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diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt new file mode 100644 index 0000000000..9dd19a1dd9 --- /dev/null +++ b/Documentation/git-interpret-trailers.txt @@ -0,0 +1,381 @@ +git-interpret-trailers(1) +========================= + +NAME +---- +git-interpret-trailers - add or parse structured information in commit messages + +SYNOPSIS +-------- +[verse] +'git interpret-trailers' [options] [(--trailer <token>[(=|:)<value>])...] [<file>...] +'git interpret-trailers' [options] [--parse] [<file>...] + +DESCRIPTION +----------- +Help parsing or adding 'trailers' lines, that look similar to RFC 822 e-mail +headers, at the end of the otherwise free-form part of a commit +message. + +This command reads some patches or commit messages from either the +<file> arguments or the standard input if no <file> is specified. If +`--parse` is specified, the output consists of the parsed trailers. + +Otherwise, this command applies the arguments passed using the +`--trailer` option, if any, to the commit message part of each input +file. The result is emitted on the standard output. + +Some configuration variables control the way the `--trailer` arguments +are applied to each commit message and the way any existing trailer in +the commit message is changed. They also make it possible to +automatically add some trailers. + +By default, a '<token>=<value>' or '<token>:<value>' argument given +using `--trailer` will be appended after the existing trailers only if +the last trailer has a different (<token>, <value>) pair (or if there +is no existing trailer). The <token> and <value> parts will be trimmed +to remove starting and trailing whitespace, and the resulting trimmed +<token> and <value> will appear in the message like this: + +------------------------------------------------ +token: value +------------------------------------------------ + +This means that the trimmed <token> and <value> will be separated by +`': '` (one colon followed by one space). + +By default the new trailer will appear at the end of all the existing +trailers. If there is no existing trailer, the new trailer will appear +after the commit message part of the output, and, if there is no line +with only spaces at the end of the commit message part, one blank line +will be added before the new trailer. + +Existing trailers are extracted from the input message by looking for +a group of one or more lines that (i) are all trailers, or (ii) contains at +least one Git-generated or user-configured trailer and consists of at +least 25% trailers. +The group must be preceded by one or more empty (or whitespace-only) lines. +The group must either be at the end of the message or be the last +non-whitespace lines before a line that starts with '---'. Such three +minus signs start the patch part of the message. + +When reading trailers, there can be whitespaces after the +token, the separator and the value. There can also be whitespaces +inside the token and the value. The value may be split over multiple lines with +each subsequent line starting with whitespace, like the "folding" in RFC 822. + +Note that 'trailers' do not follow and are not intended to follow many +rules for RFC 822 headers. For example they do not follow +the encoding rules and probably many other rules. + +OPTIONS +------- +--in-place:: + Edit the files in place. + +--trim-empty:: + If the <value> part of any trailer contains only whitespace, + the whole trailer will be removed from the resulting message. + This applies to existing trailers as well as new trailers. + +--trailer <token>[(=|:)<value>]:: + Specify a (<token>, <value>) pair that should be applied as a + trailer to the input messages. See the description of this + command. + +--where <placement>:: +--no-where:: + Specify where all new trailers will be added. A setting + provided with '--where' overrides all configuration variables + and applies to all '--trailer' options until the next occurrence of + '--where' or '--no-where'. + +--if-exists <action>:: +--no-if-exists:: + Specify what action will be performed when there is already at + least one trailer with the same <token> in the message. A setting + provided with '--if-exists' overrides all configuration variables + and applies to all '--trailer' options until the next occurrence of + '--if-exists' or '--no-if-exists'. + +--if-missing <action>:: +--no-if-missing:: + Specify what action will be performed when there is no other + trailer with the same <token> in the message. A setting + provided with '--if-missing' overrides all configuration variables + and applies to all '--trailer' options until the next occurrence of + '--if-missing' or '--no-if-missing'. + +--only-trailers:: + Output only the trailers, not any other parts of the input. + +--only-input:: + Output only trailers that exist in the input; do not add any + from the command-line or by following configured `trailer.*` + rules. + +--unfold:: + Remove any whitespace-continuation in trailers, so that each + trailer appears on a line by itself with its full content. + +--parse:: + A convenience alias for `--only-trailers --only-input + --unfold`. + +CONFIGURATION VARIABLES +----------------------- + +trailer.separators:: + This option tells which characters are recognized as trailer + separators. By default only ':' is recognized as a trailer + separator, except that '=' is always accepted on the command + line for compatibility with other git commands. ++ +The first character given by this option will be the default character +used when another separator is not specified in the config for this +trailer. ++ +For example, if the value for this option is "%=$", then only lines +using the format '<token><sep><value>' with <sep> containing '%', '=' +or '$' and then spaces will be considered trailers. And '%' will be +the default separator used, so by default trailers will appear like: +'<token>% <value>' (one percent sign and one space will appear between +the token and the value). + +trailer.where:: + This option tells where a new trailer will be added. ++ +This can be `end`, which is the default, `start`, `after` or `before`. ++ +If it is `end`, then each new trailer will appear at the end of the +existing trailers. ++ +If it is `start`, then each new trailer will appear at the start, +instead of the end, of the existing trailers. ++ +If it is `after`, then each new trailer will appear just after the +last trailer with the same <token>. ++ +If it is `before`, then each new trailer will appear just before the +first trailer with the same <token>. + +trailer.ifexists:: + This option makes it possible to choose what action will be + performed when there is already at least one trailer with the + same <token> in the message. ++ +The valid values for this option are: `addIfDifferentNeighbor` (this +is the default), `addIfDifferent`, `add`, `replace` or `doNothing`. ++ +With `addIfDifferentNeighbor`, a new trailer will be added only if no +trailer with the same (<token>, <value>) pair is above or below the line +where the new trailer will be added. ++ +With `addIfDifferent`, a new trailer will be added only if no trailer +with the same (<token>, <value>) pair is already in the message. ++ +With `add`, a new trailer will be added, even if some trailers with +the same (<token>, <value>) pair are already in the message. ++ +With `replace`, an existing trailer with the same <token> will be +deleted and the new trailer will be added. The deleted trailer will be +the closest one (with the same <token>) to the place where the new one +will be added. ++ +With `doNothing`, nothing will be done; that is no new trailer will be +added if there is already one with the same <token> in the message. + +trailer.ifmissing:: + This option makes it possible to choose what action will be + performed when there is not yet any trailer with the same + <token> in the message. ++ +The valid values for this option are: `add` (this is the default) and +`doNothing`. ++ +With `add`, a new trailer will be added. ++ +With `doNothing`, nothing will be done. + +trailer.<token>.key:: + This `key` will be used instead of <token> in the trailer. At + the end of this key, a separator can appear and then some + space characters. By default the only valid separator is ':', + but this can be changed using the `trailer.separators` config + variable. ++ +If there is a separator, then the key will be used instead of both the +<token> and the default separator when adding the trailer. + +trailer.<token>.where:: + This option takes the same values as the 'trailer.where' + configuration variable and it overrides what is specified by + that option for trailers with the specified <token>. + +trailer.<token>.ifexists:: + This option takes the same values as the 'trailer.ifexists' + configuration variable and it overrides what is specified by + that option for trailers with the specified <token>. + +trailer.<token>.ifmissing:: + This option takes the same values as the 'trailer.ifmissing' + configuration variable and it overrides what is specified by + that option for trailers with the specified <token>. + +trailer.<token>.command:: + This option can be used to specify a shell command that will + be called to automatically add or modify a trailer with the + specified <token>. ++ +When this option is specified, the behavior is as if a special +'<token>=<value>' argument were added at the beginning of the command +line, where <value> is taken to be the standard output of the +specified command with any leading and trailing whitespace trimmed +off. ++ +If the command contains the `$ARG` string, this string will be +replaced with the <value> part of an existing trailer with the same +<token>, if any, before the command is launched. ++ +If some '<token>=<value>' arguments are also passed on the command +line, when a 'trailer.<token>.command' is configured, the command will +also be executed for each of these arguments. And the <value> part of +these arguments, if any, will be used to replace the `$ARG` string in +the command. + +EXAMPLES +-------- + +* Configure a 'sign' trailer with a 'Signed-off-by' key, and then + add two of these trailers to a message: ++ +------------ +$ git config trailer.sign.key "Signed-off-by" +$ cat msg.txt +subject + +message +$ cat msg.txt | git interpret-trailers --trailer 'sign: Alice <alice@example.com>' --trailer 'sign: Bob <bob@example.com>' +subject + +message + +Signed-off-by: Alice <alice@example.com> +Signed-off-by: Bob <bob@example.com> +------------ + +* Use the `--in-place` option to edit a message file in place: ++ +------------ +$ cat msg.txt +subject + +message + +Signed-off-by: Bob <bob@example.com> +$ git interpret-trailers --trailer 'Acked-by: Alice <alice@example.com>' --in-place msg.txt +$ cat msg.txt +subject + +message + +Signed-off-by: Bob <bob@example.com> +Acked-by: Alice <alice@example.com> +------------ + +* Extract the last commit as a patch, and add a 'Cc' and a + 'Reviewed-by' trailer to it: ++ +------------ +$ git format-patch -1 +0001-foo.patch +$ git interpret-trailers --trailer 'Cc: Alice <alice@example.com>' --trailer 'Reviewed-by: Bob <bob@example.com>' 0001-foo.patch >0001-bar.patch +------------ + +* Configure a 'sign' trailer with a command to automatically add a + 'Signed-off-by: ' with the author information only if there is no + 'Signed-off-by: ' already, and show how it works: ++ +------------ +$ git config trailer.sign.key "Signed-off-by: " +$ git config trailer.sign.ifmissing add +$ git config trailer.sign.ifexists doNothing +$ git config trailer.sign.command 'echo "$(git config user.name) <$(git config user.email)>"' +$ git interpret-trailers <<EOF +> EOF + +Signed-off-by: Bob <bob@example.com> +$ git interpret-trailers <<EOF +> Signed-off-by: Alice <alice@example.com> +> EOF + +Signed-off-by: Alice <alice@example.com> +------------ + +* Configure a 'fix' trailer with a key that contains a '#' and no + space after this character, and show how it works: ++ +------------ +$ git config trailer.separators ":#" +$ git config trailer.fix.key "Fix #" +$ echo "subject" | git interpret-trailers --trailer fix=42 +subject + +Fix #42 +------------ + +* Configure a 'see' trailer with a command to show the subject of a + commit that is related, and show how it works: ++ +------------ +$ git config trailer.see.key "See-also: " +$ git config trailer.see.ifExists "replace" +$ git config trailer.see.ifMissing "doNothing" +$ git config trailer.see.command "git log -1 --oneline --format=\"%h (%s)\" --abbrev-commit --abbrev=14 \$ARG" +$ git interpret-trailers <<EOF +> subject +> +> message +> +> see: HEAD~2 +> EOF +subject + +message + +See-also: fe3187489d69c4 (subject of related commit) +------------ + +* Configure a commit template with some trailers with empty values + (using sed to show and keep the trailing spaces at the end of the + trailers), then configure a commit-msg hook that uses + 'git interpret-trailers' to remove trailers with empty values and + to add a 'git-version' trailer: ++ +------------ +$ sed -e 's/ Z$/ /' >commit_template.txt <<EOF +> ***subject*** +> +> ***message*** +> +> Fixes: Z +> Cc: Z +> Reviewed-by: Z +> Signed-off-by: Z +> EOF +$ git config commit.template commit_template.txt +$ cat >.git/hooks/commit-msg <<EOF +> #!/bin/sh +> git interpret-trailers --trim-empty --trailer "git-version: \$(git describe)" "\$1" > "\$1.new" +> mv "\$1.new" "\$1" +> EOF +$ chmod +x .git/hooks/commit-msg +------------ + +SEE ALSO +-------- +linkgit:git-commit[1], linkgit:git-format-patch[1], linkgit:git-config[1] + +GIT +--- +Part of the linkgit:git[1] suite |