# git-commit-tree(1) Manual Page

## NAME

git-commit-tree - Create a new commit object

## SYNOPSIS

    git commit-tree <tree> [(-p <parent>)…] < changelog
    git commit-tree [(-p <parent>)…] [-S[<keyid>]] [(-m <message>)…]
                      [(-F <file>)…] <tree>

## DESCRIPTION

This is usually not what an end user wants to run directly. See git-commit(1) instead.

Creates a new commit object based on the provided tree object and emits the new commit object id on stdout. The log message is read from the standard input, unless `-m` or `-F` options are given.

A commit object may have any number of parents. With exactly one parent, it is an ordinary commit. Having more than one parent makes the commit a merge between several lines of history. Initial (root) commits have no parents.

While a tree represents a particular directory state of a working directory, a commit represents that state in "time", and explains how to get there.

Normally a commit would identify a new "HEAD" state, and while Git doesn’t care where you save the note about that state, in practice we tend to just write the result to the file that is pointed at by `.git/HEAD`, so that we can always see what the last committed state was.

## OPTIONS

<tree>

  An existing tree object

-p <parent>

  Each -p indicates the id of a parent commit object.

-m <message>

  A paragraph in the commit log message. This can be given more than once and each <message> becomes its own paragraph.

-F <file>

  Read the commit log message from the given file. Use `-` to read from the standard input.

-S[<keyid>]

  GPG-sign commit.

## Commit Information

A commit encapsulates:

- all parent object ids

- author name, email and date

- committer name and email and the commit time.

While parent object ids are provided on the command line, author and committer information is taken from the following environment variables, if set:

    GIT_AUTHOR_NAME
    GIT_AUTHOR_EMAIL
    GIT_AUTHOR_DATE
    GIT_COMMITTER_NAME
    GIT_COMMITTER_EMAIL
    GIT_COMMITTER_DATE

(nb "<", ">" and "\n"s are stripped)

In case (some of) these environment variables are not set, the information is taken from the configuration items user.name and user.email, or, if not present, the environment variable EMAIL, or, if that is not set, system user name and the hostname used for outgoing mail (taken from `/etc/mailname` and falling back to the fully qualified hostname when that file does not exist).

A commit comment is read from stdin. If a changelog entry is not provided via "<" redirection, git commit-tree will just wait for one to be entered and terminated with ^D.

## DATE FORMATS

The GIT_AUTHOR_DATE, GIT_COMMITTER_DATE environment variables support the following date formats:

Git internal format

  It is `<unix timestamp> <time zone offset>`, where `<unix timestamp>` is the number of seconds since the UNIX epoch. `<time zone offset>` is a positive or negative offset from UTC. For example CET (which is 2 hours ahead UTC) is `+0200`.

RFC 2822

  The standard email format as described by RFC 2822, for example `Thu, 07 Apr 2005 22:13:13 +0200`.

ISO 8601

  Time and date specified by the ISO 8601 standard, for example `2005-04-07T22:13:13`. The parser accepts a space instead of the `T` character as well.

  Note | In addition, the date part is accepted in the following formats: `YYYY.MM.DD`, `MM/DD/YYYY` and `DD.MM.YYYY`.

## Discussion

At the core level, Git is character encoding agnostic.

- The pathnames recorded in the index and in the tree objects are treated as uninterpreted sequences of non-NUL bytes. What readdir(2) returns are what are recorded and compared with the data Git keeps track of, which in turn are expected to be what lstat(2) and creat(2) accepts. There is no such thing as pathname encoding translation.

- The contents of the blob objects are uninterpreted sequences of bytes. There is no encoding translation at the core level.

- The commit log messages are uninterpreted sequences of non-NUL bytes.

Although we encourage that the commit log messages are encoded in UTF-8, both the core and Git Porcelain are designed not to force UTF-8 on projects. If all participants of a particular project find it more convenient to use legacy encodings, Git does not forbid it. However, there are a few things to keep in mind.

1. git commit and git commit-tree issues a warning if the commit log message given to it does not look like a valid UTF-8 string, unless you explicitly say your project uses a legacy encoding. The way to say this is to have i18n.commitencoding in `.git/config` file, like this:

       [i18n]
               commitencoding = ISO-8859-1

   Commit objects created with the above setting record the value of `i18n.commitencoding` in its `encoding` header. This is to help other people who look at them later. Lack of this header implies that the commit log message is encoded in UTF-8.

2. git log, git show, git blame and friends look at the `encoding` header of a commit object, and try to re-code the log message into UTF-8 unless otherwise specified. You can specify the desired output encoding with `i18n.logoutputencoding` in `.git/config` file, like this:

       [i18n]
               logoutputencoding = ISO-8859-1

   If you do not have this configuration variable, the value of `i18n.commitencoding` is used instead.

Note that we deliberately chose not to re-code the commit log message when a commit is made to force UTF-8 at the commit object level, because re-coding to UTF-8 is not necessarily a reversible operation.

## FILES

/etc/mailname

## SEE ALSO

git-write-tree(1)

## GIT

Part of the git(1) suite