Re: [bug-diffutils] diff and symlinks

[Hugo Mildenberger]

On Thursday 02 December 2010 14:24:51 Andries E. Brouwer wrote:
[....]
> What one wants to see is the smallest list of changes that change
> one tree into the other, the input to a hypothetical version of patch.
> Certainly the diff that produces this patch input does not follow
> symlinks.
> 
> Another small change I made to my copy of diff is that two regular
> files with a length of 0 bytes are not compared. Some programs make
> empty files of mode 0 and opening them fails, but the files do not differ.
> 

Almost a month ago, in a message to bug-diffutils, I described the inverse
of this problem: running diff against a non-existing file and an equally named 
existing file file of zero length resulted in no output. Any real version of 
patch 
therefore has no chance to create that file. I repeat my example here:

$ diff --version
$ diff (GNU diffutils) 3.0
Packaged by Gentoo (3.0)

$ mkdir a/c -p
$ mkdir b/c -p
$ touch b/c/emptyfile
$ diff -urN a b


http://lists.gnu.org/archive/html/bug-diffutils/2010-11/msg00005.html