Path: utzoo!utgpu!attcan!uunet!nih-csl!elsie!ado
From: ado@elsie.UUCP (Arthur David Olson)
Newsgroups: comp.unix.wizards
Subject: Re: Is this known to unix.wizards?
Summary: Earliest reference
Message-ID: <8604@elsie.UUCP>
Date: 7 Jan 89 01:14:53 GMT
References: <13307@ncoast.UUCP>
Organization: NIH-LEC, Bethesda, MD
Lines: 47

In article <13307@ncoast.UUCP>, allbery@ncoast.UUCP (Brandon S. Allbery) writes:
> Every so often there is mention of /bin/sh's braindamaged handling of "$@"
> when there are no arguments.  I think I've worked out a way around it that
> doesn't require "if" or "case":
> 				${1+"$@"}
> . . .I find it hard to believe that I'm the first one to notice this,
> but I've never seen any discussion of it anywhere and it *certainly*
> isn't in the manual or in any of the shell books I've read.

I've attached the earliest mention of the idiom that I can find;
I don't recall how I first learned of it, but it's used in a number of scripts
here at elsie now (sccs work and carbon dating show December of '86 as the
earliest occurrence).  Thanks to David Giacomo (or whomever) for the discovery!
--
UNIX is a registered trademark of AT&T.
-- 
	Arthur David Olson    ado@ncifcrf.gov    ADO is a trademark of Ampex.

< Path: elsie!cvl!umcp-cs!seismo!ut-sally!pyramid!decwrl!sun!david
< From: david@sun.uucp (David DiGiacomo)
< Newsgroups: net.unix-wizards
< Subject: Re: Problems with System V Release 2.1 on 68010
< Message-ID: <3514@sun.uucp>
< Date: 16 Apr 86 18:15:14 GMT
< References: <401@oscvax.UUCP> <412@hropus.UUCP>
< Reply-To: david@sun.uUCp (David DiGiacomo)
< Organization: Sun Microsystems, Inc.
< Lines: 18
< 
< In article <412@hropus.UUCP> ka@hropus.UUCP (Kenneth Almquist) writes:
< >> 4) Is it true that the sh construct "$@" (in a shell script) is supposed
< >>    to be identically equal to the command-line arguments? It seems that
< >>    it should, because otherwise there is no way to get at these because
< >>    $@ = $* gets reparsed, and "$*" is one word.
< >>    In our sh, "$@" is exactly equivalent to the command line args if there
< >>    are some, otherwise it is equal to "" instead of nothing.
< >>    Seems like a bug to me. If so, how wide-spread is it?
< >
< >It's on our SVR2 on a VAX here.  The Korn shell gets this right, of course.
< 
< This also afflicts SunOS 3.0.  I find it incredibly annoying, but a simple
< workaround is to use ${1+"$@"} instead of plain "$@".
< 
< [disclaimer]
< -- 
< David DiGiacomo  {decvax, ihnp4, ucbvax}!sun!david  david@sun.arpa
< Sun Microsystems, Mt. View, CA  (415) 960-7495