1GIT-INTERPRET-TRAI(1) Git Manual GIT-INTERPRET-TRAI(1)
2
6 git-interpret-trailers - Add or parse structured information in commit
7 messages
8
10 git interpret-trailers [--in-place] [--trim-empty]
11 [(--trailer <token>[(=|:)<value>])...]
12 [--parse] [<file>...]
13
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 ':
42 ' (one colon followed by one space).
43 By default the new trailer will appear at the end of all the existing
45 trailers. If there is no existing trailer, the new trailer will appear
46 after the commit message part of the output, and, if there is no line
47 with only spaces at the end of the commit message part, one blank line
48 will be added before the new trailer.
49 Existing trailers are extracted from the input message by looking for a
51 group of one or more lines that (i) is all trailers, or (ii) contains
52 at least one Git-generated or user-configured trailer and consists of
53 at least 25% trailers. The group must be preceded by one or more empty
54 (or whitespace-only) lines. The group must either be at the end of the
55 message or be the last non-whitespace lines before a line that starts
56 with --- (followed by a space or the end of the line). Such three minus
57 signs start the patch part of the message. See also --no-divider below.
58 When reading trailers, there can be no whitespace before or inside the
60 token, but any number of regular space and tab characters are allowed
61 between the token and the separator. There can be whitespaces before,
62 inside or after the value. The value may be split over multiple lines
63 with each subsequent line starting with at least one whitespace, like
64 the "folding" in RFC 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 behaves in the same way as trailer.<token>.cmd, except
223 that it doesn’t pass anything as argument to the specified command.
224 Instead the first occurrence of substring $ARG is replaced by the
225 value that would be passed as argument.
226 The trailer.<token>.command option has been deprecated in favor of
228 trailer.<token>.cmd due to the fact that $ARG in the user’s command
229 is only replaced once and that the original way of replacing $ARG
230 is not safe.
231 When both trailer.<token>.cmd and trailer.<token>.command are given
233 for the same <token>, trailer.<token>.cmd is used and
234 trailer.<token>.command is ignored.
235 trailer.<token>.cmd
237 This option can be used to specify a shell command that will be
238 called: once to automatically add a trailer with the specified
239 <token>, and then each time a --trailer <token>=<value> argument to
240 modify the <value> of the trailer that this option would produce.
241 When the specified command is first called to add a trailer with
243 the specified <token>, the behavior is as if a special --trailer
244 <token>=<value> argument was added at the beginning of the "git
245 interpret-trailers" command, where <value> is taken to be the
246 standard output of the command with any leading and trailing
247 whitespace trimmed off.
248 If some --trailer <token>=<value> arguments are also passed on the
250 command line, the command is called again once for each of these
251 arguments with the same <token>. And the <value> part of these
252 arguments, if any, will be passed to the command as its first
253 argument. This way the command can produce a <value> computed from
254 the <value> passed in the --trailer <token>=<value> argument.
255
257 • Configure a sign trailer with a Signed-off-by key, and then add two
258 of these trailers to a message:
259 $ git config trailer.sign.key "Signed-off-by"
261 $ cat msg.txt
262 subject
263 message
265 $ cat msg.txt | git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>'
266 subject
267 message
269 Signed-off-by: Alice <alice@example.com>
271 Signed-off-by: Bob <bob@example.com>
272 • Use the --in-place option to edit a message file in place:
274 $ cat msg.txt
276 subject
277 message
279 Signed-off-by: Bob <bob@example.com>
281 $ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt
282 $ cat msg.txt
283 subject
284 message
286 Signed-off-by: Bob <bob@example.com>
288 Acked-by: Alice <alice@example.com>
289 • Extract the last commit as a patch, and add a Cc and a Reviewed-by
291 trailer to it:
292 $ git format-patch -1
294 0001-foo.patch
295 $ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch
296 • Configure a sign trailer with a command to automatically add a
298 'Signed-off-by: ' with the author information only if there is no
299 'Signed-off-by: ' already, and show how it works:
300 $ git config trailer.sign.key "Signed-off-by: "
302 $ git config trailer.sign.ifmissing add
303 $ git config trailer.sign.ifexists doNothing
304 $ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"'
305 $ git interpret-trailers <<EOF
306 > EOF
307 Signed-off-by: Bob <bob@example.com>
309 $ git interpret-trailers <<EOF
310 > Signed-off-by: Alice <alice@example.com>
311 > EOF
312 Signed-off-by: Alice <alice@example.com>
314 • Configure a fix trailer with a key that contains a # and no space
316 after this character, and show how it works:
317 $ git config trailer.separators ":#"
319 $ git config trailer.fix.key "Fix #"
320 $ echo "subject" | git interpret-trailers --trailer fix=42
321 subject
322 Fix #42
324 • Configure a help trailer with a cmd use a script glog-find-author
326 which search specified author identity from git log in git
327 repository and show how it works:
328 $ cat ~/bin/glog-find-author
330 #!/bin/sh
331 test -n "$1" && git log --author="$1" --pretty="%an <%ae>" -1 || true
332 $ git config trailer.help.key "Helped-by: "
333 $ git config trailer.help.ifExists "addIfDifferentNeighbor"
334 $ git config trailer.help.cmd "~/bin/glog-find-author"
335 $ git interpret-trailers --trailer="help:Junio" --trailer="help:Couder" <<EOF
336 > subject
337 >
338 > message
339 >
340 > EOF
341 subject
342 message
344 Helped-by: Junio C Hamano <gitster@pobox.com>
346 Helped-by: Christian Couder <christian.couder@gmail.com>
347 • Configure a ref trailer with a cmd use a script glog-grep to grep
349 last relevant commit from git log in the git repository and show
350 how it works:
351 $ cat ~/bin/glog-grep
353 #!/bin/sh
354 test -n "$1" && git log --grep "$1" --pretty=reference -1 || true
355 $ git config trailer.ref.key "Reference-to: "
356 $ git config trailer.ref.ifExists "replace"
357 $ git config trailer.ref.cmd "~/bin/glog-grep"
358 $ git interpret-trailers --trailer="ref:Add copyright notices." <<EOF
359 > subject
360 >
361 > message
362 >
363 > EOF
364 subject
365 message
367 Reference-to: 8bc9a0c769 (Add copyright notices., 2005-04-07)
369 • Configure a see trailer with a command to show the subject of a
371 commit that is related, and show how it works:
372 $ git config trailer.see.key "See-also: "
374 $ git config trailer.see.ifExists "replace"
375 $ git config trailer.see.ifMissing "doNothing"
376 $ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG"
377 $ git interpret-trailers <<EOF
378 > subject
379 >
380 > message
381 >
382 > see: HEAD~2
383 > EOF
384 subject
385 message
387 See-also: fe3187489d69c4 (subject of related commit)
389 • Configure a commit template with some trailers with empty values
391 (using sed to show and keep the trailing spaces at the end of the
392 trailers), then configure a commit-msg hook that uses git
393 interpret-trailers to remove trailers with empty values and to add
394 a git-version trailer:
395 $ sed -e 's/ Z$/ /' >commit_template.txt <<EOF
397 > ***subject***
398 >
399 > ***message***
400 >
401 > Fixes: Z
402 > Cc: Z
403 > Reviewed-by: Z
404 > Signed-off-by: Z
405 > EOF
406 $ git config commit.template commit_template.txt
407 $ cat >.git/hooks/commit-msg <<EOF
408 > #!/bin/sh
409 > git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new"
410 > mv "\$1.new" "\$1"
411 > EOF
412 $ chmod +x .git/hooks/commit-msg
413
415 git-commit(1), git-format-patch(1), git-config(1)
416
418 Part of the git(1) suite
419Git 2.39.1 2023-01-13 GIT-INTERPRET-TRAI(1)