include::diff-format.txt[]
-Operating Modes
+OPERATING MODES
---------------
You can choose whether you want to trust the index file entirely
(using the `--cached` flag) or ask the diff logic to show any files
that don't match the stat state as being "tentatively changed". Both
of these operations are very useful indeed.
-Cached Mode
+CACHED MODE
-----------
If `--cached` is specified, it allows you to ask:
asking yourself "what have I already marked for being committed, and
what's the difference to a previous tree".
-Non-cached Mode
+NON-CACHED MODE
---------------
The "non-cached" mode takes a different approach, and is potentially
the more useful of the two in that what it does can't be emulated with
The non-cached version asks the question:
show me the differences between HEAD and the currently checked out
- tree - index contents _and_ files that aren't up-to-date
+ tree - index contents _and_ files that aren't up to date
which is obviously a very useful question too, since that tells you what
you *could* commit. Again, the output matches the 'git diff-tree -r'
torvalds@ppc970:~/v2.6/linux> git diff-index --abbrev HEAD
:100644 100664 7476bb... 000000... kernel/sched.c
-i.e., it shows that the tree has changed, and that `kernel/sched.c` has is
-not up-to-date and may contain new stuff. The all-zero sha1 means that to
+i.e., it shows that the tree has changed, and that `kernel/sched.c` is
+not up to date and may contain new stuff. The all-zero sha1 means that to
get the real diff, you need to look at the object in the working directory
directly rather than do an object-to-object diff.