroups: comp.unix.questions
Subject: Re: # not honored?
Message-ID: <1990Mar28.231208.9461@athena.mit.edu>
Date: 28 Mar 90 23:12:08 GMT
References: <MCDANIEL.90Mar28143721@rollmops.amara.uucp>
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Reply-To: jik@athena.mit.edu (Jonathan I. Kamens)
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In article <MCDANIEL.90Mar28143721@rollmops.amara.uucp>, mcdaniel@amara.uucp
(Tim McDaniel) writes:
> But I had thought that "#" as the first byte of a file meant "this is
> a C shell script" (unless, of course, the first two bytes are "#!").
> It appears that the Bourne shell does not respect this rule.
> Should it?  (On systems where the C shell exists and uses this
> convention.)

  This is *almost* right.

  "#" as the first byte of a file means "this is a C shell script" *only
if the script is being executed by the C shell*.  While "#!" is a kernel
thing, the "#" by itself thing is figured out by the C shell, not by the
kernel.  From the man page csh(1):

     Since many systems use
     either the standard version 6 or version 7 shells whose
     shell scripts are not compatible with this shell, the shell
     will execute such a `standard' shell if the first character
     of a script is not a `#', i.e. if the script does not start
     with a comment.

Therefore, if your script has to always be executed by the C shell, even
when it is executed by someone using another shell, you *must* have the
"#!/bin/csh -f" at the top.

Jonathan Kamens			              USnail:
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