Documentation/git-diff-index.txt - git - 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.


            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.

	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