From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <da52034f65a1c5d41ef61abcd67ac43d@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Wed,  9 Aug 2006 21:09:20 -0500
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Environment variable
In-Reply-To: <02E129D3-32DF-41CC-9026-46BAA1FF8133@ar.aichi-u.ac.jp>
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the "problem" is backquoting.  you can see this clearly by distilling
your example:

	; a = ''
	; b = `{cat /env/a}
	; whatis b
	b: not found
	; ls -l /env/^(a b)
	--rw-rw-rw- e 0 quanstro quanstro 1 Jul  6 19:33 /env/a
	--rw-rw-rw- e 0 quanstro quanstro 0 Jul  6 19:33 /env/b

since backquoting always treats '\0' as an ifs character

	; x = `{echo -n ''}

is the same as

	; x = ()

that is, 
	; ls -l /env/x
	--rw-rw-rw- e 0 quanstro quanstro 0 Jul  6 19:33 /env/x

the only asymmetric thing to me is the fact that

	; x = ()

sets /env/x, yet $x throws an error.  (byron's rc does the opposite.)

- erik

On Wed Aug  9 05:01:18 CDT 2006, arisawa@ar.aichi-u.ac.jp wrote:
> 
> term% b=`{cat /env/a}
> term% xd -c /env/b
> 0000000
> 0000000
> term% b=`{echo $a}
> term% xd -c /env/b
> 0000000
> 0000000
> term% b=`{echo ''}	# echo null string
> term% xd -c /env/b
> 0000000
> 0000000
> term%
> 
> ??? /env/b is empty ! not same as /env/a