7900f33d4ba77c5ddf5e53869045e624105920cb
1 git-blame(1)
2 ============
4 NAME
5 ----
6 git-blame - Show what revision and author last modified each line of a file
8 SYNOPSIS
9 --------
10 [verse]
11 'git-blame' [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-p] [-w] [--incremental] [-L n,m]
12 [-S <revs-file>] [-M] [-C] [-C] [--since=<date>]
13 [<rev> | --contents <file>] [--] <file>
15 DESCRIPTION
16 -----------
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.
21 Also it can limit the range of lines annotated.
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 linkgit:git-diff[1] or the "pickaxe"
25 interface briefly mentioned in the following paragraph.
27 Apart from supporting file annotation, git also supports searching the
28 development history for when a code snippet occurred in a change. This makes it
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:
33 -----------------------------------------------------------------------------
34 $ git log --pretty=oneline -S'blame_usage'
35 5040f17eba15504bad66b14a645bddd9b015ebb7 blame -S <ancestry-file>
36 ea4c7f9bf69e781dd0cd88d2bccb2bf5cc15c9a7 git-blame: Make the output
37 -----------------------------------------------------------------------------
39 OPTIONS
40 -------
41 include::blame-options.txt[]
43 -c::
44 Use the same output mode as linkgit:git-annotate[1] (Default: off).
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.
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.
60 -n, --show-number::
61 Show line number in the original commit (Default: off).
63 -s::
64 Suppress author name and timestamp from the output.
66 -w::
67 Ignore whitespace when comparing parent's version and
68 child's to find where the lines came from.
71 THE PORCELAIN FORMAT
72 --------------------
74 In this format, each line is output after a header; the
75 header at the minimum has the first line which has:
77 - 40-byte SHA-1 of the commit the line is attributed to;
78 - the line number of the line in the original file;
79 - the line number of the line in the final file;
80 - on a line that starts a group of line from a different
81 commit than the previous one, the number of lines in this
82 group. On subsequent lines this field is absent.
84 This header line is followed by the following information
85 at least once for each commit:
87 - author name ("author"), email ("author-mail"), time
88 ("author-time"), and timezone ("author-tz"); similarly
89 for committer.
90 - filename in the commit the line is attributed to.
91 - the first line of the commit log message ("summary").
93 The contents of the actual line is output after the above
94 header, prefixed by a TAB. This is to allow adding more
95 header elements later.
98 SPECIFYING RANGES
99 -----------------
101 Unlike `git-blame` and `git-annotate` in older git, the extent
102 of annotation can be limited to both line ranges and revision
103 ranges. When you are interested in finding the origin for
104 ll. 40-60 for file `foo`, you can use `-L` option like these
105 (they mean the same thing -- both ask for 21 lines starting at
106 line 40):
108 git blame -L 40,60 foo
109 git blame -L 40,+21 foo
111 Also you can use regular expression to specify the line range.
113 git blame -L '/^sub hello {/,/^}$/' foo
115 would limit the annotation to the body of `hello` subroutine.
117 When you are not interested in changes older than the version
118 v2.6.18, or changes older than 3 weeks, you can use revision
119 range specifiers similar to `git-rev-list`:
121 git blame v2.6.18.. -- foo
122 git blame --since=3.weeks -- foo
124 When revision range specifiers are used to limit the annotation,
125 lines that have not changed since the range boundary (either the
126 commit v2.6.18 or the most recent commit that is more than 3
127 weeks old in the above example) are blamed for that range
128 boundary commit.
130 A particularly useful way is to see if an added file have lines
131 created by copy-and-paste from existing files. Sometimes this
132 indicates that the developer was being sloppy and did not
133 refactor the code properly. You can first find the commit that
134 introduced the file with:
136 git log --diff-filter=A --pretty=short -- foo
138 and then annotate the change between the commit and its
139 parents, using `commit{caret}!` notation:
141 git blame -C -C -f $commit^! -- foo
144 INCREMENTAL OUTPUT
145 ------------------
147 When called with `--incremental` option, the command outputs the
148 result as it is built. The output generally will talk about
149 lines touched by more recent commits first (i.e. the lines will
150 be annotated out of order) and is meant to be used by
151 interactive viewers.
153 The output format is similar to the Porcelain format, but it
154 does not contain the actual lines from the file that is being
155 annotated.
157 . Each blame entry always starts with a line of:
159 <40-byte hex sha1> <sourceline> <resultline> <num_lines>
160 +
161 Line numbers count from 1.
163 . The first time that commit shows up in the stream, it has various
164 other information about it printed out with a one-word tag at the
165 beginning of each line about that "extended commit info" (author,
166 email, committer, dates, summary etc).
168 . Unlike Porcelain format, the filename information is always
169 given and terminates the entry:
171 "filename" <whitespace-quoted-filename-goes-here>
172 +
173 and thus it's really quite easy to parse for some line- and word-oriented
174 parser (which should be quite natural for most scripting languages).
175 +
176 [NOTE]
177 For people who do parsing: to make it more robust, just ignore any
178 lines in between the first and last one ("<sha1>" and "filename" lines)
179 where you don't recognize the tag-words (or care about that particular
180 one) at the beginning of the "extended information" lines. That way, if
181 there is ever added information (like the commit encoding or extended
182 commit commentary), a blame viewer won't ever care.
185 SEE ALSO
186 --------
187 linkgit:git-annotate[1]
189 AUTHOR
190 ------
191 Written by Junio C Hamano <junkio@cox.net>
193 GIT
194 ---
195 Part of the linkgit:git[1] suite