1GITGLOSSARY(7) Git Manual GITGLOSSARY(7)
2
6 gitglossary - A GIT Glossary
7
9 *
10
12 alternate object database
13 Via the alternates mechanism, a repository can inherit part of its
14 object database from another object database, which is called
15 "alternate".
16 bare repository
18 A bare repository is normally an appropriately named directory with
19 a .git suffix that does not have a locally checked-out copy of any
20 of the files under revision control. That is, all of the git
21 administrative and control files that would normally be present in
22 the hidden .git sub-directory are directly present in the
23 repository.git directory instead, and no other files are present
24 and checked out. Usually publishers of public repositories make
25 bare repositories available.
26 blob object
28 Untyped object, e.g. the contents of a file.
29 branch
31 A "branch" is an active line of development. The most recent commit
32 on a branch is referred to as the tip of that branch. The tip of
33 the branch is referenced by a branch head, which moves forward as
34 additional development is done on the branch. A single git
35 repository can track an arbitrary number of branches, but your
36 working tree is associated with just one of them (the "current" or
37 "checked out" branch), and HEAD points to that branch.
38 cache
40 Obsolete for: index.
41 chain
43 A list of objects, where each object in the list contains a
44 reference to its successor (for example, the successor of a commit
45 could be one of its parents).
46 changeset
48 BitKeeper/cvsps speak for "commit". Since git does not store
49 changes, but states, it really does not make sense to use the term
50 "changesets" with git.
51 checkout
53 The action of updating all or part of the working tree with a tree
54 object or blob from the object database, and updating the index and
55 HEAD if the whole working tree has been pointed at a new branch.
56 cherry-picking
58 In SCM jargon, "cherry pick" means to choose a subset of changes
59 out of a series of changes (typically commits) and record them as a
60 new series of changes on top of a different codebase. In GIT, this
61 is performed by the "git cherry-pick" command to extract the change
62 introduced by an existing commit and to record it based on the tip
63 of the current branch as a new commit.
64 clean
66 A working tree is clean, if it corresponds to the revision
67 referenced by the current head. Also see "dirty".
68 commit
70 As a noun: A single point in the git history; the entire history of
71 a project is represented as a set of interrelated commits. The word
72 "commit" is often used by git in the same places other revision
73 control systems use the words "revision" or "version". Also used as
74 a short hand for commit object.
75 As a verb: The action of storing a new snapshot of the project’s
77 state in the git history, by creating a new commit representing the
78 current state of the index and advancing HEAD to point at the new
79 commit.
80 commit object
82 An object which contains the information about a particular
83 revision, such as parents, committer, author, date and the tree
84 object which corresponds to the top directory of the stored
85 revision.
86 core git
88 Fundamental data structures and utilities of git. Exposes only
89 limited source code management tools.
90 DAG
92 Directed acyclic graph. The commit objects form a directed acyclic
93 graph, because they have parents (directed), and the graph of
94 commit objects is acyclic (there is no chain which begins and ends
95 with the same object).
96 dangling object
98 An unreachable object which is not reachable even from other
99 unreachable objects; a dangling object has no references to it from
100 any reference or object in the repository.
101 detached HEAD
103 Normally the HEAD stores the name of a branch. However, git also
104 allows you to check out an arbitrary commit that isn’t necessarily
105 the tip of any particular branch. In this case HEAD is said to be
106 "detached".
107 dircache
109 You are waaaaay behind. See index.
110 directory
112 The list you get with "ls" :-)
113 dirty
115 A working tree is said to be "dirty" if it contains modifications
116 which have not been committed to the current branch.
117 ent
119 Favorite synonym to "tree-ish" by some total geeks. See
120 http://en.wikipedia.org/wiki/Ent_(Middle-earth) for an in-depth
121 explanation. Avoid this term, not to confuse people.
122 evil merge
124 An evil merge is a merge that introduces changes that do not appear
125 in any parent.
126 fast-forward
128 A fast-forward is a special type of merge where you have a revision
129 and you are "merging" another branch´s changes that happen to be a
130 descendant of what you have. In such these cases, you do not make a
131 new merge commit but instead just update to his revision. This will
132 happen frequently on a tracking branch of a remote repository.
133 fetch
135 Fetching a branch means to get the branch’s head ref from a remote
136 repository, to find out which objects are missing from the local
137 object database, and to get them, too. See also git-fetch(1).
138 file system
140 Linus Torvalds originally designed git to be a user space file
141 system, i.e. the infrastructure to hold files and directories. That
142 ensured the efficiency and speed of git.
143 git archive
145 Synonym for repository (for arch people).
146 grafts
148 Grafts enables two otherwise different lines of development to be
149 joined together by recording fake ancestry information for commits.
150 This way you can make git pretend the set of parents a commit has
151 is different from what was recorded when the commit was created.
152 Configured via the .git/info/grafts file.
153 hash
155 In git’s context, synonym to object name.
156 head
158 A named reference to the commit at the tip of a branch. Heads are
159 stored in $GIT_DIR/refs/heads/, except when using packed refs. (See
160 git-pack-refs(1).)
161 HEAD
163 The current branch. In more detail: Your working tree is normally
164 derived from the state of the tree referred to by HEAD. HEAD is a
165 reference to one of the heads in your repository, except when using
166 a detached HEAD, in which case it may reference an arbitrary
167 commit.
168 head ref
170 A synonym for head.
171 hook
173 During the normal execution of several git commands, call-outs are
174 made to optional scripts that allow a developer to add
175 functionality or checking. Typically, the hooks allow for a command
176 to be pre-verified and potentially aborted, and allow for a
177 post-notification after the operation is done. The hook scripts are
178 found in the $GIT_DIR/hooks/ directory, and are enabled by simply
179 removing the .sample suffix from the filename. In earlier versions
180 of git you had to make them executable.
181 index
183 A collection of files with stat information, whose contents are
184 stored as objects. The index is a stored version of your working
185 tree. Truth be told, it can also contain a second, and even a third
186 version of a working tree, which are used when merging.
187 index entry
189 The information regarding a particular file, stored in the index.
190 An index entry can be unmerged, if a merge was started, but not yet
191 finished (i.e. if the index contains multiple versions of that
192 file).
193 master
195 The default development branch. Whenever you create a git
196 repository, a branch named "master" is created, and becomes the
197 active branch. In most cases, this contains the local development,
198 though that is purely by convention and is not required.
199 merge
201 As a verb: To bring the contents of another branch (possibly from
202 an external repository) into the current branch. In the case where
203 the merged-in branch is from a different repository, this is done
204 by first fetching the remote branch and then merging the result
205 into the current branch. This combination of fetch and merge
206 operations is called a pull. Merging is performed by an automatic
207 process that identifies changes made since the branches diverged,
208 and then applies all those changes together. In cases where changes
209 conflict, manual intervention may be required to complete the
210 merge.
211 As a noun: unless it is a fast-forward, a successful merge results
213 in the creation of a new commit representing the result of the
214 merge, and having as parents the tips of the merged branches. This
215 commit is referred to as a "merge commit", or sometimes just a
216 "merge".
217 object
219 The unit of storage in git. It is uniquely identified by the SHA1
220 of its contents. Consequently, an object can not be changed.
221 object database
223 Stores a set of "objects", and an individual object is identified
224 by its object name. The objects usually live in $GIT_DIR/objects/.
225 object identifier
227 Synonym for object name.
228 object name
230 The unique identifier of an object. The hash of the object’s
231 contents using the Secure Hash Algorithm 1 and usually represented
232 by the 40 character hexadecimal encoding of the hash of the object.
233 object type
235 One of the identifiers "commit", "tree", "tag" or "blob" describing
236 the type of an object.
237 octopus
239 To merge more than two branches. Also denotes an intelligent
240 predator.
241 origin
243 The default upstream repository. Most projects have at least one
244 upstream project which they track. By default origin is used for
245 that purpose. New upstream updates will be fetched into remote
246 tracking branches named origin/name-of-upstream-branch, which you
247 can see using git branch -r.
248 pack
250 A set of objects which have been compressed into one file (to save
251 space or to transmit them efficiently).
252 pack index
254 The list of identifiers, and other information, of the objects in a
255 pack, to assist in efficiently accessing the contents of a pack.
256 parent
258 A commit object contains a (possibly empty) list of the logical
259 predecessor(s) in the line of development, i.e. its parents.
260 pickaxe
262 The term pickaxe refers to an option to the diffcore routines that
263 help select changes that add or delete a given text string. With
264 the --pickaxe-all option, it can be used to view the full changeset
265 that introduced or removed, say, a particular line of text. See
266 git-diff(1).
267 plumbing
269 Cute name for core git.
270 porcelain
272 Cute name for programs and program suites depending on core git,
273 presenting a high level access to core git. Porcelains expose more
274 of a SCM interface than the plumbing.
275 pull
277 Pulling a branch means to fetch it and merge it. See also git-
278 pull(1).
279 push
281 Pushing a branch means to get the branch’s head ref from a remote
282 repository, find out if it is a direct ancestor to the branch’s
283 local head ref, and in that case, putting all objects, which are
284 reachable from the local head ref, and which are missing from the
285 remote repository, into the remote object database, and updating
286 the remote head ref. If the remote head is not an ancestor to the
287 local head, the push fails.
288 reachable
290 All of the ancestors of a given commit are said to be "reachable"
291 from that commit. More generally, one object is reachable from
292 another if we can reach the one from the other by a chain that
293 follows tags to whatever they tag, commits to their parents or
294 trees, and trees to the trees or blobs that they contain.
295 rebase
297 To reapply a series of changes from a branch to a different base,
298 and reset the head of that branch to the result.
299 ref
301 A 40-byte hex representation of a SHA1 or a name that denotes a
302 particular object. These may be stored in $GIT_DIR/refs/.
303 reflog
305 A reflog shows the local "history" of a ref. In other words, it can
306 tell you what the 3rd last revision in this repository was, and
307 what was the current state in this repository, yesterday 9:14pm.
308 See git-reflog(1) for details.
309 refspec
311 A "refspec" is used by fetch and push to describe the mapping
312 between remote ref and local ref. They are combined with a colon in
313 the format <src>:<dst>, preceded by an optional plus sign, +. For
314 example: git fetch $URL refs/heads/master:refs/heads/origin means
315 "grab the master branch head from the $URL and store it as my
316 origin branch head". And git push $URL
317 refs/heads/master:refs/heads/to-upstream means "publish my master
318 branch head as to-upstream branch at $URL". See also git-push(1).
319 repository
321 A collection of refs together with an object database containing
322 all objects which are reachable from the refs, possibly accompanied
323 by meta data from one or more porcelains. A repository can share an
324 object database with other repositories via alternates mechanism.
325 resolve
327 The action of fixing up manually what a failed automatic merge left
328 behind.
329 revision
331 A particular state of files and directories which was stored in the
332 object database. It is referenced by a commit object.
333 rewind
335 To throw away part of the development, i.e. to assign the head to
336 an earlier revision.
337 SCM
339 Source code management (tool).
340 SHA1
342 Synonym for object name.
343 shallow repository
345 A shallow repository has an incomplete history some of whose
346 commits have parents cauterized away (in other words, git is told
347 to pretend that these commits do not have the parents, even though
348 they are recorded in the commit object). This is sometimes useful
349 when you are interested only in the recent history of a project
350 even though the real history recorded in the upstream is much
351 larger. A shallow repository is created by giving the --depth
352 option to git-clone(1), and its history can be later deepened with
353 git-fetch(1).
354 symref
356 Symbolic reference: instead of containing the SHA1 id itself, it is
357 of the format ref: refs/some/thing and when referenced, it
358 recursively dereferences to this reference. HEAD is a prime
359 example of a symref. Symbolic references are manipulated with the
360 git-symbolic-ref(1) command.
361 tag
363 A ref pointing to a tag or commit object. In contrast to a head, a
364 tag is not changed by a commit. Tags (not tag objects) are stored
365 in $GIT_DIR/refs/tags/. A git tag has nothing to do with a Lisp tag
366 (which would be called an object type in git’s context). A tag is
367 most typically used to mark a particular point in the commit
368 ancestry chain.
369 tag object
371 An object containing a ref pointing to another object, which can
372 contain a message just like a commit object. It can also contain a
373 (PGP) signature, in which case it is called a "signed tag object".
374 topic branch
376 A regular git branch that is used by a developer to identify a
377 conceptual line of development. Since branches are very easy and
378 inexpensive, it is often desirable to have several small branches
379 that each contain very well defined concepts or small incremental
380 yet related changes.
381 tracking branch
383 A regular git branch that is used to follow changes from another
384 repository. A tracking branch should not contain direct
385 modifications or have local commits made to it. A tracking branch
386 can usually be identified as the right-hand-side ref in a Pull:
387 refspec.
388 tree
390 Either a working tree, or a tree object together with the dependent
391 blob and tree objects (i.e. a stored representation of a working
392 tree).
393 tree object
395 An object containing a list of file names and modes along with refs
396 to the associated blob and/or tree objects. A tree is equivalent to
397 a directory.
398 tree-ish
400 A ref pointing to either a commit object, a tree object, or a tag
401 object pointing to a tag or commit or tree object.
402 unmerged index
404 An index which contains unmerged index entries.
405 unreachable object
407 An object which is not reachable from a branch, tag, or any other
408 reference.
409 upstream branch
411 The default branch that is merged into the branch in question (or
412 the branch in question is rebased onto). It is configured via
413 branch.<name>.remote and branch.<name>.merge. If the upstream
414 branch of A is origin/B sometimes we say "A is tracking origin/B".
415 working tree
417 The tree of actual checked out files. The working tree normally
418 contains the contents of the HEAD commit’s tree, plus any local
419 changes that you have made but not yet committed.
420
422 gittutorial(7), gittutorial-2(7), gitcvs-migration(7), Everyday git[1],
423 The Git User’s Manual[2]
424
426 Part of the git(1) suite.
427
429 1. Everyday git
430 file:///usr/share/doc/git-1.7.1/everyday.html
431 2. The Git User’s Manual
433 file:///usr/share/doc/git-1.7.1/user-manual.html
434Git 1.7.1 08/16/2017 GITGLOSSARY(7)