pretty.c: drop const-ness from pretty_print_context
[git/git.git] / Documentation / git-format-patch.txt
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1git-format-patch(1)
2===================
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3
4NAME
5----
7bd7f280 6git-format-patch - Prepare patches for e-mail submission
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7
8
9SYNOPSIS
10--------
353ce815 11[verse]
50710ce4 12'git format-patch' [-k] [(-o|--output-directory) <dir> | --stdout]
f693b7e9 13 [--no-thread | --thread[=<style>]]
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14 [(--attach|--inline)[=<boundary>] | --no-attach]
15 [-s | --signoff]
6622d9c7 16 [--signature=<signature> | --no-signature]
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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]
7952ea66 21 [--subject-prefix=Subject-Prefix] [(--reroll-count|-v) <n>]
ae6c098f 22 [--to=<email>] [--cc=<email>]
2a4c2607 23 [--[no-]cover-letter] [--quiet] [--notes[=<ref>]]
50710ce4 24 [<common diff options>]
8a1d076e 25 [ <since> | <revision range> ]
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26
27DESCRIPTION
28-----------
2052d146 29
8a1d076e 30Prepare each commit with its patch in
2052d146 31one file per commit, formatted to resemble UNIX mailbox format.
2052d146 32The output of this command is convenient for e-mail submission or
0b444cdb 33for use with 'git am'.
35ef3a4c 34
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35There are two ways to specify which commits to operate on.
36
371. 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
412. Generic <revision range> expression (see "SPECIFYING
9d83e382 42 REVISIONS" section in linkgit:gitrevisions[7]) means the
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43 commits in the specified range.
44
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45The first rule takes precedence in the case of a single <commit>. To
46apply the second rule, i.e., format everything since the beginning of
dce5ef14 47history up until <commit>, use the '\--root' option: `git format-patch
6cf378f0 48--root <commit>`. If you want to format only <commit> itself, you
dce5ef14 49can do this with `git format-patch -1 <commit>`.
8a1d076e 50
e6ff0f42 51By default, each output file is numbered sequentially from 1, and uses the
2052d146 52first line of the commit message (massaged for pathname safety) as
dce5ef14 53the filename. With the `--numbered-files` option, the output file names
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54will only be numbers, without the first line of the commit appended.
55The names of the output files are printed to standard
dce5ef14 56output, unless the `--stdout` option is specified.
66f04f38 57
dce5ef14 58If `-o` is specified, output files are created in <dir>. Otherwise
2052d146 59they are created in the current working directory.
35ef3a4c 60
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61By default, the subject of a single patch is "[PATCH] " followed by
62the concatenation of lines from the commit message up to the first blank
63line (see the DISCUSSION section of linkgit:git-commit[1]).
64
65When multiple patches are output, the subject prefix will instead be
66"[PATCH n/m] ". To force 1/1 to be added for a single patch, use `-n`.
67To omit patch numbers from the subject, use `-N`.
35ef3a4c 68
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69If given `--thread`, `git-format-patch` will generate `In-Reply-To` and
70`References` headers to make the second and subsequent patch mails appear
71as replies to the first mail; this also generates a `Message-Id` header to
cc35de84 72reference.
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73
74OPTIONS
75-------
c1a95fa6 76:git-format-patch: 1
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77include::diff-options.txt[]
78
ed5f07a6 79-<n>::
2c642ed8 80 Prepare patches from the topmost <n> commits.
ed5f07a6 81
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82-o <dir>::
83--output-directory <dir>::
35ef3a4c 84 Use <dir> to store the resulting files, instead of the
efd02016 85 current working directory.
35ef3a4c 86
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87-n::
88--numbered::
a567fdcb 89 Name output in '[PATCH n/m]' format, even with a single patch.
35ef3a4c 90
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91-N::
92--no-numbered::
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93 Name output in '[PATCH]' format.
94
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95--start-number <n>::
96 Start numbering the patches at <n> instead of 1.
97
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98--numbered-files::
99 Output file names will be a simple number sequence
100 without the default first line of the commit appended.
e6ff0f42 101
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102-k::
103--keep-subject::
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104 Do not strip/add '[PATCH]' from the first line of the
105 commit log message.
106
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107-s::
108--signoff::
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109 Add `Signed-off-by:` line to the commit message, using
110 the committer identity of yourself.
111
54ba6013 112--stdout::
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113 Print all commits to the standard output in mbox format,
114 instead of creating a file for each one.
7fc9d69f 115
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116--attach[=<boundary>]::
117 Create multipart/mixed attachment, the first part of
118 which is the commit message and the patch itself in the
dce5ef14 119 second part, with `Content-Disposition: attachment`.
c112f689 120
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121--no-attach::
122 Disable the creation of an attachment, overriding the
123 configuration setting.
124
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125--inline[=<boundary>]::
126 Create multipart/mixed attachment, the first part of
127 which is the commit message and the patch itself in the
dce5ef14 128 second part, with `Content-Disposition: inline`.
a15a44ef 129
30984ed2 130--thread[=<style>]::
f693b7e9 131--no-thread::
dce5ef14 132 Controls addition of `In-Reply-To` and `References` headers to
f693b7e9 133 make the second and subsequent mails appear as replies to the
dce5ef14 134 first. Also controls generation of the `Message-Id` header to
f693b7e9 135 reference.
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136+
137The optional <style> argument can be either `shallow` or `deep`.
fd1ff306 138'shallow' threading makes every mail a reply to the head of the
30984ed2 139series, where the head is chosen from the cover letter, the
6cf378f0 140`--in-reply-to`, and the first patch mail, in this order. 'deep'
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141threading makes every mail a reply to the previous one.
142+
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143The default is `--no-thread`, unless the 'format.thread' configuration
144is set. If `--thread` is specified without a style, it defaults to the
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145style specified by 'format.thread' if any, or else `shallow`.
146+
147Beware that the default for 'git send-email' is to thread emails
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148itself. If you want `git format-patch` to take care of threading, you
149will want to ensure that threading is disabled for `git send-email`.
28ffb898 150
da56645d 151--in-reply-to=Message-Id::
dce5ef14 152 Make the first mail (or all the mails with `--no-thread`) appear as a
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153 reply to the given Message-Id, which avoids breaking threads to
154 provide a new patch series.
155
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156--ignore-if-in-upstream::
157 Do not include a patch that matches a commit in
158 <until>..<since>. This will examine all patches reachable
159 from <since> but not from <until> and compare them with the
160 patches being generated, and any patch that matches is
161 ignored.
162
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163--subject-prefix=<Subject-Prefix>::
164 Instead of the standard '[PATCH]' prefix in the subject
165 line, instead use '[<Subject-Prefix>]'. This
166 allows for useful naming of a patch series, and can be
dce5ef14 167 combined with the `--numbered` option.
2d9e4a47 168
7952ea66 169-v <n>::
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170--reroll-count=<n>::
171 Mark the series as the <n>-th iteration of the topic. The
172 output filenames have `v<n>` pretended to them, and the
173 subject prefix ("PATCH" by default, but configurable via the
174 `--subject-prefix` option) has ` v<n>` appended to it. E.g.
175 `--reroll-count=4` may produce `v4-0001-add-makefile.patch`
176 file that has "Subject: [PATCH v4 1/20] Add makefile" in it.
177
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178--to=<email>::
179 Add a `To:` header to the email headers. This is in addition
180 to any configured headers, and may be used multiple times.
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181 The negated form `--no-to` discards all `To:` headers added so
182 far (from config or command line).
ae6c098f 183
736cc67d 184--cc=<email>::
dce5ef14 185 Add a `Cc:` header to the email headers. This is in addition
736cc67d 186 to any configured headers, and may be used multiple times.
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187 The negated form `--no-cc` discards all `Cc:` headers added so
188 far (from config or command line).
736cc67d 189
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190--add-header=<header>::
191 Add an arbitrary header to the email headers. This is in addition
192 to any configured headers, and may be used multiple times.
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193 For example, `--add-header="Organization: git-foo"`.
194 The negated form `--no-add-header` discards *all* (`To:`,
195 `Cc:`, and custom) headers added so far from config or command
196 line.
d7d9c2d0 197
2a4c2607 198--[no-]cover-letter::
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199 In addition to the patches, generate a cover letter file
200 containing the shortlog and the overall diffstat. You can
201 fill in a description in the file before sending it out.
a5a27c79 202
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203--notes[=<ref>]::
204 Append the notes (see linkgit:git-notes[1]) for the commit
205 after the three-dash line.
206+
207The expected use case of this is to write supporting explanation for
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208the commit that does not belong to the commit log message proper,
209and include it with the patch submission. While one can simply write
210these explanations after `format-patch` has run but before sending,
2de9b711 211keeping them as Git notes allows them to be maintained between versions
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212of the patch series (but see the discussion of the `notes.rewrite`
213configuration options in linkgit:git-notes[1] to use this workflow).
e422c0cf 214
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215--[no]-signature=<signature>::
216 Add a signature to each message produced. Per RFC 3676 the signature
217 is separated from the body by a line with '-- ' on it. If the
2de9b711 218 signature option is omitted the signature defaults to the Git version
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219 number.
220
03eeaeae 221--suffix=.<sfx>::
917a8f89 222 Instead of using `.patch` as the suffix for generated
02783075 223 filenames, use specified suffix. A common alternative is
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224 `--suffix=.txt`. Leaving this empty will remove the `.patch`
225 suffix.
03eeaeae 226+
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227Note that the leading character does not have to be a dot; for example,
228you can use `--suffix=-patch` to get `0001-description-of-my-change-patch`.
03eeaeae 229
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230--quiet::
231 Do not print the names of the generated files to standard output.
232
37c22a4b 233--no-binary::
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234 Do not output contents of changes in binary files, instead
235 display a notice that those files changed. Patches generated
236 using this option cannot be applied properly, but they are
237 still useful for code review.
37c22a4b 238
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239--root::
240 Treat the revision argument as a <revision range>, even if it
241 is just a single commit (that would normally be treated as a
242 <since>). Note that root commits included in the specified
243 range are always formatted as creation patches, independently
244 of this flag.
245
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246CONFIGURATION
247-------------
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248You can specify extra mail header lines to be added to each message,
249defaults for the subject prefix and file suffix, number patches when
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250outputting more than one patch, add "To" or "Cc:" headers, configure
251attachments, and sign off patches with configuration variables.
96ce6d26 252
917a8f89 253------------
96ce6d26 254[format]
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255 headers = "Organization: git-foo\n"
256 subjectprefix = CHANGE
257 suffix = .txt
258 numbered = auto
ae6c098f 259 to = <email>
fe8928e6 260 cc = <email>
0db5260b 261 attach [ = mime-boundary-string ]
1d1876e9 262 signoff = true
2a4c2607 263 coverletter = auto
917a8f89 264------------
03eeaeae 265
96ce6d26 266
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267DISCUSSION
268----------
269
270The patch produced by 'git format-patch' is in UNIX mailbox format,
271with a fixed "magic" time stamp to indicate that the file is output
272from format-patch rather than a real mailbox, like so:
273
274------------
275From 8f72bad1baf19a53459661343e21d6491c3908d3 Mon Sep 17 00:00:00 2001
276From: Tony Luck <tony.luck@intel.com>
277Date: Tue, 13 Jul 2010 11:42:54 -0700
278Subject: [PATCH] =?UTF-8?q?[IA64]=20Put=20ia64=20config=20files=20on=20the=20?=
279 =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20diet?=
280MIME-Version: 1.0
281Content-Type: text/plain; charset=UTF-8
282Content-Transfer-Encoding: 8bit
283
284arch/arm config files were slimmed down using a python script
285(See commit c2330e286f68f1c408b4aa6515ba49d57f05beae comment)
286
287Do the same for ia64 so we can have sleek & trim looking
288...
289------------
290
291Typically it will be placed in a MUA's drafts folder, edited to add
292timely commentary that should not go in the changelog after the three
293dashes, and then sent as a message whose body, in our example, starts
294with "arch/arm config files were...". On the receiving end, readers
295can save interesting patches in a UNIX mailbox and apply them with
296linkgit:git-am[1].
297
298When a patch is part of an ongoing discussion, the patch generated by
299'git format-patch' can be tweaked to take advantage of the 'git am
300--scissors' feature. After your response to the discussion comes a
301line that consists solely of "`-- >8 --`" (scissors and perforation),
302followed by the patch with unnecessary header fields removed:
303
304------------
305...
306> So we should do such-and-such.
307
308Makes sense to me. How about this patch?
309
310-- >8 --
311Subject: [IA64] Put ia64 config files on the Uwe Kleine-König diet
312
313arch/arm config files were slimmed down using a python script
314...
315------------
316
317When sending a patch this way, most often you are sending your own
318patch, so in addition to the "`From $SHA1 $magic_timestamp`" marker you
319should omit `From:` and `Date:` lines from the patch file. The patch
320title is likely to be different from the subject of the discussion the
321patch is in response to, so it is likely that you would want to keep
322the Subject: line, like the example above.
323
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324Checking for patch corruption
325~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
326Many mailers if not set up properly will corrupt whitespace. Here are
327two common types of corruption:
328
329* Empty context lines that do not have _any_ whitespace.
330
331* Non-empty context lines that have one extra whitespace at the
332 beginning.
333
334One way to test if your MUA is set up correctly is:
335
336* Send the patch to yourself, exactly the way you would, except
337 with To: and Cc: lines that do not contain the list and
338 maintainer address.
339
340* Save that patch to a file in UNIX mailbox format. Call it a.patch,
341 say.
342
343* Apply it:
344
345 $ git fetch <project> master:test-apply
346 $ git checkout test-apply
347 $ git reset --hard
348 $ git am a.patch
349
350If it does not apply correctly, there can be various reasons.
351
352* The patch itself does not apply cleanly. That is _bad_ but
353 does not have much to do with your MUA. You might want to rebase
354 the patch with linkgit:git-rebase[1] before regenerating it in
355 this case.
356
357* The MUA corrupted your patch; "am" would complain that
358 the patch does not apply. Look in the .git/rebase-apply/ subdirectory and
359 see what 'patch' file contains and check for the common
360 corruption patterns mentioned above.
361
362* While at it, check the 'info' and 'final-commit' files as well.
363 If what is in 'final-commit' is not exactly what you would want to
364 see in the commit log message, it is very likely that the
365 receiver would end up hand editing the log message when applying
366 your patch. Things like "Hi, this is my first patch.\n" in the
367 patch e-mail should come after the three-dash line that signals
368 the end of the commit message.
369
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370MUA-SPECIFIC HINTS
371------------------
372Here are some hints on how to successfully submit patches inline using
373various mailers.
374
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375GMail
376~~~~~
377GMail does not have any way to turn off line wrapping in the web
378interface, so it will mangle any emails that you send. You can however
379use "git send-email" and send your patches through the GMail SMTP server, or
380use any IMAP email client to connect to the google IMAP server and forward
381the emails through that.
382
383For hints on using 'git send-email' to send your patches through the
384GMail SMTP server, see the EXAMPLE section of linkgit:git-send-email[1].
385
386For hints on submission using the IMAP interface, see the EXAMPLE
387section of linkgit:git-imap-send[1].
388
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389Thunderbird
390~~~~~~~~~~~
391By default, Thunderbird will both wrap emails as well as flag
392them as being 'format=flowed', both of which will make the
2de9b711 393resulting email unusable by Git.
dc53151f 394
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395There are three different approaches: use an add-on to turn off line wraps,
396configure Thunderbird to not mangle patches, or use
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397an external editor to keep Thunderbird from mangling the patches.
398
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399Approach #1 (add-on)
400^^^^^^^^^^^^^^^^^^^^
401
402Install the Toggle Word Wrap add-on that is available from
403https://addons.mozilla.org/thunderbird/addon/toggle-word-wrap/
404It adds a menu entry "Enable Word Wrap" in the composer's "Options" menu
405that you can tick off. Now you can compose the message as you otherwise do
406(cut + paste, 'git format-patch' | 'git imap-send', etc), but you have to
407insert line breaks manually in any text that you type.
408
409Approach #2 (configuration)
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410^^^^^^^^^^^^^^^^^^^^^^^^^^^
411Three steps:
412
4131. Configure your mail server composition as plain text:
414 Edit...Account Settings...Composition & Addressing,
415 uncheck "Compose Messages in HTML".
416
4172. Configure your general composition window to not wrap.
418+
419In Thunderbird 2:
420Edit..Preferences..Composition, wrap plain text messages at 0
421+
422In Thunderbird 3:
423Edit..Preferences..Advanced..Config Editor. Search for
424"mail.wrap_long_lines".
425Toggle it to make sure it is set to `false`.
426
4273. Disable the use of format=flowed:
428Edit..Preferences..Advanced..Config Editor. Search for
429"mailnews.send_plaintext_flowed".
430Toggle it to make sure it is set to `false`.
431
432After that is done, you should be able to compose email as you
433otherwise would (cut + paste, 'git format-patch' | 'git imap-send', etc),
434and the patches will not be mangled.
435
b8959605 436Approach #3 (external editor)
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437^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
438
439The following Thunderbird extensions are needed:
440AboutConfig from http://aboutconfig.mozdev.org/ and
441External Editor from http://globs.org/articles.php?lng=en&pg=8
442
4431. Prepare the patch as a text file using your method of choice.
444
4452. Before opening a compose window, use Edit->Account Settings to
446 uncheck the "Compose messages in HTML format" setting in the
447 "Composition & Addressing" panel of the account to be used to
448 send the patch.
449
4503. In the main Thunderbird window, 'before' you open the compose
451 window for the patch, use Tools->about:config to set the
452 following to the indicated values:
453+
454----------
455 mailnews.send_plaintext_flowed => false
456 mailnews.wraplength => 0
457----------
458
4594. Open a compose window and click the external editor icon.
460
4615. In the external editor window, read in the patch file and exit
462 the editor normally.
463
464Side note: it may be possible to do step 2 with
465about:config and the following settings but no one's tried yet.
466
467----------
468 mail.html_compose => false
469 mail.identity.default.compose_html => false
470 mail.identity.id?.compose_html => false
471----------
472
473There is a script in contrib/thunderbird-patch-inline which can help
474you include patches with Thunderbird in an easy way. To use it, do the
475steps above and then use the script as the external editor.
476
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477KMail
478~~~~~
479This should help you to submit patches inline using KMail.
480
4811. Prepare the patch as a text file.
482
4832. Click on New Mail.
484
4853. Go under "Options" in the Composer window and be sure that
486 "Word wrap" is not set.
487
4884. Use Message -> Insert file... and insert the patch.
489
4905. Back in the compose window: add whatever other text you wish to the
491 message, complete the addressing and subject fields, and press send.
492
e0d48279 493
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494EXAMPLES
495--------
496
921177f5 497* Extract commits between revisions R1 and R2, and apply them on top of
0b444cdb 498the current branch using 'git am' to cherry-pick them:
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499+
500------------
467c0197 501$ git format-patch -k --stdout R1..R2 | git am -3 -k
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502------------
503
504* Extract all commits which are in the current branch but not in the
505origin branch:
506+
507------------
508$ git format-patch origin
509------------
510+
511For each commit a separate file is created in the current directory.
512
513* Extract all commits that lead to 'origin' since the inception of the
514project:
515+
516------------
9c67c757 517$ git format-patch --root origin
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518------------
519
520* The same as the previous one:
521+
522------------
523$ git format-patch -M -B origin
524------------
525+
526Additionally, it detects and handles renames and complete rewrites
527intelligently to produce a renaming patch. A renaming patch reduces
50710ce4 528the amount of text output, and generally makes it easier to review.
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529Note that non-Git "patch" programs won't understand renaming patches, so
530use it only when you know the recipient uses Git to apply your patch.
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531
532* Extract three topmost commits from the current branch and format them
533as e-mailable patches:
534+
535------------
536$ git format-patch -3
537------------
28ffb898 538
56ae8df5 539SEE ALSO
28ffb898 540--------
5162e697 541linkgit:git-am[1], linkgit:git-send-email[1]
28ffb898 542
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543GIT
544---
9e1f0a85 545Part of the linkgit:git[1] suite