NAME
----
-git-blame - Blame file lines on commits
+git-blame - Show what revision and author last modified each line of a file
SYNOPSIS
--------
-git-blame file [options] file [revision]
+'git-blame' [-c] [-l] [-t] [-f] [-n] [-p] [-S <revs-file>] [--] <file> [<rev>]
DESCRIPTION
-----------
-Annotates each line in the given file with information from the commit
-which introduced the line. Start annotation from the given revision.
+
+Annotates each line in the given file with information from the revision which
+last modified the line. Optionally, start annotating from the given revision.
+
+This report doesn't tell you anything about lines which have been deleted or
+replaced; you need to use a tool such as gitlink:git-diff[1] 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 occured 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
+-----------------------------------------------------------------------------
OPTIONS
-------
-c, --compatibility::
- Use the same output mode as git-annotate (Default: off).
+ Use the same output mode as gitlink:git-annotate[1] (Default: off).
-l, --long::
Show long rev (Default: off).
Show raw timestamp (Default: off).
-S, --rev-file <revs-file>::
- Use revs from revs-file instead of calling git-rev-list.
+ Use revs from revs-file instead of calling gitlink:git-rev-list[1].
+
+-f, --show-name::
+ Show filename in the original commit. By default
+ filename is shown if there is any line that came from a
+ file with different name, due to rename detection.
+
+-n, --show-number::
+ Show line number in the original commit (Default: off).
+
+-p, --porcelain::
+ Show in a format designed for machine consumption.
-h, --help::
Show help message.
+THE PORCELAIN FORMAT
+--------------------
+
+In this format, each line is output after a header; the
+header at the minumum 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 line 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:
+
+- author name ("author"), email ("author-mail"), time
+ ("author-time"), and timezone ("author-tz"); similarly
+ for committer.
+- filename in the commit 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.
+
SEE ALSO
--------
gitlink:git-annotate[1]