doc/interpret-trailers: fix "the this" typo
[git/git.git] / Documentation / git-interpret-trailers.txt
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1git-interpret-trailers(1)
2=========================
3
4NAME
5----
99e09daf 6git-interpret-trailers - add or parse structured information in commit messages
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7
8SYNOPSIS
9--------
10[verse]
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11'git interpret-trailers' [options] [(--trailer <token>[(=|:)<value>])...] [<file>...]
12'git interpret-trailers' [options] [--parse] [<file>...]
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13
14DESCRIPTION
15-----------
99e09daf 16Help parsing or adding 'trailers' lines, that look similar to RFC 822 e-mail
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17headers, at the end of the otherwise free-form part of a commit
18message.
19
20This command reads some patches or commit messages from either the
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21<file> arguments or the standard input if no <file> is specified. If
22`--parse` is specified, the output consists of the parsed trailers.
23
5a0d0c03 24Otherwise, this command applies the arguments passed using the
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25`--trailer` option, if any, to the commit message part of each input
26file. The result is emitted on the standard output.
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27
28Some configuration variables control the way the `--trailer` arguments
29are applied to each commit message and the way any existing trailer in
30the commit message is changed. They also make it possible to
31automatically add some trailers.
32
33By default, a '<token>=<value>' or '<token>:<value>' argument given
34using `--trailer` will be appended after the existing trailers only if
35the last trailer has a different (<token>, <value>) pair (or if there
36is no existing trailer). The <token> and <value> parts will be trimmed
37to remove starting and trailing whitespace, and the resulting trimmed
38<token> and <value> will appear in the message like this:
39
40------------------------------------------------
41token: value
42------------------------------------------------
43
44This means that the trimmed <token> and <value> will be separated by
45`': '` (one colon followed by one space).
46
47By default the new trailer will appear at the end of all the existing
48trailers. If there is no existing trailer, the new trailer will appear
f745acb0 49after the commit message part of the output, and, if there is no line
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50with only spaces at the end of the commit message part, one blank line
51will be added before the new trailer.
52
53Existing trailers are extracted from the input message by looking for
14624506 54a group of one or more lines that (i) are all trailers, or (ii) contains at
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55least one Git-generated or user-configured trailer and consists of at
56least 25% trailers.
14624506 57The group must be preceded by one or more empty (or whitespace-only) lines.
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58The group must either be at the end of the message or be the last
59non-whitespace lines before a line that starts with '---'. Such three
60minus signs start the patch part of the message.
61
c463a6b2 62When reading trailers, there can be whitespaces after the
dfd66ddf 63token, the separator and the value. There can also be whitespaces
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64inside the token and the value. The value may be split over multiple lines with
65each subsequent line starting with whitespace, like the "folding" in RFC 822.
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66
67Note that 'trailers' do not follow and are not intended to follow many
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68rules for RFC 822 headers. For example they do not follow
69the encoding rules and probably many other rules.
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70
71OPTIONS
72-------
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73--in-place::
74 Edit the files in place.
75
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76--trim-empty::
77 If the <value> part of any trailer contains only whitespace,
78 the whole trailer will be removed from the resulting message.
a43eb67e 79 This applies to existing trailers as well as new trailers.
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80
81--trailer <token>[(=|:)<value>]::
82 Specify a (<token>, <value>) pair that should be applied as a
83 trailer to the input messages. See the description of this
84 command.
85
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86--only-trailers::
87 Output only the trailers, not any other parts of the input.
88
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89--only-input::
90 Output only trailers that exist in the input; do not add any
91 from the command-line or by following configured `trailer.*`
92 rules.
93
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94--unfold::
95 Remove any whitespace-continuation in trailers, so that each
96 trailer appears on a line by itself with its full content.
97
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98--parse::
99 A convenience alias for `--only-trailers --only-input
100 --unfold`.
101
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102CONFIGURATION VARIABLES
103-----------------------
104
105trailer.separators::
106 This option tells which characters are recognized as trailer
107 separators. By default only ':' is recognized as a trailer
108 separator, except that '=' is always accepted on the command
109 line for compatibility with other git commands.
110+
111The first character given by this option will be the default character
112used when another separator is not specified in the config for this
113trailer.
114+
115For example, if the value for this option is "%=$", then only lines
116using the format '<token><sep><value>' with <sep> containing '%', '='
117or '$' and then spaces will be considered trailers. And '%' will be
118the default separator used, so by default trailers will appear like:
119'<token>% <value>' (one percent sign and one space will appear between
120the token and the value).
121
122trailer.where::
123 This option tells where a new trailer will be added.
124+
125This can be `end`, which is the default, `start`, `after` or `before`.
126+
127If it is `end`, then each new trailer will appear at the end of the
128existing trailers.
129+
130If it is `start`, then each new trailer will appear at the start,
131instead of the end, of the existing trailers.
132+
133If it is `after`, then each new trailer will appear just after the
134last trailer with the same <token>.
135+
136If it is `before`, then each new trailer will appear just before the
137first trailer with the same <token>.
138
139trailer.ifexists::
140 This option makes it possible to choose what action will be
141 performed when there is already at least one trailer with the
142 same <token> in the message.
143+
144The valid values for this option are: `addIfDifferentNeighbor` (this
b275da81 145is the default), `addIfDifferent`, `add`, `replace` or `doNothing`.
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146+
147With `addIfDifferentNeighbor`, a new trailer will be added only if no
148trailer with the same (<token>, <value>) pair is above or below the line
149where the new trailer will be added.
150+
151With `addIfDifferent`, a new trailer will be added only if no trailer
152with the same (<token>, <value>) pair is already in the message.
153+
154With `add`, a new trailer will be added, even if some trailers with
155the same (<token>, <value>) pair are already in the message.
156+
157With `replace`, an existing trailer with the same <token> will be
158deleted and the new trailer will be added. The deleted trailer will be
159the closest one (with the same <token>) to the place where the new one
160will be added.
161+
162With `doNothing`, nothing will be done; that is no new trailer will be
163added if there is already one with the same <token> in the message.
164
165trailer.ifmissing::
166 This option makes it possible to choose what action will be
167 performed when there is not yet any trailer with the same
168 <token> in the message.
169+
170The valid values for this option are: `add` (this is the default) and
171`doNothing`.
172+
173With `add`, a new trailer will be added.
174+
175With `doNothing`, nothing will be done.
176
177trailer.<token>.key::
178 This `key` will be used instead of <token> in the trailer. At
179 the end of this key, a separator can appear and then some
180 space characters. By default the only valid separator is ':',
181 but this can be changed using the `trailer.separators` config
182 variable.
183+
184If there is a separator, then the key will be used instead of both the
185<token> and the default separator when adding the trailer.
186
187trailer.<token>.where::
188 This option takes the same values as the 'trailer.where'
189 configuration variable and it overrides what is specified by
190 that option for trailers with the specified <token>.
191
192trailer.<token>.ifexist::
193 This option takes the same values as the 'trailer.ifexist'
194 configuration variable and it overrides what is specified by
195 that option for trailers with the specified <token>.
196
197trailer.<token>.ifmissing::
198 This option takes the same values as the 'trailer.ifmissing'
199 configuration variable and it overrides what is specified by
200 that option for trailers with the specified <token>.
201
202trailer.<token>.command::
203 This option can be used to specify a shell command that will
204 be called to automatically add or modify a trailer with the
205 specified <token>.
206+
207When this option is specified, the behavior is as if a special
208'<token>=<value>' argument were added at the beginning of the command
209line, where <value> is taken to be the standard output of the
210specified command with any leading and trailing whitespace trimmed
211off.
212+
213If the command contains the `$ARG` string, this string will be
214replaced with the <value> part of an existing trailer with the same
215<token>, if any, before the command is launched.
216+
217If some '<token>=<value>' arguments are also passed on the command
218line, when a 'trailer.<token>.command' is configured, the command will
219also be executed for each of these arguments. And the <value> part of
220these arguments, if any, will be used to replace the `$ARG` string in
221the command.
222
223EXAMPLES
224--------
225
226* Configure a 'sign' trailer with a 'Signed-off-by' key, and then
227 add two of these trailers to a message:
228+
229------------
230$ git config trailer.sign.key "Signed-off-by"
231$ cat msg.txt
232subject
233
234message
235$ cat msg.txt | git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>'
236subject
237
238message
239
240Signed-off-by: Alice <alice@example.com>
241Signed-off-by: Bob <bob@example.com>
242------------
243
bcf9626a 244* Use the `--in-place` option to edit a message file in place:
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245+
246------------
247$ cat msg.txt
248subject
249
250message
251
252Signed-off-by: Bob <bob@example.com>
253$ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt
254$ cat msg.txt
255subject
256
257message
258
259Signed-off-by: Bob <bob@example.com>
260Acked-by: Alice <alice@example.com>
261------------
262
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263* Extract the last commit as a patch, and add a 'Cc' and a
264 'Reviewed-by' trailer to it:
265+
266------------
267$ git format-patch -1
2680001-foo.patch
269$ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch
270------------
271
272* Configure a 'sign' trailer with a command to automatically add a
273 'Signed-off-by: ' with the author information only if there is no
274 'Signed-off-by: ' already, and show how it works:
275+
276------------
277$ git config trailer.sign.key "Signed-off-by: "
278$ git config trailer.sign.ifmissing add
279$ git config trailer.sign.ifexists doNothing
280$ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"'
281$ git interpret-trailers <<EOF
282> EOF
283
284Signed-off-by: Bob <bob@example.com>
285$ git interpret-trailers <<EOF
286> Signed-off-by: Alice <alice@example.com>
287> EOF
288
289Signed-off-by: Alice <alice@example.com>
290------------
291
292* Configure a 'fix' trailer with a key that contains a '#' and no
293 space after this character, and show how it works:
294+
295------------
296$ git config trailer.separators ":#"
297$ git config trailer.fix.key "Fix #"
298$ echo "subject" | git interpret-trailers --trailer fix=42
299subject
300
301Fix #42
302------------
303
304* Configure a 'see' trailer with a command to show the subject of a
305 commit that is related, and show how it works:
306+
307------------
308$ git config trailer.see.key "See-also: "
309$ git config trailer.see.ifExists "replace"
310$ git config trailer.see.ifMissing "doNothing"
311$ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG"
312$ git interpret-trailers <<EOF
313> subject
314>
315> message
316>
317> see: HEAD~2
318> EOF
319subject
320
321message
322
323See-also: fe3187489d69c4 (subject of related commit)
324------------
325
326* Configure a commit template with some trailers with empty values
327 (using sed to show and keep the trailing spaces at the end of the
328 trailers), then configure a commit-msg hook that uses
329 'git interpret-trailers' to remove trailers with empty values and
330 to add a 'git-version' trailer:
331+
332------------
333$ sed -e 's/ Z$/ /' >commit_template.txt <<EOF
334> ***subject***
335>
336> ***message***
337>
338> Fixes: Z
339> Cc: Z
340> Reviewed-by: Z
341> Signed-off-by: Z
342> EOF
343$ git config commit.template commit_template.txt
344$ cat >.git/hooks/commit-msg <<EOF
345> #!/bin/sh
346> git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new"
347> mv "\$1.new" "\$1"
348> EOF
349$ chmod +x .git/hooks/commit-msg
350------------
351
352SEE ALSO
353--------
354linkgit:git-commit[1], linkgit:git-format-patch[1], linkgit:git-config[1]
355
356GIT
357---
358Part of the linkgit:git[1] suite