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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 an "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 a 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 <<def_ref,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_graph_general]]commit graph concept, representations and usage::
79 A synonym for the <<def_DAG,DAG>> structure formed by the commits
80 in the object database, <<def_ref,referenced>> by branch tips,
81 using their <<def_chain,chain>> of linked commits.
82 This structure is the definitive commit graph. The
83 graph can be represented in other ways, e.g. the
84 <<def_commit_graph_file,"commit-graph" file>>.
86 [[def_commit_graph_file]]commit-graph file::
87 The "commit-graph" (normally hyphenated) file is a supplemental
88 representation of the <<def_commit_graph_general,commit graph>>
89 which accelerates commit graph walks. The "commit-graph" file is
90 stored either in the .git/objects/info directory or in the info
91 directory of an alternate object database.
93 [[def_commit_object]]commit object::
94 An <<def_object,object>> which contains the information about a
95 particular <<def_revision,revision>>, such as <<def_parent,parents>>, committer,
96 author, date and the <<def_tree_object,tree object>> which corresponds
97 to the top <<def_directory,directory>> of the stored
98 revision.
100 [[def_commit-ish]]commit-ish (also committish)::
101 A <<def_commit_object,commit object>> or an <<def_object,object>> that
102 can be recursively <<def_dereference,dereferenced>> to a commit object.
103 The following are all commit-ishes:
104 a commit object,
105 a <<def_tag_object,tag object>> that points to a commit
106 object,
107 a tag object that points to a tag object that points to a
108 commit object,
109 etc.
111 [[def_core_git]]core Git::
112 Fundamental data structures and utilities of Git. Exposes only limited
113 source code management tools.
115 [[def_DAG]]DAG::
116 Directed acyclic graph. The <<def_commit_object,commit objects>> form a
117 directed acyclic graph, because they have parents (directed), and the
118 graph of commit objects is acyclic (there is no <<def_chain,chain>>
119 which begins and ends with the same <<def_object,object>>).
121 [[def_dangling_object]]dangling object::
122 An <<def_unreachable_object,unreachable object>> which is not
123 <<def_reachable,reachable>> even from other unreachable objects; a
124 dangling object has no references to it from any
125 reference or <<def_object,object>> in the <<def_repository,repository>>.
127 [[def_dereference]]dereference::
128 Referring to a <<def_symref,symbolic ref>>: the action of accessing the
129 <<def_ref,reference>> pointed at by a symbolic ref. Recursive
130 dereferencing involves repeating the aforementioned process on the
131 resulting ref until a non-symbolic reference is found.
132 +
133 Referring to a <<def_tag_object,tag object>>: the action of accessing the
134 <<def_object,object>> a tag points at. Tags are recursively dereferenced by
135 repeating the operation on the result object until the result has either a
136 specified <<def_object_type,object type>> (where applicable) or any non-"tag"
137 object type. A synonym for "recursive dereference" in the context of tags is
138 "<<def_peel,peel>>".
139 +
140 Referring to a <<def_commit_object,commit object>>: the action of accessing
141 the commit's tree object. Commits cannot be dereferenced recursively.
142 +
143 Unless otherwise specified, "dereferencing" as it used in the context of Git
144 commands or protocols is implicitly recursive.
146 [[def_detached_HEAD]]detached HEAD::
147 Normally the <<def_HEAD,HEAD>> stores the name of a
148 <<def_branch,branch>>, and commands that operate on the
149 history HEAD represents operate on the history leading to the
150 tip of the branch the HEAD points at. However, Git also
151 allows you to <<def_checkout,check out>> an arbitrary
152 <<def_commit,commit>> that isn't necessarily the tip of any
153 particular branch. The HEAD in such a state is called
154 "detached".
155 +
156 Note that commands that operate on the history of the current branch
157 (e.g. `git commit` to build a new history on top of it) still work
158 while the HEAD is detached. They update the HEAD to point at the tip
159 of the updated history without affecting any branch. Commands that
160 update or inquire information _about_ the current branch (e.g. `git
161 branch --set-upstream-to` that sets what remote-tracking branch the
162 current branch integrates with) obviously do not work, as there is no
163 (real) current branch to ask about in this state.
165 [[def_directory]]directory::
166 The list you get with "ls" :-)
168 [[def_dirty]]dirty::
169 A <<def_working_tree,working tree>> is said to be "dirty" if
170 it contains modifications which have not been <<def_commit,committed>> to the current
171 <<def_branch,branch>>.
173 [[def_evil_merge]]evil merge::
174 An evil merge is a <<def_merge,merge>> that introduces changes that
175 do not appear in any <<def_parent,parent>>.
177 [[def_fast_forward]]fast-forward::
178 A fast-forward is a special type of <<def_merge,merge>> where you have a
179 <<def_revision,revision>> and you are "merging" another
180 <<def_branch,branch>>'s changes that happen to be a descendant of what
181 you have. In such a case, you do not make a new <<def_merge,merge>>
182 <<def_commit,commit>> but instead just update your branch to point at the same
183 revision as the branch you are merging. This will happen frequently on a
184 <<def_remote_tracking_branch,remote-tracking branch>> of a remote
185 <<def_repository,repository>>.
187 [[def_fetch]]fetch::
188 Fetching a <<def_branch,branch>> means to get the
189 branch's <<def_head_ref,head ref>> from a remote
190 <<def_repository,repository>>, to find out which objects are
191 missing from the local <<def_object_database,object database>>,
192 and to get them, too. See also linkgit:git-fetch[1].
194 [[def_file_system]]file system::
195 Linus Torvalds originally designed Git to be a user space file system,
196 i.e. the infrastructure to hold files and directories. That ensured the
197 efficiency and speed of Git.
199 [[def_git_archive]]Git archive::
200 Synonym for <<def_repository,repository>> (for arch people).
202 [[def_gitfile]]gitfile::
203 A plain file `.git` at the root of a working tree that
204 points at the directory that is the real repository.
206 [[def_grafts]]grafts::
207 Grafts enable two otherwise different lines of development to be joined
208 together by recording fake ancestry information for commits. This way
209 you can make Git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has
210 is different from what was recorded when the commit was
211 created. Configured via the `.git/info/grafts` file.
212 +
213 Note that the grafts mechanism is outdated and can lead to problems
214 transferring objects between repositories; see linkgit:git-replace[1]
215 for a more flexible and robust system to do the same thing.
217 [[def_hash]]hash::
218 In Git's context, synonym for <<def_object_name,object name>>.
220 [[def_head]]head::
221 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a
222 <<def_branch,branch>>. Heads are stored in a file in
223 `$GIT_DIR/refs/heads/` directory, except when using packed refs. (See
224 linkgit:git-pack-refs[1].)
226 [[def_HEAD]]HEAD::
227 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree,
228 working tree>> is normally derived from the state of the tree
229 referred to by HEAD. HEAD is a reference to one of the
230 <<def_head,heads>> in your repository, except when using a
231 <<def_detached_HEAD,detached HEAD>>, in which case it directly
232 references an arbitrary commit.
234 [[def_head_ref]]head ref::
235 A synonym for <<def_head,head>>.
237 [[def_hook]]hook::
238 During the normal execution of several Git commands, call-outs are made
239 to optional scripts that allow a developer to add functionality or
240 checking. Typically, the hooks allow for a command to be pre-verified
241 and potentially aborted, and allow for a post-notification after the
242 operation is done. The hook scripts are found in the
243 `$GIT_DIR/hooks/` directory, and are enabled by simply
244 removing the `.sample` suffix from the filename. In earlier versions
245 of Git you had to make them executable.
247 [[def_index]]index::
248 A collection of files with stat information, whose contents are stored
249 as objects. The index is a stored version of your
250 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even
251 a third version of a working tree, which are used
252 when <<def_merge,merging>>.
254 [[def_index_entry]]index entry::
255 The information regarding a particular file, stored in the
256 <<def_index,index>>. An index entry can be unmerged, if a
257 <<def_merge,merge>> was started, but not yet finished (i.e. if
258 the index contains multiple versions of that file).
260 [[def_master]]master::
261 The default development <<def_branch,branch>>. Whenever you
262 create a Git <<def_repository,repository>>, a branch named
263 "master" is created, and becomes the active branch. In most
264 cases, this contains the local development, though that is
265 purely by convention and is not required.
267 [[def_merge]]merge::
268 As a verb: To bring the contents of another
269 <<def_branch,branch>> (possibly from an external
270 <<def_repository,repository>>) into the current branch. In the
271 case where the merged-in branch is from a different repository,
272 this is done by first <<def_fetch,fetching>> the remote branch
273 and then merging the result into the current branch. This
274 combination of fetch and merge operations is called a
275 <<def_pull,pull>>. Merging is performed by an automatic process
276 that identifies changes made since the branches diverged, and
277 then applies all those changes together. In cases where changes
278 conflict, manual intervention may be required to complete the
279 merge.
280 +
281 As a noun: unless it is a <<def_fast_forward,fast-forward>>, a
282 successful merge results in the creation of a new <<def_commit,commit>>
283 representing the result of the merge, and having as
284 <<def_parent,parents>> the tips of the merged <<def_branch,branches>>.
285 This commit is referred to as a "merge commit", or sometimes just a
286 "merge".
288 [[def_object]]object::
289 The unit of storage in Git. It is uniquely identified by the
290 <<def_SHA1,SHA-1>> of its contents. Consequently, an
291 object cannot be changed.
293 [[def_object_database]]object database::
294 Stores a set of "objects", and an individual <<def_object,object>> is
295 identified by its <<def_object_name,object name>>. The objects usually
296 live in `$GIT_DIR/objects/`.
298 [[def_object_identifier]]object identifier (oid)::
299 Synonym for <<def_object_name,object name>>.
301 [[def_object_name]]object name::
302 The unique identifier of an <<def_object,object>>. The
303 object name is usually represented by a 40 character
304 hexadecimal string. Also colloquially called <<def_SHA1,SHA-1>>.
306 [[def_object_type]]object type::
307 One of the identifiers "<<def_commit_object,commit>>",
308 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or
309 "<<def_blob_object,blob>>" describing the type of an
310 <<def_object,object>>.
312 [[def_octopus]]octopus::
313 To <<def_merge,merge>> more than two <<def_branch,branches>>.
315 [[def_origin]]origin::
316 The default upstream <<def_repository,repository>>. Most projects have
317 at least one upstream project which they track. By default
318 'origin' is used for that purpose. New upstream updates
319 will be fetched into <<def_remote_tracking_branch,remote-tracking branches>> named
320 origin/name-of-upstream-branch, which you can see using
321 `git branch -r`.
323 [[def_overlay]]overlay::
324 Only update and add files to the working directory, but don't
325 delete them, similar to how 'cp -R' would update the contents
326 in the destination directory. This is the default mode in a
327 <<def_checkout,checkout>> when checking out files from the
328 <<def_index,index>> or a <<def_tree-ish,tree-ish>>. In
329 contrast, no-overlay mode also deletes tracked files not
330 present in the source, similar to 'rsync --delete'.
332 [[def_pack]]pack::
333 A set of objects which have been compressed into one file (to save space
334 or to transmit them efficiently).
336 [[def_pack_index]]pack index::
337 The list of identifiers, and other information, of the objects in a
338 <<def_pack,pack>>, to assist in efficiently accessing the contents of a
339 pack.
341 [[def_pathspec]]pathspec::
342 Pattern used to limit paths in Git commands.
343 +
344 Pathspecs are used on the command line of "git ls-files", "git
345 ls-tree", "git add", "git grep", "git diff", "git checkout",
346 and many other commands to
347 limit the scope of operations to some subset of the tree or
348 working tree. See the documentation of each command for whether
349 paths are relative to the current directory or toplevel. The
350 pathspec syntax is as follows:
351 +
352 --
354 * any path matches itself
355 * the pathspec up to the last slash represents a
356 directory prefix. The scope of that pathspec is
357 limited to that subtree.
358 * the rest of the pathspec is a pattern for the remainder
359 of the pathname. Paths relative to the directory
360 prefix will be matched against that pattern using fnmatch(3);
361 in particular, '*' and '?' _can_ match directory separators.
363 --
364 +
365 For example, Documentation/*.jpg will match all .jpg files
366 in the Documentation subtree,
367 including Documentation/chapter_1/figure_1.jpg.
368 +
369 A pathspec that begins with a colon `:` has special meaning. In the
370 short form, the leading colon `:` is followed by zero or more "magic
371 signature" letters (which optionally is terminated by another colon `:`),
372 and the remainder is the pattern to match against the path.
373 The "magic signature" consists of ASCII symbols that are neither
374 alphanumeric, glob, regex special characters nor colon.
375 The optional colon that terminates the "magic signature" can be
376 omitted if the pattern begins with a character that does not belong to
377 "magic signature" symbol set and is not a colon.
378 +
379 In the long form, the leading colon `:` is followed by an open
380 parenthesis `(`, a comma-separated list of zero or more "magic words",
381 and a close parentheses `)`, and the remainder is the pattern to match
382 against the path.
383 +
384 A pathspec with only a colon means "there is no pathspec". This form
385 should not be combined with other pathspec.
386 +
387 --
388 top;;
389 The magic word `top` (magic signature: `/`) makes the pattern
390 match from the root of the working tree, even when you are
391 running the command from inside a subdirectory.
393 literal;;
394 Wildcards in the pattern such as `*` or `?` are treated
395 as literal characters.
397 icase;;
398 Case insensitive match.
400 glob;;
401 Git treats the pattern as a shell glob suitable for
402 consumption by fnmatch(3) with the FNM_PATHNAME flag:
403 wildcards in the pattern will not match a / in the pathname.
404 For example, "Documentation/{asterisk}.html" matches
405 "Documentation/git.html" but not "Documentation/ppc/ppc.html"
406 or "tools/perf/Documentation/perf.html".
407 +
408 Two consecutive asterisks ("`**`") in patterns matched against
409 full pathname may have special meaning:
411 - A leading "`**`" followed by a slash means match in all
412 directories. For example, "`**/foo`" matches file or directory
413 "`foo`" anywhere, the same as pattern "`foo`". "`**/foo/bar`"
414 matches file or directory "`bar`" anywhere that is directly
415 under directory "`foo`".
417 - A trailing "`/**`" matches everything inside. For example,
418 "`abc/**`" matches all files inside directory "abc", relative
419 to the location of the `.gitignore` file, with infinite depth.
421 - A slash followed by two consecutive asterisks then a slash
422 matches zero or more directories. For example, "`a/**/b`"
423 matches "`a/b`", "`a/x/b`", "`a/x/y/b`" and so on.
425 - Other consecutive asterisks are considered invalid.
426 +
427 Glob magic is incompatible with literal magic.
429 attr;;
430 After `attr:` comes a space separated list of "attribute
431 requirements", all of which must be met in order for the
432 path to be considered a match; this is in addition to the
433 usual non-magic pathspec pattern matching.
434 See linkgit:gitattributes[5].
435 +
436 Each of the attribute requirements for the path takes one of
437 these forms:
439 - "`ATTR`" requires that the attribute `ATTR` be set.
441 - "`-ATTR`" requires that the attribute `ATTR` be unset.
443 - "`ATTR=VALUE`" requires that the attribute `ATTR` be
444 set to the string `VALUE`.
446 - "`!ATTR`" requires that the attribute `ATTR` be
447 unspecified.
448 +
449 Note that when matching against a tree object, attributes are still
450 obtained from working tree, not from the given tree object.
452 exclude;;
453 After a path matches any non-exclude pathspec, it will be run
454 through all exclude pathspecs (magic signature: `!` or its
455 synonym `^`). If it matches, the path is ignored. When there
456 is no non-exclude pathspec, the exclusion is applied to the
457 result set as if invoked without any pathspec.
458 --
460 [[def_parent]]parent::
461 A <<def_commit_object,commit object>> contains a (possibly empty) list
462 of the logical predecessor(s) in the line of development, i.e. its
463 parents.
465 [[def_peel]]peel::
466 The action of recursively <<def_dereference,dereferencing>> a
467 <<def_tag_object,tag object>>.
469 [[def_pickaxe]]pickaxe::
470 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore
471 routines that help select changes that add or delete a given text
472 string. With the `--pickaxe-all` option, it can be used to view the full
473 <<def_changeset,changeset>> that introduced or removed, say, a
474 particular line of text. See linkgit:git-diff[1].
476 [[def_plumbing]]plumbing::
477 Cute name for <<def_core_git,core Git>>.
479 [[def_porcelain]]porcelain::
480 Cute name for programs and program suites depending on
481 <<def_core_git,core Git>>, presenting a high level access to
482 core Git. Porcelains expose more of a <<def_SCM,SCM>>
483 interface than the <<def_plumbing,plumbing>>.
485 [[def_per_worktree_ref]]per-worktree ref::
486 Refs that are per-<<def_worktree,worktree>>, rather than
487 global. This is presently only <<def_HEAD,HEAD>> and any refs
488 that start with `refs/bisect/`, but might later include other
489 unusual refs.
491 [[def_pseudoref]]pseudoref::
492 Pseudorefs are a class of files under `$GIT_DIR` which behave
493 like refs for the purposes of rev-parse, but which are treated
494 specially by git. Pseudorefs both have names that are all-caps,
495 and always start with a line consisting of a
496 <<def_SHA1,SHA-1>> followed by whitespace. So, HEAD is not a
497 pseudoref, because it is sometimes a symbolic ref. They might
498 optionally contain some additional data. `MERGE_HEAD` and
499 `CHERRY_PICK_HEAD` are examples. Unlike
500 <<def_per_worktree_ref,per-worktree refs>>, these files cannot
501 be symbolic refs, and never have reflogs. They also cannot be
502 updated through the normal ref update machinery. Instead,
503 they are updated by directly writing to the files. However,
504 they can be read as if they were refs, so `git rev-parse
505 MERGE_HEAD` will work.
507 [[def_pull]]pull::
508 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
509 <<def_merge,merge>> it. See also linkgit:git-pull[1].
511 [[def_push]]push::
512 Pushing a <<def_branch,branch>> means to get the branch's
513 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
514 find out if it is an ancestor to the branch's local
515 head ref, and in that case, putting all
516 objects, which are <<def_reachable,reachable>> from the local
517 head ref, and which are missing from the remote
518 repository, into the remote
519 <<def_object_database,object database>>, and updating the remote
520 head ref. If the remote <<def_head,head>> is not an
521 ancestor to the local head, the push fails.
523 [[def_reachable]]reachable::
524 All of the ancestors of a given <<def_commit,commit>> are said to be
525 "reachable" from that commit. More
526 generally, one <<def_object,object>> is reachable from
527 another if we can reach the one from the other by a <<def_chain,chain>>
528 that follows <<def_tag,tags>> to whatever they tag,
529 <<def_commit_object,commits>> to their parents or trees, and
530 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>>
531 that they contain.
533 [[def_reachability_bitmap]]reachability bitmaps::
534 Reachability bitmaps store information about the
535 <<def_reachable,reachability>> of a selected set of commits in
536 a packfile, or a multi-pack index (MIDX), to speed up object search.
537 The bitmaps are stored in a ".bitmap" file. A repository may have at
538 most one bitmap file in use. The bitmap file may belong to either one
539 pack, or the repository's multi-pack index (if it exists).
541 [[def_rebase]]rebase::
542 To reapply a series of changes from a <<def_branch,branch>> to a
543 different base, and reset the <<def_head,head>> of that branch
544 to the result.
546 [[def_ref]]ref::
547 A name that begins with `refs/` (e.g. `refs/heads/master`)
548 that points to an <<def_object_name,object name>> or another
549 ref (the latter is called a <<def_symref,symbolic ref>>).
550 For convenience, a ref can sometimes be abbreviated when used
551 as an argument to a Git command; see linkgit:gitrevisions[7]
552 for details.
553 Refs are stored in the <<def_repository,repository>>.
554 +
555 The ref namespace is hierarchical.
556 Different subhierarchies are used for different purposes (e.g. the
557 `refs/heads/` hierarchy is used to represent local branches).
558 +
559 There are a few special-purpose refs that do not begin with `refs/`.
560 The most notable example is `HEAD`.
562 [[def_reflog]]reflog::
563 A reflog shows the local "history" of a ref. In other words,
564 it can tell you what the 3rd last revision in _this_ repository
565 was, and what was the current state in _this_ repository,
566 yesterday 9:14pm. See linkgit:git-reflog[1] for details.
568 [[def_refspec]]refspec::
569 A "refspec" is used by <<def_fetch,fetch>> and
570 <<def_push,push>> to describe the mapping between remote
571 <<def_ref,ref>> and local ref.
573 [[def_remote]]remote repository::
574 A <<def_repository,repository>> which is used to track the same
575 project but resides somewhere else. To communicate with remotes,
576 see <<def_fetch,fetch>> or <<def_push,push>>.
578 [[def_remote_tracking_branch]]remote-tracking branch::
579 A <<def_ref,ref>> that is used to follow changes from another
580 <<def_repository,repository>>. It typically looks like
581 'refs/remotes/foo/bar' (indicating that it tracks a branch named
582 'bar' in a remote named 'foo'), and matches the right-hand-side of
583 a configured fetch <<def_refspec,refspec>>. A remote-tracking
584 branch should not contain direct modifications or have local
585 commits made to it.
587 [[def_repository]]repository::
588 A collection of <<def_ref,refs>> together with an
589 <<def_object_database,object database>> containing all objects
590 which are <<def_reachable,reachable>> from the refs, possibly
591 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A
592 repository can share an object database with other repositories
593 via <<def_alternate_object_database,alternates mechanism>>.
595 [[def_resolve]]resolve::
596 The action of fixing up manually what a failed automatic
597 <<def_merge,merge>> left behind.
599 [[def_revision]]revision::
600 Synonym for <<def_commit,commit>> (the noun).
602 [[def_rewind]]rewind::
603 To throw away part of the development, i.e. to assign the
604 <<def_head,head>> to an earlier <<def_revision,revision>>.
606 [[def_SCM]]SCM::
607 Source code management (tool).
609 [[def_SHA1]]SHA-1::
610 "Secure Hash Algorithm 1"; a cryptographic hash function.
611 In the context of Git used as a synonym for <<def_object_name,object name>>.
613 [[def_shallow_clone]]shallow clone::
614 Mostly a synonym to <<def_shallow_repository,shallow repository>>
615 but the phrase makes it more explicit that it was created by
616 running `git clone --depth=...` command.
618 [[def_shallow_repository]]shallow repository::
619 A shallow <<def_repository,repository>> has an incomplete
620 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other
621 words, Git is told to pretend that these commits do not have the
622 parents, even though they are recorded in the <<def_commit_object,commit
623 object>>). This is sometimes useful when you are interested only in the
624 recent history of a project even though the real history recorded in the
625 upstream is much larger. A shallow repository
626 is created by giving the `--depth` option to linkgit:git-clone[1], and
627 its history can be later deepened with linkgit:git-fetch[1].
629 [[def_stash]]stash entry::
630 An <<def_object,object>> used to temporarily store the contents of a
631 <<def_dirty,dirty>> working directory and the index for future reuse.
633 [[def_submodule]]submodule::
634 A <<def_repository,repository>> that holds the history of a
635 separate project inside another repository (the latter of
636 which is called <<def_superproject, superproject>>).
638 [[def_superproject]]superproject::
639 A <<def_repository,repository>> that references repositories
640 of other projects in its working tree as <<def_submodule,submodules>>.
641 The superproject knows about the names of (but does not hold
642 copies of) commit objects of the contained submodules.
644 [[def_symref]]symref::
645 Symbolic reference: instead of containing the <<def_SHA1,SHA-1>> id
646 itself, it is of the format 'ref: refs/some/thing' and when referenced,
647 it recursively <<def_dereference,dereferences>> to this reference.
648 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic references
649 are manipulated with the linkgit:git-symbolic-ref[1] command.
651 [[def_tag]]tag::
652 A <<def_ref,ref>> under `refs/tags/` namespace that points to an
653 object of an arbitrary type (typically a tag points to either a
654 <<def_tag_object,tag>> or a <<def_commit_object,commit object>>).
655 In contrast to a <<def_head,head>>, a tag is not updated by
656 the `commit` command. A Git tag has nothing to do with a Lisp
657 tag (which would be called an <<def_object_type,object type>>
658 in Git's context). A tag is most typically used to mark a particular
659 point in the commit ancestry <<def_chain,chain>>.
661 [[def_tag_object]]tag object::
662 An <<def_object,object>> containing a <<def_ref,ref>> pointing to
663 another object, which can contain a message just like a
664 <<def_commit_object,commit object>>. It can also contain a (PGP)
665 signature, in which case it is called a "signed tag object".
667 [[def_topic_branch]]topic branch::
668 A regular Git <<def_branch,branch>> that is used by a developer to
669 identify a conceptual line of development. Since branches are very easy
670 and inexpensive, it is often desirable to have several small branches
671 that each contain very well defined concepts or small incremental yet
672 related changes.
674 [[def_tree]]tree::
675 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree
676 object>> together with the dependent <<def_blob_object,blob>> and tree objects
677 (i.e. a stored representation of a working tree).
679 [[def_tree_object]]tree object::
680 An <<def_object,object>> containing a list of file names and modes along
681 with refs to the associated blob and/or tree objects. A
682 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
684 [[def_tree-ish]]tree-ish (also treeish)::
685 A <<def_tree_object,tree object>> or an <<def_object,object>> that can
686 be recursively <<def_dereference,dereferenced>> to a tree object.
687 Dereferencing a <<def_commit_object,commit object>> yields the tree
688 object corresponding to the <<def_revision,revision>>'s top
689 <<def_directory,directory>>.
690 The following are all tree-ishes:
691 a <<def_commit-ish,commit-ish>>,
692 a tree object,
693 a <<def_tag_object,tag object>> that points to a tree object,
694 a tag object that points to a tag object that points to a tree
695 object,
696 etc.
698 [[def_unmerged_index]]unmerged index::
699 An <<def_index,index>> which contains unmerged
700 <<def_index_entry,index entries>>.
702 [[def_unreachable_object]]unreachable object::
703 An <<def_object,object>> which is not <<def_reachable,reachable>> from a
704 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
706 [[def_upstream_branch]]upstream branch::
707 The default <<def_branch,branch>> that is merged into the branch in
708 question (or the branch in question is rebased onto). It is configured
709 via branch.<name>.remote and branch.<name>.merge. If the upstream branch
710 of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'".
712 [[def_working_tree]]working tree::
713 The tree of actual checked out files. The working tree normally
714 contains the contents of the <<def_HEAD,HEAD>> commit's tree,
715 plus any local changes that you have made but not yet committed.
717 [[def_worktree]]worktree::
718 A repository can have zero (i.e. bare repository) or one or
719 more worktrees attached to it. One "worktree" consists of a
720 "working tree" and repository metadata, most of which are
721 shared among other worktrees of a single repository, and
722 some of which are maintained separately per worktree
723 (e.g. the index, HEAD and pseudorefs like MERGE_HEAD,
724 per-worktree refs and per-worktree configuration file).