git-interpret-trailers(1) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | CONFIGURATION VARIABLES | EXAMPLES | SEE ALSO | GIT | COLOPHON

GIT-INTERPRET-TRAI(1)          Git Manual          GIT-INTERPRET-TRAI(1)

NAME         top

       git-interpret-trailers - Add or parse structured information in
       commit messages

SYNOPSIS         top

       git interpret-trailers [<options>] [(--trailer <token>[(=|:)<value>])...] [<file>...]
       git interpret-trailers [<options>] [--parse] [<file>...]

DESCRIPTION         top

       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) is 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 --- (followed
       by a space or the end of the line). Such three minus signs start
       the patch part of the message. See also --no-divider below.

       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         top

       --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. Possible values are
           after, before, end or start.

       --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. Possible actions
           are addIfDifferent, addIfDifferentNeighbor, add, replace and
           doNothing.

       --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. Possible
           actions are doNothing or add.

       --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.

       --no-divider
           Do not treat --- as the end of the commit message. Use this
           when you know your input contains just the commit message
           itself (and not an email or the output of git format-patch).

CONFIGURATION VARIABLES         top

       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         top

       •   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         top

       git-commit(1), git-format-patch(1), git-config(1)

GIT         top

       Part of the git(1) suite

COLOPHON         top

       This page is part of the git (Git distributed version control
       system) project.  Information about the project can be found at
       ⟨http://git-scm.com/⟩.  If you have a bug report for this manual
       page, see ⟨http://git-scm.com/community⟩.  This page was obtained
       from the project's upstream Git repository
       ⟨https://github.com/git/git.git⟩ on 2021-04-01.  (At that time,
       the date of the most recent commit that was found in the
       repository was 2021-03-30.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

Git 2.31.1.163.ga65ce7         04/01/2021          GIT-INTERPRET-TRAI(1)

Pages that refer to this page: git(1)git-diff-tree(1)git-for-each-ref(1)git-log(1)git-rev-list(1)git-shortlog(1)git-show(1)