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1 [[def_alternate_object_database]]alternate object database::
2 Via the alternates mechanism, a <<def_repository,repository>>
3 can inherit part of its <<def_object_database,object database>>
4 from another object database, which is called "alternate".
6 [[def_bare_repository]]bare repository::
7 A bare repository is normally an appropriately
8 named <<def_directory,directory>> with a `.git` suffix that does not
9 have a locally checked-out copy of any of the files under
10 revision control. That is, all of the Git
11 administrative and control files that would normally be present in the
12 hidden `.git` sub-directory are directly present in the
13 `repository.git` directory instead,
14 and no other files are present and checked out. Usually publishers of
15 public repositories make bare repositories available.
17 [[def_blob_object]]blob object::
18 Untyped <<def_object,object>>, e.g. the contents of a file.
20 [[def_branch]]branch::
21 A "branch" is an active line of development. The most recent
22 <<def_commit,commit>> on a branch is referred to as the tip of
23 that branch. The tip of the branch is referenced by a branch
24 <<def_head,head>>, which moves forward as additional development
25 is done on the branch. A single Git
26 <<def_repository,repository>> can track an arbitrary number of
27 branches, but your <<def_working_tree,working tree>> is
28 associated with just one of them (the "current" or "checked out"
29 branch), and <<def_HEAD,HEAD>> points to that branch.
31 [[def_cache]]cache::
32 Obsolete for: <<def_index,index>>.
34 [[def_chain]]chain::
35 A list of objects, where each <<def_object,object>> in the list contains
36 a reference to its successor (for example, the successor of a
37 <<def_commit,commit>> could be one of its <<def_parent,parents>>).
39 [[def_changeset]]changeset::
40 BitKeeper/cvsps speak for "<<def_commit,commit>>". Since Git does not
41 store changes, but states, it really does not make sense to use the term
42 "changesets" with Git.
44 [[def_checkout]]checkout::
45 The action of updating all or part of the
46 <<def_working_tree,working tree>> with a <<def_tree_object,tree object>>
47 or <<def_blob_object,blob>> from the
48 <<def_object_database,object database>>, and updating the
49 <<def_index,index>> and <<def_HEAD,HEAD>> if the whole working tree has
50 been pointed at a new <<def_branch,branch>>.
52 [[def_cherry-picking]]cherry-picking::
53 In <<def_SCM,SCM>> jargon, "cherry pick" means to choose a subset of
54 changes out of a series of changes (typically commits) and record them
55 as a new series of changes on top of a different codebase. In Git, this is
56 performed by the "git cherry-pick" command to extract the change introduced
57 by an existing <<def_commit,commit>> and to record it based on the tip
58 of the current <<def_branch,branch>> as a new commit.
60 [[def_clean]]clean::
61 A <<def_working_tree,working tree>> is clean, if it
62 corresponds to the <<def_revision,revision>> referenced by the current
63 <<def_head,head>>. Also see "<<def_dirty,dirty>>".
65 [[def_commit]]commit::
66 As a noun: A single point in the
67 Git history; the entire history of a project is represented as a
68 set of interrelated commits. The word "commit" is often
69 used by Git in the same places other revision control systems
70 use the words "revision" or "version". Also used as a short
71 hand for <<def_commit_object,commit object>>.
72 +
73 As a verb: The action of storing a new snapshot of the project's
74 state in the Git history, by creating a new commit representing the current
75 state of the <<def_index,index>> and advancing <<def_HEAD,HEAD>>
76 to point at the new commit.
78 [[def_commit_object]]commit object::
79 An <<def_object,object>> which contains the information about a
80 particular <<def_revision,revision>>, such as <<def_parent,parents>>, committer,
81 author, date and the <<def_tree_object,tree object>> which corresponds
82 to the top <<def_directory,directory>> of the stored
83 revision.
85 [[def_core_git]]core Git::
86 Fundamental data structures and utilities of Git. Exposes only limited
87 source code management tools.
89 [[def_DAG]]DAG::
90 Directed acyclic graph. The <<def_commit_object,commit objects>> form a
91 directed acyclic graph, because they have parents (directed), and the
92 graph of commit objects is acyclic (there is no <<def_chain,chain>>
93 which begins and ends with the same <<def_object,object>>).
95 [[def_dangling_object]]dangling object::
96 An <<def_unreachable_object,unreachable object>> which is not
97 <<def_reachable,reachable>> even from other unreachable objects; a
98 dangling object has no references to it from any
99 reference or <<def_object,object>> in the <<def_repository,repository>>.
101 [[def_detached_HEAD]]detached HEAD::
102 Normally the <<def_HEAD,HEAD>> stores the name of a
103 <<def_branch,branch>>, and commands that operate on the
104 history HEAD represents operate on the history leading to the
105 tip of the branch the HEAD points at. However, Git also
106 allows you to <<def_checkout,check out>> an arbitrary
107 <<def_commit,commit>> that isn't necessarily the tip of any
108 particular branch. The HEAD in such a state is called
109 "detached".
110 +
111 Note that commands that operate on the history of the current branch
112 (e.g. `git commit` to build a new history on top of it) still work
113 while the HEAD is detached. They update the HEAD to point at the tip
114 of the updated history without affecting any branch. Commands that
115 update or inquire information _about_ the current branch (e.g. `git
116 branch --set-upstream-to` that sets what remote tracking branch the
117 current branch integrates with) obviously do not work, as there is no
118 (real) current branch to ask about in this state.
120 [[def_dircache]]dircache::
121 You are *waaaaay* behind. See <<def_index,index>>.
123 [[def_directory]]directory::
124 The list you get with "ls" :-)
126 [[def_dirty]]dirty::
127 A <<def_working_tree,working tree>> is said to be "dirty" if
128 it contains modifications which have not been <<def_commit,committed>> to the current
129 <<def_branch,branch>>.
131 [[def_ent]]ent::
132 Favorite synonym to "<<def_tree-ish,tree-ish>>" by some total geeks. See
133 http://en.wikipedia.org/wiki/Ent_(Middle-earth) for an in-depth
134 explanation. Avoid this term, not to confuse people.
136 [[def_evil_merge]]evil merge::
137 An evil merge is a <<def_merge,merge>> that introduces changes that
138 do not appear in any <<def_parent,parent>>.
140 [[def_fast_forward]]fast-forward::
141 A fast-forward is a special type of <<def_merge,merge>> where you have a
142 <<def_revision,revision>> and you are "merging" another
143 <<def_branch,branch>>'s changes that happen to be a descendant of what
144 you have. In such these cases, you do not make a new <<def_merge,merge>>
145 <<def_commit,commit>> but instead just update to his
146 revision. This will happen frequently on a
147 <<def_remote_tracking_branch,remote-tracking branch>> of a remote
148 <<def_repository,repository>>.
150 [[def_fetch]]fetch::
151 Fetching a <<def_branch,branch>> means to get the
152 branch's <<def_head_ref,head ref>> from a remote
153 <<def_repository,repository>>, to find out which objects are
154 missing from the local <<def_object_database,object database>>,
155 and to get them, too. See also linkgit:git-fetch[1].
157 [[def_file_system]]file system::
158 Linus Torvalds originally designed Git to be a user space file system,
159 i.e. the infrastructure to hold files and directories. That ensured the
160 efficiency and speed of Git.
162 [[def_git_archive]]Git archive::
163 Synonym for <<def_repository,repository>> (for arch people).
165 [[def_gitfile]]gitfile::
166 A plain file `.git` at the root of a working tree that
167 points at the directory that is the real repository.
169 [[def_grafts]]grafts::
170 Grafts enables two otherwise different lines of development to be joined
171 together by recording fake ancestry information for commits. This way
172 you can make Git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has
173 is different from what was recorded when the commit was
174 created. Configured via the `.git/info/grafts` file.
176 [[def_hash]]hash::
177 In Git's context, synonym to <<def_object_name,object name>>.
179 [[def_head]]head::
180 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a
181 <<def_branch,branch>>. Heads are stored in a file in
182 `$GIT_DIR/refs/heads/` directory, except when using packed refs. (See
183 linkgit:git-pack-refs[1].)
185 [[def_HEAD]]HEAD::
186 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree,
187 working tree>> is normally derived from the state of the tree
188 referred to by HEAD. HEAD is a reference to one of the
189 <<def_head,heads>> in your repository, except when using a
190 <<def_detached_HEAD,detached HEAD>>, in which case it directly
191 references an arbitrary commit.
193 [[def_head_ref]]head ref::
194 A synonym for <<def_head,head>>.
196 [[def_hook]]hook::
197 During the normal execution of several Git commands, call-outs are made
198 to optional scripts that allow a developer to add functionality or
199 checking. Typically, the hooks allow for a command to be pre-verified
200 and potentially aborted, and allow for a post-notification after the
201 operation is done. The hook scripts are found in the
202 `$GIT_DIR/hooks/` directory, and are enabled by simply
203 removing the `.sample` suffix from the filename. In earlier versions
204 of Git you had to make them executable.
206 [[def_index]]index::
207 A collection of files with stat information, whose contents are stored
208 as objects. The index is a stored version of your
209 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even
210 a third version of a working tree, which are used
211 when <<def_merge,merging>>.
213 [[def_index_entry]]index entry::
214 The information regarding a particular file, stored in the
215 <<def_index,index>>. An index entry can be unmerged, if a
216 <<def_merge,merge>> was started, but not yet finished (i.e. if
217 the index contains multiple versions of that file).
219 [[def_master]]master::
220 The default development <<def_branch,branch>>. Whenever you
221 create a Git <<def_repository,repository>>, a branch named
222 "master" is created, and becomes the active branch. In most
223 cases, this contains the local development, though that is
224 purely by convention and is not required.
226 [[def_merge]]merge::
227 As a verb: To bring the contents of another
228 <<def_branch,branch>> (possibly from an external
229 <<def_repository,repository>>) into the current branch. In the
230 case where the merged-in branch is from a different repository,
231 this is done by first <<def_fetch,fetching>> the remote branch
232 and then merging the result into the current branch. This
233 combination of fetch and merge operations is called a
234 <<def_pull,pull>>. Merging is performed by an automatic process
235 that identifies changes made since the branches diverged, and
236 then applies all those changes together. In cases where changes
237 conflict, manual intervention may be required to complete the
238 merge.
239 +
240 As a noun: unless it is a <<def_fast_forward,fast-forward>>, a
241 successful merge results in the creation of a new <<def_commit,commit>>
242 representing the result of the merge, and having as
243 <<def_parent,parents>> the tips of the merged <<def_branch,branches>>.
244 This commit is referred to as a "merge commit", or sometimes just a
245 "merge".
247 [[def_object]]object::
248 The unit of storage in Git. It is uniquely identified by the
249 <<def_SHA1,SHA1>> of its contents. Consequently, an
250 object can not be changed.
252 [[def_object_database]]object database::
253 Stores a set of "objects", and an individual <<def_object,object>> is
254 identified by its <<def_object_name,object name>>. The objects usually
255 live in `$GIT_DIR/objects/`.
257 [[def_object_identifier]]object identifier::
258 Synonym for <<def_object_name,object name>>.
260 [[def_object_name]]object name::
261 The unique identifier of an <<def_object,object>>. The <<def_hash,hash>>
262 of the object's contents using the Secure Hash Algorithm
263 1 and usually represented by the 40 character hexadecimal encoding of
264 the <<def_hash,hash>> of the object.
266 [[def_object_type]]object type::
267 One of the identifiers "<<def_commit_object,commit>>",
268 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or
269 "<<def_blob_object,blob>>" describing the type of an
270 <<def_object,object>>.
272 [[def_octopus]]octopus::
273 To <<def_merge,merge>> more than two <<def_branch,branches>>. Also denotes an
274 intelligent predator.
276 [[def_origin]]origin::
277 The default upstream <<def_repository,repository>>. Most projects have
278 at least one upstream project which they track. By default
279 'origin' is used for that purpose. New upstream updates
280 will be fetched into remote <<def_remote_tracking_branch,remote-tracking branches>> named
281 origin/name-of-upstream-branch, which you can see using
282 `git branch -r`.
284 [[def_pack]]pack::
285 A set of objects which have been compressed into one file (to save space
286 or to transmit them efficiently).
288 [[def_pack_index]]pack index::
289 The list of identifiers, and other information, of the objects in a
290 <<def_pack,pack>>, to assist in efficiently accessing the contents of a
291 pack.
293 [[def_pathspec]]pathspec::
294 Pattern used to specify paths.
295 +
296 Pathspecs are used on the command line of "git ls-files", "git
297 ls-tree", "git add", "git grep", "git diff", "git checkout",
298 and many other commands to
299 limit the scope of operations to some subset of the tree or
300 worktree. See the documentation of each command for whether
301 paths are relative to the current directory or toplevel. The
302 pathspec syntax is as follows:
304 * any path matches itself
305 * the pathspec up to the last slash represents a
306 directory prefix. The scope of that pathspec is
307 limited to that subtree.
308 * the rest of the pathspec is a pattern for the remainder
309 of the pathname. Paths relative to the directory
310 prefix will be matched against that pattern using fnmatch(3);
311 in particular, '*' and '?' _can_ match directory separators.
312 +
313 For example, Documentation/*.jpg will match all .jpg files
314 in the Documentation subtree,
315 including Documentation/chapter_1/figure_1.jpg.
317 +
318 A pathspec that begins with a colon `:` has special meaning. In the
319 short form, the leading colon `:` is followed by zero or more "magic
320 signature" letters (which optionally is terminated by another colon `:`),
321 and the remainder is the pattern to match against the path. The optional
322 colon that terminates the "magic signature" can be omitted if the pattern
323 begins with a character that cannot be a "magic signature" and is not a
324 colon.
325 +
326 In the long form, the leading colon `:` is followed by a open
327 parenthesis `(`, a comma-separated list of zero or more "magic words",
328 and a close parentheses `)`, and the remainder is the pattern to match
329 against the path.
330 +
331 The "magic signature" consists of an ASCII symbol that is not
332 alphanumeric.
333 +
334 --
335 top `/`;;
336 The magic word `top` (mnemonic: `/`) makes the pattern match
337 from the root of the working tree, even when you are running
338 the command from inside a subdirectory.
339 --
340 +
341 Currently only the slash `/` is recognized as the "magic signature",
342 but it is envisioned that we will support more types of magic in later
343 versions of Git.
344 +
345 A pathspec with only a colon means "there is no pathspec". This form
346 should not be combined with other pathspec.
348 [[def_parent]]parent::
349 A <<def_commit_object,commit object>> contains a (possibly empty) list
350 of the logical predecessor(s) in the line of development, i.e. its
351 parents.
353 [[def_pickaxe]]pickaxe::
354 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore
355 routines that help select changes that add or delete a given text
356 string. With the `--pickaxe-all` option, it can be used to view the full
357 <<def_changeset,changeset>> that introduced or removed, say, a
358 particular line of text. See linkgit:git-diff[1].
360 [[def_plumbing]]plumbing::
361 Cute name for <<def_core_git,core Git>>.
363 [[def_porcelain]]porcelain::
364 Cute name for programs and program suites depending on
365 <<def_core_git,core Git>>, presenting a high level access to
366 core Git. Porcelains expose more of a <<def_SCM,SCM>>
367 interface than the <<def_plumbing,plumbing>>.
369 [[def_pull]]pull::
370 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
371 <<def_merge,merge>> it. See also linkgit:git-pull[1].
373 [[def_push]]push::
374 Pushing a <<def_branch,branch>> means to get the branch's
375 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
376 find out if it is a direct ancestor to the branch's local
377 head ref, and in that case, putting all
378 objects, which are <<def_reachable,reachable>> from the local
379 head ref, and which are missing from the remote
380 repository, into the remote
381 <<def_object_database,object database>>, and updating the remote
382 head ref. If the remote <<def_head,head>> is not an
383 ancestor to the local head, the push fails.
385 [[def_reachable]]reachable::
386 All of the ancestors of a given <<def_commit,commit>> are said to be
387 "reachable" from that commit. More
388 generally, one <<def_object,object>> is reachable from
389 another if we can reach the one from the other by a <<def_chain,chain>>
390 that follows <<def_tag,tags>> to whatever they tag,
391 <<def_commit_object,commits>> to their parents or trees, and
392 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>>
393 that they contain.
395 [[def_rebase]]rebase::
396 To reapply a series of changes from a <<def_branch,branch>> to a
397 different base, and reset the <<def_head,head>> of that branch
398 to the result.
400 [[def_ref]]ref::
401 A 40-byte hex representation of a <<def_SHA1,SHA1>> or a name that
402 denotes a particular <<def_object,object>>. They may be stored in
403 a file under `$GIT_DIR/refs/` directory, or
404 in the `$GIT_DIR/packed-refs` file.
406 [[def_reflog]]reflog::
407 A reflog shows the local "history" of a ref. In other words,
408 it can tell you what the 3rd last revision in _this_ repository
409 was, and what was the current state in _this_ repository,
410 yesterday 9:14pm. See linkgit:git-reflog[1] for details.
412 [[def_refspec]]refspec::
413 A "refspec" is used by <<def_fetch,fetch>> and
414 <<def_push,push>> to describe the mapping between remote
415 <<def_ref,ref>> and local ref. They are combined with a colon in
416 the format <src>:<dst>, preceded by an optional plus sign, +.
417 For example: `git fetch $URL
418 refs/heads/master:refs/heads/origin` means "grab the master
419 <<def_branch,branch>> <<def_head,head>> from the $URL and store
420 it as my origin branch head". And `git push
421 $URL refs/heads/master:refs/heads/to-upstream` means "publish my
422 master branch head as to-upstream branch at $URL". See also
423 linkgit:git-push[1].
425 [[def_remote_tracking_branch]]remote-tracking branch::
426 A regular Git <<def_branch,branch>> that is used to follow changes from
427 another <<def_repository,repository>>. A remote-tracking
428 branch should not contain direct modifications or have local commits
429 made to it. A remote-tracking branch can usually be
430 identified as the right-hand-side <<def_ref,ref>> in a Pull:
431 <<def_refspec,refspec>>.
433 [[def_repository]]repository::
434 A collection of <<def_ref,refs>> together with an
435 <<def_object_database,object database>> containing all objects
436 which are <<def_reachable,reachable>> from the refs, possibly
437 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A
438 repository can share an object database with other repositories
439 via <<def_alternate_object_database,alternates mechanism>>.
441 [[def_resolve]]resolve::
442 The action of fixing up manually what a failed automatic
443 <<def_merge,merge>> left behind.
445 [[def_revision]]revision::
446 A particular state of files and directories which was stored in the
447 <<def_object_database,object database>>. It is referenced by a
448 <<def_commit_object,commit object>>.
450 [[def_rewind]]rewind::
451 To throw away part of the development, i.e. to assign the
452 <<def_head,head>> to an earlier <<def_revision,revision>>.
454 [[def_SCM]]SCM::
455 Source code management (tool).
457 [[def_SHA1]]SHA1::
458 Synonym for <<def_object_name,object name>>.
460 [[def_shallow_repository]]shallow repository::
461 A shallow <<def_repository,repository>> has an incomplete
462 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other
463 words, Git is told to pretend that these commits do not have the
464 parents, even though they are recorded in the <<def_commit_object,commit
465 object>>). This is sometimes useful when you are interested only in the
466 recent history of a project even though the real history recorded in the
467 upstream is much larger. A shallow repository
468 is created by giving the `--depth` option to linkgit:git-clone[1], and
469 its history can be later deepened with linkgit:git-fetch[1].
471 [[def_symref]]symref::
472 Symbolic reference: instead of containing the <<def_SHA1,SHA1>>
473 id itself, it is of the format 'ref: refs/some/thing' and when
474 referenced, it recursively dereferences to this reference.
475 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic
476 references are manipulated with the linkgit:git-symbolic-ref[1]
477 command.
479 [[def_tag]]tag::
480 A <<def_ref,ref>> under `refs/tags/` namespace that points to an
481 object of an arbitrary type (typically a tag points to either a
482 <<def_tag_object,tag>> or a <<def_commit_object,commit object>>).
483 In contrast to a <<def_head,head>>, a tag is not updated by
484 the `commit` command. A Git tag has nothing to do with a Lisp
485 tag (which would be called an <<def_object_type,object type>>
486 in Git's context). A tag is most typically used to mark a particular
487 point in the commit ancestry <<def_chain,chain>>.
489 [[def_tag_object]]tag object::
490 An <<def_object,object>> containing a <<def_ref,ref>> pointing to
491 another object, which can contain a message just like a
492 <<def_commit_object,commit object>>. It can also contain a (PGP)
493 signature, in which case it is called a "signed tag object".
495 [[def_topic_branch]]topic branch::
496 A regular Git <<def_branch,branch>> that is used by a developer to
497 identify a conceptual line of development. Since branches are very easy
498 and inexpensive, it is often desirable to have several small branches
499 that each contain very well defined concepts or small incremental yet
500 related changes.
502 [[def_tree]]tree::
503 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree
504 object>> together with the dependent <<def_blob_object,blob>> and tree objects
505 (i.e. a stored representation of a working tree).
507 [[def_tree_object]]tree object::
508 An <<def_object,object>> containing a list of file names and modes along
509 with refs to the associated blob and/or tree objects. A
510 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
512 [[def_tree-ish]]tree-ish::
513 A <<def_ref,ref>> pointing to either a <<def_commit_object,commit
514 object>>, a <<def_tree_object,tree object>>, or a <<def_tag_object,tag
515 object>> pointing to a tag or commit or tree object.
517 [[def_unmerged_index]]unmerged index::
518 An <<def_index,index>> which contains unmerged
519 <<def_index_entry,index entries>>.
521 [[def_unreachable_object]]unreachable object::
522 An <<def_object,object>> which is not <<def_reachable,reachable>> from a
523 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
525 [[def_upstream_branch]]upstream branch::
526 The default <<def_branch,branch>> that is merged into the branch in
527 question (or the branch in question is rebased onto). It is configured
528 via branch.<name>.remote and branch.<name>.merge. If the upstream branch
529 of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'".
531 [[def_working_tree]]working tree::
532 The tree of actual checked out files. The working tree normally
533 contains the contents of the <<def_HEAD,HEAD>> commit's tree,
534 plus any local changes that you have made but not yet committed.