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GIT-BLAME(1) | Git Manual | GIT-BLAME(1) |
NAME¶
git-blame - Show what revision and author last modified each line of a fileSYNOPSIS¶
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>] [--abbrev=<n>] [<rev> | --contents <file> | --reverse <rev>] [--] <file>
DESCRIPTION¶
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
OPTIONS¶
-bShow 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 :<regex>
Annotate only the given line range. 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:
-l
•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 “:<regex>” is given in place of <start> and
<end>, it denotes the range from the first funcname line that matches
<regex>, up to the next funcname line. “:<regex>”
searches from the end of the previous -L range, if any, otherwise from the
start of file. “^:<regex>” searches from the start of
file.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
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.
-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>
When <rev> is not specified, the command annotates
the changes starting backwards from the working tree copy. This flag makes the
command pretend as if the working tree copy has the contents of the named file
(specify - to make the command read from the standard input).
--date <format>
The value is one of the following alternatives:
{relative,local,default,iso,rfc,short}. 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 more information, See the
discussion of the --date option at git-log(1).
-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.
-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 author name (Default:
off).
-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 <n>+1 digits. Note that 1 column is
used for a caret to mark the boundary commit.
THE PORCELAIN FORMAT¶
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 is 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
SPECIFYING RANGES¶
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
git blame -L '/^sub hello {/,/^}$/' foo
git blame v2.6.18.. -- foo git blame --since=3.weeks -- foo
git log --diff-filter=A --pretty=short -- foo
git blame -C -C -f $commit^! -- foo
INCREMENTAL OUTPUT¶
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:
Line numbers count from 1.
<40-byte hex sha1> <sourceline> <resultline> <num_lines>
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:
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.
"filename" <whitespace-quoted-filename-goes-here>
MAPPING AUTHORS¶
If the file .mailmap exists at the toplevel of the repository, or at the location pointed to by the mailmap.file or mailmap.blob configuration options, it is used to map author and committer names and email addresses to canonical real names and email addresses. In the simple form, each line in the file consists of the canonical real name of an author, whitespace, and an email address used in the commit (enclosed by < and >) to map to the name. For example:Proper Name <commit@email.xx>
<proper@email.xx> <commit@email.xx>
Proper Name <proper@email.xx> <commit@email.xx>
Proper Name <proper@email.xx> Commit Name <commit@email.xx>
Joe Developer <joe@example.com> Joe R. Developer <joe@example.com> Jane Doe <jane@example.com> Jane Doe <jane@laptop.(none)> Jane D. <jane@desktop.(none)>
Jane Doe <jane@desktop.(none)> Joe R. Developer <joe@example.com>
nick1 <bugs@company.xx> nick2 <bugs@company.xx> nick2 <nick2@company.xx> santa <me@company.xx> claus <me@company.xx> CTO <cto@coompany.xx>
<cto@company.xx> <cto@coompany.xx> Some Dude <some@dude.xx> nick1 <bugs@company.xx> Other Author <other@author.xx> nick2 <bugs@company.xx> Other Author <other@author.xx> <nick2@company.xx> Santa Claus <santa.claus@northpole.xx> <me@company.xx>
SEE ALSO¶
git-annotate(1)GIT¶
Part of the git(1) suite05/28/2018 | Git 2.1.4 |