"Matias A. Fonzo" <s...@dragora.org> writes:
> On Tue, 15 Dec 2009 10:37:36 +0100
> Andreas Schwab <sch...@linux-m68k.org> wrote:
>
>> "Matias A. Fonzo" <s...@dragora.org> writes:
>>
>> > On Mon, 14 Dec 2009 12:21:12 +0000
>> > Marc Herbert <marc.herb...@gmail.com> wrote:
>> >
>> >> Matias A. Fonzo a écrit :
>> >> > On Fri, 11 Dec 2009 16:16:13 +0000
>> >> > Marc Herbert <marc.herb...@gmail.com> wrote:
>> >>
>> >> >> In case anyone is interested my winner (so far) is:
>> >> >>
>> >> >> exists()
>> >> >> {
>> >> >> [ -e "$1" -o -L "$1" ]
>> >> >> }
>> >> >>
>> >> >
>> >>
>> >> > The -L is redundant.
>> >>
>> >> Not for me. I need -L because I want to consider broken symlinks just
>> >> like anything else. A broken symlink would be a bug in my code and I want
>> >> to
>> >> detect it ASAP.
>> >>
>> >>
>> >> > Because, if the symlink is not broken, the regular file "exists" ( -e ).
>> >>
>> >> Please forget about correct symlinks. The -L is here for *broken*
>> >> symlinks.
>> >>
>> >
>> > The [ -L "foo" -a ! -e "foo" ] is a specific case to check dangling
>> > symlinks.
>>
>> Combine that with the existence check and you have exactly the
>> expression above.
>>
>
> Not quite.
>
> Here an interesting quote from the Greg's FAQ:
>
> "The -e test (like all other tests besides -L or -h) follows the symbolic
> link, and therefore it checks on the thing pointed to, not on the link
> itself. The -L test does not follow the symlink, so it's checking on the link
> itself. Together, they can indicate the presence of a dangling symlink."
>
> You can see, creating a dangling symlink:
>
> $ ln -sf x y
> $ sh -c '[ -e "y" ] && echo true || echo false'
> false
> $ sh -c '[ -L "a" ] && echo true || echo false'
> true
Combine the two tests and you have exactly the expression above.
Andreas.
--
Andreas Schwab, sch...@linux-m68k.org
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"And now for something completely different."
