1git-interpret-trailers(1) 2========================= 3 4NAME 5---- 6git-interpret-trailers - Add or parse structured information in commit messages 7 8SYNOPSIS 9-------- 10[verse] 11'git interpret-trailers' [<options>] [(--trailer <token>[(=|:)<value>])...] [<file>...] 12'git interpret-trailers' [<options>] [--parse] [<file>...] 13 14DESCRIPTION 15----------- 16Help parsing or adding 'trailers' lines, that look similar to RFC 822 e-mail 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 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 24Otherwise, this command applies the arguments passed using the 25`--trailer` option, if any, to the commit message part of each input 26file. The result is emitted on the standard output. 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 49after the commit message part of the output, and, if there is no line 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 54a group of one or more lines that (i) is all trailers, or (ii) contains at 55least one Git-generated or user-configured trailer and consists of at 56least 25% trailers. 57The group must be preceded by one or more empty (or whitespace-only) lines. 58The group must either be at the end of the message or be the last 59non-whitespace lines before a line that starts with '---' (followed by a 60space or the end of the line). Such three minus signs start the patch 61part of the message. See also `--no-divider` below. 62 63When reading trailers, there can be whitespaces after the 64token, the separator and the value. There can also be whitespaces 65inside the token and the value. The value may be split over multiple lines with 66each subsequent line starting with whitespace, like the "folding" in RFC 822. 67 68Note that 'trailers' do not follow and are not intended to follow many 69rules for RFC 822 headers. For example they do not follow 70the encoding rules and probably many other rules. 71 72OPTIONS 73------- 74--in-place:: 75 Edit the files in place. 76 77--trim-empty:: 78 If the <value> part of any trailer contains only whitespace, 79 the whole trailer will be removed from the resulting message. 80 This applies to existing trailers as well as new trailers. 81 82--trailer <token>[(=|:)<value>]:: 83 Specify a (<token>, <value>) pair that should be applied as a 84 trailer to the input messages. See the description of this 85 command. 86 87--where <placement>:: 88--no-where:: 89 Specify where all new trailers will be added. A setting 90 provided with '--where' overrides all configuration variables 91 and applies to all '--trailer' options until the next occurrence of 92 '--where' or '--no-where'. Possible values are `after`, `before`, 93 `end` or `start`. 94 95--if-exists <action>:: 96--no-if-exists:: 97 Specify what action will be performed when there is already at 98 least one trailer with the same <token> in the message. A setting 99 provided with '--if-exists' overrides all configuration variables 100 and applies to all '--trailer' options until the next occurrence of 101 '--if-exists' or '--no-if-exists'. Possible actions are `addIfDifferent`, 102 `addIfDifferentNeighbor`, `add`, `replace` and `doNothing`. 103 104--if-missing <action>:: 105--no-if-missing:: 106 Specify what action will be performed when there is no other 107 trailer with the same <token> in the message. A setting 108 provided with '--if-missing' overrides all configuration variables 109 and applies to all '--trailer' options until the next occurrence of 110 '--if-missing' or '--no-if-missing'. Possible actions are `doNothing` 111 or `add`. 112 113--only-trailers:: 114 Output only the trailers, not any other parts of the input. 115 116--only-input:: 117 Output only trailers that exist in the input; do not add any 118 from the command-line or by following configured `trailer.*` 119 rules. 120 121--unfold:: 122 Remove any whitespace-continuation in trailers, so that each 123 trailer appears on a line by itself with its full content. 124 125--parse:: 126 A convenience alias for `--only-trailers --only-input 127 --unfold`. 128 129--no-divider:: 130 Do not treat `---` as the end of the commit message. Use this 131 when you know your input contains just the commit message itself 132 (and not an email or the output of `git format-patch`). 133 134CONFIGURATION VARIABLES 135----------------------- 136 137trailer.separators:: 138 This option tells which characters are recognized as trailer 139 separators. By default only ':' is recognized as a trailer 140 separator, except that '=' is always accepted on the command 141 line for compatibility with other git commands. 142+ 143The first character given by this option will be the default character 144used when another separator is not specified in the config for this 145trailer. 146+ 147For example, if the value for this option is "%=$", then only lines 148using the format '<token><sep><value>' with <sep> containing '%', '=' 149or '$' and then spaces will be considered trailers. And '%' will be 150the default separator used, so by default trailers will appear like: 151'<token>% <value>' (one percent sign and one space will appear between 152the token and the value). 153 154trailer.where:: 155 This option tells where a new trailer will be added. 156+ 157This can be `end`, which is the default, `start`, `after` or `before`. 158+ 159If it is `end`, then each new trailer will appear at the end of the 160existing trailers. 161+ 162If it is `start`, then each new trailer will appear at the start, 163instead of the end, of the existing trailers. 164+ 165If it is `after`, then each new trailer will appear just after the 166last trailer with the same <token>. 167+ 168If it is `before`, then each new trailer will appear just before the 169first trailer with the same <token>. 170 171trailer.ifexists:: 172 This option makes it possible to choose what action will be 173 performed when there is already at least one trailer with the 174 same <token> in the message. 175+ 176The valid values for this option are: `addIfDifferentNeighbor` (this 177is the default), `addIfDifferent`, `add`, `replace` or `doNothing`. 178+ 179With `addIfDifferentNeighbor`, a new trailer will be added only if no 180trailer with the same (<token>, <value>) pair is above or below the line 181where the new trailer will be added. 182+ 183With `addIfDifferent`, a new trailer will be added only if no trailer 184with the same (<token>, <value>) pair is already in the message. 185+ 186With `add`, a new trailer will be added, even if some trailers with 187the same (<token>, <value>) pair are already in the message. 188+ 189With `replace`, an existing trailer with the same <token> will be 190deleted and the new trailer will be added. The deleted trailer will be 191the closest one (with the same <token>) to the place where the new one 192will be added. 193+ 194With `doNothing`, nothing will be done; that is no new trailer will be 195added if there is already one with the same <token> in the message. 196 197trailer.ifmissing:: 198 This option makes it possible to choose what action will be 199 performed when there is not yet any trailer with the same 200 <token> in the message. 201+ 202The valid values for this option are: `add` (this is the default) and 203`doNothing`. 204+ 205With `add`, a new trailer will be added. 206+ 207With `doNothing`, nothing will be done. 208 209trailer.<token>.key:: 210 This `key` will be used instead of <token> in the trailer. At 211 the end of this key, a separator can appear and then some 212 space characters. By default the only valid separator is ':', 213 but this can be changed using the `trailer.separators` config 214 variable. 215+ 216If there is a separator, then the key will be used instead of both the 217<token> and the default separator when adding the trailer. 218 219trailer.<token>.where:: 220 This option takes the same values as the 'trailer.where' 221 configuration variable and it overrides what is specified by 222 that option for trailers with the specified <token>. 223 224trailer.<token>.ifexists:: 225 This option takes the same values as the 'trailer.ifexists' 226 configuration variable and it overrides what is specified by 227 that option for trailers with the specified <token>. 228 229trailer.<token>.ifmissing:: 230 This option takes the same values as the 'trailer.ifmissing' 231 configuration variable and it overrides what is specified by 232 that option for trailers with the specified <token>. 233 234trailer.<token>.command:: 235 This option can be used to specify a shell command that will 236 be called to automatically add or modify a trailer with the 237 specified <token>. 238+ 239When this option is specified, the behavior is as if a special 240'<token>=<value>' argument were added at the beginning of the command 241line, where <value> is taken to be the standard output of the 242specified command with any leading and trailing whitespace trimmed 243off. 244+ 245If the command contains the `$ARG` string, this string will be 246replaced with the <value> part of an existing trailer with the same 247<token>, if any, before the command is launched. 248+ 249If some '<token>=<value>' arguments are also passed on the command 250line, when a 'trailer.<token>.command' is configured, the command will 251also be executed for each of these arguments. And the <value> part of 252these arguments, if any, will be used to replace the `$ARG` string in 253the command. 254 255EXAMPLES 256-------- 257 258* Configure a 'sign' trailer with a 'Signed-off-by' key, and then 259 add two of these trailers to a message: 260+ 261------------ 262$ git config trailer.sign.key "Signed-off-by" 263$ cat msg.txt 264subject 265 266message 267$ cat msg.txt | git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>' 268subject 269 270message 271 272Signed-off-by: Alice <alice@example.com> 273Signed-off-by: Bob <bob@example.com> 274------------ 275 276* Use the `--in-place` option to edit a message file in place: 277+ 278------------ 279$ cat msg.txt 280subject 281 282message 283 284Signed-off-by: Bob <bob@example.com> 285$ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt 286$ cat msg.txt 287subject 288 289message 290 291Signed-off-by: Bob <bob@example.com> 292Acked-by: Alice <alice@example.com> 293------------ 294 295* Extract the last commit as a patch, and add a 'Cc' and a 296 'Reviewed-by' trailer to it: 297+ 298------------ 299$ git format-patch -1 3000001-foo.patch 301$ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch 302------------ 303 304* Configure a 'sign' trailer with a command to automatically add a 305 'Signed-off-by: ' with the author information only if there is no 306 'Signed-off-by: ' already, and show how it works: 307+ 308------------ 309$ git config trailer.sign.key "Signed-off-by: " 310$ git config trailer.sign.ifmissing add 311$ git config trailer.sign.ifexists doNothing 312$ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"' 313$ git interpret-trailers <<EOF 314> EOF 315 316Signed-off-by: Bob <bob@example.com> 317$ git interpret-trailers <<EOF 318> Signed-off-by: Alice <alice@example.com> 319> EOF 320 321Signed-off-by: Alice <alice@example.com> 322------------ 323 324* Configure a 'fix' trailer with a key that contains a '#' and no 325 space after this character, and show how it works: 326+ 327------------ 328$ git config trailer.separators ":#" 329$ git config trailer.fix.key "Fix #" 330$ echo "subject" | git interpret-trailers --trailer fix=42 331subject 332 333Fix #42 334------------ 335 336* Configure a 'see' trailer with a command to show the subject of a 337 commit that is related, and show how it works: 338+ 339------------ 340$ git config trailer.see.key "See-also: " 341$ git config trailer.see.ifExists "replace" 342$ git config trailer.see.ifMissing "doNothing" 343$ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG" 344$ git interpret-trailers <<EOF 345> subject 346> 347> message 348> 349> see: HEAD~2 350> EOF 351subject 352 353message 354 355See-also: fe3187489d69c4 (subject of related commit) 356------------ 357 358* Configure a commit template with some trailers with empty values 359 (using sed to show and keep the trailing spaces at the end of the 360 trailers), then configure a commit-msg hook that uses 361 'git interpret-trailers' to remove trailers with empty values and 362 to add a 'git-version' trailer: 363+ 364------------ 365$ sed -e 's/ Z$/ /' >commit_template.txt <<EOF 366> ***subject*** 367> 368> ***message*** 369> 370> Fixes: Z 371> Cc: Z 372> Reviewed-by: Z 373> Signed-off-by: Z 374> EOF 375$ git config commit.template commit_template.txt 376$ cat >.git/hooks/commit-msg <<EOF 377> #!/bin/sh 378> git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new" 379> mv "\$1.new" "\$1" 380> EOF 381$ chmod +x .git/hooks/commit-msg 382------------ 383 384SEE ALSO 385-------- 386linkgit:git-commit[1], linkgit:git-format-patch[1], linkgit:git-config[1] 387 388GIT 389--- 390Part of the linkgit:git[1] suite