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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | THE DEFAULT FORMAT | THE PORCELAIN FORMAT | SPECIFYING RANGES | INCREMENTAL OUTPUT | MAPPING AUTHORS | CONFIGURATION | SEE ALSO | GIT | COLOPHON |
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GIT-BLAME(1) Git Manual GIT-BLAME(1)
git-blame - Show what revision and author last modified each line
of a file
git blame [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-e] [-p] [-w] [--incremental]
[-L <range>] [-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>]
[--ignore-rev <rev>] [--ignore-revs-file <file>]
[--color-lines] [--color-by-age] [--progress] [--abbrev=<n>]
[ --contents <file> ] [<rev> | --reverse <rev>..<rev>] [--] <file>
Annotates each line in the given file with information from the
revision which last modified the line. Optionally, start
annotating from the given revision.
When specified one or more times, -L restricts annotation to the
requested lines.
The origin of lines is automatically followed across whole-file
renames (currently there is no option to turn the
rename-following off). To follow lines moved from one file to
another, or to follow lines that were copied and pasted from
another file, etc., see the -C and -M options.
The report does not tell you anything about lines which have been
deleted or replaced; you need to use a tool such as git diff or
the "pickaxe" interface briefly mentioned in the following
paragraph.
Apart from supporting file annotation, Git also supports
searching the development history for when a code snippet
occurred in a change. This makes it possible to track when a code
snippet was added to a file, moved or copied between files, and
eventually deleted or replaced. It works by searching for a text
string in the diff. A small example of the pickaxe interface that
searches for blame_usage:
$ git log --pretty=oneline -S'blame_usage'
5040f17eba15504bad66b14a645bddd9b015ebb7 blame -S <ancestry-file>
ea4c7f9bf69e781dd0cd88d2bccb2bf5cc15c9a7 git-blame: Make the output
-b
Show blank SHA-1 for boundary commits. This can also be
controlled via the blame.blankBoundary config option.
--root
Do not treat root commits as boundaries. This can also be
controlled via the blame.showRoot config option.
--show-stats
Include additional statistics at the end of blame output.
-L <start>,<end>, -L :<funcname>
Annotate only the line range given by <start>,<end>, or by
the function name regex <funcname>. May be specified multiple
times. Overlapping ranges are allowed.
<start> and <end> are optional. -L <start> or -L <start>,
spans from <start> to end of file. -L ,<end> spans from
start of file to <end>.
<start> and <end> can take one of these forms:
• number
If <start> or <end> is a number, it specifies an absolute
line number (lines count from 1).
• /regex/
This form will use the first line matching the given
POSIX regex. If <start> is a regex, it will search from
the end of the previous -L range, if any, otherwise from
the start of file. If <start> is ^/regex/, it will search
from the start of file. If <end> is a regex, it will
search starting at the line given by <start>.
• +offset or -offset
This is only valid for <end> and will specify a number of
lines before or after the line given by <start>.
If :<funcname> is given in place of <start> and <end>, it is
a regular expression that denotes the range from the first
funcname line that matches <funcname>, up to the next
funcname line. :<funcname> searches from the end of the
previous -L range, if any, otherwise from the start of file.
^:<funcname> searches from the start of file. The function
names are determined in the same way as git diff works out
patch hunk headers (see Defining a custom hunk-header in
gitattributes(5)).
-l
Show long rev (Default: off).
-t
Show raw timestamp (Default: off).
-S <revs-file>
Use revisions from revs-file instead of calling
git-rev-list(1).
--reverse <rev>..<rev>
Walk history forward instead of backward. Instead of showing
the revision in which a line appeared, this shows the last
revision in which a line has existed. This requires a range
of revision like START..END where the path to blame exists in
START. git blame --reverse START is taken as git blame
--reverse START..HEAD for convenience.
--first-parent
Follow only the first parent commit upon seeing a merge
commit. This option can be used to determine when a line was
introduced to a particular integration branch, rather than
when it was introduced to the history overall.
-p, --porcelain
Show in a format designed for machine consumption.
--line-porcelain
Show the porcelain format, but output commit information for
each line, not just the first time a commit is referenced.
Implies --porcelain.
--incremental
Show the result incrementally in a format designed for
machine consumption.
--encoding=<encoding>
Specifies the encoding used to output author names and commit
summaries. Setting it to none makes blame output unconverted
data. For more information see the discussion about encoding
in the git-log(1) manual page.
--contents <file>
Annotate using the contents from the named file, starting
from <rev> if it is specified, and HEAD otherwise. You may
specify - to make the command read from the standard input
for the file contents.
--date <format>
Specifies the format used to output dates. If --date is not
provided, the value of the blame.date config variable is
used. If the blame.date config variable is also not set, the
iso format is used. For supported values, see the discussion
of the --date option at git-log(1).
--[no-]progress
Progress status is reported on the standard error stream by
default when it is attached to a terminal. This flag enables
progress reporting even if not attached to a terminal. Can’t
use --progress together with --porcelain or --incremental.
-M[<num>]
Detect moved or copied lines within a file. When a commit
moves or copies a block of lines (e.g. the original file has
A and then B, and the commit changes it to B and then A), the
traditional blame algorithm notices only half of the movement
and typically blames the lines that were moved up (i.e. B) to
the parent and assigns blame to the lines that were moved
down (i.e. A) to the child commit. With this option, both
groups of lines are blamed on the parent by running extra
passes of inspection.
<num> is optional but it is the lower bound on the number of
alphanumeric characters that Git must detect as
moving/copying within a file for it to associate those lines
with the parent commit. The default value is 20.
-C[<num>]
In addition to -M, detect lines moved or copied from other
files that were modified in the same commit. This is useful
when you reorganize your program and move code around across
files. When this option is given twice, the command
additionally looks for copies from other files in the commit
that creates the file. When this option is given three times,
the command additionally looks for copies from other files in
any commit.
<num> is optional but it is the lower bound on the number of
alphanumeric characters that Git must detect as
moving/copying between files for it to associate those lines
with the parent commit. And the default value is 40. If there
are more than one -C options given, the <num> argument of the
last -C will take effect.
--ignore-rev <rev>
Ignore changes made by the revision when assigning blame, as
if the change never happened. Lines that were changed or
added by an ignored commit will be blamed on the previous
commit that changed that line or nearby lines. This option
may be specified multiple times to ignore more than one
revision. If the blame.markIgnoredLines config option is set,
then lines that were changed by an ignored commit and
attributed to another commit will be marked with a ? in the
blame output. If the blame.markUnblamableLines config option
is set, then those lines touched by an ignored commit that we
could not attribute to another revision are marked with a *.
--ignore-revs-file <file>
Ignore revisions listed in file, which must be in the same
format as an fsck.skipList. This option may be repeated, and
these files will be processed after any files specified with
the blame.ignoreRevsFile config option. An empty file name,
"", will clear the list of revs from previously processed
files.
--color-lines
Color line annotations in the default format differently if
they come from the same commit as the preceding line. This
makes it easier to distinguish code blocks introduced by
different commits. The color defaults to cyan and can be
adjusted using the color.blame.repeatedLines config option.
--color-by-age
Color line annotations depending on the age of the line in
the default format. The color.blame.highlightRecent config
option controls what color is used for each range of age.
-h
Show help message.
-c
Use the same output mode as git-annotate(1) (Default: off).
--score-debug
Include debugging information related to the movement of
lines between files (see -C) and lines moved within a file
(see -M). The first number listed is the score. This is the
number of alphanumeric characters detected as having been
moved between or within files. This must be above a certain
threshold for git blame to consider those lines of code to
have been moved.
-f, --show-name
Show the filename in the original commit. By default the
filename is shown if there is any line that came from a file
with a different name, due to rename detection.
-n, --show-number
Show the line number in the original commit (Default: off).
-s
Suppress the author name and timestamp from the output.
-e, --show-email
Show the author email instead of the author name (Default:
off). This can also be controlled via the blame.showEmail
config option.
-w
Ignore whitespace when comparing the parent’s version and the
child’s to find where the lines came from.
--abbrev=<n>
Instead of using the default 7+1 hexadecimal digits as the
abbreviated object name, use <m>+1 digits, where <m> is at
least <n> but ensures the commit object names are unique.
Note that 1 column is used for a caret to mark the boundary
commit.
When neither --porcelain nor --incremental option is specified,
git blame will output annotation for each line with:
• abbreviated object name for the commit the line came from;
• author ident (by default the author name and date, unless -s
or -e is specified); and
• line number
before the line contents.
In this format, each line is output after a header; the header at
the minimum has the first line which has:
• 40-byte SHA-1 of the commit the line is attributed to;
• the line number of the line in the original file;
• the line number of the line in the final file;
• on a line that starts a group of lines from a different
commit than the previous one, the number of lines in this
group. On subsequent lines this field is absent.
This header line is followed by the following information at
least once for each commit:
• the author name ("author"), email ("author-mail"), time
("author-time"), and time zone ("author-tz"); similarly for
committer.
• the filename in the commit that the line is attributed to.
• the first line of the commit log message ("summary").
The contents of the actual line are output after the above
header, prefixed by a TAB. This is to allow adding more header
elements later.
The porcelain format generally suppresses commit information that
has already been seen. For example, two lines that are blamed to
the same commit will both be shown, but the details for that
commit will be shown only once. This is more efficient, but may
require more state be kept by the reader. The --line-porcelain
option can be used to output full commit information for each
line, allowing simpler (but less efficient) usage like:
# count the number of lines attributed to each author
git blame --line-porcelain file |
sed -n 's/^author //p' |
sort | uniq -c | sort -rn
Unlike git blame and git annotate in older versions of git, the
extent of the annotation can be limited to both line ranges and
revision ranges. The -L option, which limits annotation to a
range of lines, may be specified multiple times.
When you are interested in finding the origin for lines 40-60 for
file foo, you can use the -L option like so (they mean the same
thing — both ask for 21 lines starting at line 40):
git blame -L 40,60 foo
git blame -L 40,+21 foo
Also you can use a regular expression to specify the line range:
git blame -L '/^sub hello {/,/^}$/' foo
which limits the annotation to the body of the hello subroutine.
When you are not interested in changes older than version
v2.6.18, or changes older than 3 weeks, you can use revision
range specifiers similar to git rev-list:
git blame v2.6.18.. -- foo
git blame --since=3.weeks -- foo
When revision range specifiers are used to limit the annotation,
lines that have not changed since the range boundary (either the
commit v2.6.18 or the most recent commit that is more than 3
weeks old in the above example) are blamed for that range
boundary commit.
A particularly useful way is to see if an added file has lines
created by copy-and-paste from existing files. Sometimes this
indicates that the developer was being sloppy and did not
refactor the code properly. You can first find the commit that
introduced the file with:
git log --diff-filter=A --pretty=short -- foo
and then annotate the change between the commit and its parents,
using commit^! notation:
git blame -C -C -f $commit^! -- foo
When called with --incremental option, the command outputs the
result as it is built. The output generally will talk about lines
touched by more recent commits first (i.e. the lines will be
annotated out of order) and is meant to be used by interactive
viewers.
The output format is similar to the Porcelain format, but it does
not contain the actual lines from the file that is being
annotated.
1. Each blame entry always starts with a line of:
<40-byte hex sha1> <sourceline> <resultline> <num_lines>
Line numbers count from 1.
2. The first time that a commit shows up in the stream, it has
various other information about it printed out with a
one-word tag at the beginning of each line describing the
extra commit information (author, email, committer, dates,
summary, etc.).
3. Unlike the Porcelain format, the filename information is
always given and terminates the entry:
"filename" <whitespace-quoted-filename-goes-here>
and thus it is really quite easy to parse for some line- and
word-oriented parser (which should be quite natural for most
scripting languages).
Note
For people who do parsing: to make it more robust, just
ignore any lines between the first and last one ("<sha1>"
and "filename" lines) where you do not recognize the tag
words (or care about that particular one) at the
beginning of the "extended information" lines. That way,
if there is ever added information (like the commit
encoding or extended commit commentary), a blame viewer
will not care.
See gitmailmap(5).
Everything below this line in this section is selectively
included from the git-config(1) documentation. The content is the
same as what’s found there:
blame.blankBoundary
Show blank commit object name for boundary commits in
git-blame(1). This option defaults to false.
blame.coloring
This determines the coloring scheme to be applied to blame
output. It can be repeatedLines, highlightRecent, or none
which is the default.
blame.date
Specifies the format used to output dates in git-blame(1). If
unset the iso format is used. For supported values, see the
discussion of the --date option at git-log(1).
blame.showEmail
Show the author email instead of author name in git-blame(1).
This option defaults to false.
blame.showRoot
Do not treat root commits as boundaries in git-blame(1). This
option defaults to false.
blame.ignoreRevsFile
Ignore revisions listed in the file, one unabbreviated object
name per line, in git-blame(1). Whitespace and comments
beginning with # are ignored. This option may be repeated
multiple times. Empty file names will reset the list of
ignored revisions. This option will be handled before the
command line option --ignore-revs-file.
blame.markUnblamableLines
Mark lines that were changed by an ignored revision that we
could not attribute to another commit with a * in the output
of git-blame(1).
blame.markIgnoredLines
Mark lines that were changed by an ignored revision that we
attributed to another commit with a ? in the output of
git-blame(1).
git-annotate(1)
Part of the git(1) suite
This page is part of the git (Git distributed version control
system) project. Information about the project can be found at
⟨http://git-scm.com/⟩. If you have a bug report for this manual
page, see ⟨http://git-scm.com/community⟩. This page was obtained
from the project's upstream Git repository
⟨https://github.com/git/git.git⟩ on 2023-12-22. (At that time,
the date of the most recent commit that was found in the
repository was 2023-12-20.) If you discover any rendering
problems in this HTML version of the page, or you believe there
is a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
Git 2.43.0.174.g055bb6 2023-12-20 GIT-BLAME(1)
Pages that refer to this page: git(1), git-annotate(1), git-bisect(1), git-blame(1), git-config(1), git-diff-tree(1), git-log(1), git-rev-list(1), git-show(1), gitweb.conf(5), gitworkflows(7)
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HTML rendering created 2023-12-22 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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