Re: A few usability question about git diff --cached

> Miklos Vajna <vmiklos@frugalware.org> writes:
>
> > On Thu, Oct 04, 2007 at 02:27:41PM +0200, Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com> wrote:
> >> Why do we have the option "--cached" and not "--index"?
> >
> > according to glossary.txt, 'cache' is an obsolete for 'index'. probably
> > this is the reason
> >
> > probably cache.h will be never renamed to index.h, i don't know if diff
> > --cached will be ever renamed to diff --index
>
> Probably never.

> Some commands support both --index and --cached and have
> different meanings.  For them,
>
>  * --index means work on both index and work tree;
>  * --cached means work only on index and ignore work tree.
>
> In the case of "diff --cached", the latter is exactly what's
> happening.  We do not say "git diff-index --index $commit"
> because "git diff-index" (and by extension, when you give only
> one commit to "git diff" as parameter) is all about a commit vs
> your uncommitted changes, so having you say "--index" is just
> silly.  "git diff --cached" is just a shorthand for "git diff
> --cached HEAD".  Because --cached would make sense to no other
> form of diff, its presense by definition means you are talking
> about the one-tree form of diff i.e. compare a commit with your
> uncommitted changes.