GIT-FORMAT-PATCH(1)                                        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]
                          [-n | --numbered | -N | --no-numbered]
                          [--start-number <n>] [--numbered-files]
                          [--in-reply-to=Message-Id] [--suffix=.<sfx>]
                          [--ignore-if-in-upstream]
                          [--subject-prefix=Subject-Prefix]
                          [--to=<email>] [--cc=<email>]
                          [--cover-letter] [--quiet]
                          [<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.


       By default, the subject of a single patch is "[PATCH] First Line" and
       the subject when multiple patches are output is "[PATCH n/m] First
       Line". 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.


       --patience
              Generate a diff using the "patience diff" algorithm.


       --stat[=<width>[,<name-width>]]
              Generate a diffstat. You can override the default output width
              for 80-column terminal by --stat=<width>. The width of the
              filename part can be controlled by giving another width to it
              separated by a comma.


       --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.


       --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.


       --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.


       --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 only a
              partial prefix. This is independent of the --full-index option
              above, which controls the diff-patch output format. 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&#8217;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&#8217;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&#8217;t changed.


       -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 nor git apply; this
              is solely for people who want to just concentrate on reviewing
              the text after the change. In addition, the output obviously
              lack 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>
              Output the patch in the order specified in the <orderfile>,
              which has one shell glob pattern per line.


       -a, --text
              Treat all files as text.


       --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.


       --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.


       --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.


       --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.


              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 Signed-off-by: line to the commit message, using the
              committer identity of yourself.


       --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.


       --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.


       --to=<email>
              Add a To: header to the email headers. This is in addition to
              any configured headers, and may be used multiple times.


       --cc=<email>
              Add a Cc: header to the email headers. This is in addition to
              any configured headers, and may be used multiple times.


       --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"


       --cover-letter
              In addition to the patches, generate a cover letter file
              containing the shortlog and the overall diffstat. You can fill
              in a description in the file before sending it out.


       --[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.


       --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.


       --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.


       --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.


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, 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





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&#8217;s drafts folder, edited to
       add timely commentary that should not go in the changelog after the
       three dashes, and then sent as a message whose body, in our example,
       starts with "arch/arm config files were...". On the receiving end,
       readers can save interesting patches in a UNIX mailbox and apply them
       with git-am(1).


       When a patch is part of an ongoing discussion, the patch generated by
       git format-patch can be tweaked to take advantage of the git am
       --scissors feature. After your response to the discussion comes a line
       that consists solely of "-- >8 --" (scissors and perforation), followed
       by the patch with unnecessary header fields removed:

       ...
       > So we should do such-and-such.

       Makes sense to me.  How about this patch?

       -- >8 --
       Subject: [IA64] Put ia64 config files on the Uwe Kleine-Konig diet

       arch/arm config files were slimmed down using a python script
       ...





       When sending a patch this way, most often you are sending your own
       patch, so in addition to the "From $SHA1 $magic_timestamp" marker you
       should omit From: and Date: lines from the patch file. The patch title
       is likely to be different from the subject of the discussion the patch
       is in response to, so it is likely that you would want to keep the
       Subject: line, like the example above.


   Checking for patch corruption
       Many mailers if not set up properly will corrupt whitespace. Here are
       two common types of corruption:


       o  Empty context lines that do not have any whitespace.

       o  Non-empty context lines that have one extra whitespace at the
          beginning.

       One way to test if your MUA is set up correctly is:


       o  Send the patch to yourself, exactly the way you would, except with
          To: and Cc: lines that do not contain the list and maintainer
          address.

       o  Save that patch to a file in UNIX mailbox format. Call it a.patch,
          say.

       o  Apply it:

          $ git fetch <project> master:test-apply
          $ git checkout test-apply
          $ git reset --hard
          $ git am a.patch

       If it does not apply correctly, there can be various reasons.


       o  The patch itself does not apply cleanly. That is bad but does not
          have much to do with your MUA. You might want to rebase the patch
          with git-rebase(1) before regenerating it in this case.

       o  The MUA corrupted your patch; "am" would complain that the patch
          does not apply. Look in the .git/rebase-apply/ subdirectory and see
          what patch file contains and check for the common corruption
          patterns mentioned above.

       o  While at it, check the info and final-commit files as well. If what
          is in final-commit is not exactly what you would want to see in the
          commit log message, it is very likely that the receiver would end up
          hand editing the log message when applying your patch. Things like
          "Hi, this is my first patch.\n" in the patch e-mail should come
          after the three-dash line that signals the end of the commit
          message.

MUA-SPECIFIC HINTS
       Here are some hints on how to successfully submit patches inline using
       various mailers.


   GMail
       GMail does not have any way to turn off line wrapping in the web
       interface, so it will mangle any emails that you send. You can however
       use "git send-email" and send your patches through the GMail SMTP
       server, or use any IMAP email client to connect to the google IMAP
       server and forward the emails through that.


       For hints on using git send-email to send your patches through the
       GMail SMTP server, see the EXAMPLE section of git-send-email(1).


       For hints on submission using the IMAP interface, see the EXAMPLE
       section of git-imap-send(1).


   Thunderbird
       By default, Thunderbird will both wrap emails as well as flag them as
       being format=flowed, both of which will make the resulting email
       unusable by git.


       There are three different approaches: use an add-on to turn off line
       wraps, configure Thunderbird to not mangle patches, or use an external
       editor to keep Thunderbird from mangling the patches.


       Install the Toggle Word Wrap add-on that is available from
       https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/:
       https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/ It adds
       a menu entry "Enable Word Wrap" in the composer&#8217;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.


       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.

       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.


       The following Thunderbird extensions are needed: AboutConfig from
       http://aboutconfig.mozdev.org/: http://aboutconfig.mozdev.org/ and
       External Editor from http://globs.org/articles.php?lng=en&pg=8:
       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&#8594;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&#8594;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&#8217;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 &#8594; 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.

EXAMPLES
       o  Extract commits between revisions R1 and R2, and apply them on top
          of the current branch using git am to cherry-pick them:


          $ git format-patch -k --stdout R1..R2 | git am -3 -k


       o  Extract all commits which are in the current branch but not in the
          origin branch:


          $ git format-patch origin


          For each commit a separate file is created in the current directory.

       o  Extract all commits that lead to origin since the inception of the
          project:


          $ git format-patch --root origin


       o  The same as the previous one:


          $ git format-patch -M -B origin


          Additionally, it detects and handles renames and complete rewrites
          intelligently to produce a renaming patch. A renaming patch reduces
          the amount of text output, and generally makes it easier to review.
          Note that non-git "patch" programs won&#8217;t understand renaming
          patches, so use it only when you know the recipient uses git to
          apply your patch.

       o  Extract three topmost commits from the current branch and format
          them as e-mailable patches:


          $ git format-patch -3


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


GIT
       Part of the git(1) suite




                                                           GIT-FORMAT-PATCH(1)
