GNU bug report logs - #6124
basename/dirname are not POSIX compliant on arg starting with a dash

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Message #23 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Vincent Lefevre <vincent <at> vinc17.net>
To: Eric Blake <eblake <at> redhat.com>
Cc: bug-coreutils <at> gnu.org, 580492 <at> bugs.debian.org
Subject: Re: bug#6124: basename/dirname are not POSIX compliant on arg
	starting with a dash
Date: Thu, 6 May 2010 16:24:10 +0200

On 2010-05-06 07:41:59 -0600, Eric Blake wrote:
> No, you're missing one other key point of POSIX:
> 
> http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap01.html
> Section 1.4, OPTIONS:
> 
>     Default Behavior: When this section is listed as "None.", it means
> that the implementation need not support any options. Standard utilities
> that do not accept options, but that do accept operands, shall recognize
> "--" as a first argument to be discarded.

OK, an alternative way would be that an exception is added to POSIX,
just like for "echo".

>     The requirement for recognizing "--" is because conforming
> applications need a way to shield their operands from any arbitrary
> options that the implementation may provide as an extension. For
> example, if the standard utility foo is listed as taking no options, and
> the application needed to give it a pathname with a leading <hyphen>, it
> could safely do it as:
> 
>     foo -- -myfile
> 
>     and avoid any problems with -m used as an extension.

However, if extensions are allowed, this would mean that many scripts
would have to be fixed.

-- 
Vincent Lefèvre <vincent <at> vinc17.net> - Web: <http://www.vinc17.net/>
100% accessible validated (X)HTML - Blog: <http://www.vinc17.net/blog/>
Work: CR INRIA - computer arithmetic / Arénaire project (LIP, ENS-Lyon)

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