git-format-patch

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]
                          [--cover-from-description=<mode>]
                          [--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 commit with its patch in one file per commit, formatted to
       resemble UNIX mailbox format. The output of this command is convenient
       for e-mail submission or for use with git am.

       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 this 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. The width of the graph part can be limited by using
           --stat-graph-width=<width> (affects all commands generating a stat
           graph) or by setting diff.statGraphWidth=<width> (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[<param1,param2,...>], --dirstat[=<param1,param2,...>]
           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[=<param1,param2>...]
           Synonym for --dirstat=files,param1,param2...

       --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 require O(n^2) processing time where n is the
           number of potential rename/copy targets. This option prevents
           rename/copy detection from running if the number of rename/copy
           targets exceeds the specified number.

       -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".

       --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=<lines>
           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[=<when>]
           Ignore changes to submodules in the diff generation. <when> can be
           either "none", "untracked", "dirty" or "all", which 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.

       --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. If --thread is specified without a style, it defaults to the
           style specified by format.thread if any, or else 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.

       --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.

       --subject-prefix=<subject prefix>
           Instead of the standard [PATCH] prefix in the subject line, instead
           use [<subject prefix>]. This allows for useful naming of a patch
           series, and can be combined with the --numbered option.

       --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
           Alias for --subject-prefix="RFC PATCH". RFC means "Request For
           Comments"; use this when sending an experimental patch for discussion
           rather than application.

       -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.

       --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.

       --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.

       --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
           http://aboutconfig.mozdev.org/ and External Editor from
           http://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 track base commit automatically,
       the base commit will be the merge base of tip commit of the
       remote-tracking branch and revision-range specified in cmdline. For a
       local branch, you need 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


SEE ALSO
       git-am(1), git-send-email(1)

GIT
       Part of the git(1) suite



Git 2.30.0                         12/28/2020                GIT-FORMAT-PATCH(1)