1git-interpret-trailers(1) 2========================= 3 4NAME 5---- 6git-interpret-trailers - help add structured information into commit messages 7 8SYNOPSIS 9-------- 10[verse] 11'git interpret-trailers' [--in-place] [--trim-empty] [(--trailer <token>[(=|:)<value>])...] [<file>...] 12 13DESCRIPTION 14----------- 15Help adding 'trailers' lines, that look similar to RFC 822 e-mail 16headers, at the end of the otherwise free-form part of a commit 17message. 18 19This command reads some patches or commit messages from either the 20<file> arguments or the standard input if no <file> is specified. Then 21this command applies the arguments passed using the `--trailer` 22option, if any, to the commit message part of each input file. The 23result is emitted on the standard output. 24 25Some configuration variables control the way the `--trailer` arguments 26are applied to each commit message and the way any existing trailer in 27the commit message is changed. They also make it possible to 28automatically add some trailers. 29 30By default, a '<token>=<value>' or '<token>:<value>' argument given 31using `--trailer` will be appended after the existing trailers only if 32the last trailer has a different (<token>, <value>) pair (or if there 33is no existing trailer). The <token> and <value> parts will be trimmed 34to remove starting and trailing whitespace, and the resulting trimmed 35<token> and <value> will appear in the message like this: 36 37------------------------------------------------ 38token: value 39------------------------------------------------ 40 41This means that the trimmed <token> and <value> will be separated by 42`': '` (one colon followed by one space). 43 44By default the new trailer will appear at the end of all the existing 45trailers. If there is no existing trailer, the new trailer will appear 46after the commit message part of the output, and, if there is no line 47with only spaces at the end of the commit message part, one blank line 48will be added before the new trailer. 49 50Existing trailers are extracted from the input message by looking for 51a group of one or more lines that contain a colon (by default), where 52the group is preceded by one or more empty (or whitespace-only) lines. 53The group must either be at the end of the message or be the last 54non-whitespace lines before a line that starts with '---'. Such three 55minus signs start the patch part of the message. 56 57When reading trailers, there can be whitespaces before and after the 58token, the separator and the value. There can also be whitespaces 59inside the token and the value. 60 61Note that 'trailers' do not follow and are not intended to follow many 62rules for RFC 822 headers. For example they do not follow the line 63folding rules, the encoding rules and probably many other rules. 64 65OPTIONS 66------- 67--in-place:: 68 Edit the files in place. 69 70--trim-empty:: 71 If the <value> part of any trailer contains only whitespace, 72 the whole trailer will be removed from the resulting message. 73 This applies to existing trailers as well as new trailers. 74 75--trailer <token>[(=|:)<value>]:: 76 Specify a (<token>, <value>) pair that should be applied as a 77 trailer to the input messages. See the description of this 78 command. 79 80CONFIGURATION VARIABLES 81----------------------- 82 83trailer.separators:: 84 This option tells which characters are recognized as trailer 85 separators. By default only ':' is recognized as a trailer 86 separator, except that '=' is always accepted on the command 87 line for compatibility with other git commands. 88+ 89The first character given by this option will be the default character 90used when another separator is not specified in the config for this 91trailer. 92+ 93For example, if the value for this option is "%=$", then only lines 94using the format '<token><sep><value>' with <sep> containing '%', '=' 95or '$' and then spaces will be considered trailers. And '%' will be 96the default separator used, so by default trailers will appear like: 97'<token>% <value>' (one percent sign and one space will appear between 98the token and the value). 99 100trailer.where:: 101 This option tells where a new trailer will be added. 102+ 103This can be `end`, which is the default, `start`, `after` or `before`. 104+ 105If it is `end`, then each new trailer will appear at the end of the 106existing trailers. 107+ 108If it is `start`, then each new trailer will appear at the start, 109instead of the end, of the existing trailers. 110+ 111If it is `after`, then each new trailer will appear just after the 112last trailer with the same <token>. 113+ 114If it is `before`, then each new trailer will appear just before the 115first trailer with the same <token>. 116 117trailer.ifexists:: 118 This option makes it possible to choose what action will be 119 performed when there is already at least one trailer with the 120 same <token> in the message. 121+ 122The valid values for this option are: `addIfDifferentNeighbor` (this 123is the default), `addIfDifferent`, `add`, `overwrite` or `doNothing`. 124+ 125With `addIfDifferentNeighbor`, a new trailer will be added only if no 126trailer with the same (<token>, <value>) pair is above or below the line 127where the new trailer will be added. 128+ 129With `addIfDifferent`, a new trailer will be added only if no trailer 130with the same (<token>, <value>) pair is already in the message. 131+ 132With `add`, a new trailer will be added, even if some trailers with 133the same (<token>, <value>) pair are already in the message. 134+ 135With `replace`, an existing trailer with the same <token> will be 136deleted and the new trailer will be added. The deleted trailer will be 137the closest one (with the same <token>) to the place where the new one 138will be added. 139+ 140With `doNothing`, nothing will be done; that is no new trailer will be 141added if there is already one with the same <token> in the message. 142 143trailer.ifmissing:: 144 This option makes it possible to choose what action will be 145 performed when there is not yet any trailer with the same 146 <token> in the message. 147+ 148The valid values for this option are: `add` (this is the default) and 149`doNothing`. 150+ 151With `add`, a new trailer will be added. 152+ 153With `doNothing`, nothing will be done. 154 155trailer.<token>.key:: 156 This `key` will be used instead of <token> in the trailer. At 157 the end of this key, a separator can appear and then some 158 space characters. By default the only valid separator is ':', 159 but this can be changed using the `trailer.separators` config 160 variable. 161+ 162If there is a separator, then the key will be used instead of both the 163<token> and the default separator when adding the trailer. 164 165trailer.<token>.where:: 166 This option takes the same values as the 'trailer.where' 167 configuration variable and it overrides what is specified by 168 that option for trailers with the specified <token>. 169 170trailer.<token>.ifexist:: 171 This option takes the same values as the 'trailer.ifexist' 172 configuration variable and it overrides what is specified by 173 that option for trailers with the specified <token>. 174 175trailer.<token>.ifmissing:: 176 This option takes the same values as the 'trailer.ifmissing' 177 configuration variable and it overrides what is specified by 178 that option for trailers with the specified <token>. 179 180trailer.<token>.command:: 181 This option can be used to specify a shell command that will 182 be called to automatically add or modify a trailer with the 183 specified <token>. 184+ 185When this option is specified, the behavior is as if a special 186'<token>=<value>' argument were added at the beginning of the command 187line, where <value> is taken to be the standard output of the 188specified command with any leading and trailing whitespace trimmed 189off. 190+ 191If the command contains the `$ARG` string, this string will be 192replaced with the <value> part of an existing trailer with the same 193<token>, if any, before the command is launched. 194+ 195If some '<token>=<value>' arguments are also passed on the command 196line, when a 'trailer.<token>.command' is configured, the command will 197also be executed for each of these arguments. And the <value> part of 198these arguments, if any, will be used to replace the `$ARG` string in 199the command. 200 201EXAMPLES 202-------- 203 204* Configure a 'sign' trailer with a 'Signed-off-by' key, and then 205 add two of these trailers to a message: 206+ 207------------ 208$ git config trailer.sign.key "Signed-off-by" 209$ cat msg.txt 210subject 211 212message 213$ cat msg.txt | git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>' 214subject 215 216message 217 218Signed-off-by: Alice <alice@example.com> 219Signed-off-by: Bob <bob@example.com> 220------------ 221 222* Use the `--in-place` option to edit a message file in place: 223+ 224------------ 225$ cat msg.txt 226subject 227 228message 229 230Signed-off-by: Bob <bob@example.com> 231$ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt 232$ cat msg.txt 233subject 234 235message 236 237Signed-off-by: Bob <bob@example.com> 238Acked-by: Alice <alice@example.com> 239------------ 240 241* Extract the last commit as a patch, and add a 'Cc' and a 242 'Reviewed-by' trailer to it: 243+ 244------------ 245$ git format-patch -1 2460001-foo.patch 247$ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch 248------------ 249 250* Configure a 'sign' trailer with a command to automatically add a 251 'Signed-off-by: ' with the author information only if there is no 252 'Signed-off-by: ' already, and show how it works: 253+ 254------------ 255$ git config trailer.sign.key "Signed-off-by: " 256$ git config trailer.sign.ifmissing add 257$ git config trailer.sign.ifexists doNothing 258$ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"' 259$ git interpret-trailers <<EOF 260> EOF 261 262Signed-off-by: Bob <bob@example.com> 263$ git interpret-trailers <<EOF 264> Signed-off-by: Alice <alice@example.com> 265> EOF 266 267Signed-off-by: Alice <alice@example.com> 268------------ 269 270* Configure a 'fix' trailer with a key that contains a '#' and no 271 space after this character, and show how it works: 272+ 273------------ 274$ git config trailer.separators ":#" 275$ git config trailer.fix.key "Fix #" 276$ echo "subject" | git interpret-trailers --trailer fix=42 277subject 278 279Fix #42 280------------ 281 282* Configure a 'see' trailer with a command to show the subject of a 283 commit that is related, and show how it works: 284+ 285------------ 286$ git config trailer.see.key "See-also: " 287$ git config trailer.see.ifExists "replace" 288$ git config trailer.see.ifMissing "doNothing" 289$ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG" 290$ git interpret-trailers <<EOF 291> subject 292> 293> message 294> 295> see: HEAD~2 296> EOF 297subject 298 299message 300 301See-also: fe3187489d69c4 (subject of related commit) 302------------ 303 304* Configure a commit template with some trailers with empty values 305 (using sed to show and keep the trailing spaces at the end of the 306 trailers), then configure a commit-msg hook that uses 307 'git interpret-trailers' to remove trailers with empty values and 308 to add a 'git-version' trailer: 309+ 310------------ 311$ sed -e 's/ Z$/ /' >commit_template.txt <<EOF 312> ***subject*** 313> 314> ***message*** 315> 316> Fixes: Z 317> Cc: Z 318> Reviewed-by: Z 319> Signed-off-by: Z 320> EOF 321$ git config commit.template commit_template.txt 322$ cat >.git/hooks/commit-msg <<EOF 323> #!/bin/sh 324> git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new" 325> mv "\$1.new" "\$1" 326> EOF 327$ chmod +x .git/hooks/commit-msg 328------------ 329 330SEE ALSO 331-------- 332linkgit:git-commit[1], linkgit:git-format-patch[1], linkgit:git-config[1] 333 334GIT 335--- 336Part of the linkgit:git[1] suite