三十五、git commit简介

翻译整理自： http://web.mit.edu/~mkgray/project/silk/root/afs/sipb/project/git/git-doc/git-commit.html

在用git来进行版本控制时，我需要执行git commit命令，将索引内容添加到仓库中。

示例1：

git commit -m "提交的描述信息"

如果我们这里不用-m参数的话，git将调到一个文本编译器（通常是vim）来让你输入提交的描述信息

可能一天下来，你对工作树中的许多文档都进行了更新（文档添加、修改、删除），但是我忘记了它们的名字，此时若将所做的全部更新添加到索引中，比较轻省的做法就是：

git commit -a -m "提交的描述信息"

git commit 命令的-a 选项可只将所有被修改或者已删除的且已经被git管理的文档提交倒仓库中。如果只是修改或者删除了已被Git 管理的文档，是没必要使用git add 命令的。

git add .命令除了能够判断出当前目录（包括其子目录）所有被修改或者已删除的文档，还能判断用户所添加的新文档，并将其信息追加到索引中。

另外，要注意的问题是，Git 不会主动记录你对文档进行的更新，除非你对它发号施令（比如通过git add命令）

语法

DESCRIPTION

Stores the current contents of the index in a new commit along with a log message from the user describing the changes.

The content to be added can be specified in several ways:

by using git add to incrementally "add" changes to the index before using the commit command (Note: even modified files must be "added");
by using git rm to remove files from the working tree and the index, again before using the commit command;
by listing files as arguments to the commit command, in which case the commit will ignore changes staged in the index, and instead record the current content of the listed files (which must already be known to git);
by using the -a switch with the commit command to automatically "add" changes from all known files (i.e. all files that are already listed in the index) and to automatically "rm" files in the index that have been removed from the working tree, and then perform the actual commit;
by using the --interactive or --patch switches with the commit command to decide one by one which files or hunks should be part of the commit, before finalizing the operation. See the `Interactive Mode` section of git-add(1) to learn how to operate these modes.

The --dry-run option can be used to obtain a summary of what is included by any of the above for the next commit by giving the same set of parameters (options and paths).

If you make a commit and then find a mistake immediately after that, you can recover from it with git reset.

OPTIONS

-a

--all

Tell the command to automatically stage files that have been modified and deleted, but new files you have not told git about are not affected.

-p

--patch

Use the interactive patch selection interface to chose which changes to commit. See git-add(1) for details.

-C <commit>

--reuse-message=<commit>

Take an existing commit object, and reuse the log message and the authorship information (including the timestamp) when creating the commit.

-c <commit>

--reedit-message=<commit>

Like -C, but with -c the editor is invoked, so that the user can further edit the commit message.

--fixup=<commit>

Construct a commit message for use with rebase --autosquash. The commit message will be the subject line from the specified commit with a prefix of "fixup! ". See git-rebase(1) for details.

--squash=<commit>

Construct a commit message for use with rebase --autosquash. The commit message subject line is taken from the specified commit with a prefix of "squash! ". Can be used with additional commit message options (-m/-c/-C/-F). See git-rebase(1) for details.

--reset-author

When used with -C/-c/--amend options, or when committing after a a conflicting cherry-pick, declare that the authorship of the resulting commit now belongs of the committer. This also renews the author timestamp.

--short

When doing a dry-run, give the output in the short-format. See git-status(1) for details. Implies --dry-run.

--porcelain

When doing a dry-run, give the output in a porcelain-ready format. See git-status(1) for details. Implies --dry-run.

-z

When showing short or porcelain status output, terminate entries in the status output with NUL, instead of LF. If no format is given, implies the --porcelain output format.

-F <file>

--file=<file>

Take the commit message from the given file. Use - to read the message from the standard input.

--author=<author>

Override the commit author. Specify an explicit author using the standard A U Thor <author@example.com> format. Otherwise <author> is assumed to be a pattern and is used to search for an existing commit by that author (i.e. rev-list --all -i --author=<author>); the commit author is then copied from the first such commit found.

--date=<date>

Override the author date used in the commit.

-m <msg>

--message=<msg>

Use the given <msg> as the commit message.

-t <file>

--template=<file>

Use the contents of the given file as the initial version of the commit message. The editor is invoked and you can make subsequent changes. If a message is specified using the -m or -F options, this option has no effect. This overrides the commit.template configuration variable.

-s

--signoff

Add Signed-off-by line by the committer at the end of the commit log message.

-n

--no-verify

This option bypasses the pre-commit and commit-msg hooks. See also githooks(5).

--allow-empty

Usually recording a commit that has the exact same tree as its sole parent commit is a mistake, and the command prevents you from making such a commit. This option bypasses the safety, and is primarily for use by foreign SCM interface scripts.

--allow-empty-message

Like --allow-empty this command is primarily for use by foreign SCM interface scripts. It allows you to create a commit with an empty commit message without using plumbing commands like git-commit-tree(1).

--cleanup=<mode>

This option sets how the commit message is cleaned up. The <mode> can be one of verbatim, whitespace, strip, and default. The default mode will strip leading and trailing empty lines and #commentary from the commit message only if the message is to be edited. Otherwise only whitespace removed. The verbatim mode does not change message at all, whitespace removes just leading/trailing whitespace lines and stripremoves both whitespace and commentary.

-e

--edit

The message taken from file with -F, command line with -m, and from file with -C are usually used as the commit log message unmodified. This option lets you further edit the message taken from these sources.

--amend

Used to amend the tip of the current branch. Prepare the tree object you would want to replace the latest commit as usual (this includes the usual -i/-o and explicit paths), and the commit log editor is seeded with the commit message from the tip of the current branch. The commit you create replaces the current tip?—?if it was a merge, it will have the parents of the current tip as parents?—?so the current top commit is discarded.

It is a rough equivalent for:

        $ git reset --soft HEAD^         $ ... do something else to come up with the right tree ...         $ git commit -c ORIG_HEAD

but can be used to amend a merge commit.

You should understand the implications of rewriting history if you amend a commit that has already been published. (See the "RECOVERING FROM UPSTREAM REBASE" section in git-rebase(1).)

-i

--include

Before making a commit out of staged contents so far, stage the contents of paths given on the command line as well. This is usually not what you want unless you are concluding a conflicted merge.

-o

--only

Make a commit only from the paths specified on the command line, disregarding any contents that have been staged so far. This is the default mode of operation of git commit if any paths are given on the command line, in which case this option can be omitted. If this option is specified together with --amend, then no paths need to be specified, which can be used to amend the last commit without committing changes that have already been staged.

-u[<mode>]

--untracked-files[=<mode>]

Show untracked files.

The mode parameter is optional (defaults to all), and is used to specify the handling of untracked files; when -u is not used, the default is normal, i.e. show untracked files and directories.

The possible options are:

no - Show no untracked files
normal - Shows untracked files and directories
all - Also shows individual files in untracked directories.

The default can be changed using the status.showUntrackedFiles configuration variable documented in git-config(1).

-v

--verbose

Show unified diff between the HEAD commit and what would be committed at the bottom of the commit message template. Note that this diff output doesn’t have its lines prefixed with #.

-q

--quiet

Suppress commit summary message.

--dry-run

Do not create a commit, but show a list of paths that are to be committed, paths with local changes that will be left uncommitted and paths that are untracked.

--status

Include the output of git-status(1) in the commit message template when using an editor to prepare the commit message. Defaults to on, but can be used to override configuration variable commit.status.

--no-status

Do not include the output of git-status(1) in the commit message template when using an editor to prepare the default commit message.

--

Do not interpret any more arguments as options.

<file>…

When files are given on the command line, the command commits the contents of the named files, without recording the changes already staged. The contents of these files are also staged for the next commit on top of what have been staged before.

DATE FORMATS

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

Git internal format

It is <unix timestamp> <timezone offset>, where <unix timestamp> is the number of seconds since the UNIX epoch. <timezone 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`.

EXAMPLES

When recording your own work, the contents of modified files in your working tree are temporarily stored to a staging area called the "index" with git add. A file can be reverted back, only in the index but not in the working tree, to that of the last commit with git reset HEAD -- <file>, which effectively reverts git add and prevents the changes to this file from participating in the next commit. After building the state to be committed incrementally with these commands, git commit (without any pathname parameter) is used to record what has been staged so far. This is the most basic form of the command. An example:

$ edit hello.c $ git rm goodbye.c $ git add hello.c $ git commit

Instead of staging files after each individual change, you can tell git commit to notice the changes to the files whose contents are tracked in your working tree and do corresponding git add and git rm for you. That is, this example does the same as the earlier example if there is no other change in your working tree:

$ edit hello.c $ rm goodbye.c $ git commit -a

The command git commit -a first looks at your working tree, notices that you have modified hello.c and removed goodbye.c, and performs necessarygit add and git rm for you.

After staging changes to many files, you can alter the order the changes are recorded in, by giving pathnames to git commit. When pathnames are given, the command makes a commit that only records the changes made to the named paths:

$ edit hello.c hello.h $ git add hello.c hello.h $ edit Makefile $ git commit Makefile

This makes a commit that records the modification to Makefile. The changes staged for hello.c and hello.h are not included in the resulting commit. However, their changes are not lost?—?they are still staged and merely held back. After the above sequence, if you do:

$ git commit

this second commit would record the changes to hello.c and hello.h as expected.

After a merge (initiated by git merge or git pull) stops because of conflicts, cleanly merged paths are already staged to be committed for you, and paths that conflicted are left in unmerged state. You would have to first check which paths are conflicting with git status and after fixing them manually in your working tree, you would stage the result as usual with git add:

$ git status | grep unmerged unmerged: hello.c $ edit hello.c $ git add hello.c

After resolving conflicts and staging the result, git ls-files -u would stop mentioning the conflicted path. When you are done, run git commit to finally record the merge:

$ git commit

As with the case to record your own changes, you can use -a option to save typing. One difference is that during a merge resolution, you cannot use git commit with pathnames to alter the order the changes are committed, because the merge should be recorded as a single commit. In fact, the command refuses to run when given pathnames (but see -i option).

DISCUSSION

Though not required, it’s a good idea to begin the commit message with a single short (less than 50 character) line summarizing the change, followed by a blank line and then a more thorough description. Tools that turn commits into email, for example, use the first line on the Subject: line and the rest of the commit in the body.

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.

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.
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.

ENVIRONMENT AND CONFIGURATION VARIABLES

The editor used to edit the commit log message will be chosen from the GIT_EDITOR environment variable, the core.editor configuration variable, the VISUAL environment variable, or the EDITOR environment variable (in that order). See git-var(1) for details.

HOOKS

This command can run commit-msg, prepare-commit-msg, pre-commit, and post-commit hooks. See githooks(5) for more information.