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8f2b72a9 JF |
1 | git-blame(1) |
2 | ============ | |
3 | ||
4 | NAME | |
5 | ---- | |
26e8c5d3 | 6 | git-blame - Show what revision and author last modified each line of a file |
8f2b72a9 JF |
7 | |
8 | SYNOPSIS | |
9 | -------- | |
acca687f | 10 | [verse] |
093dc5be | 11 | 'git-blame' [-c] [-b] [--root] [-s] [-l] [-t] [-f] [-n] [-p] [--incremental] [-L n,m] |
635f4a30 AR |
12 | [-S <revs-file>] [-M] [-C] [-C] [--since=<date>] |
13 | [<rev> | --contents <file>] [--] <file> | |
8f2b72a9 JF |
14 | |
15 | DESCRIPTION | |
16 | ----------- | |
26e8c5d3 JF |
17 | |
18 | Annotates each line in the given file with information from the revision which | |
19 | last modified the line. Optionally, start annotating from the given revision. | |
20 | ||
acca687f JH |
21 | Also it can limit the range of lines annotated. |
22 | ||
26e8c5d3 JF |
23 | This report doesn't tell you anything about lines which have been deleted or |
24 | replaced; you need to use a tool such as gitlink:git-diff[1] or the "pickaxe" | |
25 | interface briefly mentioned in the following paragraph. | |
26 | ||
27 | Apart from supporting file annotation, git also supports searching the | |
23bfbb81 | 28 | development history for when a code snippet occurred in a change. This makes it |
26e8c5d3 JF |
29 | possible to track when a code snippet was added to a file, moved or copied |
30 | between files, and eventually deleted or replaced. It works by searching for | |
31 | a text string in the diff. A small example: | |
32 | ||
33 | ----------------------------------------------------------------------------- | |
34 | $ git log --pretty=oneline -S'blame_usage' | |
35 | 5040f17eba15504bad66b14a645bddd9b015ebb7 blame -S <ancestry-file> | |
36 | ea4c7f9bf69e781dd0cd88d2bccb2bf5cc15c9a7 git-blame: Make the output | |
37 | ----------------------------------------------------------------------------- | |
8f2b72a9 JF |
38 | |
39 | OPTIONS | |
40 | ------- | |
635f4a30 | 41 | include::blame-options.txt[] |
b19ee24b | 42 | |
635f4a30 AR |
43 | -c:: |
44 | Use the same output mode as gitlink:git-annotate[1] (Default: off). | |
8f2b72a9 | 45 | |
635f4a30 AR |
46 | --score-debug:: |
47 | Include debugging information related to the movement of | |
48 | lines between files (see `-C`) and lines moved within a | |
49 | file (see `-M`). The first number listed is the score. | |
50 | This is the number of alphanumeric characters detected | |
51 | to be moved between or within files. This must be above | |
52 | a certain threshold for git-blame to consider those lines | |
53 | of code to have been moved. | |
8f2b72a9 | 54 | |
b24642b2 JH |
55 | -f, --show-name:: |
56 | Show filename in the original commit. By default | |
57 | filename is shown if there is any line that came from a | |
58 | file with different name, due to rename detection. | |
59 | ||
60 | -n, --show-number:: | |
61 | Show line number in the original commit (Default: off). | |
62 | ||
093dc5be JH |
63 | -s:: |
64 | Suppress author name and timestamp from the output. | |
65 | ||
b24642b2 JH |
66 | THE PORCELAIN FORMAT |
67 | -------------------- | |
68 | ||
69 | In this format, each line is output after a header; the | |
23bfbb81 | 70 | header at the minimum has the first line which has: |
b24642b2 JH |
71 | |
72 | - 40-byte SHA-1 of the commit the line is attributed to; | |
73 | - the line number of the line in the original file; | |
74 | - the line number of the line in the final file; | |
75 | - on a line that starts a group of line from a different | |
76 | commit than the previous one, the number of lines in this | |
77 | group. On subsequent lines this field is absent. | |
78 | ||
79 | This header line is followed by the following information | |
80 | at least once for each commit: | |
81 | ||
82 | - author name ("author"), email ("author-mail"), time | |
83 | ("author-time"), and timezone ("author-tz"); similarly | |
84 | for committer. | |
85 | - filename in the commit the line is attributed to. | |
86 | - the first line of the commit log message ("summary"). | |
87 | ||
88 | The contents of the actual line is output after the above | |
89 | header, prefixed by a TAB. This is to allow adding more | |
90 | header elements later. | |
91 | ||
acca687f | 92 | |
23bfbb81 RS |
93 | SPECIFYING RANGES |
94 | ----------------- | |
acca687f JH |
95 | |
96 | Unlike `git-blame` and `git-annotate` in older git, the extent | |
97 | of annotation can be limited to both line ranges and revision | |
98 | ranges. When you are interested in finding the origin for | |
42f62db9 JH |
99 | ll. 40-60 for file `foo`, you can use `-L` option like these |
100 | (they mean the same thing -- both ask for 21 lines starting at | |
101 | line 40): | |
acca687f JH |
102 | |
103 | git blame -L 40,60 foo | |
42f62db9 | 104 | git blame -L 40,+21 foo |
acca687f | 105 | |
18d5453e JH |
106 | Also you can use regular expression to specify the line range. |
107 | ||
108 | git blame -L '/^sub hello {/,/^}$/' foo | |
109 | ||
110 | would limit the annotation to the body of `hello` subroutine. | |
111 | ||
acca687f JH |
112 | When you are not interested in changes older than the version |
113 | v2.6.18, or changes older than 3 weeks, you can use revision | |
114 | range specifiers similar to `git-rev-list`: | |
115 | ||
116 | git blame v2.6.18.. -- foo | |
117 | git blame --since=3.weeks -- foo | |
118 | ||
119 | When revision range specifiers are used to limit the annotation, | |
120 | lines that have not changed since the range boundary (either the | |
121 | commit v2.6.18 or the most recent commit that is more than 3 | |
122 | weeks old in the above example) are blamed for that range | |
123 | boundary commit. | |
124 | ||
125 | A particularly useful way is to see if an added file have lines | |
126 | created by copy-and-paste from existing files. Sometimes this | |
127 | indicates that the developer was being sloppy and did not | |
128 | refactor the code properly. You can first find the commit that | |
129 | introduced the file with: | |
130 | ||
131 | git log --diff-filter=A --pretty=short -- foo | |
132 | ||
133 | and then annotate the change between the commit and its | |
134 | parents, using `commit{caret}!` notation: | |
135 | ||
136 | git blame -C -C -f $commit^! -- foo | |
137 | ||
138 | ||
57e7a0a4 JH |
139 | INCREMENTAL OUTPUT |
140 | ------------------ | |
141 | ||
142 | When called with `--incremental` option, the command outputs the | |
143 | result as it is built. The output generally will talk about | |
144 | lines touched by more recent commits first (i.e. the lines will | |
145 | be annotated out of order) and is meant to be used by | |
146 | interactive viewers. | |
147 | ||
148 | The output format is similar to the Porcelain format, but it | |
149 | does not contain the actual lines from the file that is being | |
150 | annotated. | |
151 | ||
152 | . Each blame entry always starts with a line of: | |
153 | ||
154 | <40-byte hex sha1> <sourceline> <resultline> <num_lines> | |
155 | + | |
156 | Line numbers count from 1. | |
157 | ||
158 | . The first time that commit shows up in the stream, it has various | |
159 | other information about it printed out with a one-word tag at the | |
160 | beginning of each line about that "extended commit info" (author, | |
161 | email, committer, dates, summary etc). | |
162 | ||
163 | . Unlike Porcelain format, the filename information is always | |
164 | given and terminates the entry: | |
165 | ||
166 | "filename" <whitespace-quoted-filename-goes-here> | |
167 | + | |
168 | and thus it's really quite easy to parse for some line- and word-oriented | |
169 | parser (which should be quite natural for most scripting languages). | |
170 | + | |
171 | [NOTE] | |
172 | For people who do parsing: to make it more robust, just ignore any | |
173 | lines in between the first and last one ("<sha1>" and "filename" lines) | |
174 | where you don't recognize the tag-words (or care about that particular | |
175 | one) at the beginning of the "extended information" lines. That way, if | |
176 | there is ever added information (like the commit encoding or extended | |
177 | commit commentary), a blame viewer won't ever care. | |
178 | ||
179 | ||
8f2b72a9 JF |
180 | SEE ALSO |
181 | -------- | |
182 | gitlink:git-annotate[1] | |
183 | ||
184 | AUTHOR | |
185 | ------ | |
acca687f | 186 | Written by Junio C Hamano <junkio@cox.net> |
8f2b72a9 JF |
187 | |
188 | GIT | |
189 | --- | |
190 | Part of the gitlink:git[7] suite |