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.
> A solution to check the broken symlink is:
>
> [ -e "foo" -o -L "foo" -a ! -e "foo" ]
For which type of "foo" object does this return a different value than
the above? None.
If common sense is not enough, here is a formal proof that your third
and last test is redundant:
-e or (-L and ! -e) == (-e or -L) and (-e or ! -e) distributivity
(-e or -L) and 1 complements
-e or -L boundedness
<http://en.wikipedia.org/wiki/Boolean_logic#Properties>
