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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>>. However, Git also allows you to <<def_checkout,check out>>
104 an arbitrary <<def_commit,commit>> that isn't necessarily the tip of any
105 particular branch. In this case HEAD is said to be "detached".
107 [[def_dircache]]dircache::
108 You are *waaaaay* behind. See <<def_index,index>>.
110 [[def_directory]]directory::
111 The list you get with "ls" :-)
113 [[def_dirty]]dirty::
114 A <<def_working_tree,working tree>> is said to be "dirty" if
115 it contains modifications which have not been <<def_commit,committed>> to the current
116 <<def_branch,branch>>.
118 [[def_ent]]ent::
119 Favorite synonym to "<<def_tree-ish,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.
123 [[def_evil_merge]]evil merge::
124 An evil merge is a <<def_merge,merge>> that introduces changes that
125 do not appear in any <<def_parent,parent>>.
127 [[def_fast_forward]]fast-forward::
128 A fast-forward is a special type of <<def_merge,merge>> where you have a
129 <<def_revision,revision>> and you are "merging" another
130 <<def_branch,branch>>'s changes that happen to be a descendant of what
131 you have. In such these cases, you do not make a new <<def_merge,merge>>
132 <<def_commit,commit>> but instead just update to his
133 revision. This will happen frequently on a
134 <<def_remote_tracking_branch,remote-tracking branch>> of a remote
135 <<def_repository,repository>>.
137 [[def_fetch]]fetch::
138 Fetching a <<def_branch,branch>> means to get the
139 branch's <<def_head_ref,head ref>> from a remote
140 <<def_repository,repository>>, to find out which objects are
141 missing from the local <<def_object_database,object database>>,
142 and to get them, too. See also linkgit:git-fetch[1].
144 [[def_file_system]]file system::
145 Linus Torvalds originally designed Git to be a user space file system,
146 i.e. the infrastructure to hold files and directories. That ensured the
147 efficiency and speed of Git.
149 [[def_git_archive]]Git archive::
150 Synonym for <<def_repository,repository>> (for arch people).
152 [[def_gitfile]]gitfile::
153 A plain file `.git` at the root of a working tree that
154 points at the directory that is the real repository.
156 [[def_grafts]]grafts::
157 Grafts enables two otherwise different lines of development to be joined
158 together by recording fake ancestry information for commits. This way
159 you can make Git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has
160 is different from what was recorded when the commit was
161 created. Configured via the `.git/info/grafts` file.
163 [[def_hash]]hash::
164 In Git's context, synonym to <<def_object_name,object name>>.
166 [[def_head]]head::
167 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a
168 <<def_branch,branch>>. Heads are stored in a file in
169 `$GIT_DIR/refs/heads/` directory, except when using packed refs. (See
170 linkgit:git-pack-refs[1].)
172 [[def_HEAD]]HEAD::
173 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree,
174 working tree>> is normally derived from the state of the tree
175 referred to by HEAD. HEAD is a reference to one of the
176 <<def_head,heads>> in your repository, except when using a
177 <<def_detached_HEAD,detached HEAD>>, in which case it directly
178 references an arbitrary commit.
180 [[def_head_ref]]head ref::
181 A synonym for <<def_head,head>>.
183 [[def_hook]]hook::
184 During the normal execution of several Git commands, call-outs are made
185 to optional scripts that allow a developer to add functionality or
186 checking. Typically, the hooks allow for a command to be pre-verified
187 and potentially aborted, and allow for a post-notification after the
188 operation is done. The hook scripts are found in the
189 `$GIT_DIR/hooks/` directory, and are enabled by simply
190 removing the `.sample` suffix from the filename. In earlier versions
191 of Git you had to make them executable.
193 [[def_index]]index::
194 A collection of files with stat information, whose contents are stored
195 as objects. The index is a stored version of your
196 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even
197 a third version of a working tree, which are used
198 when <<def_merge,merging>>.
200 [[def_index_entry]]index entry::
201 The information regarding a particular file, stored in the
202 <<def_index,index>>. An index entry can be unmerged, if a
203 <<def_merge,merge>> was started, but not yet finished (i.e. if
204 the index contains multiple versions of that file).
206 [[def_master]]master::
207 The default development <<def_branch,branch>>. Whenever you
208 create a Git <<def_repository,repository>>, a branch named
209 "master" is created, and becomes the active branch. In most
210 cases, this contains the local development, though that is
211 purely by convention and is not required.
213 [[def_merge]]merge::
214 As a verb: To bring the contents of another
215 <<def_branch,branch>> (possibly from an external
216 <<def_repository,repository>>) into the current branch. In the
217 case where the merged-in branch is from a different repository,
218 this is done by first <<def_fetch,fetching>> the remote branch
219 and then merging the result into the current branch. This
220 combination of fetch and merge operations is called a
221 <<def_pull,pull>>. Merging is performed by an automatic process
222 that identifies changes made since the branches diverged, and
223 then applies all those changes together. In cases where changes
224 conflict, manual intervention may be required to complete the
225 merge.
226 +
227 As a noun: unless it is a <<def_fast_forward,fast-forward>>, a
228 successful merge results in the creation of a new <<def_commit,commit>>
229 representing the result of the merge, and having as
230 <<def_parent,parents>> the tips of the merged <<def_branch,branches>>.
231 This commit is referred to as a "merge commit", or sometimes just a
232 "merge".
234 [[def_object]]object::
235 The unit of storage in Git. It is uniquely identified by the
236 <<def_SHA1,SHA1>> of its contents. Consequently, an
237 object can not be changed.
239 [[def_object_database]]object database::
240 Stores a set of "objects", and an individual <<def_object,object>> is
241 identified by its <<def_object_name,object name>>. The objects usually
242 live in `$GIT_DIR/objects/`.
244 [[def_object_identifier]]object identifier::
245 Synonym for <<def_object_name,object name>>.
247 [[def_object_name]]object name::
248 The unique identifier of an <<def_object,object>>. The <<def_hash,hash>>
249 of the object's contents using the Secure Hash Algorithm
250 1 and usually represented by the 40 character hexadecimal encoding of
251 the <<def_hash,hash>> of the object.
253 [[def_object_type]]object type::
254 One of the identifiers "<<def_commit_object,commit>>",
255 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or
256 "<<def_blob_object,blob>>" describing the type of an
257 <<def_object,object>>.
259 [[def_octopus]]octopus::
260 To <<def_merge,merge>> more than two <<def_branch,branches>>. Also denotes an
261 intelligent predator.
263 [[def_origin]]origin::
264 The default upstream <<def_repository,repository>>. Most projects have
265 at least one upstream project which they track. By default
266 'origin' is used for that purpose. New upstream updates
267 will be fetched into remote <<def_remote_tracking_branch,remote-tracking branches>> named
268 origin/name-of-upstream-branch, which you can see using
269 `git branch -r`.
271 [[def_pack]]pack::
272 A set of objects which have been compressed into one file (to save space
273 or to transmit them efficiently).
275 [[def_pack_index]]pack index::
276 The list of identifiers, and other information, of the objects in a
277 <<def_pack,pack>>, to assist in efficiently accessing the contents of a
278 pack.
280 [[def_pathspec]]pathspec::
281 Pattern used to specify paths.
282 +
283 Pathspecs are used on the command line of "git ls-files", "git
284 ls-tree", "git add", "git grep", "git diff", "git checkout",
285 and many other commands to
286 limit the scope of operations to some subset of the tree or
287 worktree. See the documentation of each command for whether
288 paths are relative to the current directory or toplevel. The
289 pathspec syntax is as follows:
291 * any path matches itself
292 * the pathspec up to the last slash represents a
293 directory prefix. The scope of that pathspec is
294 limited to that subtree.
295 * the rest of the pathspec is a pattern for the remainder
296 of the pathname. Paths relative to the directory
297 prefix will be matched against that pattern using fnmatch(3);
298 in particular, '*' and '?' _can_ match directory separators.
299 +
300 For example, Documentation/*.jpg will match all .jpg files
301 in the Documentation subtree,
302 including Documentation/chapter_1/figure_1.jpg.
304 +
305 A pathspec that begins with a colon `:` has special meaning. In the
306 short form, the leading colon `:` is followed by zero or more "magic
307 signature" letters (which optionally is terminated by another colon `:`),
308 and the remainder is the pattern to match against the path. The optional
309 colon that terminates the "magic signature" can be omitted if the pattern
310 begins with a character that cannot be a "magic signature" and is not a
311 colon.
312 +
313 In the long form, the leading colon `:` is followed by a open
314 parenthesis `(`, a comma-separated list of zero or more "magic words",
315 and a close parentheses `)`, and the remainder is the pattern to match
316 against the path.
317 +
318 The "magic signature" consists of an ASCII symbol that is not
319 alphanumeric.
320 +
321 --
322 top `/`;;
323 The magic word `top` (mnemonic: `/`) makes the pattern match
324 from the root of the working tree, even when you are running
325 the command from inside a subdirectory.
326 --
327 +
328 Currently only the slash `/` is recognized as the "magic signature",
329 but it is envisioned that we will support more types of magic in later
330 versions of Git.
331 +
332 A pathspec with only a colon means "there is no pathspec". This form
333 should not be combined with other pathspec.
335 [[def_parent]]parent::
336 A <<def_commit_object,commit object>> contains a (possibly empty) list
337 of the logical predecessor(s) in the line of development, i.e. its
338 parents.
340 [[def_pickaxe]]pickaxe::
341 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore
342 routines that help select changes that add or delete a given text
343 string. With the `--pickaxe-all` option, it can be used to view the full
344 <<def_changeset,changeset>> that introduced or removed, say, a
345 particular line of text. See linkgit:git-diff[1].
347 [[def_plumbing]]plumbing::
348 Cute name for <<def_core_git,core Git>>.
350 [[def_porcelain]]porcelain::
351 Cute name for programs and program suites depending on
352 <<def_core_git,core Git>>, presenting a high level access to
353 core Git. Porcelains expose more of a <<def_SCM,SCM>>
354 interface than the <<def_plumbing,plumbing>>.
356 [[def_pull]]pull::
357 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
358 <<def_merge,merge>> it. See also linkgit:git-pull[1].
360 [[def_push]]push::
361 Pushing a <<def_branch,branch>> means to get the branch's
362 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
363 find out if it is a direct ancestor to the branch's local
364 head ref, and in that case, putting all
365 objects, which are <<def_reachable,reachable>> from the local
366 head ref, and which are missing from the remote
367 repository, into the remote
368 <<def_object_database,object database>>, and updating the remote
369 head ref. If the remote <<def_head,head>> is not an
370 ancestor to the local head, the push fails.
372 [[def_reachable]]reachable::
373 All of the ancestors of a given <<def_commit,commit>> are said to be
374 "reachable" from that commit. More
375 generally, one <<def_object,object>> is reachable from
376 another if we can reach the one from the other by a <<def_chain,chain>>
377 that follows <<def_tag,tags>> to whatever they tag,
378 <<def_commit_object,commits>> to their parents or trees, and
379 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>>
380 that they contain.
382 [[def_rebase]]rebase::
383 To reapply a series of changes from a <<def_branch,branch>> to a
384 different base, and reset the <<def_head,head>> of that branch
385 to the result.
387 [[def_ref]]ref::
388 A 40-byte hex representation of a <<def_SHA1,SHA1>> or a name that
389 denotes a particular <<def_object,object>>. They may be stored in
390 a file under `$GIT_DIR/refs/` directory, or
391 in the `$GIT_DIR/packed-refs` file.
393 [[def_reflog]]reflog::
394 A reflog shows the local "history" of a ref. In other words,
395 it can tell you what the 3rd last revision in _this_ repository
396 was, and what was the current state in _this_ repository,
397 yesterday 9:14pm. See linkgit:git-reflog[1] for details.
399 [[def_refspec]]refspec::
400 A "refspec" is used by <<def_fetch,fetch>> and
401 <<def_push,push>> to describe the mapping between remote
402 <<def_ref,ref>> and local ref. They are combined with a colon in
403 the format <src>:<dst>, preceded by an optional plus sign, +.
404 For example: `git fetch $URL
405 refs/heads/master:refs/heads/origin` means "grab the master
406 <<def_branch,branch>> <<def_head,head>> from the $URL and store
407 it as my origin branch head". And `git push
408 $URL refs/heads/master:refs/heads/to-upstream` means "publish my
409 master branch head as to-upstream branch at $URL". See also
410 linkgit:git-push[1].
412 [[def_remote_tracking_branch]]remote-tracking branch::
413 A regular Git <<def_branch,branch>> that is used to follow changes from
414 another <<def_repository,repository>>. A remote-tracking
415 branch should not contain direct modifications or have local commits
416 made to it. A remote-tracking branch can usually be
417 identified as the right-hand-side <<def_ref,ref>> in a Pull:
418 <<def_refspec,refspec>>.
420 [[def_repository]]repository::
421 A collection of <<def_ref,refs>> together with an
422 <<def_object_database,object database>> containing all objects
423 which are <<def_reachable,reachable>> from the refs, possibly
424 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A
425 repository can share an object database with other repositories
426 via <<def_alternate_object_database,alternates mechanism>>.
428 [[def_resolve]]resolve::
429 The action of fixing up manually what a failed automatic
430 <<def_merge,merge>> left behind.
432 [[def_revision]]revision::
433 A particular state of files and directories which was stored in the
434 <<def_object_database,object database>>. It is referenced by a
435 <<def_commit_object,commit object>>.
437 [[def_rewind]]rewind::
438 To throw away part of the development, i.e. to assign the
439 <<def_head,head>> to an earlier <<def_revision,revision>>.
441 [[def_SCM]]SCM::
442 Source code management (tool).
444 [[def_SHA1]]SHA1::
445 Synonym for <<def_object_name,object name>>.
447 [[def_shallow_repository]]shallow repository::
448 A shallow <<def_repository,repository>> has an incomplete
449 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other
450 words, Git is told to pretend that these commits do not have the
451 parents, even though they are recorded in the <<def_commit_object,commit
452 object>>). This is sometimes useful when you are interested only in the
453 recent history of a project even though the real history recorded in the
454 upstream is much larger. A shallow repository
455 is created by giving the `--depth` option to linkgit:git-clone[1], and
456 its history can be later deepened with linkgit:git-fetch[1].
458 [[def_symref]]symref::
459 Symbolic reference: instead of containing the <<def_SHA1,SHA1>>
460 id itself, it is of the format 'ref: refs/some/thing' and when
461 referenced, it recursively dereferences to this reference.
462 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic
463 references are manipulated with the linkgit:git-symbolic-ref[1]
464 command.
466 [[def_tag]]tag::
467 A <<def_ref,ref>> under `refs/tags/` namespace that points to an
468 object of an arbitrary type (typically a tag points to either a
469 <<def_tag_object,tag>> or a <<def_commit_object,commit object>>).
470 In contrast to a <<def_head,head>>, a tag is not updated by
471 the `commit` command. A Git tag has nothing to do with a Lisp
472 tag (which would be called an <<def_object_type,object type>>
473 in Git's context). A tag is most typically used to mark a particular
474 point in the commit ancestry <<def_chain,chain>>.
476 [[def_tag_object]]tag object::
477 An <<def_object,object>> containing a <<def_ref,ref>> pointing to
478 another object, which can contain a message just like a
479 <<def_commit_object,commit object>>. It can also contain a (PGP)
480 signature, in which case it is called a "signed tag object".
482 [[def_topic_branch]]topic branch::
483 A regular Git <<def_branch,branch>> that is used by a developer to
484 identify a conceptual line of development. Since branches are very easy
485 and inexpensive, it is often desirable to have several small branches
486 that each contain very well defined concepts or small incremental yet
487 related changes.
489 [[def_tree]]tree::
490 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree
491 object>> together with the dependent <<def_blob_object,blob>> and tree objects
492 (i.e. a stored representation of a working tree).
494 [[def_tree_object]]tree object::
495 An <<def_object,object>> containing a list of file names and modes along
496 with refs to the associated blob and/or tree objects. A
497 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
499 [[def_tree-ish]]tree-ish::
500 A <<def_ref,ref>> pointing to either a <<def_commit_object,commit
501 object>>, a <<def_tree_object,tree object>>, or a <<def_tag_object,tag
502 object>> pointing to a tag or commit or tree object.
504 [[def_unmerged_index]]unmerged index::
505 An <<def_index,index>> which contains unmerged
506 <<def_index_entry,index entries>>.
508 [[def_unreachable_object]]unreachable object::
509 An <<def_object,object>> which is not <<def_reachable,reachable>> from a
510 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
512 [[def_upstream_branch]]upstream branch::
513 The default <<def_branch,branch>> that is merged into the branch in
514 question (or the branch in question is rebased onto). It is configured
515 via branch.<name>.remote and branch.<name>.merge. If the upstream branch
516 of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'".
518 [[def_working_tree]]working tree::
519 The tree of actual checked out files. The working tree normally
520 contains the contents of the <<def_HEAD,HEAD>> commit's tree,
521 plus any local changes that you have made but not yet committed.