git-format-rev(1) Git Manual git-format-rev(1)
NAME
git-format-rev - EXPERIMENTAL: Pretty format revisions on demand
SYNOPSIS
(EXPERIMENTAL!) git format-rev --stdin-mode=<mode> --format=<pretty> [--[no-]notes=<ref>] [-z] [--[no-]null-output] [--[no-]null-input]
DESCRIPTION
Pretty format revisions from standard input.
THIS COMMAND IS EXPERIMENTAL. THE BEHAVIOR MAY CHANGE.
OPTIONS
--stdin-mode=<mode>
How to interpret standard input data:
revs
Each line or record (see the INPUT AND OUTPUT FORMATS section) is
interpreted as a commit. Any kind of revision expression can be
used (see gitrevisions(7)). Annotated tags are peeled (see
gitglossary(7)).
The argument rev is also accepted.
text
Formats all commit object names found in freeform text. These
must be full object names, i.e. abbreviated hexadecimal object
names will not be interpreted.
Anything that is parsed as an object name but that is not found
to be a commit object name is left alone (echoed).
--format=<pretty>
Pretty format string.
--notes=<ref>, --no-notes
Custom notes ref. Notes are displayed when using the %N atom. See
git-notes(1).
-z, --null
Use NUL character to terminate both input and output instead of
newline. This option cannot be negated.
This is useful if both the input and output could contain newlines or
if the input to this command also uses NUL character termination; see
the INPUT AND OUTPUT FORMATS section below.
The mode --stdin-mode=text can have use for this option when it needs
to process input like for example git last-modified -z; see the
EXAMPLES section below.
--null-output, --no-null-output
Use NUL character to terminate output instead of newline. The default
is --no-null-output.
This is useful if the output could contain newlines, for example if
the %n (newline) atom is used.
--null-input, --no-null-input
Use NUL character to terminate input instead of newline. The default
is --no-null-input.
This is useful if the input revision expressions could contain
newlines.
INPUT AND OUTPUT FORMAT
The command uses newlines for both input and output termination by
default. See the -z, --null-output, and --null-input options for using
NUL character as the terminator.
The mode --stdin-mode=revs outputs one formatted commit followed by the
terminator. This could either be called a line or a record in case "line"
is too suggestive of newline termination.
Note that this means that the terminator character (newline or NUL) acts
as a terminator, not a separator. In other words, the final line or
record is also terminated by the terminator character.
The mode --stdin-mode=text replaces each object name with the formatted
commit, i.e. the format "%s" would transform some commit object name to
"<subject>" without any termination. Like this:
Did we not fix this in "<subject>"?
It is safe to interactively read and write from this command since each
record is immediately flushed.
EXAMPLES
The command git-last-modified(1) shows the commit that each file was last
modified in.
$ git last-modified -- README.md Makefile
7798034171030be0909c56377a4e0e10e6d2df93 Makefile
c50fbb2dd225e7e82abba4380423ae105089f4d7 README.md
We can pipe the result to this command in order to replace the object
name with the commit author.
$ git last-modified -- README.md Makefile |
git format-rev --stdin-mode=text --format=%an
Junio C Hamano Makefile
Todd Zullinger README.md
Another example is formatting commits in commit messages. Given this
commit message:
Fix off-by-one error
Fix off-by-one error introduced in
e83c5163316f89bfbde7d9ab23ca2e25604af290.
We thought we fixed this in 5569bf9bbedd63a00780fc5c110e0cfab3aa97b9 but
that only covered 1/3 of the faulty cases.
We can format the commits and use par(1) to reflow the text, say in a
commit-msg hook:
$ git config set hook.reference-commits.event commit-msg
$ git config set hook.reference-commits.command reference-commits
$ cat $(which reference-commits)
#/bin/sh
msg="$1"
rewritten=$(mktemp)
git format-rev --stdin-mode=text --format=reference <"$msg" |
par >"$rewritten"
mv "$rewritten" "$msg"
Which will produce something like this:
Fix off-by-one error
Fix off-by-one error introduced in e83c5163316 (Implement better memory
allocator, 2005-04-07).
We thought we fixed this in 5569bf9bbed (Fix memory allocator,
2005-06-22) but that only covered 1/3 of the faulty cases.
DISCUSSION
This command lets you format any number of revisions in any order through
one command invocation. Consider the git-last-modified(1) case from the
EXAMPLES section above:
1. There might be hundreds of files
2. Commits can be repeated, i.e. two or more files were last modified in
the same commit
Two widely-used commands which pretty formats commits are git-log(1) and
git-show(1). It turns out that they are not a good fit for the above use
case.
o The output of git-last-modified(1) would have to be processed in
stages since you need to transform the first column separately and
then link the author to the filename. But this is surmountable.
o You can feed each commit to git show or git log --no-walk -1. But
that means that you need to create a process for each line.
o Let's say that you want to use one process, not one per line. So you
want to feed all the commits to the command. Now you face the problem
that you have to feed all the commits to the commands before you get
any output (this is also the case for the --stdin modes). In other
words, you cannot loop through each line, get the author for the
commit, and output the author and the filename. You need to feed all
the commits, get back all the output, and match the output with the
filename.
o But the next problem is that commands will deduplicate the input and
only output one commit one single time only. Thus you cannot make the
output order match the input order, since a commit could have been
repeated in the original input.
In short, it is straightforward to use these two commands if you use one
process per line. It is much more work if you just want to use one
process, but still doable. In contrast, this problem is solved with just
another shell pipeline with this command.
SEE ALSO
git-name-rev(1), git-log(1).
GIT
Part of the git(1) suite
Git 2.56.0 2026-09-27 git-format-rev(1)
git 2.56.0 - Generated Thu Oct 1 16:04:35 CDT 2026