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215a7ad1 | 1 | git-diff-index(1) |
2cf565c5 | 2 | ================= |
2cf565c5 DG |
3 | |
4 | NAME | |
5 | ---- | |
b3d6e6e7 | 6 | git-diff-index - Compare a tree to the working tree or index |
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7 | |
8 | ||
9 | SYNOPSIS | |
10 | -------- | |
7791a1d9 | 11 | [verse] |
b1889c36 | 12 | 'git diff-index' [-m] [--cached] [<common diff options>] <tree-ish> [<path>...] |
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13 | |
14 | DESCRIPTION | |
15 | ----------- | |
b3d6e6e7 JH |
16 | Compares the content and mode of the blobs found in a tree object |
17 | with the corresponding tracked files in the working tree, or with the | |
18 | corresponding paths in the index. When <path> arguments are present, | |
19 | compares only paths matching those patterns. Otherwise all tracked | |
20 | files are compared. | |
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21 | |
22 | OPTIONS | |
23 | ------- | |
dda2d79a JH |
24 | include::diff-options.txt[] |
25 | ||
2cf565c5 DG |
26 | <tree-ish>:: |
27 | The id of a tree object to diff against. | |
28 | ||
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29 | --cached:: |
30 | do not consider the on-disk file at all | |
31 | ||
32 | -m:: | |
33 | By default, files recorded in the index but not checked | |
34 | out are reported as deleted. This flag makes | |
0b444cdb | 35 | 'git diff-index' say that all non-checked-out files are up |
2cf565c5 DG |
36 | to date. |
37 | ||
2cf565c5 DG |
38 | include::diff-format.txt[] |
39 | ||
76a8788c | 40 | OPERATING MODES |
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41 | --------------- |
42 | You can choose whether you want to trust the index file entirely | |
bcf9626a | 43 | (using the `--cached` flag) or ask the diff logic to show any files |
2cf565c5 DG |
44 | that don't match the stat state as being "tentatively changed". Both |
45 | of these operations are very useful indeed. | |
46 | ||
76a8788c | 47 | CACHED MODE |
2cf565c5 | 48 | ----------- |
bcf9626a | 49 | If `--cached` is specified, it allows you to ask: |
2cf565c5 | 50 | |
5f3aa197 | 51 | show me the differences between HEAD and the current index |
0b444cdb | 52 | contents (the ones I'd write using 'git write-tree') |
2cf565c5 | 53 | |
2c6e4771 | 54 | For example, let's say that you have worked on your working directory, updated |
89438677 | 55 | some files in the index and are ready to commit. You want to see exactly |
44b27ec9 | 56 | *what* you are going to commit, without having to write a new tree |
2c6e4771 | 57 | object and compare it that way, and to do that, you just do |
2cf565c5 | 58 | |
b1889c36 | 59 | git diff-index --cached HEAD |
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60 | |
61 | Example: let's say I had renamed `commit.c` to `git-commit.c`, and I had | |
483bc4f0 JN |
62 | done an `update-index` to make that effective in the index file. |
63 | `git diff-files` wouldn't show anything at all, since the index file | |
0b444cdb | 64 | matches my working directory. But doing a 'git diff-index' does: |
2cf565c5 | 65 | |
b1889c36 | 66 | torvalds@ppc970:~/git> git diff-index --cached HEAD |
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67 | -100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 commit.c |
68 | +100644 blob 4161aecc6700a2eb579e842af0b7f22b98443f74 git-commit.c | |
69 | ||
44b27ec9 | 70 | You can see easily that the above is a rename. |
2cf565c5 | 71 | |
483bc4f0 | 72 | In fact, `git diff-index --cached` *should* always be entirely equivalent to |
0b444cdb | 73 | actually doing a 'git write-tree' and comparing that. Except this one is much |
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74 | nicer for the case where you just want to check where you are. |
75 | ||
0b444cdb | 76 | So doing a `git diff-index --cached` is basically very useful when you are |
a6080a0a | 77 | asking yourself "what have I already marked for being committed, and |
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78 | what's the difference to a previous tree". |
79 | ||
76a8788c | 80 | NON-CACHED MODE |
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81 | --------------- |
82 | The "non-cached" mode takes a different approach, and is potentially | |
83 | the more useful of the two in that what it does can't be emulated with | |
0b444cdb | 84 | a 'git write-tree' + 'git diff-tree'. Thus that's the default mode. |
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85 | The non-cached version asks the question: |
86 | ||
df8baa42 | 87 | show me the differences between HEAD and the currently checked out |
7560f547 | 88 | tree - index contents _and_ files that aren't up to date |
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89 | |
90 | which is obviously a very useful question too, since that tells you what | |
0b444cdb | 91 | you *could* commit. Again, the output matches the 'git diff-tree -r' |
2cf565c5 DG |
92 | output to a tee, but with a twist. |
93 | ||
5f3aa197 | 94 | The twist is that if some file doesn't match the index, we don't have |
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95 | a backing store thing for it, and we use the magic "all-zero" sha1 to |
96 | show that. So let's say that you have edited `kernel/sched.c`, but | |
0b444cdb | 97 | have not actually done a 'git update-index' on it yet - there is no |
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98 | "object" associated with the new state, and you get: |
99 | ||
62b42d34 JK |
100 | torvalds@ppc970:~/v2.6/linux> git diff-index --abbrev HEAD |
101 | :100644 100664 7476bb... 000000... kernel/sched.c | |
2cf565c5 | 102 | |
7560f547 MÅ |
103 | i.e., it shows that the tree has changed, and that `kernel/sched.c` is |
104 | not up to date and may contain new stuff. The all-zero sha1 means that to | |
2cf565c5 DG |
105 | get the real diff, you need to look at the object in the working directory |
106 | directly rather than do an object-to-object diff. | |
107 | ||
0b444cdb | 108 | NOTE: As with other commands of this type, 'git diff-index' does not |
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109 | actually look at the contents of the file at all. So maybe |
110 | `kernel/sched.c` hasn't actually changed, and it's just that you | |
111 | touched it. In either case, it's a note that you need to | |
0b444cdb | 112 | 'git update-index' it to make the index be in sync. |
2cf565c5 | 113 | |
df8baa42 | 114 | NOTE: You can have a mixture of files show up as "has been updated" |
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115 | and "is still dirty in the working directory" together. You can always |
116 | tell which file is in which state, since the "has been updated" ones | |
117 | show a valid sha1, and the "not in sync with the index" ones will | |
118 | always have the special all-zero sha1. | |
119 | ||
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120 | GIT |
121 | --- | |
9e1f0a85 | 122 | Part of the linkgit:git[1] suite |