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
Regards,
Matías
