# git-format-patch

## 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]
                              [--[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:
    
           •   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).
    
           •   The second and subsequent paragraphs of the commit log
               message.
    
           •   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 instead of the usual
               three.
    
           **--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.
    
           **--**[**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:
    
               •   Blank lines are ignored, so they can be used as separators
                   for readability.
    
               •   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.
    
               •   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-diff(1) and git-log(1), but
               not for 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
               **diff.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.
    
           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
               Controls 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>
               Controls which parts of the cover letter will be automatically
               populated using the branch’s description.
    
               If _< mode>_ is **message** or **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.
    
               If _< mode>_ is **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.
    
               If _< mode>_ is **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.
    
               If _< mode>_ is **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>
               Instead of the standard _[PATCH]_ prefix in the subject line,
               instead use _[ <subject-prefix>]_. 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 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, use
               the committer ident.
    
               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**.
    
           --[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.
    
           --[no-]cover-letter
               In addition to the patches, generate a cover letter file
               containing the branch description, shortlog and the overall
               diffstat. You can fill in a description in the file before
               sending it out.
    
           --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.
    
           --[no-]signature=<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[=<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
                       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-König 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:
    
           •   Empty context lines that do not have _any_ whitespace.
    
           •   Non-empty context lines that have one extra whitespace at the
               beginning.
    
           One way to test if your MUA is set up correctly is:
    
           •   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.
    
           •   Save that patch to a file in UNIX mailbox format. Call it
               a.patch, say.
    
           •   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.
    
           •   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.
    
           •   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.
    
           •   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 Word Wrap add-on that is available from
               **https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/ **
               It adds a menu entry "Enable Word Wrap" in the composer’s
               "Options" menu 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.
    
           **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



           •   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
    
           •   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.
    
           •   Extract all commits that lead to _origin_ since the inception of
               the project:
    
                   $ git format-patch --root origin
    
           •   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.
    
           •   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.
    


## GIT



           Part of the git(1) suite
    


* * *