# git-blame

## NAME



           git-blame - Show what revision and author last modified each line
           of a file
    


## SYNOPSIS



           _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>
    


## 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



           -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 _*_. In the porcelain
               modes, we print _ignored_ and _unblamable_ on a newline
               respectively.
    
           --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.
    


## THE DEFAULT FORMAT



           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.
    


## 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 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. Information which is specific to
           individual lines will not be grouped together, like revs to be
           marked _ignored_ or _unblamable_. 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
    
           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
    


## 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:
    
                   <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.
    


## CONFIGURATION



           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



           Part of the git(1) suite
    


* * *