Documentation: a few spelling fixes
[git/git.git] / Documentation / git-blame.txt
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1git-blame(1)
2============
3
4NAME
5----
26e8c5d3 6git-blame - Show what revision and author last modified each line of a file
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7
8SYNOPSIS
9--------
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10[verse]
11'git-blame' [-c] [-l] [-t] [-f] [-n] [-p] [-L n,m] [-S <revs-file>]
12 [-M] [-C] [-C] [--since=<date>] [<rev>] [--] <file>
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13
14DESCRIPTION
15-----------
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16
17Annotates each line in the given file with information from the revision which
18last modified the line. Optionally, start annotating from the given revision.
19
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20Also it can limit the range of lines annotated.
21
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22This report doesn't tell you anything about lines which have been deleted or
23replaced; you need to use a tool such as gitlink:git-diff[1] or the "pickaxe"
24interface briefly mentioned in the following paragraph.
25
26Apart from supporting file annotation, git also supports searching the
23bfbb81 27development history for when a code snippet occurred in a change. This makes it
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28possible to track when a code snippet was added to a file, moved or copied
29between files, and eventually deleted or replaced. It works by searching for
30a text string in the diff. A small example:
31
32-----------------------------------------------------------------------------
33$ git log --pretty=oneline -S'blame_usage'
345040f17eba15504bad66b14a645bddd9b015ebb7 blame -S <ancestry-file>
35ea4c7f9bf69e781dd0cd88d2bccb2bf5cc15c9a7 git-blame: Make the output
36-----------------------------------------------------------------------------
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37
38OPTIONS
39-------
abda1ef5 40-c, --compatibility::
26e8c5d3 41 Use the same output mode as gitlink:git-annotate[1] (Default: off).
8f2b72a9 42
acca687f 43-L n,m::
18d5453e 44 Annotate only the specified line range (lines count from 1).
acca687f 45
8f2b72a9 46-l, --long::
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47 Show long rev (Default: off).
48
49-t, --time::
50 Show raw timestamp (Default: off).
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51
52-S, --rev-file <revs-file>::
26e8c5d3 53 Use revs from revs-file instead of calling gitlink:git-rev-list[1].
8f2b72a9 54
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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
63-p, --porcelain::
64 Show in a format designed for machine consumption.
65
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66-M::
67 Detect moving lines in the file as well. When a commit
68 moves a block of lines in a file (e.g. the original file
69 has A and then B, and the commit changes it to B and
70 then A), traditional 'blame' algorithm typically blames
71 the lines that were moved up (i.e. B) to the parent and
72 assigns blame to the lines that were moved down (i.e. A)
73 to the child commit. With this option, both groups of
74 lines are blamed on the parent.
75
76-C::
77 In addition to `-M`, detect lines copied from other
78 files that were modified in the same commit. This is
79 useful when you reorganize your program and move code
80 around across files. When this option is given twice,
81 the command looks for copies from all other files in the
82 parent for the commit that creates the file in addition.
83
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84-h, --help::
85 Show help message.
86
87
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88THE PORCELAIN FORMAT
89--------------------
90
91In this format, each line is output after a header; the
23bfbb81 92header at the minimum has the first line which has:
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93
94- 40-byte SHA-1 of the commit the line is attributed to;
95- the line number of the line in the original file;
96- the line number of the line in the final file;
97- on a line that starts a group of line from a different
98 commit than the previous one, the number of lines in this
99 group. On subsequent lines this field is absent.
100
101This header line is followed by the following information
102at least once for each commit:
103
104- author name ("author"), email ("author-mail"), time
105 ("author-time"), and timezone ("author-tz"); similarly
106 for committer.
107- filename in the commit the line is attributed to.
108- the first line of the commit log message ("summary").
109
110The contents of the actual line is output after the above
111header, prefixed by a TAB. This is to allow adding more
112header elements later.
113
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115SPECIFYING RANGES
116-----------------
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117
118Unlike `git-blame` and `git-annotate` in older git, the extent
119of annotation can be limited to both line ranges and revision
120ranges. When you are interested in finding the origin for
121ll. 40-60 for file `foo`, you can use `-L` option like this:
122
123 git blame -L 40,60 foo
124
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125Also you can use regular expression to specify the line range.
126
127 git blame -L '/^sub hello {/,/^}$/' foo
128
129would limit the annotation to the body of `hello` subroutine.
130
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131When you are not interested in changes older than the version
132v2.6.18, or changes older than 3 weeks, you can use revision
133range specifiers similar to `git-rev-list`:
134
135 git blame v2.6.18.. -- foo
136 git blame --since=3.weeks -- foo
137
138When revision range specifiers are used to limit the annotation,
139lines that have not changed since the range boundary (either the
140commit v2.6.18 or the most recent commit that is more than 3
141weeks old in the above example) are blamed for that range
142boundary commit.
143
144A particularly useful way is to see if an added file have lines
145created by copy-and-paste from existing files. Sometimes this
146indicates that the developer was being sloppy and did not
147refactor the code properly. You can first find the commit that
148introduced the file with:
149
150 git log --diff-filter=A --pretty=short -- foo
151
152and then annotate the change between the commit and its
153parents, using `commit{caret}!` notation:
154
155 git blame -C -C -f $commit^! -- foo
156
157
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158SEE ALSO
159--------
160gitlink:git-annotate[1]
161
162AUTHOR
163------
acca687f 164Written by Junio C Hamano <junkio@cox.net>
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165
166GIT
167---
168Part of the gitlink:git[7] suite