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1 git-format-patch(1)
2 ===================
3
4 NAME
5 ----
6 git-format-patch - Prepare patches for e-mail submission
7
8
9 SYNOPSIS
10 --------
11 [verse]
12 'git format-patch' [-k] [(-o|--output-directory) <dir> | --stdout]
13 [--no-thread | --thread[=<style>]]
14 [(--attach|--inline)[=<boundary>] | --no-attach]
15 [-s | --signoff]
16 [--signature=<signature> | --no-signature]
17 [-n | --numbered | -N | --no-numbered]
18 [--start-number <n>] [--numbered-files]
19 [--in-reply-to=Message-Id] [--suffix=.<sfx>]
20 [--ignore-if-in-upstream]
21 [--subject-prefix=Subject-Prefix]
22 [--to=<email>] [--cc=<email>]
23 [--cover-letter] [--quiet]
24 [<common diff options>]
25 [ <since> | <revision range> ]
26
27 DESCRIPTION
28 -----------
29
30 Prepare each commit with its patch in
31 one file per commit, formatted to resemble UNIX mailbox format.
32 The output of this command is convenient for e-mail submission or
33 for use with 'git am'.
34
35 There are two ways to specify which commits to operate on.
36
37 1. A single commit, <since>, specifies that the commits leading
38 to the tip of the current branch that are not in the history
39 that leads to the <since> to be output.
40
41 2. Generic <revision range> expression (see "SPECIFYING
42 REVISIONS" section in linkgit:gitrevisions[7]) means the
43 commits in the specified range.
44
45 The first rule takes precedence in the case of a single <commit>. To
46 apply the second rule, i.e., format everything since the beginning of
47 history up until <commit>, use the '\--root' option: `git format-patch
48 \--root <commit>`. If you want to format only <commit> itself, you
49 can do this with `git format-patch -1 <commit>`.
50
51 By default, each output file is numbered sequentially from 1, and uses the
52 first line of the commit message (massaged for pathname safety) as
53 the filename. With the `--numbered-files` option, the output file names
54 will only be numbers, without the first line of the commit appended.
55 The names of the output files are printed to standard
56 output, unless the `--stdout` option is specified.
57
58 If `-o` is specified, output files are created in <dir>. Otherwise
59 they are created in the current working directory.
60
61 By default, the subject of a single patch is "[PATCH] First Line" and
62 the subject when multiple patches are output is "[PATCH n/m] First
63 Line". To force 1/1 to be added for a single patch, use `-n`. To omit
64 patch numbers from the subject, use `-N`.
65
66 If given `--thread`, `git-format-patch` will generate `In-Reply-To` and
67 `References` headers to make the second and subsequent patch mails appear
68 as replies to the first mail; this also generates a `Message-Id` header to
69 reference.
70
71 OPTIONS
72 -------
73 :git-format-patch: 1
74 include::diff-options.txt[]
75
76 -<n>::
77 Prepare patches from the topmost <n> commits.
78
79 -o <dir>::
80 --output-directory <dir>::
81 Use <dir> to store the resulting files, instead of the
82 current working directory.
83
84 -n::
85 --numbered::
86 Name output in '[PATCH n/m]' format, even with a single patch.
87
88 -N::
89 --no-numbered::
90 Name output in '[PATCH]' format.
91
92 --start-number <n>::
93 Start numbering the patches at <n> instead of 1.
94
95 --numbered-files::
96 Output file names will be a simple number sequence
97 without the default first line of the commit appended.
98
99 -k::
100 --keep-subject::
101 Do not strip/add '[PATCH]' from the first line of the
102 commit log message.
103
104 -s::
105 --signoff::
106 Add `Signed-off-by:` line to the commit message, using
107 the committer identity of yourself.
108
109 --stdout::
110 Print all commits to the standard output in mbox format,
111 instead of creating a file for each one.
112
113 --attach[=<boundary>]::
114 Create multipart/mixed attachment, the first part of
115 which is the commit message and the patch itself in the
116 second part, with `Content-Disposition: attachment`.
117
118 --no-attach::
119 Disable the creation of an attachment, overriding the
120 configuration setting.
121
122 --inline[=<boundary>]::
123 Create multipart/mixed attachment, the first part of
124 which is the commit message and the patch itself in the
125 second part, with `Content-Disposition: inline`.
126
127 --thread[=<style>]::
128 --no-thread::
129 Controls addition of `In-Reply-To` and `References` headers to
130 make the second and subsequent mails appear as replies to the
131 first. Also controls generation of the `Message-Id` header to
132 reference.
133 +
134 The optional <style> argument can be either `shallow` or `deep`.
135 'shallow' threading makes every mail a reply to the head of the
136 series, where the head is chosen from the cover letter, the
137 `\--in-reply-to`, and the first patch mail, in this order. 'deep'
138 threading makes every mail a reply to the previous one.
139 +
140 The default is `--no-thread`, unless the 'format.thread' configuration
141 is set. If `--thread` is specified without a style, it defaults to the
142 style specified by 'format.thread' if any, or else `shallow`.
143 +
144 Beware that the default for 'git send-email' is to thread emails
145 itself. If you want `git format-patch` to take care of threading, you
146 will want to ensure that threading is disabled for `git send-email`.
147
148 --in-reply-to=Message-Id::
149 Make the first mail (or all the mails with `--no-thread`) appear as a
150 reply to the given Message-Id, which avoids breaking threads to
151 provide a new patch series.
152
153 --ignore-if-in-upstream::
154 Do not include a patch that matches a commit in
155 <until>..<since>. This will examine all patches reachable
156 from <since> but not from <until> and compare them with the
157 patches being generated, and any patch that matches is
158 ignored.
159
160 --subject-prefix=<Subject-Prefix>::
161 Instead of the standard '[PATCH]' prefix in the subject
162 line, instead use '[<Subject-Prefix>]'. This
163 allows for useful naming of a patch series, and can be
164 combined with the `--numbered` option.
165
166 --to=<email>::
167 Add a `To:` header to the email headers. This is in addition
168 to any configured headers, and may be used multiple times.
169
170 --cc=<email>::
171 Add a `Cc:` header to the email headers. This is in addition
172 to any configured headers, and may be used multiple times.
173
174 --add-header=<header>::
175 Add an arbitrary header to the email headers. This is in addition
176 to any configured headers, and may be used multiple times.
177 For example, `--add-header="Organization: git-foo"`
178
179 --cover-letter::
180 In addition to the patches, generate a cover letter file
181 containing the shortlog and the overall diffstat. You can
182 fill in a description in the file before sending it out.
183
184 --[no]-signature=<signature>::
185 Add a signature to each message produced. Per RFC 3676 the signature
186 is separated from the body by a line with '-- ' on it. If the
187 signature option is omitted the signature defaults to the git version
188 number.
189
190 --suffix=.<sfx>::
191 Instead of using `.patch` as the suffix for generated
192 filenames, use specified suffix. A common alternative is
193 `--suffix=.txt`. Leaving this empty will remove the `.patch`
194 suffix.
195 +
196 Note that the leading character does not have to be a dot; for example,
197 you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`.
198
199 --quiet::
200 Do not print the names of the generated files to standard output.
201
202 --no-binary::
203 Do not output contents of changes in binary files, instead
204 display a notice that those files changed. Patches generated
205 using this option cannot be applied properly, but they are
206 still useful for code review.
207
208 --root::
209 Treat the revision argument as a <revision range>, even if it
210 is just a single commit (that would normally be treated as a
211 <since>). Note that root commits included in the specified
212 range are always formatted as creation patches, independently
213 of this flag.
214
215 CONFIGURATION
216 -------------
217 You can specify extra mail header lines to be added to each message,
218 defaults for the subject prefix and file suffix, number patches when
219 outputting more than one patch, add "To" or "Cc:" headers, configure
220 attachments, and sign off patches with configuration variables.
221
222 ------------
223 [format]
224 headers = "Organization: git-foo\n"
225 subjectprefix = CHANGE
226 suffix = .txt
227 numbered = auto
228 to = <email>
229 cc = <email>
230 attach [ = mime-boundary-string ]
231 signoff = true
232 ------------
233
234
235 DISCUSSION
236 ----------
237
238 The patch produced by 'git format-patch' is in UNIX mailbox format,
239 with a fixed "magic" time stamp to indicate that the file is output
240 from format-patch rather than a real mailbox, like so:
241
242 ------------
243 From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
244 From: Tony Luck <tony.luck@intel.com>
245 Date: Tue, 13 Jul 2010 11:42:54 -0700
246 Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
247 =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
248 MIME-Version: 1.0
249 Content-Type: text/plain; charset=UTF-8
250 Content-Transfer-Encoding: 8bit
251
252 arch/arm config files were slimmed down using a python script
253 (See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
254
255 Do the same for ia64 so we can have sleek & trim looking
256 ...
257 ------------
258
259 Typically it will be placed in a MUA's drafts folder, edited to add
260 timely commentary that should not go in the changelog after the three
261 dashes, and then sent as a message whose body, in our example, starts
262 with "arch/arm config files were...". On the receiving end, readers
263 can save interesting patches in a UNIX mailbox and apply them with
264 linkgit:git-am[1].
265
266 When a patch is part of an ongoing discussion, the patch generated by
267 'git format-patch' can be tweaked to take advantage of the 'git am
268 --scissors' feature. After your response to the discussion comes a
269 line that consists solely of "`-- >8 --`" (scissors and perforation),
270 followed by the patch with unnecessary header fields removed:
271
272 ------------
273 ...
274 > So we should do such-and-such.
275
276 Makes sense to me. How about this patch?
277
278 -- >8 --
279 Subject: [IA64] Put ia64 config files on the Uwe Kleine-König diet
280
281 arch/arm config files were slimmed down using a python script
282 ...
283 ------------
284
285 When sending a patch this way, most often you are sending your own
286 patch, so in addition to the "`From $SHA1 $magic_timestamp`" marker you
287 should omit `From:` and `Date:` lines from the patch file. The patch
288 title is likely to be different from the subject of the discussion the
289 patch is in response to, so it is likely that you would want to keep
290 the Subject: line, like the example above.
291
292 Checking for patch corruption
293 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
294 Many mailers if not set up properly will corrupt whitespace. Here are
295 two common types of corruption:
296
297 * Empty context lines that do not have _any_ whitespace.
298
299 * Non-empty context lines that have one extra whitespace at the
300 beginning.
301
302 One way to test if your MUA is set up correctly is:
303
304 * Send the patch to yourself, exactly the way you would, except
305 with To: and Cc: lines that do not contain the list and
306 maintainer address.
307
308 * Save that patch to a file in UNIX mailbox format. Call it a.patch,
309 say.
310
311 * Apply it:
312
313 $ git fetch <project> master:test-apply
314 $ git checkout test-apply
315 $ git reset --hard
316 $ git am a.patch
317
318 If it does not apply correctly, there can be various reasons.
319
320 * The patch itself does not apply cleanly. That is _bad_ but
321 does not have much to do with your MUA. You might want to rebase
322 the patch with linkgit:git-rebase[1] before regenerating it in
323 this case.
324
325 * The MUA corrupted your patch; "am" would complain that
326 the patch does not apply. Look in the .git/rebase-apply/ subdirectory and
327 see what 'patch' file contains and check for the common
328 corruption patterns mentioned above.
329
330 * While at it, check the 'info' and 'final-commit' files as well.
331 If what is in 'final-commit' is not exactly what you would want to
332 see in the commit log message, it is very likely that the
333 receiver would end up hand editing the log message when applying
334 your patch. Things like "Hi, this is my first patch.\n" in the
335 patch e-mail should come after the three-dash line that signals
336 the end of the commit message.
337
338 MUA-SPECIFIC HINTS
339 ------------------
340 Here are some hints on how to successfully submit patches inline using
341 various mailers.
342
343 GMail
344 ~~~~~
345 GMail does not have any way to turn off line wrapping in the web
346 interface, so it will mangle any emails that you send. You can however
347 use "git send-email" and send your patches through the GMail SMTP server, or
348 use any IMAP email client to connect to the google IMAP server and forward
349 the emails through that.
350
351 For hints on using 'git send-email' to send your patches through the
352 GMail SMTP server, see the EXAMPLE section of linkgit:git-send-email[1].
353
354 For hints on submission using the IMAP interface, see the EXAMPLE
355 section of linkgit:git-imap-send[1].
356
357 Thunderbird
358 ~~~~~~~~~~~
359 By default, Thunderbird will both wrap emails as well as flag
360 them as being 'format=flowed', both of which will make the
361 resulting email unusable by git.
362
363 There are three different approaches: use an add-on to turn off line wraps,
364 configure Thunderbird to not mangle patches, or use
365 an external editor to keep Thunderbird from mangling the patches.
366
367 Approach #1 (add-on)
368 ^^^^^^^^^^^^^^^^^^^^
369
370 Install the Toggle Word Wrap add-on that is available from
371 https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/
372 It adds a menu entry "Enable Word Wrap" in the composer's "Options" menu
373 that you can tick off. Now you can compose the message as you otherwise do
374 (cut + paste, 'git format-patch' | 'git imap-send', etc), but you have to
375 insert line breaks manually in any text that you type.
376
377 Approach #2 (configuration)
378 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
379 Three steps:
380
381 1. Configure your mail server composition as plain text:
382 Edit...Account Settings...Composition & Addressing,
383 uncheck "Compose Messages in HTML".
384
385 2. Configure your general composition window to not wrap.
386 +
387 In Thunderbird 2:
388 Edit..Preferences..Composition, wrap plain text messages at 0
389 +
390 In Thunderbird 3:
391 Edit..Preferences..Advanced..Config Editor. Search for
392 "mail.wrap_long_lines".
393 Toggle it to make sure it is set to `false`.
394
395 3. Disable the use of format=flowed:
396 Edit..Preferences..Advanced..Config Editor. Search for
397 "mailnews.send_plaintext_flowed".
398 Toggle it to make sure it is set to `false`.
399
400 After that is done, you should be able to compose email as you
401 otherwise would (cut + paste, 'git format-patch' | 'git imap-send', etc),
402 and the patches will not be mangled.
403
404 Approach #3 (external editor)
405 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
406
407 The following Thunderbird extensions are needed:
408 AboutConfig from http://aboutconfig.mozdev.org/ and
409 External Editor from http://globs.org/articles.php?lng=en&pg=8
410
411 1. Prepare the patch as a text file using your method of choice.
412
413 2. Before opening a compose window, use Edit->Account Settings to
414 uncheck the "Compose messages in HTML format" setting in the
415 "Composition & Addressing" panel of the account to be used to
416 send the patch.
417
418 3. In the main Thunderbird window, 'before' you open the compose
419 window for the patch, use Tools->about:config to set the
420 following to the indicated values:
421 +
422 ----------
423 mailnews.send_plaintext_flowed => false
424 mailnews.wraplength => 0
425 ----------
426
427 4. Open a compose window and click the external editor icon.
428
429 5. In the external editor window, read in the patch file and exit
430 the editor normally.
431
432 Side note: it may be possible to do step 2 with
433 about:config and the following settings but no one's tried yet.
434
435 ----------
436 mail.html_compose => false
437 mail.identity.default.compose_html => false
438 mail.identity.id?.compose_html => false
439 ----------
440
441 There is a script in contrib/thunderbird-patch-inline which can help
442 you include patches with Thunderbird in an easy way. To use it, do the
443 steps above and then use the script as the external editor.
444
445 KMail
446 ~~~~~
447 This should help you to submit patches inline using KMail.
448
449 1. Prepare the patch as a text file.
450
451 2. Click on New Mail.
452
453 3. Go under "Options" in the Composer window and be sure that
454 "Word wrap" is not set.
455
456 4. Use Message -> Insert file... and insert the patch.
457
458 5. Back in the compose window: add whatever other text you wish to the
459 message, complete the addressing and subject fields, and press send.
460
461
462 EXAMPLES
463 --------
464
465 * Extract commits between revisions R1 and R2, and apply them on top of
466 the current branch using 'git am' to cherry-pick them:
467 +
468 ------------
469 $ git format-patch -k --stdout R1..R2 | git am -3 -k
470 ------------
471
472 * Extract all commits which are in the current branch but not in the
473 origin branch:
474 +
475 ------------
476 $ git format-patch origin
477 ------------
478 +
479 For each commit a separate file is created in the current directory.
480
481 * Extract all commits that lead to 'origin' since the inception of the
482 project:
483 +
484 ------------
485 $ git format-patch --root origin
486 ------------
487
488 * The same as the previous one:
489 +
490 ------------
491 $ git format-patch -M -B origin
492 ------------
493 +
494 Additionally, it detects and handles renames and complete rewrites
495 intelligently to produce a renaming patch. A renaming patch reduces
496 the amount of text output, and generally makes it easier to review.
497 Note that non-git "patch" programs won't understand renaming patches, so
498 use it only when you know the recipient uses git to apply your patch.
499
500 * Extract three topmost commits from the current branch and format them
501 as e-mailable patches:
502 +
503 ------------
504 $ git format-patch -3
505 ------------
506
507 SEE ALSO
508 --------
509 linkgit:git-am[1], linkgit:git-send-email[1]
510
511 GIT
512 ---
513 Part of the linkgit:git[1] suite