git-diff-index.txt - external/gitster/git-htmldocs - Git at Google

 git-diff-index(1)
 =================

 NAME
 ----
 git-diff-index - Compares content and mode of blobs between the index and repository


 SYNOPSIS
 --------
 'git diff-index' [-m] [--cached] [<common diff options>] <tree-ish> [<path>...]

 DESCRIPTION
 -----------
 Compares the content and mode of the blobs found via a tree
 object with the content of the current index and, optionally
 ignoring the stat state of the file on disk. When paths are
 specified, compares only those named paths. Otherwise all
 entries in the index are compared.

 OPTIONS
 -------
 include::diff-options.txt[]

 <tree-ish>::
 The id of a tree object to diff against.

 --cached::
 do not consider the on-disk file at all

 -m::
 By default, files recorded in the index but not checked
 out are reported as deleted. This flag makes
 'git-diff-index' say that all non-checked-out files are up
 to date.

 Output format
 -------------
 include::diff-format.txt[]

 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
 -----------
 If '--cached' is specified, it allows you to ask:

 show me the differences between HEAD and the current index
 contents (the ones I'd write using 'git-write-tree')

 For example, let's say that you have worked on your working directory, updated
 some files in the index and are ready to commit. You want to see exactly
 *what* you are going to commit, without having to write a new tree
 object and compare it that way, and to do that, you just do

 git diff-index --cached HEAD

 Example: let's say I had renamed `commit.c` to `git-commit.c`, and I had
 done an `update-index` to make that effective in the index file.
 `git diff-files` wouldn't show anything at all, since the index file
 matches my working directory. But doing a 'git-diff-index' does:

  torvalds@ppc970:~/git> git diff-index --cached HEAD
  -100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 commit.c
  +100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 git-commit.c

 You can see easily that the above is a rename.

 In fact, `git diff-index --cached` *should* always be entirely equivalent to
 actually doing a 'git-write-tree' and comparing that. Except this one is much
 nicer for the case where you just want to check where you are.

 So doing a 'git-diff-index --cached' is basically very useful when you are
 asking yourself "what have I already marked for being committed, and
 what's the difference to a previous tree".

 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
 a 'git-write-tree' + 'git-diff-tree'. Thus that's the default mode.
 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

 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'
 output to a tee, but with a twist.

 The twist is that if some file doesn't match the index, we don't have
 a backing store thing for it, and we use the magic "all-zero" sha1 to
 show that. So let's say that you have edited `kernel/sched.c`, but
 have not actually done a 'git-update-index' on it yet - there is no
 "object" associated with the new state, and you get:

  torvalds@ppc970:~/v2.6/linux> git diff-index HEAD
  *100644->100664 blob 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
 get the real diff, you need to look at the object in the working directory
 directly rather than do an object-to-object diff.

 NOTE: As with other commands of this type, 'git-diff-index' does not
 actually look at the contents of the file at all. So maybe
 `kernel/sched.c` hasn't actually changed, and it's just that you
 touched it. In either case, it's a note that you need to
 'git-update-index' it to make the index be in sync.

 NOTE: You can have a mixture of files show up as "has been updated"
 and "is still dirty in the working directory" together. You can always
 tell which file is in which state, since the "has been updated" ones
 show a valid sha1, and the "not in sync with the index" ones will
 always have the special all-zero sha1.


 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org>

 Documentation
 --------------
 Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.

 GIT
 ---
 Part of the linkgit:git[1] suite
	git-diff-index(1)
	=================

	NAME
	----
	git-diff-index - Compares content and mode of blobs between the index and repository


	SYNOPSIS
	--------
	'git diff-index' [-m] [--cached] [<common diff options>] <tree-ish> [<path>...]

	DESCRIPTION
	-----------
	Compares the content and mode of the blobs found via a tree
	object with the content of the current index and, optionally
	ignoring the stat state of the file on disk. When paths are
	specified, compares only those named paths. Otherwise all
	entries in the index are compared.

	OPTIONS
	-------
	include::diff-options.txt[]

	<tree-ish>::
	The id of a tree object to diff against.

	--cached::
	do not consider the on-disk file at all

	-m::
	By default, files recorded in the index but not checked
	out are reported as deleted. This flag makes
	'git-diff-index' say that all non-checked-out files are up
	to date.

	Output format
	-------------
	include::diff-format.txt[]

	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
	-----------
	If '--cached' is specified, it allows you to ask:

	show me the differences between HEAD and the current index
	contents (the ones I'd write using 'git-write-tree')

	For example, let's say that you have worked on your working directory, updated
	some files in the index and are ready to commit. You want to see exactly
	what you are going to commit, without having to write a new tree
	object and compare it that way, and to do that, you just do

	git diff-index --cached HEAD

	Example: let's say I had renamed `commit.c` to `git-commit.c`, and I had
	done an `update-index` to make that effective in the index file.
	`git diff-files` wouldn't show anything at all, since the index file
	matches my working directory. But doing a 'git-diff-index' does:

	torvalds@ppc970:~/git> git diff-index --cached HEAD
	-100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 commit.c
	+100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 git-commit.c

	You can see easily that the above is a rename.

	In fact, `git diff-index --cached` should always be entirely equivalent to
	actually doing a 'git-write-tree' and comparing that. Except this one is much
	nicer for the case where you just want to check where you are.

	So doing a 'git-diff-index --cached' is basically very useful when you are
	asking yourself "what have I already marked for being committed, and
	what's the difference to a previous tree".

	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
	a 'git-write-tree' + 'git-diff-tree'. Thus that's the default mode.
	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

	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'
	output to a tee, but with a twist.

	The twist is that if some file doesn't match the index, we don't have
	a backing store thing for it, and we use the magic "all-zero" sha1 to
	show that. So let's say that you have edited `kernel/sched.c`, but
	have not actually done a 'git-update-index' on it yet - there is no
	"object" associated with the new state, and you get:

	torvalds@ppc970:~/v2.6/linux> git diff-index HEAD
	*100644->100664 blob 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
	get the real diff, you need to look at the object in the working directory
	directly rather than do an object-to-object diff.

	NOTE: As with other commands of this type, 'git-diff-index' does not
	actually look at the contents of the file at all. So maybe
	`kernel/sched.c` hasn't actually changed, and it's just that you
	touched it. In either case, it's a note that you need to
	'git-update-index' it to make the index be in sync.

	NOTE: You can have a mixture of files show up as "has been updated"
	and "is still dirty in the working directory" together. You can always
	tell which file is in which state, since the "has been updated" ones
	show a valid sha1, and the "not in sync with the index" ones will
	always have the special all-zero sha1.


	Author
	------
	Written by Linus Torvalds <torvalds@osdl.org>

	Documentation
	--------------
	Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.

	GIT
	---
	Part of the linkgit:git[1] suite