Re: diff "--git"

[Paolo Bonzini]

On 02/18/2010 03:45 PM, Alfred M. Szmidt wrote:
>     $ diff --git
>     diff: unrecognized option '--git'
>
>     I think diff should say at this point "real diff, at least up to year
>     2010, does not have a --git option, you are probably getting that idea
>     from git output" or something.
>
> That is what it says, though not in so many words.  Having an option
> for each VS would really be a headache (SCCS, RCS, CVS, hg, darcs,
> bzr, tla, git, ...).

On the contrary, I think we could make a stab at implementing "diff 
--git": prepend a/ and b/ in some way to the paths(*), outputting 
create/delete if one of the comparands is /dev/null, printing changes in 
mode.  The only part that we shouldn't care about is the index.

   (*) example: if the paths are entirely the same, print a/SECOND/PATH
   and b/SECOND/PATH, if they are different, replace the first element
   of each path with a/ and b/ respectively.

Dually, patch would recognize changes in mode and apply them.

Paolo