1GIT-INTERPRET-TRAI(1) Git Manual GIT-INTERPRET-TRAI(1)
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6 git-interpret-trailers - Add or parse structured information in commit
7 messages
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10 git interpret-trailers [<options>] [(--trailer <token>[(=|:)<value>])...] [<file>...]
11 git interpret-trailers [<options>] [--parse] [<file>...]
12
15 Help parsing or adding trailers lines, that look similar to RFC 822
16 e-mail headers, at the end of the otherwise free-form part of a commit
17 message.
18 This command reads some patches or commit messages from either the
20 <file> arguments or the standard input if no <file> is specified. If
21 --parse is specified, the output consists of the parsed trailers.
22 Otherwise, this command applies the arguments passed using the
24 --trailer option, if any, to the commit message part of each input
25 file. The result is emitted on the standard output.
26 Some configuration variables control the way the --trailer arguments
28 are applied to each commit message and the way any existing trailer in
29 the commit message is changed. They also make it possible to
30 automatically add some trailers.
31 By default, a <token>=<value> or <token>:<value> argument given using
33 --trailer will be appended after the existing trailers only if the last
34 trailer has a different (<token>, <value>) pair (or if there is no
35 existing trailer). The <token> and <value> parts will be trimmed to
36 remove starting and trailing whitespace, and the resulting trimmed
37 <token> and <value> will appear in the message like this:
38 token: value
40 This means that the trimmed <token> and <value> will be separated by ':
43 ' (one colon followed by one space).
44 By default the new trailer will appear at the end of all the existing
46 trailers. If there is no existing trailer, the new trailer will appear
47 after the commit message part of the output, and, if there is no line
48 with only spaces at the end of the commit message part, one blank line
49 will be added before the new trailer.
50 Existing trailers are extracted from the input message by looking for a
52 group of one or more lines that (i) is all trailers, or (ii) contains
53 at least one Git-generated or user-configured trailer and consists of
54 at least 25% trailers. The group must be preceded by one or more empty
55 (or whitespace-only) lines. The group must either be at the end of the
56 message or be the last non-whitespace lines before a line that starts
57 with --- (followed by a space or the end of the line). Such three minus
58 signs start the patch part of the message. See also --no-divider below.
59 When reading trailers, there can be whitespaces after the token, the
61 separator and the value. There can also be whitespaces inside the token
62 and the value. The value may be split over multiple lines with each
63 subsequent line starting with whitespace, like the "folding" in RFC
64 822.
65 Note that trailers do not follow and are not intended to follow many
67 rules for RFC 822 headers. For example they do not follow the encoding
68 rules and probably many other rules.
69
71 --in-place
72 Edit the files in place.
73 --trim-empty
75 If the <value> part of any trailer contains only whitespace, the
76 whole trailer will be removed from the resulting message. This
77 applies to existing trailers as well as new trailers.
78 --trailer <token>[(=|:)<value>]
80 Specify a (<token>, <value>) pair that should be applied as a
81 trailer to the input messages. See the description of this command.
82 --where <placement>, --no-where
84 Specify where all new trailers will be added. A setting provided
85 with --where overrides all configuration variables and applies to
86 all --trailer options until the next occurrence of --where or
87 --no-where. Possible values are after, before, end or start.
88 --if-exists <action>, --no-if-exists
90 Specify what action will be performed when there is already at
91 least one trailer with the same <token> in the message. A setting
92 provided with --if-exists overrides all configuration variables and
93 applies to all --trailer options until the next occurrence of
94 --if-exists or --no-if-exists. Possible actions are addIfDifferent,
95 addIfDifferentNeighbor, add, replace and doNothing.
96 --if-missing <action>, --no-if-missing
98 Specify what action will be performed when there is no other
99 trailer with the same <token> in the message. A setting provided
100 with --if-missing overrides all configuration variables and applies
101 to all --trailer options until the next occurrence of --if-missing
102 or --no-if-missing. Possible actions are doNothing or add.
103 --only-trailers
105 Output only the trailers, not any other parts of the input.
106 --only-input
108 Output only trailers that exist in the input; do not add any from
109 the command-line or by following configured trailer.* rules.
110 --unfold
112 Remove any whitespace-continuation in trailers, so that each
113 trailer appears on a line by itself with its full content.
114 --parse
116 A convenience alias for --only-trailers --only-input --unfold.
117 --no-divider
119 Do not treat --- as the end of the commit message. Use this when
120 you know your input contains just the commit message itself (and
121 not an email or the output of git format-patch).
122
124 trailer.separators
125 This option tells which characters are recognized as trailer
126 separators. By default only : is recognized as a trailer separator,
127 except that = is always accepted on the command line for
128 compatibility with other git commands.
129 The first character given by this option will be the default
131 character used when another separator is not specified in the
132 config for this trailer.
133 For example, if the value for this option is "%=$", then only lines
135 using the format <token><sep><value> with <sep> containing %, = or
136 $ and then spaces will be considered trailers. And % will be the
137 default separator used, so by default trailers will appear like:
138 <token>% <value> (one percent sign and one space will appear
139 between the token and the value).
140 trailer.where
142 This option tells where a new trailer will be added.
143 This can be end, which is the default, start, after or before.
145 If it is end, then each new trailer will appear at the end of the
147 existing trailers.
148 If it is start, then each new trailer will appear at the start,
150 instead of the end, of the existing trailers.
151 If it is after, then each new trailer will appear just after the
153 last trailer with the same <token>.
154 If it is before, then each new trailer will appear just before the
156 first trailer with the same <token>.
157 trailer.ifexists
159 This option makes it possible to choose what action will be
160 performed when there is already at least one trailer with the same
161 <token> in the message.
162 The valid values for this option are: addIfDifferentNeighbor (this
164 is the default), addIfDifferent, add, replace or doNothing.
165 With addIfDifferentNeighbor, a new trailer will be added only if no
167 trailer with the same (<token>, <value>) pair is above or below the
168 line where the new trailer will be added.
169 With addIfDifferent, a new trailer will be added only if no trailer
171 with the same (<token>, <value>) pair is already in the message.
172 With add, a new trailer will be added, even if some trailers with
174 the same (<token>, <value>) pair are already in the message.
175 With replace, an existing trailer with the same <token> will be
177 deleted and the new trailer will be added. The deleted trailer will
178 be the closest one (with the same <token>) to the place where the
179 new one will be added.
180 With doNothing, nothing will be done; that is no new trailer will
182 be added if there is already one with the same <token> in the
183 message.
184 trailer.ifmissing
186 This option makes it possible to choose what action will be
187 performed when there is not yet any trailer with the same <token>
188 in the message.
189 The valid values for this option are: add (this is the default) and
191 doNothing.
192 With add, a new trailer will be added.
194 With doNothing, nothing will be done.
196 trailer.<token>.key
198 This key will be used instead of <token> in the trailer. At the end
199 of this key, a separator can appear and then some space characters.
200 By default the only valid separator is :, but this can be changed
201 using the trailer.separators config variable.
202 If there is a separator, then the key will be used instead of both
204 the <token> and the default separator when adding the trailer.
205 trailer.<token>.where
207 This option takes the same values as the trailer.where
208 configuration variable and it overrides what is specified by that
209 option for trailers with the specified <token>.
210 trailer.<token>.ifexists
212 This option takes the same values as the trailer.ifexists
213 configuration variable and it overrides what is specified by that
214 option for trailers with the specified <token>.
215 trailer.<token>.ifmissing
217 This option takes the same values as the trailer.ifmissing
218 configuration variable and it overrides what is specified by that
219 option for trailers with the specified <token>.
220 trailer.<token>.command
222 This option can be used to specify a shell command that will be
223 called to automatically add or modify a trailer with the specified
224 <token>.
225 When this option is specified, the behavior is as if a special
227 <token>=<value> argument were added at the beginning of the command
228 line, where <value> is taken to be the standard output of the
229 specified command with any leading and trailing whitespace trimmed
230 off.
231 If the command contains the $ARG string, this string will be
233 replaced with the <value> part of an existing trailer with the same
234 <token>, if any, before the command is launched.
235 If some <token>=<value> arguments are also passed on the command
237 line, when a trailer.<token>.command is configured, the command
238 will also be executed for each of these arguments. And the <value>
239 part of these arguments, if any, will be used to replace the $ARG
240 string in the command.
241
243 · Configure a sign trailer with a Signed-off-by key, and then add two
244 of these trailers to a message:
245 $ git config trailer.sign.key "Signed-off-by"
247 $ cat msg.txt
248 subject
249 message
251 $ cat msg.txt | git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>'
252 subject
253 message
255 Signed-off-by: Alice <alice@example.com>
257 Signed-off-by: Bob <bob@example.com>
258 · Use the --in-place option to edit a message file in place:
261 $ cat msg.txt
263 subject
264 message
266 Signed-off-by: Bob <bob@example.com>
268 $ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt
269 $ cat msg.txt
270 subject
271 message
273 Signed-off-by: Bob <bob@example.com>
275 Acked-by: Alice <alice@example.com>
276 · Extract the last commit as a patch, and add a Cc and a Reviewed-by
279 trailer to it:
280 $ git format-patch -1
282 0001-foo.patch
283 $ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch
284 · Configure a sign trailer with a command to automatically add a
287 'Signed-off-by: ' with the author information only if there is no
288 'Signed-off-by: ' already, and show how it works:
289 $ git config trailer.sign.key "Signed-off-by: "
291 $ git config trailer.sign.ifmissing add
292 $ git config trailer.sign.ifexists doNothing
293 $ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"'
294 $ git interpret-trailers <<EOF
295 > EOF
296 Signed-off-by: Bob <bob@example.com>
298 $ git interpret-trailers <<EOF
299 > Signed-off-by: Alice <alice@example.com>
300 > EOF
301 Signed-off-by: Alice <alice@example.com>
303 · Configure a fix trailer with a key that contains a # and no space
306 after this character, and show how it works:
307 $ git config trailer.separators ":#"
309 $ git config trailer.fix.key "Fix #"
310 $ echo "subject" | git interpret-trailers --trailer fix=42
311 subject
312 Fix #42
314 · Configure a see trailer with a command to show the subject of a
317 commit that is related, and show how it works:
318 $ git config trailer.see.key "See-also: "
320 $ git config trailer.see.ifExists "replace"
321 $ git config trailer.see.ifMissing "doNothing"
322 $ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG"
323 $ git interpret-trailers <<EOF
324 > subject
325 >
326 > message
327 >
328 > see: HEAD~2
329 > EOF
330 subject
331 message
333 See-also: fe3187489d69c4 (subject of related commit)
335 · Configure a commit template with some trailers with empty values
338 (using sed to show and keep the trailing spaces at the end of the
339 trailers), then configure a commit-msg hook that uses git
340 interpret-trailers to remove trailers with empty values and to add
341 a git-version trailer:
342 $ sed -e 's/ Z$/ /' >commit_template.txt <<EOF
344 > ***subject***
345 >
346 > ***message***
347 >
348 > Fixes: Z
349 > Cc: Z
350 > Reviewed-by: Z
351 > Signed-off-by: Z
352 > EOF
353 $ git config commit.template commit_template.txt
354 $ cat >.git/hooks/commit-msg <<EOF
355 > #!/bin/sh
356 > git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new"
357 > mv "\$1.new" "\$1"
358 > EOF
359 $ chmod +x .git/hooks/commit-msg
360
363 git-commit(1), git-format-patch(1), git-config(1)
364
366 Part of the git(1) suite
367Git 2.24.1 12/10/2019 GIT-INTERPRET-TRAI(1)