git-blame
Show what revision and author last modified each line
TLDR
SYNOPSIS
git blame [options] [rev] [--] file
DESCRIPTION
git blame shows what revision and author last modified each line of a file. It annotates each line with commit information, helping identify when and why changes were made.The command is essential for code archaeology, understanding code history, and finding who to ask about specific code. Options like -M and -C detect moved and copied code across files to show original authorship rather than the person who relocated it.Line ranges can be specified with -L to focus on specific sections, and -w ignores whitespace changes to find meaningful modifications. The output is invaluable for debugging, code review, and understanding the evolution of specific code sections.
PARAMETERS
FILE
File to annotate.-L START,END
Annotate specific line range.-e, --show-email
Show author email.-w
Ignore whitespace changes.-M
Detect moved lines within file.-C
Detect lines copied from other files.-C, -C -C
Detect lines copied from other files. Repeat to widen the search beyond the files the commit touched.--since DATE
Show only commits since date.--ignore-rev REV
Ignore a revision when assigning blame, e.g. a bulk reformatting commit.--ignore-revs-file FILE
Ignore every revision listed in a file. Often set repository-wide via blame.ignoreRevsFile.--reverse START..END
Walk history forwards, showing the last revision in which each line still existed.--porcelain, --line-porcelain
Stable, machine-readable output for scripts.-l
Show the full, unabbreviated commit hash.-s
Suppress the author name and timestamp.-f, --show-name
Show the filename of the originating commit.-n, --show-number
Show the line number in the originating commit.--help
Display help information.
INSTALL
CAVEATS
Blame reports the commit that last touched a line, which is not necessarily the commit that introduced the behaviour you are investigating. Whitespace fixes, renames and code moves all claim lines they did not really author unless you pass -w, -M or -C.A repository-wide reformat buries real history behind one mechanical commit. Record such commits in a file and point blame.ignoreRevsFile at it, so git blame skips past them by default.Annotating a large file over deep history is slow, because git reconstructs and diffs many revisions. Narrow the work with -L when only a few lines matter.The default output format is meant for humans and is not stable across versions; parse --porcelain or --line-porcelain instead.Blame follows renames of the file by default. Rewriting history with rebase or filter-branch changes the commits blame points at, so links to blame output can go stale.
HISTORY
git blame was added in 2006, adopting the name used by CVS and Subversion for the same idea. git annotate exists alongside it as a compatibility spelling with a different output format. The --ignore-rev and --ignore-revs-file options arrived in git 2.23 (2019), in response to the problem of repository-wide reformatting commits.
SEE ALSO
git-annotate(1), git-log(1), git-bisect(1), git-show(1), git-diff(1)