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To: 9fans@cse.psu.edu
Subject: Re: [9fans] ls, rc question -- proposed change to rc/glob.c
From: Geoff Collyer <geoff@collyer.net>
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Date: Fri, 19 Mar 2004 00:47:32 -0800
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But in the case of a union directory with duplicate names, potentially
representing distinct files, there are multiple names, not all of them
distinct, in the directory.  Since rc(1) doesn't say ``one for each
distinct [or unique] path name matched'', one could argue that neither
code nor manual needs change.

If it's really a problem,

	fn nodup {ls -d $*|uniq}
	pr `{nodup *} | lp

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To: 9fans@cse.psu.edu
Subject: Re: [9fans] ls, rc question -- proposed change to rc/glob.c
From: Richard Miller <rm@hamnavoe.com>
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> i don't like changing the shell to mask kernel behavior. it leads
> to surprises.  consider unix shells that `fix' cd in a way that it
> differs from the chdir system call.

But filename pattern matching in the shell is already different from
just reading a directory in the kernel.  By saying 'ls /tmp/*.c'
instead of 'ls /tmp' you are asking for a selection of names.  The
question is how many times to select a name which matches more than
one file.

As David has pointed out, the rc manual at present unambiguously says
"A pattern is replaced by a list of arguments, one for each path
name matched" -- not "one for each file matched".  So if rc isn't
changed, the manual does need to be corrected.

But I would vote for changing rc.  Although I am (after some years
of experience) sufficiently used to unions that I don't find the
behaviour surprising, I do find it irritating: for example, when
doing 'grep XXX *.c' in a union directory produces duplicate output
for files which occur in more than one underlying directory.

-- Richard

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