man pages section 1: User Commands

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Updated: July 2014

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 n,m]
[-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>] [--abbrev=<n>]
[<rev> | --contents <file> | --reverse <rev>] [--] <file>


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 n,m]
                 [-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>] [--abbrev=<n>]
                 [<rev> | --contents <file> | --reverse <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.

     The command can also limit the range of lines annotated.

     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:

         $ git log --pretty=oneline -S'blame_usage'
         5040f17eba15504bad66b14a645bddd9b015ebb7 blame -S <ancestry-file>
         ea4c7f9bf69e781dd0cd88d2bccb2bf5cc15c9a7 git-blame: Make the output

         Show blank SHA-1 for boundary commits. This can also be
         controlled via the blame.blankboundary config option.

         Do not treat root commits as boundaries. This can also
         be controlled via the blame.showroot config option.

         Include additional statistics at the end of blame

     -L <start>,<end>
         Annotate only the given line range. <start> and <end>
         can take one of these forms:

         o   number

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Git Manual                                           GIT-BLAME(1)

             If <start> or <end> is a number, it specifies an
             absolute line number (lines count from 1).

         o   /regex/

             This form will use the first line matching the given
             POSIX regex. If <end> is a regex, it will search
             starting at the line given by <start>.

         o   +offset or -offset

             This is only valid for <end> and will specify a
             number of lines before or after the line given by

         Show long rev (Default: off).

         Show raw timestamp (Default: off).

     -S <revs-file>
         Use revisions from revs-file instead of calling git-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.

     -p, --porcelain
         Show in a format designed for machine consumption.

         Show the porcelain format, but output commit information
         for each line, not just the first time a commit is
         referenced. Implies --porcelain.

         Show the result incrementally in a format designed for
         machine consumption.

         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

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Git Manual                                           GIT-BLAME(1)

         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 config variable is
         used. If the 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).

         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

         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

         Show help message.

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Git Manual                                           GIT-BLAME(1)

         Use the same output mode as git-annotate(1) (Default:

         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:

         Suppress the author name and timestamp from the output.

     -e, --show-email
         Show the author email instead of author name (Default:

         Ignore whitespace when comparing the parent's version
         and the child's to find where the lines came from.

         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

     In this format, each line is output after a header; the
     header at the minimum has the first line which has:

     o   40-byte SHA-1 of the commit the line is attributed to;

     o   the line number of the line in the original file;

     o   the line number of the line in the final file;

     o   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.

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Git Manual                                           GIT-BLAME(1)

     This header line is followed by the following information at
     least once for each commit:

     o   the author name ("author"), email ("author-mail"), time
         ("author-time"), and timezone ("author-tz"); similarly
         for committer.

     o   the filename in the commit that the line is attributed

     o   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

     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. 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

         git blame -L '/^sub hello {/,/^}$/' foo

     which limits the annotation to the body of the hello

     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:

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Git Manual                                           GIT-BLAME(1)

         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

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Git Manual                                           GIT-BLAME(1)

         for most scripting languages).

             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.

     If the file .mailmap exists at the toplevel of the
     repository, or at the location pointed to by the
     mailmap.file configuration option, 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>

     The more complex forms are:

         <proper@email.xx> <commit@email.xx>

     which allows mailmap to replace only the email part of a
     commit, and:

         Proper Name <proper@email.xx> <commit@email.xx>

     which allows mailmap to replace both the name and the email
     of a commit matching the specified commit email address,

         Proper Name <proper@email.xx> Commit Name <commit@email.xx>

     which allows mailmap to replace both the name and the email
     of a commit matching both the specified commit name and
     email address.

     Example 1: Your history contains commits by two authors,
     Jane and Joe, whose names appear in the repository under
     several forms:

         Joe Developer <>
         Joe R. Developer <>
         Jane Doe <>

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Git Manual                                           GIT-BLAME(1)

         Jane Doe <jane@laptop.(none)>
         Jane D. <jane@desktop.(none)>

     Now suppose that Joe wants his middle name initial used, and
     Jane prefers her family name fully spelled out. A proper
     .mailmap file would look like:

         Jane Doe         <jane@desktop.(none)>
         Joe R. Developer <>

     Note how there is no need for an entry for
     <jane@laptop[1].(none)>, because the real name of that
     author is already correct.

     Example 2: Your repository contains commits from the
     following authors:

         nick1 <bugs@company.xx>
         nick2 <bugs@company.xx>
         nick2 <nick2@company.xx>
         santa <me@company.xx>
         claus <me@company.xx>
         CTO <cto@coompany.xx>

     Then you might want a .mailmap file that looks like:

         <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>

     Use hash # for comments that are either on their own line,
     or after the email address.

     See attributes(5) for descriptions of the following

     |Availability   | developer/versioning/git |
     |Stability      | Uncommitted              |

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Git Manual                                           GIT-BLAME(1)


     Part of the git(1) suite

      1. jane@laptop

     This software was built from source available at  The original
     community source was downloaded from  http://git-

     Further information about this software can be found on the
     open source community website at

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