1GIT-BLAME(1) Git Manual GIT-BLAME(1)
2
6 git-blame - Show what revision and author last modified each line of a
7 file
8
10 git blame [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-e] [-p] [-w] [--incremental]
11 [-L <range>] [-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>]
12 [--progress] [--abbrev=<n>] [<rev> | --contents <file> | --reverse <rev>..<rev>]
13 [--] <file>
14
17 Annotates each line in the given file with information from the
18 revision which last modified the line. Optionally, start annotating
19 from the given revision.
20 When specified one or more times, -L restricts annotation to the
22 requested lines.
23 The origin of lines is automatically followed across whole-file renames
25 (currently there is no option to turn the rename-following off). To
26 follow lines moved from one file to another, or to follow lines that
27 were copied and pasted from another file, etc., see the -C and -M
28 options.
29 The report does not tell you anything about lines which have been
31 deleted or replaced; you need to use a tool such as git diff or the
32 "pickaxe" interface briefly mentioned in the following paragraph.
33 Apart from supporting file annotation, Git also supports searching the
35 development history for when a code snippet occurred in a change. This
36 makes it possible to track when a code snippet was added to a file,
37 moved or copied between files, and eventually deleted or replaced. It
38 works by searching for a text string in the diff. A small example of
39 the pickaxe interface that searches for blame_usage:
40 $ git log --pretty=oneline -S'blame_usage'
42 5040f17eba15504bad66b14a645bddd9b015ebb7 blame -S <ancestry-file>
43 ea4c7f9bf69e781dd0cd88d2bccb2bf5cc15c9a7 git-blame: Make the output
44
47 -b
48 Show blank SHA-1 for boundary commits. This can also be controlled
49 via the blame.blankboundary config option.
50 --root
52 Do not treat root commits as boundaries. This can also be
53 controlled via the blame.showRoot config option.
54 --show-stats
56 Include additional statistics at the end of blame output.
57 -L <start>,<end>, -L :<funcname>
59 Annotate only the given line range. May be specified multiple
60 times. Overlapping ranges are allowed.
61 <start> and <end> are optional. “-L <start>” or “-L <start>,” spans
63 from <start> to end of file. “-L ,<end>” spans from start of file
64 to <end>.
65 <start> and <end> can take one of these forms:
67 · number
69 If <start> or <end> is a number, it specifies an absolute line
71 number (lines count from 1).
72 · /regex/
74 This form will use the first line matching the given POSIX
76 regex. If <start> is a regex, it will search from the end of
77 the previous -L range, if any, otherwise from the start of
78 file. If <start> is “^/regex/”, it will search from the start
79 of file. If <end> is a regex, it will search starting at the
80 line given by <start>.
81 · +offset or -offset
83 This is only valid for <end> and will specify a number of lines
85 before or after the line given by <start>.
86 If “:<funcname>” is given in place of <start> and <end>, it is a
88 regular expression that denotes the range from the first funcname
89 line that matches <funcname>, up to the next funcname line.
90 “:<funcname>” searches from the end of the previous -L range, if
91 any, otherwise from the start of file. “^:<funcname>” searches from
92 the start of file.
93 -l
95 Show long rev (Default: off).
96 -t
98 Show raw timestamp (Default: off).
99 -S <revs-file>
101 Use revisions from revs-file instead of calling git-rev-list(1).
102 --reverse <rev>..<rev>
104 Walk history forward instead of backward. Instead of showing the
105 revision in which a line appeared, this shows the last revision in
106 which a line has existed. This requires a range of revision like
107 START..END where the path to blame exists in START. git blame
108 --reverse START is taken as git blame --reverse START..HEAD for
109 convenience.
110 -p, --porcelain
112 Show in a format designed for machine consumption.
113 --line-porcelain
115 Show the porcelain format, but output commit information for each
116 line, not just the first time a commit is referenced. Implies
117 --porcelain.
118 --incremental
120 Show the result incrementally in a format designed for machine
121 consumption.
122 --encoding=<encoding>
124 Specifies the encoding used to output author names and commit
125 summaries. Setting it to none makes blame output unconverted data.
126 For more information see the discussion about encoding in the git-
127 log(1) manual page.
128 --contents <file>
130 When <rev> is not specified, the command annotates the changes
131 starting backwards from the working tree copy. This flag makes the
132 command pretend as if the working tree copy has the contents of the
133 named file (specify - to make the command read from the standard
134 input).
135 --date <format>
137 Specifies the format used to output dates. If --date is not
138 provided, the value of the blame.date config variable is used. If
139 the blame.date config variable is also not set, the iso format is
140 used. For supported values, see the discussion of the --date option
141 at git-log(1).
142 --[no-]progress
144 Progress status is reported on the standard error stream by default
145 when it is attached to a terminal. This flag enables progress
146 reporting even if not attached to a terminal. Can’t use --progress
147 together with --porcelain or --incremental.
148 -M[<num>]
150 Detect moved or copied lines within a file. When a commit moves or
151 copies a block of lines (e.g. the original file has A and then B,
152 and the commit changes it to B and then A), the traditional blame
153 algorithm notices only half of the movement and typically blames
154 the lines that were moved up (i.e. B) to the parent and assigns
155 blame to the lines that were moved down (i.e. A) to the child
156 commit. With this option, both groups of lines are blamed on the
157 parent by running extra passes of inspection.
158 <num> is optional but it is the lower bound on the number of
160 alphanumeric characters that Git must detect as moving/copying
161 within a file for it to associate those lines with the parent
162 commit. The default value is 20.
163 -C[<num>]
165 In addition to -M, detect lines moved or copied from other files
166 that were modified in the same commit. This is useful when you
167 reorganize your program and move code around across files. When
168 this option is given twice, the command additionally looks for
169 copies from other files in the commit that creates the file. When
170 this option is given three times, the command additionally looks
171 for copies from other files in any commit.
172 <num> is optional but it is the lower bound on the number of
174 alphanumeric characters that Git must detect as moving/copying
175 between files for it to associate those lines with the parent
176 commit. And the default value is 40. If there are more than one -C
177 options given, the <num> argument of the last -C will take effect.
178 -h
180 Show help message.
181 -c
183 Use the same output mode as git-annotate(1) (Default: off).
184 --score-debug
186 Include debugging information related to the movement of lines
187 between files (see -C) and lines moved within a file (see -M). The
188 first number listed is the score. This is the number of
189 alphanumeric characters detected as having been moved between or
190 within files. This must be above a certain threshold for git blame
191 to consider those lines of code to have been moved.
192 -f, --show-name
194 Show the filename in the original commit. By default the filename
195 is shown if there is any line that came from a file with a
196 different name, due to rename detection.
197 -n, --show-number
199 Show the line number in the original commit (Default: off).
200 -s
202 Suppress the author name and timestamp from the output.
203 -e, --show-email
205 Show the author email instead of author name (Default: off). This
206 can also be controlled via the blame.showEmail config option.
207 -w
209 Ignore whitespace when comparing the parent’s version and the
210 child’s to find where the lines came from.
211 --abbrev=<n>
213 Instead of using the default 7+1 hexadecimal digits as the
214 abbreviated object name, use <n>+1 digits. Note that 1 column is
215 used for a caret to mark the boundary commit.
216
218 In this format, each line is output after a header; the header at the
219 minimum has the first line which has:
220 · 40-byte SHA-1 of the commit the line is attributed to;
222 · the line number of the line in the original file;
224 · the line number of the line in the final file;
226 · on a line that starts a group of lines from a different commit than
228 the previous one, the number of lines in this group. On subsequent
229 lines this field is absent.
230 This header line is followed by the following information at least once
232 for each commit:
233 · the author name ("author"), email ("author-mail"), time
235 ("author-time"), and time zone ("author-tz"); similarly for
236 committer.
237 · the filename in the commit that the line is attributed to.
239 · the first line of the commit log message ("summary").
241 The contents of the actual line is output after the above header,
243 prefixed by a TAB. This is to allow adding more header elements later.
244 The porcelain format generally suppresses commit information that has
246 already been seen. For example, two lines that are blamed to the same
247 commit will both be shown, but the details for that commit will be
248 shown only once. This is more efficient, but may require more state be
249 kept by the reader. The --line-porcelain option can be used to output
250 full commit information for each line, allowing simpler (but less
251 efficient) usage like:
252 # count the number of lines attributed to each author
254 git blame --line-porcelain file |
255 sed -n 's/^author //p' |
256 sort | uniq -c | sort -rn
257
259 Unlike git blame and git annotate in older versions of git, the extent
260 of the annotation can be limited to both line ranges and revision
261 ranges. The -L option, which limits annotation to a range of lines, may
262 be specified multiple times.
263 When you are interested in finding the origin for lines 40-60 for file
265 foo, you can use the -L option like so (they mean the same thing — both
266 ask for 21 lines starting at line 40):
267 git blame -L 40,60 foo
269 git blame -L 40,+21 foo
270 Also you can use a regular expression to specify the line range:
272 git blame -L '/^sub hello {/,/^}$/' foo
274 which limits the annotation to the body of the hello subroutine.
276 When you are not interested in changes older than version v2.6.18, or
278 changes older than 3 weeks, you can use revision range specifiers
279 similar to git rev-list:
280 git blame v2.6.18.. -- foo
282 git blame --since=3.weeks -- foo
283 When revision range specifiers are used to limit the annotation, lines
285 that have not changed since the range boundary (either the commit
286 v2.6.18 or the most recent commit that is more than 3 weeks old in the
287 above example) are blamed for that range boundary commit.
288 A particularly useful way is to see if an added file has lines created
290 by copy-and-paste from existing files. Sometimes this indicates that
291 the developer was being sloppy and did not refactor the code properly.
292 You can first find the commit that introduced the file with:
293 git log --diff-filter=A --pretty=short -- foo
295 and then annotate the change between the commit and its parents, using
297 commit^! notation:
298 git blame -C -C -f $commit^! -- foo
300
302 When called with --incremental option, the command outputs the result
303 as it is built. The output generally will talk about lines touched by
304 more recent commits first (i.e. the lines will be annotated out of
305 order) and is meant to be used by interactive viewers.
306 The output format is similar to the Porcelain format, but it does not
308 contain the actual lines from the file that is being annotated.
309 1. Each blame entry always starts with a line of:
311 <40-byte hex sha1> <sourceline> <resultline> <num_lines>
313 Line numbers count from 1.
315 2. The first time that a commit shows up in the stream, it has various
317 other information about it printed out with a one-word tag at the
318 beginning of each line describing the extra commit information
319 (author, email, committer, dates, summary, etc.).
320 3. Unlike the Porcelain format, the filename information is always
322 given and terminates the entry:
323 "filename" <whitespace-quoted-filename-goes-here>
325 and thus it is really quite easy to parse for some line- and
327 word-oriented parser (which should be quite natural for most
328 scripting languages).
329 Note
331 For people who do parsing: to make it more robust, just ignore
332 any lines between the first and last one ("<sha1>" and
333 "filename" lines) where you do not recognize the tag words (or
334 care about that particular one) at the beginning of the
335 "extended information" lines. That way, if there is ever added
336 information (like the commit encoding or extended commit
337 commentary), a blame viewer will not care.
338
340 If the file .mailmap exists at the toplevel of the repository, or at
341 the location pointed to by the mailmap.file or mailmap.blob
342 configuration options, it is used to map author and committer names and
343 email addresses to canonical real names and email addresses.
344 In the simple form, each line in the file consists of the canonical
346 real name of an author, whitespace, and an email address used in the
347 commit (enclosed by < and >) to map to the name. For example:
348 Proper Name <commit@email.xx>
350 The more complex forms are:
352 <proper@email.xx> <commit@email.xx>
354 which allows mailmap to replace only the email part of a commit, and:
356 Proper Name <proper@email.xx> <commit@email.xx>
358 which allows mailmap to replace both the name and the email of a commit
360 matching the specified commit email address, and:
361 Proper Name <proper@email.xx> Commit Name <commit@email.xx>
363 which allows mailmap to replace both the name and the email of a commit
365 matching both the specified commit name and email address.
366 Example 1: Your history contains commits by two authors, Jane and Joe,
368 whose names appear in the repository under several forms:
369 Joe Developer <joe@example.com>
371 Joe R. Developer <joe@example.com>
372 Jane Doe <jane@example.com>
373 Jane Doe <jane@laptop.(none)>
374 Jane D. <jane@desktop.(none)>
375 Now suppose that Joe wants his middle name initial used, and Jane
378 prefers her family name fully spelled out. A proper .mailmap file would
379 look like:
380 Jane Doe <jane@desktop.(none)>
382 Joe R. Developer <joe@example.com>
383 Note how there is no need for an entry for <jane@laptop.(none)>,
386 because the real name of that author is already correct.
387 Example 2: Your repository contains commits from the following authors:
389 nick1 <bugs@company.xx>
391 nick2 <bugs@company.xx>
392 nick2 <nick2@company.xx>
393 santa <me@company.xx>
394 claus <me@company.xx>
395 CTO <cto@coompany.xx>
396 Then you might want a .mailmap file that looks like:
399 <cto@company.xx> <cto@coompany.xx>
401 Some Dude <some@dude.xx> nick1 <bugs@company.xx>
402 Other Author <other@author.xx> nick2 <bugs@company.xx>
403 Other Author <other@author.xx> <nick2@company.xx>
404 Santa Claus <santa.claus@northpole.xx> <me@company.xx>
405 Use hash # for comments that are either on their own line, or after the
408 email address.
409
411 git-annotate(1)
412
414 Part of the git(1) suite
415Git 2.18.1 05/14/2019 GIT-BLAME(1)