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.
32 Obsolete for: <<def_index,index>>.
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.
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>>.
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
85 [[def_commit-ish]]commit-ish (also committish)::
86 A <<def_commit_object,commit object>> or an
87 <<def_object,object>> that can be recursively dereferenced to
89 The following are all commit-ishes:
91 a <<def_tag_object,tag object>> that points to a commit
93 a tag object that points to a tag object that points to a
97 [[def_core_git]]core Git::
98 Fundamental data structures and utilities of Git. Exposes only limited
99 source code management tools.
102 Directed acyclic graph. The <<def_commit_object,commit objects>> form a
103 directed acyclic graph, because they have parents (directed), and the
104 graph of commit objects is acyclic (there is no <<def_chain,chain>>
105 which begins and ends with the same <<def_object,object>>).
107 [[def_dangling_object]]dangling object::
108 An <<def_unreachable_object,unreachable object>> which is not
109 <<def_reachable,reachable>> even from other unreachable objects; a
110 dangling object has no references to it from any
111 reference or <<def_object,object>> in the <<def_repository,repository>>.
113 [[def_detached_HEAD]]detached HEAD::
114 Normally the <<def_HEAD,HEAD>> stores the name of a
115 <<def_branch,branch>>, and commands that operate on the
116 history HEAD represents operate on the history leading to the
117 tip of the branch the HEAD points at. However, Git also
118 allows you to <<def_checkout,check out>> an arbitrary
119 <<def_commit,commit>> that isn't necessarily the tip of any
120 particular branch. The HEAD in such a state is called
123 Note that commands that operate on the history of the current branch
124 (e.g. `git commit` to build a new history on top of it) still work
125 while the HEAD is detached. They update the HEAD to point at the tip
126 of the updated history without affecting any branch. Commands that
127 update or inquire information _about_ the current branch (e.g. `git
128 branch --set-upstream-to` that sets what remote-tracking branch the
129 current branch integrates with) obviously do not work, as there is no
130 (real) current branch to ask about in this state.
132 [[def_directory]]directory::
133 The list you get with "ls" :-)
136 A <<def_working_tree,working tree>> is said to be "dirty" if
137 it contains modifications which have not been <<def_commit,committed>> to the current
138 <<def_branch,branch>>.
140 [[def_evil_merge]]evil merge::
141 An evil merge is a <<def_merge,merge>> that introduces changes that
142 do not appear in any <<def_parent,parent>>.
144 [[def_fast_forward]]fast-forward::
145 A fast-forward is a special type of <<def_merge,merge>> where you have a
146 <<def_revision,revision>> and you are "merging" another
147 <<def_branch,branch>>'s changes that happen to be a descendant of what
148 you have. In such these cases, you do not make a new <<def_merge,merge>>
149 <<def_commit,commit>> but instead just update to his
150 revision. This will happen frequently on a
151 <<def_remote_tracking_branch,remote-tracking branch>> of a remote
152 <<def_repository,repository>>.
155 Fetching a <<def_branch,branch>> means to get the
156 branch's <<def_head_ref,head ref>> from a remote
157 <<def_repository,repository>>, to find out which objects are
158 missing from the local <<def_object_database,object database>>,
159 and to get them, too. See also linkgit:git-fetch[1].
161 [[def_file_system]]file system::
162 Linus Torvalds originally designed Git to be a user space file system,
163 i.e. the infrastructure to hold files and directories. That ensured the
164 efficiency and speed of Git.
166 [[def_git_archive]]Git archive::
167 Synonym for <<def_repository,repository>> (for arch people).
169 [[def_gitfile]]gitfile::
170 A plain file `.git` at the root of a working tree that
171 points at the directory that is the real repository.
173 [[def_grafts]]grafts::
174 Grafts enables two otherwise different lines of development to be joined
175 together by recording fake ancestry information for commits. This way
176 you can make Git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has
177 is different from what was recorded when the commit was
178 created. Configured via the `.git/info/grafts` file.
181 In Git's context, synonym for <<def_object_name,object name>>.
184 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a
185 <<def_branch,branch>>. Heads are stored in a file in
186 `$GIT_DIR/refs/heads/` directory, except when using packed refs. (See
187 linkgit:git-pack-refs[1].)
190 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree,
191 working tree>> is normally derived from the state of the tree
192 referred to by HEAD. HEAD is a reference to one of the
193 <<def_head,heads>> in your repository, except when using a
194 <<def_detached_HEAD,detached HEAD>>, in which case it directly
195 references an arbitrary commit.
197 [[def_head_ref]]head ref::
198 A synonym for <<def_head,head>>.
201 During the normal execution of several Git commands, call-outs are made
202 to optional scripts that allow a developer to add functionality or
203 checking. Typically, the hooks allow for a command to be pre-verified
204 and potentially aborted, and allow for a post-notification after the
205 operation is done. The hook scripts are found in the
206 `$GIT_DIR/hooks/` directory, and are enabled by simply
207 removing the `.sample` suffix from the filename. In earlier versions
208 of Git you had to make them executable.
211 A collection of files with stat information, whose contents are stored
212 as objects. The index is a stored version of your
213 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even
214 a third version of a working tree, which are used
215 when <<def_merge,merging>>.
217 [[def_index_entry]]index entry::
218 The information regarding a particular file, stored in the
219 <<def_index,index>>. An index entry can be unmerged, if a
220 <<def_merge,merge>> was started, but not yet finished (i.e. if
221 the index contains multiple versions of that file).
223 [[def_master]]master::
224 The default development <<def_branch,branch>>. Whenever you
225 create a Git <<def_repository,repository>>, a branch named
226 "master" is created, and becomes the active branch. In most
227 cases, this contains the local development, though that is
228 purely by convention and is not required.
231 As a verb: To bring the contents of another
232 <<def_branch,branch>> (possibly from an external
233 <<def_repository,repository>>) into the current branch. In the
234 case where the merged-in branch is from a different repository,
235 this is done by first <<def_fetch,fetching>> the remote branch
236 and then merging the result into the current branch. This
237 combination of fetch and merge operations is called a
238 <<def_pull,pull>>. Merging is performed by an automatic process
239 that identifies changes made since the branches diverged, and
240 then applies all those changes together. In cases where changes
241 conflict, manual intervention may be required to complete the
244 As a noun: unless it is a <<def_fast_forward,fast-forward>>, a
245 successful merge results in the creation of a new <<def_commit,commit>>
246 representing the result of the merge, and having as
247 <<def_parent,parents>> the tips of the merged <<def_branch,branches>>.
248 This commit is referred to as a "merge commit", or sometimes just a
251 [[def_object]]object::
252 The unit of storage in Git. It is uniquely identified by the
253 <<def_SHA1,SHA-1>> of its contents. Consequently, an
254 object can not be changed.
256 [[def_object_database]]object database::
257 Stores a set of "objects", and an individual <<def_object,object>> is
258 identified by its <<def_object_name,object name>>. The objects usually
259 live in `$GIT_DIR/objects/`.
261 [[def_object_identifier]]object identifier::
262 Synonym for <<def_object_name,object name>>.
264 [[def_object_name]]object name::
265 The unique identifier of an <<def_object,object>>. The
266 object name is usually represented by a 40 character
267 hexadecimal string. Also colloquially called <<def_SHA1,SHA-1>>.
269 [[def_object_type]]object type::
270 One of the identifiers "<<def_commit_object,commit>>",
271 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or
272 "<<def_blob_object,blob>>" describing the type of an
273 <<def_object,object>>.
275 [[def_octopus]]octopus::
276 To <<def_merge,merge>> more than two <<def_branch,branches>>.
278 [[def_origin]]origin::
279 The default upstream <<def_repository,repository>>. Most projects have
280 at least one upstream project which they track. By default
281 'origin' is used for that purpose. New upstream updates
282 will be fetched into <<def_remote_tracking_branch,remote-tracking branches>> named
283 origin/name-of-upstream-branch, which you can see using
287 A set of objects which have been compressed into one file (to save space
288 or to transmit them efficiently).
290 [[def_pack_index]]pack index::
291 The list of identifiers, and other information, of the objects in a
292 <<def_pack,pack>>, to assist in efficiently accessing the contents of a
295 [[def_pathspec]]pathspec::
296 Pattern used to limit paths in Git commands.
298 Pathspecs are used on the command line of "git ls-files", "git
299 ls-tree", "git add", "git grep", "git diff", "git checkout",
300 and many other commands to
301 limit the scope of operations to some subset of the tree or
302 worktree. See the documentation of each command for whether
303 paths are relative to the current directory or toplevel. The
304 pathspec syntax is as follows:
308 * any path matches itself
309 * the pathspec up to the last slash represents a
310 directory prefix. The scope of that pathspec is
311 limited to that subtree.
312 * the rest of the pathspec is a pattern for the remainder
313 of the pathname. Paths relative to the directory
314 prefix will be matched against that pattern using fnmatch(3);
315 in particular, '*' and '?' _can_ match directory separators.
319 For example, Documentation/*.jpg will match all .jpg files
320 in the Documentation subtree,
321 including Documentation/chapter_1/figure_1.jpg.
323 A pathspec that begins with a colon `:` has special meaning. In the
324 short form, the leading colon `:` is followed by zero or more "magic
325 signature" letters (which optionally is terminated by another colon `:`),
326 and the remainder is the pattern to match against the path. The optional
327 colon that terminates the "magic signature" can be omitted if the pattern
328 begins with a character that cannot be a "magic signature" and is not a
331 In the long form, the leading colon `:` is followed by a open
332 parenthesis `(`, a comma-separated list of zero or more "magic words",
333 and a close parentheses `)`, and the remainder is the pattern to match
336 The "magic signature" consists of an ASCII symbol that is not
341 The magic word `top` (mnemonic: `/`) makes the pattern match
342 from the root of the working tree, even when you are running
343 the command from inside a subdirectory.
346 Wildcards in the pattern such as `*` or `?` are treated
347 as literal characters.
350 Case insensitive match.
353 Git treats the pattern as a shell glob suitable for
354 consumption by fnmatch(3) with the FNM_PATHNAME flag:
355 wildcards in the pattern will not match a / in the pathname.
356 For example, "Documentation/{asterisk}.html" matches
357 "Documentation/git.html" but not "Documentation/ppc/ppc.html"
358 or "tools/perf/Documentation/perf.html".
360 Two consecutive asterisks ("`**`") in patterns matched against
361 full pathname may have special meaning:
363 - A leading "`**`" followed by a slash means match in all
364 directories. For example, "`**/foo`" matches file or directory
365 "`foo`" anywhere, the same as pattern "`foo`". "`**/foo/bar`"
366 matches file or directory "`bar`" anywhere that is directly
367 under directory "`foo`".
369 - A trailing "`/**`" matches everything inside. For example,
370 "`abc/**`" matches all files inside directory "abc", relative
371 to the location of the `.gitignore` file, with infinite depth.
373 - A slash followed by two consecutive asterisks then a slash
374 matches zero or more directories. For example, "`a/**/b`"
375 matches "`a/b`", "`a/x/b`", "`a/x/y/b`" and so on.
377 - Other consecutive asterisks are considered invalid.
379 Glob magic is incompatible with literal magic.
382 Currently only the slash `/` is recognized as the "magic signature",
383 but it is envisioned that we will support more types of magic in later
386 A pathspec with only a colon means "there is no pathspec". This form
387 should not be combined with other pathspec.
389 [[def_parent]]parent::
390 A <<def_commit_object,commit object>> contains a (possibly empty) list
391 of the logical predecessor(s) in the line of development, i.e. its
394 [[def_pickaxe]]pickaxe::
395 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore
396 routines that help select changes that add or delete a given text
397 string. With the `--pickaxe-all` option, it can be used to view the full
398 <<def_changeset,changeset>> that introduced or removed, say, a
399 particular line of text. See linkgit:git-diff[1].
401 [[def_plumbing]]plumbing::
402 Cute name for <<def_core_git,core Git>>.
404 [[def_porcelain]]porcelain::
405 Cute name for programs and program suites depending on
406 <<def_core_git,core Git>>, presenting a high level access to
407 core Git. Porcelains expose more of a <<def_SCM,SCM>>
408 interface than the <<def_plumbing,plumbing>>.
411 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
412 <<def_merge,merge>> it. See also linkgit:git-pull[1].
415 Pushing a <<def_branch,branch>> means to get the branch's
416 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
417 find out if it is a direct ancestor to the branch's local
418 head ref, and in that case, putting all
419 objects, which are <<def_reachable,reachable>> from the local
420 head ref, and which are missing from the remote
421 repository, into the remote
422 <<def_object_database,object database>>, and updating the remote
423 head ref. If the remote <<def_head,head>> is not an
424 ancestor to the local head, the push fails.
426 [[def_reachable]]reachable::
427 All of the ancestors of a given <<def_commit,commit>> are said to be
428 "reachable" from that commit. More
429 generally, one <<def_object,object>> is reachable from
430 another if we can reach the one from the other by a <<def_chain,chain>>
431 that follows <<def_tag,tags>> to whatever they tag,
432 <<def_commit_object,commits>> to their parents or trees, and
433 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>>
436 [[def_rebase]]rebase::
437 To reapply a series of changes from a <<def_branch,branch>> to a
438 different base, and reset the <<def_head,head>> of that branch
442 A name that begins with `refs/` (e.g. `refs/heads/master`)
443 that points to an <<def_object_name,object name>> or another
444 ref (the latter is called a <<def_symref,symbolic ref>>).
445 For convenience, a ref can sometimes be abbreviated when used
446 as an argument to a Git command; see linkgit:gitrevisions[7]
448 Refs are stored in the <<def_repository,repository>>.
450 The ref namespace is hierarchical.
451 Different subhierarchies are used for different purposes (e.g. the
452 `refs/heads/` hierarchy is used to represent local branches).
454 There are a few special-purpose refs that do not begin with `refs/`.
455 The most notable example is `HEAD`.
457 [[def_reflog]]reflog::
458 A reflog shows the local "history" of a ref. In other words,
459 it can tell you what the 3rd last revision in _this_ repository
460 was, and what was the current state in _this_ repository,
461 yesterday 9:14pm. See linkgit:git-reflog[1] for details.
463 [[def_refspec]]refspec::
464 A "refspec" is used by <<def_fetch,fetch>> and
465 <<def_push,push>> to describe the mapping between remote
466 <<def_ref,ref>> and local ref.
468 [[def_remote_tracking_branch]]remote-tracking branch::
469 A <<def_ref,ref>> that is used to follow changes from another
470 <<def_repository,repository>>. It typically looks like
471 'refs/remotes/foo/bar' (indicating that it tracks a branch named
472 'bar' in a remote named 'foo'), and matches the right-hand-side of
473 a configured fetch <<def_refspec,refspec>>. A remote-tracking
474 branch should not contain direct modifications or have local
477 [[def_repository]]repository::
478 A collection of <<def_ref,refs>> together with an
479 <<def_object_database,object database>> containing all objects
480 which are <<def_reachable,reachable>> from the refs, possibly
481 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A
482 repository can share an object database with other repositories
483 via <<def_alternate_object_database,alternates mechanism>>.
485 [[def_resolve]]resolve::
486 The action of fixing up manually what a failed automatic
487 <<def_merge,merge>> left behind.
489 [[def_revision]]revision::
490 Synonym for <<def_commit,commit>> (the noun).
492 [[def_rewind]]rewind::
493 To throw away part of the development, i.e. to assign the
494 <<def_head,head>> to an earlier <<def_revision,revision>>.
497 Source code management (tool).
500 "Secure Hash Algorithm 1"; a cryptographic hash function.
501 In the context of Git used as a synonym for <<def_object_name,object name>>.
503 [[def_shallow_repository]]shallow repository::
504 A shallow <<def_repository,repository>> has an incomplete
505 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other
506 words, Git is told to pretend that these commits do not have the
507 parents, even though they are recorded in the <<def_commit_object,commit
508 object>>). This is sometimes useful when you are interested only in the
509 recent history of a project even though the real history recorded in the
510 upstream is much larger. A shallow repository
511 is created by giving the `--depth` option to linkgit:git-clone[1], and
512 its history can be later deepened with linkgit:git-fetch[1].
514 [[def_symref]]symref::
515 Symbolic reference: instead of containing the <<def_SHA1,SHA-1>>
516 id itself, it is of the format 'ref: refs/some/thing' and when
517 referenced, it recursively dereferences to this reference.
518 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic
519 references are manipulated with the linkgit:git-symbolic-ref[1]
523 A <<def_ref,ref>> under `refs/tags/` namespace that points to an
524 object of an arbitrary type (typically a tag points to either a
525 <<def_tag_object,tag>> or a <<def_commit_object,commit object>>).
526 In contrast to a <<def_head,head>>, a tag is not updated by
527 the `commit` command. A Git tag has nothing to do with a Lisp
528 tag (which would be called an <<def_object_type,object type>>
529 in Git's context). A tag is most typically used to mark a particular
530 point in the commit ancestry <<def_chain,chain>>.
532 [[def_tag_object]]tag object::
533 An <<def_object,object>> containing a <<def_ref,ref>> pointing to
534 another object, which can contain a message just like a
535 <<def_commit_object,commit object>>. It can also contain a (PGP)
536 signature, in which case it is called a "signed tag object".
538 [[def_topic_branch]]topic branch::
539 A regular Git <<def_branch,branch>> that is used by a developer to
540 identify a conceptual line of development. Since branches are very easy
541 and inexpensive, it is often desirable to have several small branches
542 that each contain very well defined concepts or small incremental yet
546 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree
547 object>> together with the dependent <<def_blob_object,blob>> and tree objects
548 (i.e. a stored representation of a working tree).
550 [[def_tree_object]]tree object::
551 An <<def_object,object>> containing a list of file names and modes along
552 with refs to the associated blob and/or tree objects. A
553 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
555 [[def_tree-ish]]tree-ish (also treeish)::
556 A <<def_tree_object,tree object>> or an <<def_object,object>>
557 that can be recursively dereferenced to a tree object.
558 Dereferencing a <<def_commit_object,commit object>> yields the
559 tree object corresponding to the <<def_revision,revision>>'s
560 top <<def_directory,directory>>.
561 The following are all tree-ishes:
562 a <<def_commit-ish,commit-ish>>,
564 a <<def_tag_object,tag object>> that points to a tree object,
565 a tag object that points to a tag object that points to a tree
569 [[def_unmerged_index]]unmerged index::
570 An <<def_index,index>> which contains unmerged
571 <<def_index_entry,index entries>>.
573 [[def_unreachable_object]]unreachable object::
574 An <<def_object,object>> which is not <<def_reachable,reachable>> from a
575 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
577 [[def_upstream_branch]]upstream branch::
578 The default <<def_branch,branch>> that is merged into the branch in
579 question (or the branch in question is rebased onto). It is configured
580 via branch.<name>.remote and branch.<name>.merge. If the upstream branch
581 of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'".
583 [[def_working_tree]]working tree::
584 The tree of actual checked out files. The working tree normally
585 contains the contents of the <<def_HEAD,HEAD>> commit's tree,
586 plus any local changes that you have made but not yet committed.
projects / git / blob