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