'\" t
.\"     Title: git-format-rev
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 2026-06-29
.\"    Manual: Git Manual
.\"    Source: Git 2.55.0
.\"  Language: English
.\"
.TH "GIT\-FORMAT\-REV" "1" "2026\-06\-29" "Git 2\&.55\&.0" "Git Manual"
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.SH "NAME"
git-format-rev \- EXPERIMENTAL: Pretty format revisions on demand
.SH "SYNOPSIS"
.sp
.nf
(\fBEXPERIMENTAL\fR!) \fBgit\fR \fBformat\-rev\fR \fB\-\-stdin\-mode=\fR\fI<mode>\fR \fB\-\-format=\fR\fI<pretty>\fR [\fB\-\-\fR[\fBno\-\fR]\fBnotes=\fR\fI<ref>\fR] [\fB\-z\fR] [\fB\-\-\fR[\fBno\-\fR]\fBnull\-output\fR] [\fB\-\-\fR[\fBno\-\fR]\fBnull\-input\fR]
.fi
.sp
.SH "DESCRIPTION"
.sp
Pretty format revisions from standard input\&.
.sp
THIS COMMAND IS EXPERIMENTAL\&. THE BEHAVIOR MAY CHANGE\&.
.SH "OPTIONS"
.PP
\fB\-\-stdin\-mode=\fR\fI<mode>\fR
.RS 4
How to interpret standard input data:
.PP
\fBrevs\fR
.RS 4
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
\fBgitrevisions\fR(7))\&. Annotated tags are peeled (see
\fBgitglossary\fR(7))\&.
.sp
The argument
\fBrev\fR
is also accepted\&.
.RE
.PP
\fBtext\fR
.RS 4
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\&.
.sp
Anything that is parsed as an object name but that is not found to be a commit object name is left alone (echoed)\&.
.RE
.RE
.PP
\fB\-\-format=\fR\fI<pretty>\fR
.RS 4
Pretty format string\&.
.RE
.PP
\fB\-\-notes=\fR\fI<ref>\fR, \fB\-\-no\-notes\fR
.RS 4
Custom notes ref\&. Notes are displayed when using the
\fB%N\fR
atom\&. See
\fBgit-notes\fR(1)\&.
.RE
.PP
\fB\-z\fR, \fB\-\-null\fR
.RS 4
Use
\fINUL\fR
character to terminate both input and output instead of newline\&. This option cannot be negated\&.
.sp
This is useful if both the input and output could contain newlines or if the input to this command also uses
\fINUL\fR
character termination; see the
INPUT AND OUTPUT FORMATS
section below\&.
.sp
The mode
\fB\-\-stdin\-mode=text\fR
can have use for this option when it needs to process input like for example
\fBgit\fR
\fBlast\-modified\fR
\fB\-z\fR; see the
EXAMPLES
section below\&.
.RE
.PP
\fB\-\-null\-output\fR, \fB\-\-no\-null\-output\fR
.RS 4
Use
\fINUL\fR
character to terminate output instead of newline\&. The default is
\fB\-\-no\-null\-output\fR\&.
.sp
This is useful if the output could contain newlines, for example if the
\fB%n\fR
(newline) atom is used\&.
.RE
.PP
\fB\-\-null\-input\fR, \fB\-\-no\-null\-input\fR
.RS 4
Use
\fINUL\fR
character to terminate input instead of newline\&. The default is
\fB\-\-no\-null\-input\fR\&.
.sp
This is useful if the input revision expressions could contain newlines\&.
.RE
.SH "INPUT AND OUTPUT FORMAT"
.sp
The command uses newlines for both input and output termination by default\&. See the \fB\-z\fR, \fB\-\-null\-output\fR, and \fB\-\-null\-input\fR options for using \fINUL\fR character as the terminator\&.
.sp
The mode \fB\-\-stdin\-mode=revs\fR outputs one formatted commit followed by the terminator\&. This could either be called a \fIline\fR or a \fIrecord\fR in case "line" is too suggestive of newline termination\&.
.sp
Note that this means that the terminator character (newline or \fINUL\fR) acts as a \fIterminator\fR, not a \fIseparator\fR\&. In other words, the final line or record is also terminated by the terminator character\&.
.sp
The mode \fB\-\-stdin\-mode=text\fR replaces each object name with the formatted commit, i\&.e\&. the format \fB%s\fR would transform some commit object name to \fI<subject>\fR without any termination\&. Like this:
.sp
.if n \{\
.RS 4
.\}
.nf
Did we not fix this in "<subject>"?
.fi
.if n \{\
.RE
.\}
.sp
.sp
It is safe to interactively read and write from this command since each record is immediately flushed\&.
.SH "EXAMPLES"
.sp
The command \fBgit-last-modified\fR(1) shows the commit that each file was last modified in\&.
.sp
.if n \{\
.RS 4
.\}
.nf
$ git last\-modified \-\- README\&.md Makefile
7798034171030be0909c56377a4e0e10e6d2df93        Makefile
c50fbb2dd225e7e82abba4380423ae105089f4d7        README\&.md
.fi
.if n \{\
.RE
.\}
.sp
.sp
We can pipe the result to this command in order to replace the object name with the commit author\&.
.sp
.if n \{\
.RS 4
.\}
.nf
$ git last\-modified \-\- README\&.md Makefile |
    git format\-rev \-\-stdin\-mode=text \-\-format=%an
Junio C Hamano  Makefile
Todd Zullinger  README\&.md
.fi
.if n \{\
.RE
.\}
.sp
.sp
Another example is \fIformatting commits in commit messages\fR\&. Given this commit message:
.sp
.if n \{\
.RS 4
.\}
.nf
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\&.
.fi
.if n \{\
.RE
.\}
.sp
.sp
We can format the commits and use par(1) to reflow the text, say in a \fBcommit\-msg\fR hook:
.sp
.if n \{\
.RS 4
.\}
.nf
$ 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"
.fi
.if n \{\
.RE
.\}
.sp
.sp
Which will produce something like this:
.sp
.if n \{\
.RS 4
.\}
.nf
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\&.
.fi
.if n \{\
.RE
.\}
.sp
.SH "DISCUSSION"
.sp
This command lets you format any number of revisions in any order through one command invocation\&. Consider the \fBgit-last-modified\fR(1) case from the EXAMPLES section above:
.sp
.RS 4
.ie n \{\
\h'-04' 1.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  1." 4.2
.\}
There might be hundreds of files
.RE
.sp
.RS 4
.ie n \{\
\h'-04' 2.\h'+01'\c
.\}
.el \{\
.sp -1
.IP "  2." 4.2
.\}
Commits can be repeated, i\&.e\&. two or more files were last modified in the same commit
.RE
.sp
Two widely\-used commands which pretty formats commits are \fBgit-log\fR(1) and \fBgit-show\fR(1)\&. It turns out that they are not a good fit for the above use case\&.
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
The output of
\fBgit-last-modified\fR(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\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
You can feed each commit to
\fBgit\fR
\fBshow\fR
or
\fBgit\fR
\fBlog\fR
\fB\-\-no\-walk\fR
\fB\-1\fR\&. But that means that you need to create a process for each line\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
Let\(cqs 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
\fB\-\-stdin\fR
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\&.
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
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\&.
.RE
.sp
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\&.
.SH "SEE ALSO"
.sp
\fBgit-name-rev\fR(1), \fBgit-log\fR(1)\&.
.SH "GIT"
.sp
Part of the \fBgit\fR(1) suite