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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 |
2cf565c5 DG |
7 | |
8 | ||
9 | SYNOPSIS | |
10 | -------- | |
7791a1d9 | 11 | [verse] |
133db54d | 12 | 'git diff-index' [-m] [--cached] [--merge-base] [<common-diff-options>] <tree-ish> [<path>...] |
2cf565c5 DG |
13 | |
14 | DESCRIPTION | |
15 | ----------- | |
cf6cac20 | 16 | Compare the content and mode of the blobs found in a tree object |
b3d6e6e7 JH |
17 | with the corresponding tracked files in the working tree, or with the |
18 | corresponding paths in the index. When <path> arguments are present, | |
cf6cac20 | 19 | compare only paths matching those patterns. Otherwise all tracked |
b3d6e6e7 | 20 | files are compared. |
2cf565c5 DG |
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 | ||
2cf565c5 | 29 | --cached:: |
b277b737 | 30 | Do not consider the on-disk file at all. |
2cf565c5 | 31 | |
0f5a1d44 DL |
32 | --merge-base:: |
33 | Instead of comparing <tree-ish> directly, use the merge base | |
34 | between <tree-ish> and HEAD instead. <tree-ish> must be a | |
35 | commit. | |
36 | ||
2cf565c5 DG |
37 | -m:: |
38 | By default, files recorded in the index but not checked | |
39 | out are reported as deleted. This flag makes | |
0b444cdb | 40 | 'git diff-index' say that all non-checked-out files are up |
2cf565c5 DG |
41 | to date. |
42 | ||
2cf565c5 DG |
43 | include::diff-format.txt[] |
44 | ||
76a8788c | 45 | OPERATING MODES |
2cf565c5 DG |
46 | --------------- |
47 | You can choose whether you want to trust the index file entirely | |
bcf9626a | 48 | (using the `--cached` flag) or ask the diff logic to show any files |
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49 | that don't match the stat state as being "tentatively changed". Both |
50 | of these operations are very useful indeed. | |
51 | ||
76a8788c | 52 | CACHED MODE |
2cf565c5 | 53 | ----------- |
bcf9626a | 54 | If `--cached` is specified, it allows you to ask: |
2cf565c5 | 55 | |
5f3aa197 | 56 | show me the differences between HEAD and the current index |
0b444cdb | 57 | contents (the ones I'd write using 'git write-tree') |
2cf565c5 | 58 | |
2c6e4771 | 59 | For example, let's say that you have worked on your working directory, updated |
89438677 | 60 | some files in the index and are ready to commit. You want to see exactly |
44b27ec9 | 61 | *what* you are going to commit, without having to write a new tree |
2c6e4771 | 62 | object and compare it that way, and to do that, you just do |
2cf565c5 | 63 | |
b1889c36 | 64 | git diff-index --cached HEAD |
2cf565c5 DG |
65 | |
66 | Example: let's say I had renamed `commit.c` to `git-commit.c`, and I had | |
483bc4f0 JN |
67 | done an `update-index` to make that effective in the index file. |
68 | `git diff-files` wouldn't show anything at all, since the index file | |
0b444cdb | 69 | matches my working directory. But doing a 'git diff-index' does: |
2cf565c5 | 70 | |
b1889c36 | 71 | torvalds@ppc970:~/git> git diff-index --cached HEAD |
1971510c PB |
72 | :100644 000000 4161aecc6700a2eb579e842af0b7f22b98443f74 0000000000000000000000000000000000000000 D commit.c |
73 | :000000 100644 0000000000000000000000000000000000000000 4161aecc6700a2eb579e842af0b7f22b98443f74 A git-commit.c | |
2cf565c5 | 74 | |
44b27ec9 | 75 | You can see easily that the above is a rename. |
2cf565c5 | 76 | |
483bc4f0 | 77 | In fact, `git diff-index --cached` *should* always be entirely equivalent to |
0b444cdb | 78 | actually doing a 'git write-tree' and comparing that. Except this one is much |
2cf565c5 DG |
79 | nicer for the case where you just want to check where you are. |
80 | ||
0b444cdb | 81 | So doing a `git diff-index --cached` is basically very useful when you are |
a6080a0a | 82 | asking yourself "what have I already marked for being committed, and |
2cf565c5 DG |
83 | what's the difference to a previous tree". |
84 | ||
76a8788c | 85 | NON-CACHED MODE |
2cf565c5 DG |
86 | --------------- |
87 | The "non-cached" mode takes a different approach, and is potentially | |
88 | the more useful of the two in that what it does can't be emulated with | |
0b444cdb | 89 | a 'git write-tree' + 'git diff-tree'. Thus that's the default mode. |
2cf565c5 DG |
90 | The non-cached version asks the question: |
91 | ||
df8baa42 | 92 | show me the differences between HEAD and the currently checked out |
7560f547 | 93 | tree - index contents _and_ files that aren't up to date |
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94 | |
95 | which is obviously a very useful question too, since that tells you what | |
0b444cdb | 96 | you *could* commit. Again, the output matches the 'git diff-tree -r' |
2cf565c5 DG |
97 | output to a tee, but with a twist. |
98 | ||
5f3aa197 | 99 | The twist is that if some file doesn't match the index, we don't have |
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100 | a backing store thing for it, and we use the magic "all-zero" sha1 to |
101 | show that. So let's say that you have edited `kernel/sched.c`, but | |
0b444cdb | 102 | have not actually done a 'git update-index' on it yet - there is no |
2cf565c5 DG |
103 | "object" associated with the new state, and you get: |
104 | ||
62b42d34 | 105 | torvalds@ppc970:~/v2.6/linux> git diff-index --abbrev HEAD |
1971510c | 106 | :100644 100644 7476bb5ba 000000000 M kernel/sched.c |
2cf565c5 | 107 | |
7560f547 MÅ |
108 | i.e., it shows that the tree has changed, and that `kernel/sched.c` is |
109 | not up to date and may contain new stuff. The all-zero sha1 means that to | |
2cf565c5 DG |
110 | get the real diff, you need to look at the object in the working directory |
111 | directly rather than do an object-to-object diff. | |
112 | ||
0b444cdb | 113 | NOTE: As with other commands of this type, 'git diff-index' does not |
2cf565c5 DG |
114 | actually look at the contents of the file at all. So maybe |
115 | `kernel/sched.c` hasn't actually changed, and it's just that you | |
116 | touched it. In either case, it's a note that you need to | |
0b444cdb | 117 | 'git update-index' it to make the index be in sync. |
2cf565c5 | 118 | |
df8baa42 | 119 | NOTE: You can have a mixture of files show up as "has been updated" |
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120 | and "is still dirty in the working directory" together. You can always |
121 | tell which file is in which state, since the "has been updated" ones | |
122 | show a valid sha1, and the "not in sync with the index" ones will | |
123 | always have the special all-zero sha1. | |
124 | ||
2cf565c5 DG |
125 | GIT |
126 | --- | |
9e1f0a85 | 127 | Part of the linkgit:git[1] suite |