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Path: utzoo!linus!decvax!ucbvax!ucdavis!lll-crg!seismo!hao!nbires!bdaemon!carl
From: carl@bdaemon.UUCP (carl)
Newsgroups: net.unix-wizards
Subject: Re: Redirection quirks: 2>&1 >file  -- vs. --  >file 2>&1
Message-ID: <350@bdaemon.UUCP>
Date: Sun, 5-Jan-86 23:50:24 EST
Article-I.D.: bdaemon.350
Posted: Sun Jan  5 23:50:24 1986
Date-Received: Tue, 7-Jan-86 06:32:57 EST
References: <649@watmath.UUCP> <424@well.UUCP>
Organization: Daemon Assoc., Boulder, CO
Lines: 22

> In article <649@watmath.UUCP> idallen@watmath.UUCP writes:
> >Consider:
> >
> >    $ command 2>&1 >file
> >    $ command >file 2>&1
> >
> >These are not equivalent using our 4.2bsd Bourne shell.  (The 2>&1 in the
> >first line redirects unit 2 to the tty, not to the file.)
> 

The real explanation for all of this is that once a Bourne shell command
line has been read (up to \n or ; or & etc.) it is evaluated from right to
left.  To convince yourself, try

	foobar=${foo}${bar} foo="hello" bar=" world"

versus

	foo="hello" bar=" world" foobar=${foo}${bar} 

Carl Brandauer
{allegra|amd|attunix|cbosgd|ucbvax|ut-sally}!nbires!bdaemon!carl