我们把在Git里常用的一些名词做了解释列在这里。这些名词(terms)全部来自Git Glossary。
alternate object database
Via the alternates mechanism, a repository
can inherit part of its object database from another object database, which is called "alternate".
bare repository
A bare repository is normally an appropriately
named directory with a `.git` suffix that does not have a locally checked-out copy of any of the files under revision control. That is, all of the `git` administrative and control files that would normally be present in the hidden `.git` sub-directory are directly present in the `repository.git` directory instead, and no other files are present and checked out. Usually publishers of public repositories make bare repositories available.
祼仓库
A bare repository is normally an appropriately named directory with a `.git` suffix that does not have a locally checked-out copy of any of the files under revision control. That is, all of the `git` administrative and control files that would normally be present in the hidden `.git` sub-directory are directly present in the `repository.git` directory instead, and no other files are present and checked out. Usually publishers of public repositories make bare repositories available.
blob object（二进制对象）
没有类型的数据对象。例如：一个文件的内容。
branch
A "branch" is an active line of development. The most recent
commit on a branch is referred to as the tip of that branch. The tip of the branch is referenced by a branch head, which moves forward as additional development is done on the branch. A single git repository can track an arbitrary number of branches, but your working tree is associated with just one of them (the "current" or "checked out" branch), and HEAD points to that branch.
分支
一个“分支”是开发过程中的(active line)。。。。
cache（缓存）
索引(index)的旧称(obsolete).
chain（链表）
一串对象，其中每个对象都有指向其后继对象的引用(reference to its successor)。例如：一个提交(commit)的后继对象就是它的父对象。
changeset（修改集）
BitKeeper/cvsps 里对于提交(commit)的说法。但是 git 只存储快照(states)，不存储修改；所以这个词用在 git 里有点不大合适。
checkout（签出）
用对象仓库(object database)里的一个树对象(tree object)更新当前整个工作树(worktree)，或者一个二进制对象(blob object)更新工作树的一部分；如果工作树指向了一个新的分支，那么就会更新索引(index)和HEAD。
cherry-picking
In SCM jargon, "cherry pick" means to choose a subset of
changes out of a series of changes (typically commits) and record them as a new series of changes on top of a different codebase. In GIT, this is performed by the "git cherry-pick" command to extract the change introduced by an existing commit and to record it based on the tip of the current branch as a new commit.
cherry-picking
在SCM的行话里，“cherry pick“ 意味着从一系列的修改中选出一部分修改(通常是提交)，应用到当前代码中。()
clean（干净）
如果一个工作树(working tree)中所有的修改都已提交到了当前分支里(current head)，那么就说它是干净的(clean)，反之它就是脏的(dirty)。
commit
As a verb: The action of storing a new snapshot of the project's
state in the git history, by creating a new commit representing the current state of the index and advancing HEAD to point at the new commit.
commit（提交）
作为名词：指向git历史的某一点的指针；整个项目的历史就由一组相互关联的提交组成的。提交(commit)在其它版本控制系统中也做"revision"或"version"。同时做为提交对象(commit object)的缩写。
作为动词：创建一新的提交(commit)来表示当前索引(index)的状态的行为，把 HEAD 指向新创建的提交，这一系列把项目在某一时间上的快照(snapshot)保存在git历史中的操作。
提交对象
一个关于特定版本信息(particular revision)的对象。包括父对象名，提交者，作者，日期和存储了此版本内容的树对象名(tree object)。
core git
Git的基本数据结构和工具，它只对外提供简单的代码管理工具。
DAG
有向无环图。众多提交对象(commit objects)组成了一个有向无环图；因为它们都有直接父对象(direct parent)，且没有一条提交线路(chain)的起点和终点都是同一个对象。
dangling object（悬空对象）
一个甚至从其它不可达对象也不可达的对象(unreachable object)；仓库里的一个悬空对象没有任何引用(reference)或是对象(object)引用它。
detached HEAD（分离的HEAD）
通常情况下HEAD里是存放当前分支的名字。然而 git 有时也允许你签出任意的一个提交(commit)，而不一定是某分支的最近的提交(the tip of any particular branch)；在这种情况下，HEAD就是处于分离的状态(detached)。 译者注：这时
.git/HEAD中存储的就是签出的提交的SHA串值。
dircache
请参见索引(index)。
directory（目录）
执行"ls"命令所显示的结果 :-)
dirty（脏）
一个工作树里有没有提交到当前分支里修改，那么我就说它是脏的(dirty)。
ent
某些人给树名(tree-ish)起的另外一个别名，这里
http://en.wikipedia.org/wiki/Ent_(Middle-earth)有更详细的解释。最好不要使用这个名词，以免让大家糊涂。
evil merge（坏的合并）
如果一次合并引入一些不存在于任何父对象(parent)中的修改，那么就称它是一个坏的合并(evil merge)。
fast forward
A fast-forward is a special type of merge where you have a
revision and you are "merging" another branch's changes that happen to be a descendant of what you have. In such these cases, you do not make a new merge commit but instead just update to his revision. This will happen frequently on a tracking branch of a remote repository.
快速向前
“fast-forward”是一种特殊的合并,()。 在这种情况下，并没有创建一个合并提交(merge commit)，只是更新了版本信息。 当本地分支是远端仓库(remote repository)的跟踪分支时，这种情况经常出现。
fetch（抓取）
抓取一个分支意味着：得到远端仓库(remote repository)分支的head ref，找出本地对象数据库所缺少的对象，并把它们下载下来。你可以参考一下 git fetch。
file system（文件系统）
Linus Torvalds 最初设计 git 时，是把它设计成一个在用户空间(user space)运行的文件系统；也就是一个用来保存文件和目录的 infrastructure，这样就保证了git的速度和效率。
git archive
对玩架构的人来说，这就是仓库的同义词。
grafts
Grafts enables two otherwise different lines of development to be joined
together by recording fake ancestry information for commits. This way you can make git pretend the set of parents a commit has is different from what was recorded when the commit was created. Configured via the `.git/info/grafts` file.
hash（哈希）
在git里，这就是对象名(object name)的同义词。
head
指向一个分支最新提交的命名引用(named reference)。除非使用了打包引用(packed refs)，heads 一般存储在
$GIT_DIR/refs/heads/。 参见: git pack-refs
HEAD
当前分支。详细的讲是：你的工作树(working tree)通是从HEAD所指向的tree所派生的来的。 HEAD 必须是指向一个你仓库里的head，除非你使用分离的HEAD(detached HEAD)。
head ref
head的同义词。
hook
During the normal execution of several git commands, call-outs are made
to optional scripts that allow a developer to add functionality or checking. Typically, the hooks allow for a command to be pre-verified and potentially aborted, and allow for a post-notification after the operation is done. The hook scripts are found in the `$GIT_DIR/hooks/` directory, and are enabled by simply removing the `.sample` suffix from the filename. In earlier versions of git you had to make them executable.
钩子
在一些git命令的执行过程中, () 允许开发人员调用特别的脚本来添加功能或检查。
()
Typically，钩子允许对一个命令做pre-verified并且可以中止此命令的运行；同时也可在这个命令执行完后做后继的通知工作。这些钩子脚本放在`$GIT_DIR/hooks/`目录下，你只要把这它们文件名的`.sample`后缀删掉就可以了。不过在git的早期版本，你需要为这些钩子脚本加上可执行属性。
index
A collection of files with stat information, whose contents are stored
as objects. The index is a stored version of your working tree. Truth be told, it can also contain a second, and even a third version of a working tree, which are used when merging.
索引
描述项目状态信息的文件，。索引里保存的是你的工作树的版本记录。()
index entry
The information regarding a particular file, stored in the
index. An index entry can be unmerged, if a merge was started, but not yet finished (i.e. if the index contains multiple versions of that file).
索引条目
主分支 (master)
默认的开发分支。当你创建了一个git仓库，一个叫"master"的分支就被创建并且成为当前活动分支(active branch)。在多数情况下，这个分支里就包含有本地的开发内容。
merge
As a verb: To bring the contents of another
branch (possibly from an external repository) into the current branch. In the case where the merged-in branch is from a different repository, this is done by first fetching the remote branch and then merging the result into the current branch. This combination of fetch and merge operations is called a pull. Merging is performed by an automatic process that identifies changes made since the branches diverged, and then applies all those changes together. In cases where changes conflict, manual intervention may be required to complete the merge.
merge（合并）
作为动词：把另外一个分支(也许来自另外一个仓库)的内容合并进当前的分支。()
作为名词：除非合并的结果是 fast forward；那么一次成功的合并会创建一个新的提交(commit)来表示这次合并，并且把合并了的分支做为此提交(commit)的父对象。这个提交(commit)也可以表述为“合并提交”(merge commit)，或者就是"合并"(merge 名词)。
object（对象）
Git的存储单位，它以对象内容的SHA1值做为唯一对象名；因此对象内容是不能被修改的。
object database（对象仓库）
用来存储一组对象(objects)，每个对象通过对象名来区别。对象(objects)通常保存在
$GIT_DIR/objects/。
object identifier（对象标识符）
对象名(object name)的同义词。
object name（对象名）
一个对象的唯一标识符(unique identifier)。它是使用SHA1算法(Secure Hash Algorithm 1)给对象内容进行哈希(hash)计算，产生的一个40个字节长的16进制编码的串。
object type（对象类型）
Git有4种对象类型：提交(commit)，树(tree)，标签(tag)和二进制块(blob)。
octopus（章鱼）
一次多于两个分支的合并(merge)。也用来表示聪明的肉食动物。
origin
默认的上游仓库(upstream repository)。每个项目至少有一个它追踪(track)的上游(upstream)仓库，通常情况 origin 就是用来表示它。你可以用 ”｀git branch -r`“ 命令查看上游仓库(upstream repository)里所有的分支，再用 origin/name-of-upstream-branch 的名字来抓取(fetch)远程追踪分支里的内容。
pack（包）
一个文件，里面有一些压缩了的对象。(用以节约空间或是提高传输效率)。
pack index（包索引）
包(pack)里的一些标识符和其它相关信息，用于帮助git快速的访问包(pack)里面的对象。
parent
A commit object contains a (possibly empty) list
of the logical predecessor(s) in the line of development, i.e. its parents.
父对象
一个提交对象(commit object)，()。
pickaxe
The term pickaxe refers to an option to the diffcore
routines that help select changes that add or delete a given text string. With the `--pickaxe-all` option, it can be used to view the full changeset that introduced or removed, say, a particular line of text. See git diff.
plumbing
core git的别名(cute name)。
porcelain
Cute name for programs and program suites depending on
core git, presenting a high level access to core git. Porcelains expose more of a SCM interface than the plumbing.
pull（拉）
拉(pull)一个分支意味着，把它抓取(fetch)下来并合并(merge)进当前的分支。可以参考 git pull.
push
Pushing a branch means to get the branch's
head ref from a remote repository, find out if it is a direct ancestor to the branch's local head ref, and in that case, putting all objects, which are reachable from the local head ref, and which are missing from the remote repository, into the remote object database, and updating the remote head ref. If the remote head is not an ancestor to the local head, the push fails.
推
()
reachable
All of the ancestors of a given commit are said to be
"reachable" from that commit. More generally, one object is reachable from another if we can reach the one from the other by a chain that follows tags to whatever they tag, commits to their parents or trees, and trees to the trees or blobs that they contain.可达的
rebase
重新应用(reapply)当前点(branch)和另一个点(base)间的修改；并且根据rebase的结果重置当前分支的 head。 译者注：这个功能可以修改历史提交。
ref（引用）
一个40字节长的SHA1串或是表示某个对象的名字。它们可能存储在
$GIT_DIR/refs/。
reflog
reflog用以表示本地的ref的历史记录。从另外一角度也可以说，它能行告诉你这个仓库最近的第3个版本(revision)是什么，还可以告诉你昨天晚上9点14分时你是在这个仓库的哪个分支下工作。可以参见:git reflog。
refspec
"refspec"用于描述在抓取和推的过程中，远程ref和本地ref之间的映射关系。它用冒号连接：:，前面也可以加一个加号：“+“。 例如：
git fetch $URL refs/heads/master:refs/heads/origin意味着：从$URL抓取主分支的 head 并把它保存到本地的origin分支的head中。git push $URL refs/heads/master:refs/heads/to-upstream意味着：把我本地主分支 head 推到$URL上的 to-upstream分支里。具体可以参见： git push。
repository
A collection of refs together with an
object database containing all objects which are reachable from the refs, possibly accompanied by meta data from one or more porcelains. A repository can share an object database with other repositories via alternates mechanism.
resolve
在自动合并失败后，手工修复合并冲突的行为。
revision（版本）
对象仓库(object database)保存的文件和目录在某一特定时间点的状态；它会被一个提交对象(commit object)所引用。
rewind
丢弃某一部分开发成果。例如：把head 指向早期的版本。
SCM
源代码管理工作。
SHA1
对象名(object name)的同义词。
shallow repository
A shallow repository has an incomplete
history some of whose commits have parents cauterized away (in other words, git is told to pretend that these commits do not have the parents, even though they are recorded in the commit object). This is sometimes useful when you are interested only in the recent history of a project even though the real history recorded in the upstream is much larger. A shallow repository is created by giving the `--depth` option to git clone, and its history can be later deepened with git fetch.
symref
Symbolic reference: instead of containing the SHA1
id itself, it is of the format 'ref: refs/some/thing' and when referenced, it recursively dereferences to this reference. 'HEAD' is a prime example of a symref. Symbolic references are manipulated with the git symbolic-ref command.
tag（标签）
一个ref指向一个标签或提交对象。与 head 相反，标签并不会在一次提交操作后改变。标签(不是标签对象)存储在
$GIT_DIR/refs/tags/。 一个标签通常是用来标识提交家族链(commit ancerstry chain)里的某一点。
tag object（标签对象）
一个含有指向其它对象的引用(ref)的对象，对象里包括注释消息。如果它里面可以含有一个PGP签名，那么就称为一个“签名标签对象”(signed tag object)。
topic branch
A regular git branch that is used by a developer to
identify a conceptual line of development. Since branches are very easy and inexpensive, it is often desirable to have several small branches that each contain very well defined concepts or small incremental yet related changes.
tracking branch
A regular git branch that is used to follow changes from
another repository. A tracking branch should not contain direct modifications or have local commits made to it. A tracking branch can usually be identified as the right-hand-side ref in a Pull:
refspec.
追踪分支
一个用以追踪(follow)另外一个仓库的修改的git分支。()
tree（树）
可以是一个工作树(working tree)，也可以是一个树对象(tree object)。
tree object（树对象）
包含有一串(list)文件名和模式(mode)，并且指向与之相关的二进制对象(blob object)和树对象(tree object)。一个树(tree)等价于一个目录。
tree-ish（树名）
一个指向的提交对象(commit object)，树对象(tree object)或是标签对象(tag object)的引用(ref)。
unmerged index（未合并索引）
一个索引中包含有未合并的索引条目(index entries)。
unreachable object（不可达对象）
从任何一个分支、标签或是其它引用(reference)做为起点都无法到达的一个对象。
working tree（工作树）
签出(checkout)用于编辑的文件目录树。 工作树一般等价于 HEAD 加本地没有提交的修改。