git-format-patch(1) Git Manual git-format-patch(1)
NAME
git-format-patch - Prepare patches for e-mail submission
SYNOPSIS
git format-patch [-k] [(-o|--output-directory) <dir> | --stdout]
[--no-thread | --thread[=<style>]]
[(--attach|--inline)[=<boundary>] | --no-attach]
[-s | --signoff]
[--signature=<signature> | --no-signature]
[--signature-file=<file>]
[-n | --numbered | -N | --no-numbered]
[--start-number <n>] [--numbered-files]
[--in-reply-to=<message-id>] [--suffix=.<sfx>]
[--ignore-if-in-upstream] [--always]
[--cover-from-description=<mode>]
[--rfc[=<rfc>]] [--subject-prefix=<subject-prefix>]
[(--reroll-count|-v) <n>]
[--to=<email>] [--cc=<email>]
[--[no-]cover-letter] [--quiet]
[--commit-list-format=<format-spec>]
[--[no-]encode-email-headers]
[--no-notes | --notes[=<ref>]]
[--interdiff=<previous>]
[--range-diff=<previous> [--creation-factor=<percent>]]
[--filename-max-length=<n>]
[--progress]
[<common-diff-options>]
[ <since> | <revision-range> ]
DESCRIPTION
Prepare each non-merge commit with its "patch" in one "message" per
commit, formatted to resemble a UNIX mailbox. The output of this command
is convenient for e-mail submission or for use with git am.
A "message" generated by the command consists of three parts:
o A brief metadata header that begins with From <commit> with a fixed
Mon Sep 17 00:00:00 2001 datestamp to help programs like file(1) to
recognize that the file is an output from this command, fields that
record the author identity, the author date, and the title of the
change (taken from the first paragraph of the commit log message).
o The second and subsequent paragraphs of the commit log message.
o The "patch", which is the diff -p --stat output (see git-diff(1))
between the commit and its parent.
The log message and the patch are separated by a line with a three-dash
line.
There are two ways to specify which commits to operate on.
1. A single commit, <since>, specifies that the commits leading to the
tip of the current branch that are not in the history that leads to
the <since> to be output.
2. Generic <revision-range> expression (see SPECIFYING REVISIONS section
in gitrevisions(7)) means the commits in the specified range.
The first rule takes precedence in the case of a single <commit>. To
apply the second rule, i.e., format everything since the beginning of
history up until <commit>, use the --root option: git format-patch --root
<commit>. If you want to format only <commit> itself, you can do this
with git format-patch -1 <commit>.
By default, each output file is numbered sequentially from 1, and uses
the first line of the commit message (massaged for pathname safety) as
the filename. With the --numbered-files option, the output file names
will only be numbers, without the first line of the commit appended. The
names of the output files are printed to standard output, unless the
--stdout option is specified.
If -o is specified, output files are created in <dir>. Otherwise they are
created in the current working directory. The default path can be set
with the format.outputDirectory configuration option. The -o option takes
precedence over format.outputDirectory. To store patches in the current
working directory even when format.outputDirectory points elsewhere, use
-o .. All directory components will be created.
By default, the subject of a single patch is "[PATCH] " followed by the
concatenation of lines from the commit message up to the first blank line
(see the DISCUSSION section of git-commit(1)).
When multiple patches are output, the subject prefix will instead be
"[PATCH n/m] ". To force 1/1 to be added for a single patch, use -n. To
omit patch numbers from the subject, use -N.
If given --thread, git-format-patch will generate In-Reply-To and
References headers to make the second and subsequent patch mails appear
as replies to the first mail; this also generates a Message-ID header to
reference.
OPTIONS
-p, --no-stat
Generate plain patches without any diffstats.
-U<n>, --unified=<n>
Generate diffs with <n> lines of context. The number of context lines
defaults to diff.context or 3 if the configuration variable is unset.
(-U without <n> is silently accepted as a synonym for -p due to a
historical accident).
--output=<file>
Output to a specific file instead of stdout.
--output-indicator-new=<char>, --output-indicator-old=<char>,
--output-indicator-context=<char>
Specify the character used to indicate new, old or context lines in
the generated patch. Normally they are +, - and ' ' respectively.
--indent-heuristic
Enable the heuristic that shifts diff hunk boundaries to make patches
easier to read. This is the default.
--no-indent-heuristic
Disable the indent heuristic.
--minimal
Spend extra time to make sure the smallest possible diff is produced.
--patience
Generate a diff using the "patience diff" algorithm.
--histogram
Generate a diff using the "histogram diff" algorithm.
--anchored=<text>
Generate a diff using the "anchored diff" algorithm.
This option may be specified more than once.
If a line exists in both the source and destination, exists only
once, and starts with <text>, this algorithm attempts to prevent it
from appearing as a deletion or addition in the output. It uses the
"patience diff" algorithm internally.
--diff-algorithm=(patience|minimal|histogram|myers)
Choose a diff algorithm. The variants are as follows:
default, myers
The basic greedy diff algorithm. Currently, this is the default.
minimal
Spend extra time to make sure the smallest possible diff is
produced.
patience
Use "patience diff" algorithm when generating patches.
histogram
This algorithm extends the patience algorithm to "support
low-occurrence common elements".
For instance, if you configured the diff.algorithm variable to a
non-default value and want to use the default one, then you have to
use --diff-algorithm=default option.
--stat[=<width>[,<name-width>[,<count>]]]
Generate a diffstat. By default, as much space as necessary will be
used for the filename part, and the rest for the graph part. Maximum
width defaults to terminal width, or 80 columns if not connected to a
terminal, and can be overridden by <width>. The width of the filename
part can be limited by giving another width <name-width> after a
comma or by setting diff.statNameWidth=<name-width>. The width of the
graph part can be limited by using --stat-graph-width=<graph-width>
or by setting diff.statGraphWidth=<graph-width>. Using --stat or
--stat-graph-width affects all commands generating a stat graph,
while setting diff.statNameWidth or diff.statGraphWidth does not
affect git format-patch. By giving a third parameter <count>, you can
limit the output to the first <count> lines, followed by ... if there
are more.
These parameters can also be set individually with
--stat-width=<width>, --stat-name-width=<name-width> and
--stat-count=<count>.
--compact-summary
Output a condensed summary of extended header information such as
file creations or deletions ("new" or "gone", optionally +l if it's a
symlink) and mode changes (+x or -x for adding or removing executable
bit respectively) in diffstat. The information is put between the
filename part and the graph part. Implies --stat.
--numstat
Similar to --stat, but shows number of added and deleted lines in
decimal notation and pathname without abbreviation, to make it more
machine friendly. For binary files, outputs two - instead of saying 0
0.
--shortstat
Output only the last line of the --stat format containing total
number of modified files, as well as number of added and deleted
lines.
-X [<param>,...], --dirstat[=<param>,...]
Output the distribution of relative amount of changes for each
sub-directory. The behavior of --dirstat can be customized by passing
it a comma separated list of parameters. The defaults are controlled
by the diff.dirstat configuration variable (see git-config(1)). The
following parameters are available:
changes
Compute the dirstat numbers by counting the lines that have been
removed from the source, or added to the destination. This
ignores the amount of pure code movements within a file. In other
words, rearranging lines in a file is not counted as much as
other changes. This is the default behavior when no parameter is
given.
lines
Compute the dirstat numbers by doing the regular line-based diff
analysis, and summing the removed/added line counts. (For binary
files, count 64-byte chunks instead, since binary files have no
natural concept of lines). This is a more expensive --dirstat
behavior than the changes behavior, but it does count rearranged
lines within a file as much as other changes. The resulting
output is consistent with what you get from the other --*stat
options.
files
Compute the dirstat numbers by counting the number of files
changed. Each changed file counts equally in the dirstat
analysis. This is the computationally cheapest --dirstat
behavior, since it does not have to look at the file contents at
all.
cumulative
Count changes in a child directory for the parent directory as
well. Note that when using cumulative, the sum of the percentages
reported may exceed 100%. The default (non-cumulative) behavior
can be specified with the noncumulative parameter.
<limit>
An integer parameter specifies a cut-off percent (3% by default).
Directories contributing less than this percentage of the changes
are not shown in the output.
Example: The following will count changed files, while ignoring
directories with less than 10% of the total amount of changed files,
and accumulating child directory counts in the parent directories:
--dirstat=files,10,cumulative.
--cumulative
Synonym for --dirstat=cumulative.
--dirstat-by-file[=<param>,...]
Synonym for --dirstat=files,<param>,....
--summary
Output a condensed summary of extended header information such as
creations, renames and mode changes.
--no-renames
Turn off rename detection, even when the configuration file gives the
default to do so.
--rename-empty, --no-rename-empty
Whether to use empty blobs as rename source.
--full-index
Instead of the first handful of characters, show the full pre- and
post-image blob object names on the "index" line when generating
patch format output.
--binary
In addition to --full-index, output a binary diff that can be applied
with git-apply.
--abbrev[=<n>]
Instead of showing the full 40-byte hexadecimal object name in
diff-raw format output and diff-tree header lines, show the shortest
prefix that is at least <n> hexdigits long that uniquely refers the
object. In diff-patch output format, --full-index takes higher
precedence, i.e. if --full-index is specified, full blob names will
be shown regardless of --abbrev. Non default number of digits can be
specified with --abbrev=<n>.
-B[<n>][/<m>], --break-rewrites[=[<n>][/<m>]]
Break complete rewrite changes into pairs of delete and create. This
serves two purposes:
It affects the way a change that amounts to a total rewrite of a file
not as a series of deletion and insertion mixed together with a very
few lines that happen to match textually as the context, but as a
single deletion of everything old followed by a single insertion of
everything new, and the number <m> controls this aspect of the -B
option (defaults to 60%). -B/70% specifies that less than 30% of the
original should remain in the result for Git to consider it a total
rewrite (i.e. otherwise the resulting patch will be a series of
deletion and insertion mixed together with context lines).
When used with -M, a totally-rewritten file is also considered as the
source of a rename (usually -M only considers a file that disappeared
as the source of a rename), and the number <n> controls this aspect
of the -B option (defaults to 50%). -B20% specifies that a change
with addition and deletion compared to 20% or more of the file's size
are eligible for being picked up as a possible source of a rename to
another file.
-M[<n>], --find-renames[=<n>]
Detect renames. If <n> is specified, it is a threshold on the
similarity index (i.e. amount of addition/deletions compared to the
file's size). For example, -M90% means Git should consider a
delete/add pair to be a rename if more than 90% of the file hasn't
changed. Without a % sign, the number is to be read as a fraction,
with a decimal point before it. I.e., -M5 becomes 0.5, and is thus
the same as -M50%. Similarly, -M05 is the same as -M5%. To limit
detection to exact renames, use -M100%. The default similarity index
is 50%.
-C[<n>], --find-copies[=<n>]
Detect copies as well as renames. See also --find-copies-harder. If
<n> is specified, it has the same meaning as for -M<n>.
--find-copies-harder
For performance reasons, by default, -C option finds copies only if
the original file of the copy was modified in the same changeset.
This flag makes the command inspect unmodified files as candidates
for the source of copy. This is a very expensive operation for large
projects, so use it with caution. Giving more than one -C option has
the same effect.
-D, --irreversible-delete
Omit the preimage for deletes, i.e. print only the header but not the
diff between the preimage and /dev/null. The resulting patch is not
meant to be applied with patch or git apply; this is solely for
people who want to just concentrate on reviewing the text after the
change. In addition, the output obviously lacks enough information to
apply such a patch in reverse, even manually, hence the name of the
option.
When used together with -B, omit also the preimage in the deletion
part of a delete/create pair.
-l<num>
The -M and -C options involve some preliminary steps that can detect
subsets of renames/copies cheaply, followed by an exhaustive fallback
portion that compares all remaining unpaired destinations to all
relevant sources. (For renames, only remaining unpaired sources are
relevant; for copies, all original sources are relevant.) For N
sources and destinations, this exhaustive check is O(N^2). This
option prevents the exhaustive portion of rename/copy detection from
running if the number of source/destination files involved exceeds
the specified number. Defaults to diff.renameLimit. Note that a value
of 0 is treated as unlimited.
-O<orderfile>
Control the order in which files appear in the output. This overrides
the diff.orderFile configuration variable (see git-config(1)). To
cancel diff.orderFile, use -O/dev/null.
The output order is determined by the order of glob patterns in
<orderfile>. All files with pathnames that match the first pattern
are output first, all files with pathnames that match the second
pattern (but not the first) are output next, and so on. All files
with pathnames that do not match any pattern are output last, as if
there was an implicit match-all pattern at the end of the file. If
multiple pathnames have the same rank (they match the same pattern
but no earlier patterns), their output order relative to each other
is the normal order.
<orderfile> is parsed as follows:
o Blank lines are ignored, so they can be used as separators for
readability.
o Lines starting with a hash ("#") are ignored, so they can be used
for comments. Add a backslash ("\") to the beginning of the
pattern if it starts with a hash.
o Each other line contains a single pattern.
Patterns have the same syntax and semantics as patterns used for
fnmatch(3) without the FNM_PATHNAME flag, except a pathname also
matches a pattern if removing any number of the final pathname
components matches the pattern. For example, the pattern "foo*bar"
matches "fooasdfbar" and "foo/bar/baz/asdf" but not "foobarx".
--skip-to=<file>, --rotate-to=<file>
Discard the files before the named <file> from the output (i.e. skip
to), or move them to the end of the output (i.e. rotate to). These
options were invented primarily for the use of the git difftool
command, and may not be very useful otherwise.
--relative[=<path>], --no-relative
When run from a subdirectory of the project, it can be told to
exclude changes outside the directory and show pathnames relative to
it with this option. When you are not in a subdirectory (e.g. in a
bare repository), you can name which subdirectory to make the output
relative to by giving a <path> as an argument. --no-relative can be
used to countermand both diff.relative config option and previous
--relative.
-a, --text
Treat all files as text.
--ignore-cr-at-eol
Ignore carriage-return at the end of line when doing a comparison.
--ignore-space-at-eol
Ignore changes in whitespace at EOL.
-b, --ignore-space-change
Ignore changes in amount of whitespace. This ignores whitespace at
line end, and considers all other sequences of one or more whitespace
characters to be equivalent.
-w, --ignore-all-space
Ignore whitespace when comparing lines. This ignores differences even
if one line has whitespace where the other line has none.
--ignore-blank-lines
Ignore changes whose lines are all blank.
-I<regex>, --ignore-matching-lines=<regex>
Ignore changes whose all lines match <regex>. This option may be
specified more than once.
--inter-hunk-context=<number>
Show the context between diff hunks, up to the specified <number> of
lines, thereby fusing hunks that are close to each other. Defaults to
diff.interHunkContext or 0 if the config option is unset.
-W, --function-context
Show whole function as context lines for each change. The function
names are determined in the same way as git diff works out patch hunk
headers (see "Defining a custom hunk-header" in gitattributes(5)).
--ext-diff
Allow an external diff helper to be executed. If you set an external
diff driver with gitattributes(5), you need to use this option with
git-log(1) and friends.
--no-ext-diff
Disallow external diff drivers.
--textconv, --no-textconv
Allow (or disallow) external text conversion filters to be run when
comparing binary files. See gitattributes(5) for details. Because
textconv filters are typically a one-way conversion, the resulting
diff is suitable for human consumption, but cannot be applied. For
this reason, textconv filters are enabled by default only for git-
git-format-patch(1) or diff
plumbing commands.
--ignore-submodules[=(none|untracked|dirty|all)]
Ignore changes to submodules in the diff generation. all is the
default. Using none will consider the submodule modified when it
either contains untracked or modified files or its HEAD differs from
the commit recorded in the superproject and can be used to override
any settings of the ignore option in git-config(1) or gitmodules(5).
When untracked is used submodules are not considered dirty when they
only contain untracked content (but they are still scanned for
modified content). Using dirty ignores all changes to the work tree
of submodules, only changes to the commits stored in the superproject
are shown (this was the behavior until 1.7.0). Using all hides all
changes to submodules.
--src-prefix=<prefix>
Show the given source <prefix> instead of "a/".
--dst-prefix=<prefix>
Show the given destination <prefix> instead of "b/".
--no-prefix
Do not show any source or destination prefix.
--default-prefix
Use the default source and destination prefixes ("a/" and "b/"). This
overrides configuration variables such as format.noprefix,
diff.srcPrefix, diff.dstPrefix, and diff.mnemonicPrefix (see git-
config(1)).
--line-prefix=<prefix>
Prepend an additional <prefix> to every line of output.
--ita-invisible-in-index
By default entries added by git add -N appear as an existing empty
file in git diff and a new file in git diff --cached. This option
makes the entry appear as a new file in git diff and non-existent in
git diff --cached. This option could be reverted with
--ita-visible-in-index. Both options are experimental and could be
removed in future.
--max-depth=<depth>
For each pathspec given on command line, descend at most <depth>
levels of directories. A value of -1 means no limit. Cannot be
combined with wildcards in the pathspec. Given a tree containing
foo/bar/baz, the following list shows the matches generated by each
set of options:
o --max-depth=0 -- foo: foo
o --max-depth=1 -- foo: foo/bar
o --max-depth=1 -- foo/bar: foo/bar/baz
o --max-depth=1 -- foo foo/bar: foo/bar/baz
o --max-depth=2 -- foo: foo/bar/baz
If no pathspec is given, the depth is measured as if all top-level
entries were specified. Note that this is different than measuring
from the root, in that --max-depth=0 would still return foo. This
allows you to still limit depth while asking for a subset of the
top-level entries.
Note that this option is only supported for diffs between tree
objects, not against the index or working tree.
For more detailed explanation on these common options, see also
gitdiffcore(7).
-<n>
Prepare patches from the topmost <n> commits.
-o <dir>, --output-directory=<dir>
Use <dir> to store the resulting files, instead of the current
working directory.
-n, --numbered
Name output in [PATCH n/m] format, even with a single patch.
-N, --no-numbered
Name output in [PATCH] format.
--start-number <n>
Start numbering the patches at <n> instead of 1.
--numbered-files
Output file names will be a simple number sequence without the
default first line of the commit appended.
-k, --keep-subject
Do not strip/add [PATCH] from the first line of the commit log
message.
-s, --signoff
Add a Signed-off-by trailer to the commit message, using the
committer identity of yourself. See the signoff option in git-
commit(1) for more information.
--stdout
Print all commits to the standard output in mbox format, instead of
creating a file for each one.
--attach[=<boundary>]
Create multipart/mixed attachment, the first part of which is the
commit message and the patch itself in the second part, with
Content-Disposition: attachment.
--no-attach
Disable the creation of an attachment, overriding the configuration
setting.
--inline[=<boundary>]
Create multipart/mixed attachment, the first part of which is the
commit message and the patch itself in the second part, with
Content-Disposition: inline.
--thread[=<style>], --no-thread
Control addition of In-Reply-To and References headers to make the
second and subsequent mails appear as replies to the first. Also
controls generation of the Message-ID header to reference.
The optional <style> argument can be either shallow or deep. shallow
threading makes every mail a reply to the head of the series, where
the head is chosen from the cover letter, the --in-reply-to, and the
first patch mail, in this order. deep threading makes every mail a
reply to the previous one.
The default is --no-thread, unless the format.thread configuration is
set. --thread without an argument is equivalent to --thread=shallow.
Beware that the default for git send-email is to thread emails
itself. If you want git format-patch to take care of threading, you
will want to ensure that threading is disabled for git send-email.
--in-reply-to=<message-id>
Make the first mail (or all the mails with --no-thread) appear as a
reply to the given <message-id>, which avoids breaking threads to
provide a new patch series.
--ignore-if-in-upstream
Do not include a patch that matches a commit in <until>..<since>.
This will examine all patches reachable from <since> but not from
<until> and compare them with the patches being generated, and any
patch that matches is ignored.
--always
Include patches for commits that do not introduce any change, which
are omitted by default.
--cover-from-description=<mode>
Control which parts of the cover letter will be automatically
populated using the branch's description.
<mode> can have the following values:
message, default
the cover letter subject will be populated with placeholder text.
The body of the cover letter will be populated with the branch's
description. This is the default mode when no configuration nor
command line option is specified.
subject
the first paragraph of the branch description will populate the
cover letter subject. The remainder of the description will
populate the body of the cover letter.
auto
if the first paragraph of the branch description is greater than
100 bytes, then the mode will be message, otherwise subject will
be used.
none
both the cover letter subject and body will be populated with
placeholder text.
--description-file=<file>
Use the contents of <file> instead of the branch's description for
generating the cover letter.
--subject-prefix=<subject-prefix>
Use [<subject-prefix>] instead of the standard [PATCH] prefix in the
subject line. This can be used to name a patch series, and can be
combined with the --numbered option.
The configuration variable format.subjectPrefix may also be used to
configure a subject prefix to apply to a given repository for all
patches. This is often useful on mailing lists which receive patches
for several repositories and can be used to disambiguate the patches
(with a value of e.g. "PATCH my-project").
--filename-max-length=<n>
Instead of the standard 64 bytes, chomp the generated output
filenames at around <n> bytes (too short a value will be silently
raised to a reasonable length). Defaults to the value of the
format.filenameMaxLength configuration variable, or 64 if
unconfigured.
--rfc[=<rfc>]
Prepends the string <rfc> (defaults to "RFC") to the subject prefix.
As the subject prefix defaults to "PATCH", you'll get "RFC PATCH" by
default.
RFC means "Request For Comments"; use this when sending an
experimental patch for discussion rather than application.
"--rfc=WIP" may also be a useful way to indicate that a patch is not
complete yet ("WIP" stands for "Work In Progress").
If the convention of the receiving community for a particular extra
string is to have it after the subject prefix, the string <rfc> can
be prefixed with a dash ("-") to signal that the rest of the <rfc>
string should be appended to the subject prefix instead, e.g.,
--rfc='-(WIP)' results in "PATCH (WIP)".
-v <n>, --reroll-count=<n>
Mark the series as the <n>-th iteration of the topic. The output
filenames have v<n> prepended to them, and the subject prefix
("PATCH" by default, but configurable via the --subject-prefix
option) has v<n> appended to it. E.g. --reroll-count=4 may produce
v4-0001-add-makefile.patch file that has "Subject: [PATCH v4 1/20]
Add makefile" in it. <n> does not have to be an integer (e.g.
--reroll-count=4.4, or --reroll-count=4rev2 are allowed), but the
downside of using such a reroll-count is that the
range-diff/interdiff with the previous version does not state exactly
which version the new iteration is compared against.
--to=<email>
Add a To: header to the email headers. This is in addition to any
configured headers, and may be used multiple times. The negated form
--no-to discards all To: headers added so far (from config or command
line).
--cc=<email>
Add a Cc: header to the email headers. This is in addition to any
configured headers, and may be used multiple times. The negated form
--no-cc discards all Cc: headers added so far (from config or command
line).
--from, --from=<ident>
Use <ident> in the From: header of each email. In case of a commit
email, if the author ident of the commit is not textually identical
to the provided <ident>, place a From: header in the body of the
message with the original author. If no <ident> is given, or if the
option is not passed at all, use the ident of the current committer.
Note that this option is only useful if you are actually sending the
emails and want to identify yourself as the sender, but retain the
original author (and git am will correctly pick up the in-body
header). Note also that git send-email already handles this
transformation for you, and this option should not be used if you are
feeding the result to git send-email.
--force-in-body-from, --no-force-in-body-from
With the e-mail sender specified via the --from option, by default,
an in-body "From:" to identify the real author of the commit is added
at the top of the commit log message if the sender is different from
the author. With this option, the in-body "From:" is added even when
the sender and the author have the same name and address, which may
help if the mailing list software mangles the sender's identity.
Defaults to the value of the format.forceInBodyFrom configuration
variable.
--add-header=<header>
Add an arbitrary header to the email headers. This is in addition to
any configured headers, and may be used multiple times. For example,
--add-header="Organization: git-foo". The negated form
--no-add-header discards all (To:, Cc:, and custom) headers added so
far from config or command line.
--cover-letter, --no-cover-letter
In addition to the patches, generate a cover letter file containing
the branch description, commit list and the overall diffstat. You can
fill in a description in the file before sending it out.
--commit-list-format=<format-spec>
Specify the format in which to generate the commit list of the patch
series. The accepted values for format-spec are shortlog, modern or a
format-string prefixed with log:. E.g. log: %s (%an). modern is the
same as log:%w(72)[%(count)/%(total)] %s. The log: prefix can be
omitted if the format-string has a % in it (expecting that it is part
of %<placeholder>). Defaults to the format.commitListFormat
configuration variable, if set, or shortlog. This option given from
the command-line implies the use of --cover-letter unless
--no-cover-letter is given.
--encode-email-headers, --no-encode-email-headers
Encode email headers that have non-ASCII characters with "Q-encoding"
(described in RFC 2047), instead of outputting the headers verbatim.
Defaults to the value of the format.encodeEmailHeaders configuration
variable.
--interdiff=<previous>
As a reviewer aid, insert an interdiff into the cover letter, or as
commentary of the lone patch of a 1-patch series, showing the
differences between the previous version of the patch series and the
series currently being formatted. <previous> is a single revision
naming the tip of the previous series which shares a common base with
the series being formatted (for example git format-patch
--cover-letter --interdiff=feature/v1 -3 feature/v2).
--range-diff=<previous>
As a reviewer aid, insert a range-diff (see git-range-diff(1)) into
the cover letter, or as commentary of the lone patch of a 1-patch
series, showing the differences between the previous version of the
patch series and the series currently being formatted. <previous>
can be a single revision naming the tip of the previous series if it
shares a common base with the series being formatted (for example git
format-patch --cover-letter --range-diff=feature/v1 -3 feature/v2),
or a revision range if the two versions of the series are disjoint
(for example git format-patch --cover-letter
--range-diff=feature/v1~3..feature/v1 -3 feature/v2).
Note that diff options passed to the command affect how the primary
product of format-patch is generated, and they are not passed to the
underlying range-diff machinery used to generate the cover-letter
material (this may change in the future).
--creation-factor=<percent>
Used with --range-diff, tweak the heuristic which matches up commits
between the previous and current series of patches by adjusting the
creation/deletion cost fudge factor. See git-range-diff(1)) for
details.
Defaults to 999 (the git-range-diff(1) uses 60), as the use case is
to show comparison with an older iteration of the same topic and the
tool should find more correspondence between the two sets of patches.
--notes[=<ref>], --no-notes
Append the notes (see git-notes(1)) for the commit after the
three-dash line.
The expected use case of this is to write supporting explanation for
the commit that does not belong to the commit log message proper, and
include it with the patch submission. While one can simply write
these explanations after format-patch has run but before sending,
keeping them as Git notes allows them to be maintained between
versions of the patch series (but see the discussion of the
notes.rewrite configuration options in git-notes(1) to use this
workflow).
The default is --no-notes, unless the format.notes configuration is
set.
--signature=<signature>, --no-signature
Add a signature to each message produced. Per RFC 3676 the signature
is separated from the body by a line with "-- " on it. If the
signature option is omitted the signature defaults to the Git version
number.
--signature-file=<file>
Works just like --signature except the signature is read from a file.
--suffix=.<sfx>
Instead of using .patch as the suffix for generated filenames, use
specified suffix. A common alternative is --suffix=.txt. Leaving this
empty will remove the .patch suffix.
Note that the leading character does not have to be a dot; for
example, you can use --suffix=-patch to get
0001-description-of-my-change-patch.
-q, --quiet
Do not print the names of the generated files to standard output.
--no-binary
Do not output contents of changes in binary files, instead display a
notice that those files changed. Patches generated using this option
cannot be applied properly, but they are still useful for code
review.
--zero-commit
Output an all-zero hash in each patch's From header instead of the
hash of the commit.
--no-base, --base[=<commit>]
Record the base tree information to identify the state the patch
series applies to. See the BASE TREE INFORMATION section below for
details. If <commit> is auto, a base commit is automatically chosen.
The --no-base option overrides a format.useAutoBase configuration.
--root
Treat the revision argument as a <revision-range>, even if it is just
a single commit (that would normally be treated as a <since>). Note
that root commits included in the specified range are always
formatted as creation patches, independently of this flag.
--progress
Show progress reports on stderr as patches are generated.
CONFIGURATION
You can specify extra mail header lines to be added to each message,
defaults for the subject prefix and file suffix, number patches when
outputting more than one patch, add "To:" or "Cc:" headers, configure
attachments, change the patch output directory, and sign off patches with
configuration variables.
[format]
headers = "Organization: git-foo\n"
subjectPrefix = CHANGE
suffix = .txt
numbered = auto
to = <email>
cc = <email>
attach [ = mime-boundary-string ]
signOff = true
outputDirectory = <directory>
coverLetter = auto
commitListFormat = shortlog
coverFromDescription = auto
DISCUSSION
The patch produced by git format-patch is in UNIX mailbox format, with a
fixed "magic" time stamp to indicate that the file is output from
format-patch rather than a real mailbox, like so:
From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
From: Tony Luck <tony.luck@intel.com>
Date: Tue, 13 Jul 2010 11:42:54 -0700
Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
=?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
arch/arm config files were slimmed down using a python script
(See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
Do the same for ia64 so we can have sleek & trim looking
...
Typically it will be placed in a MUA's drafts folder, edited to add
timely commentary that should not go in the changelog after the three
dashes, and then sent as a message whose body, in our example, starts
with "arch/arm config files were...". On the receiving end, readers can
save interesting patches in a UNIX mailbox and apply them with git-am(1).
When a patch is part of an ongoing discussion, the patch generated by git
format-patch can be tweaked to take advantage of the git am --scissors
feature. After your response to the discussion comes a line that consists
solely of "-- >8 --" (scissors and perforation), followed by the patch
with unnecessary header fields removed:
...
> So we should do such-and-such.
Makes sense to me. How about this patch?
-- >8 --
Subject: [IA64] Put ia64 config files on the Uwe Kleine-Konig diet
arch/arm config files were slimmed down using a python script
...
When sending a patch this way, most often you are sending your own patch,
so in addition to the "From $SHA1 $magic_timestamp" marker you should
omit From: and Date: lines from the patch file. The patch title is likely
to be different from the subject of the discussion the patch is in
response to, so it is likely that you would want to keep the Subject:
line, like the example above.
Checking for patch corruption
Many mailers if not set up properly will corrupt whitespace. Here are two
common types of corruption:
o Empty context lines that do not have any whitespace.
o Non-empty context lines that have one extra whitespace at the
beginning.
One way to test if your MUA is set up correctly is:
o Send the patch to yourself, exactly the way you would, except with
To: and Cc: lines that do not contain the list and maintainer
address.
o Save that patch to a file in UNIX mailbox format. Call it a.patch,
say.
o Apply it:
$ git fetch <project> master:test-apply
$ git switch test-apply
$ git restore --source=HEAD --staged --worktree :/
$ git am a.patch
If it does not apply correctly, there can be various reasons.
o The patch itself does not apply cleanly. That is bad but does not
have much to do with your MUA. You might want to rebase the patch
with git-rebase(1) before regenerating it in this case.
o The MUA corrupted your patch; "am" would complain that the patch does
not apply. Look in the .git/rebase-apply/ subdirectory and see what
patch file contains and check for the common corruption patterns
mentioned above.
o While at it, check the info and final-commit files as well. If what
is in final-commit is not exactly what you would want to see in the
commit log message, it is very likely that the receiver would end up
hand editing the log message when applying your patch. Things like
"Hi, this is my first patch.\n" in the patch e-mail should come after
the three-dash line that signals the end of the commit message.
MUA-SPECIFIC HINTS
Here are some hints on how to successfully submit patches inline using
various mailers.
GMail
GMail does not have any way to turn off line wrapping in the web
interface, so it will mangle any emails that you send. You can however
use git send-email and send your patches through the GMail SMTP server,
or use any IMAP email client to connect to the google IMAP server and
forward the emails through that.
For hints on using git send-email to send your patches through the GMail
SMTP server, see the EXAMPLE section of git-send-email(1).
For hints on submission using the IMAP interface, see the EXAMPLE section
of git-imap-send(1).
Thunderbird
By default, Thunderbird will both wrap emails as well as flag them as
being format=flowed, both of which will make the resulting email unusable
by Git.
There are three different approaches: use an add-on to turn off line
wraps, configure Thunderbird to not mangle patches, or use an external
editor to keep Thunderbird from mangling the patches.
Approach #1 (add-on)
Install the Toggle Line Wrap add-on that is available from
https://addons.thunderbird.net/thunderbird/addon/toggle-line-wrap It
adds a button "Line Wrap" to the composer's toolbar that you can tick
off. Now you can compose the message as you otherwise do (cut +
paste, git format-patch | git imap-send, etc), but you have to insert
line breaks manually in any text that you type.
As a bonus feature, the add-on can detect patch text in the composer
and warns when line wrapping has not yet been turned off.
The add-on requires a few tweaks of the advanced configuration
(about:config). These are listed on the download page.
Approach #2 (configuration)
Three steps:
1. Configure your mail server composition as plain text: Edit...
Account Settings...Composition & Addressing, uncheck "Compose
Messages in HTML".
2. Configure your general composition window to not wrap.
In Thunderbird 2: Edit..Preferences..Composition, wrap plain text
messages at 0
In Thunderbird 3: Edit..Preferences..Advanced..Config Editor.
Search for "mail.wrap_long_lines". Toggle it to make sure it is
set to false. Also, search for "mailnews.wraplength" and set the
value to 0.
3. Disable the use of format=flowed:
Edit..Preferences..Advanced..Config Editor. Search for
"mailnews.send_plaintext_flowed". Toggle it to make sure it is
set to false.
After that is done, you should be able to compose email as you
otherwise would (cut + paste, git format-patch | git imap-send, etc),
and the patches will not be mangled.
Approach #3 (external editor)
The following Thunderbird extensions are needed: AboutConfig from
https://mjg.github.io/AboutConfig/ and External Editor from
https://globs.org/articles.php?lng=en&pg=8
1. Prepare the patch as a text file using your method of choice.
2. Before opening a compose window, use Edit->Account Settings to
uncheck the "Compose messages in HTML format" setting in the
"Composition & Addressing" panel of the account to be used to
send the patch.
3. In the main Thunderbird window, before you open the compose
window for the patch, use Tools->about:config to set the
following to the indicated values:
mailnews.send_plaintext_flowed => false
mailnews.wraplength => 0
4. Open a compose window and click the external editor icon.
5. In the external editor window, read in the patch file and exit
the editor normally.
Side note: it may be possible to do step 2 with about:config and the
following settings but no one's tried yet.
mail.html_compose => false
mail.identity.default.compose_html => false
mail.identity.id?.compose_html => false
There is a script in contrib/thunderbird-patch-inline which can help
you include patches with Thunderbird in an easy way. To use it, do
the steps above and then use the script as the external editor.
KMail
This should help you to submit patches inline using KMail.
1. Prepare the patch as a text file.
2. Click on New Mail.
3. Go under "Options" in the Composer window and be sure that "Word
wrap" is not set.
4. Use Message -> Insert file... and insert the patch.
5. Back in the compose window: add whatever other text you wish to the
message, complete the addressing and subject fields, and press send.
BASE TREE INFORMATION
The base tree information block is used for maintainers or third party
testers to know the exact state the patch series applies to. It consists
of the "base commit", which is a well-known commit that is part of the
stable part of the project history everybody else works off of, and zero
or more "prerequisite patches", which are well-known patches in flight
that is not yet part of the "base commit" that need to be applied on top
of "base commit" in topological order before the patches can be applied.
The "base commit" is shown as "base-commit: " followed by the 40-hex of
the commit object name. A "prerequisite patch" is shown as
"prerequisite-patch-id: " followed by the 40-hex "patch id", which can be
obtained by passing the patch through the git patch-id --stable command.
Imagine that on top of the public commit P, you applied well-known
patches X, Y and Z from somebody else, and then built your three-patch
series A, B, C, the history would be like:
---P---X---Y---Z---A---B---C
With git format-patch --base=P -3 C (or variants thereof, e.g. with
--cover-letter or using Z..C instead of -3 C to specify the range), the
base tree information block is shown at the end of the first message the
command outputs (either the first patch, or the cover letter), like this:
base-commit: P
prerequisite-patch-id: X
prerequisite-patch-id: Y
prerequisite-patch-id: Z
For non-linear topology, such as
---P---X---A---M---C
\ /
Y---Z---B
You can also use git format-patch --base=P -3 C to generate patches for
A, B and C, and the identifiers for P, X, Y, Z are appended at the end of
the first message.
If set --base=auto in cmdline, it will automatically compute the base
commit as the merge base of tip commit of the remote-tracking branch and
revision-range specified in cmdline. For a local branch, you need to make
it to track a remote branch by git branch --set-upstream-to before using
this option.
EXAMPLES
o Extract commits between revisions R1 and R2, and apply them on top of
the current branch using git am to cherry-pick them:
$ git format-patch -k --stdout R1..R2 | git am -3 -k
o Extract all commits which are in the current branch but not in the
origin branch:
$ git format-patch origin
For each commit a separate file is created in the current directory.
o Extract all commits that lead to origin since the inception of the
project:
$ git format-patch --root origin
o The same as the previous one:
$ git format-patch -M -B origin
Additionally, it detects and handles renames and complete rewrites
intelligently to produce a renaming patch. A renaming patch reduces
the amount of text output, and generally makes it easier to review.
Note that non-Git patch programs won't understand renaming patches,
so use it only when you know the recipient uses Git to apply your
patch.
o Extract three topmost commits from the current branch and format them
as e-mailable patches:
$ git format-patch -3
CAVEATS
Note that format-patch will omit merge commits from the output, even if
they are part of the requested range. A simple "patch" does not include
enough information for the receiving end to reproduce the same merge
commit.
PATCH APPLICATION
The output from git-format-patch(1) can lead to a different commit
message when applied with git-am(1). The patch that is applied may also
be different from the one that was generated, or patch application may
fail outright.
Any line that is of the form:
o three-dashes and end-of-line, or
o a line that begins with diff -, or
o a line that begins with `Index: `
is taken as the beginning of a patch, and the commit log message is
terminated before the first occurrence of such a line.
Note that this is especially problematic for unindented diffs that occur
in the commit message; the diff in the commit message might get applied
along with the patch section, or the patch application machinery might
trip up because the patch target doesn't apply. This could for example be
caused by a diff in a Markdown code block.
The solution for this is to indent the diff or other text that could
cause problems.
This loss of fidelity might be simple to notice if you are applying
patches directly from a mailbox. However, changes originating from Git
could be applied in bulk, in which case this would be much harder to
notice. This could for example be a Linux distribution which uses patch
files to apply changes on top of the commits from the upstream
repositories. This goes to show that this behavior does not only impact
email workflows.
Given these limitations, one might be tempted to use a general-purpose
utility like patch(1) instead. However, patch(1) will not only look for
unindented diffs (like git-am(1)) but will try to apply indented diffs as
well.
SEE ALSO
git-am(1), git-send-email(1)
GIT
Part of the git(1) suite
Git 2.56.0 2026-09-27 git-format-patch(1)
git 2.56.0 - Generated Thu Oct 1 16:03:44 CDT 2026