1GITGLOSSARY(7)                    Git Manual                    GITGLOSSARY(7)


6       gitglossary - A Git Glossary


9       *


12       alternate object database
13           Via the alternates mechanism, a repository can inherit part of its
14           object database from another object database, which is called an
15           "alternate".
17       bare repository
18           A bare repository is normally an appropriately named directory with
19           a .git suffix that does not have a locally checked-out copy of any
20           of the files under revision control. That is, all of the Git
21           administrative and control files that would normally be present in
22           the hidden .git sub-directory are directly present in the
23           repository.git directory instead, and no other files are present
24           and checked out. Usually publishers of public repositories make
25           bare repositories available.
27       blob object
28           Untyped object, e.g. the contents of a file.
30       branch
31           A "branch" is an active line of development. The most recent commit
32           on a branch is referred to as the tip of that branch. The tip of
33           the branch is referenced by a branch head, which moves forward as
34           additional development is done on the branch. A single Git
35           repository can track an arbitrary number of branches, but your
36           working tree is associated with just one of them (the "current" or
37           "checked out" branch), and HEAD points to that branch.
39       cache
40           Obsolete for: index.
42       chain
43           A list of objects, where each object in the list contains a
44           reference to its successor (for example, the successor of a commit
45           could be one of its parents).
47       changeset
48           BitKeeper/cvsps speak for "commit". Since Git does not store
49           changes, but states, it really does not make sense to use the term
50           "changesets" with Git.
52       checkout
53           The action of updating all or part of the working tree with a tree
54           object or blob from the object database, and updating the index and
55           HEAD if the whole working tree has been pointed at a new branch.
57       cherry-picking
58           In SCM jargon, "cherry pick" means to choose a subset of changes
59           out of a series of changes (typically commits) and record them as a
60           new series of changes on top of a different codebase. In Git, this
61           is performed by the "git cherry-pick" command to extract the change
62           introduced by an existing commit and to record it based on the tip
63           of the current branch as a new commit.
65       clean
66           A working tree is clean, if it corresponds to the revision
67           referenced by the current head. Also see "dirty".
69       commit
70           As a noun: A single point in the Git history; the entire history of
71           a project is represented as a set of interrelated commits. The word
72           "commit" is often used by Git in the same places other revision
73           control systems use the words "revision" or "version". Also used as
74           a short hand for commit object.
76           As a verb: The action of storing a new snapshot of the project’s
77           state in the Git history, by creating a new commit representing the
78           current state of the index and advancing HEAD to point at the new
79           commit.
81       commit object
82           An object which contains the information about a particular
83           revision, such as parents, committer, author, date and the tree
84           object which corresponds to the top directory of the stored
85           revision.
87       commit-ish (also committish)
88           A commit object or an object that can be recursively dereferenced
89           to a commit object. The following are all commit-ishes: a commit
90           object, a tag object that points to a commit object, a tag object
91           that points to a tag object that points to a commit object, etc.
93       core Git
94           Fundamental data structures and utilities of Git. Exposes only
95           limited source code management tools.
97       DAG
98           Directed acyclic graph. The commit objects form a directed acyclic
99           graph, because they have parents (directed), and the graph of
100           commit objects is acyclic (there is no chain which begins and ends
101           with the same object).
103       dangling object
104           An unreachable object which is not reachable even from other
105           unreachable objects; a dangling object has no references to it from
106           any reference or object in the repository.
108       detached HEAD
109           Normally the HEAD stores the name of a branch, and commands that
110           operate on the history HEAD represents operate on the history
111           leading to the tip of the branch the HEAD points at. However, Git
112           also allows you to check out an arbitrary commit that isn’t
113           necessarily the tip of any particular branch. The HEAD in such a
114           state is called "detached".
116           Note that commands that operate on the history of the current
117           branch (e.g.  git commit to build a new history on top of it) still
118           work while the HEAD is detached. They update the HEAD to point at
119           the tip of the updated history without affecting any branch.
120           Commands that update or inquire information about the current
121           branch (e.g.  git branch --set-upstream-to that sets what
122           remote-tracking branch the current branch integrates with)
123           obviously do not work, as there is no (real) current branch to ask
124           about in this state.
126       directory
127           The list you get with "ls" :-)
129       dirty
130           A working tree is said to be "dirty" if it contains modifications
131           which have not been committed to the current branch.
133       evil merge
134           An evil merge is a merge that introduces changes that do not appear
135           in any parent.
137       fast-forward
138           A fast-forward is a special type of merge where you have a revision
139           and you are "merging" another branch's changes that happen to be a
140           descendant of what you have. In such a case, you do not make a new
141           merge commit but instead just update to his revision. This will
142           happen frequently on a remote-tracking branch of a remote
143           repository.
145       fetch
146           Fetching a branch means to get the branch’s head ref from a remote
147           repository, to find out which objects are missing from the local
148           object database, and to get them, too. See also git-fetch(1).
150       file system
151           Linus Torvalds originally designed Git to be a user space file
152           system, i.e. the infrastructure to hold files and directories. That
153           ensured the efficiency and speed of Git.
155       Git archive
156           Synonym for repository (for arch people).
158       gitfile
159           A plain file .git at the root of a working tree that points at the
160           directory that is the real repository.
162       grafts
163           Grafts enables two otherwise different lines of development to be
164           joined together by recording fake ancestry information for commits.
165           This way you can make Git pretend the set of parents a commit has
166           is different from what was recorded when the commit was created.
167           Configured via the .git/info/grafts file.
169           Note that the grafts mechanism is outdated and can lead to problems
170           transferring objects between repositories; see git-replace(1) for a
171           more flexible and robust system to do the same thing.
173       hash
174           In Git’s context, synonym for object name.
176       head
177           A named reference to the commit at the tip of a branch. Heads are
178           stored in a file in $GIT_DIR/refs/heads/ directory, except when
179           using packed refs. (See git-pack-refs(1).)
181       HEAD
182           The current branch. In more detail: Your working tree is normally
183           derived from the state of the tree referred to by HEAD. HEAD is a
184           reference to one of the heads in your repository, except when using
185           a detached HEAD, in which case it directly references an arbitrary
186           commit.
188       head ref
189           A synonym for head.
191       hook
192           During the normal execution of several Git commands, call-outs are
193           made to optional scripts that allow a developer to add
194           functionality or checking. Typically, the hooks allow for a command
195           to be pre-verified and potentially aborted, and allow for a
196           post-notification after the operation is done. The hook scripts are
197           found in the $GIT_DIR/hooks/ directory, and are enabled by simply
198           removing the .sample suffix from the filename. In earlier versions
199           of Git you had to make them executable.
201       index
202           A collection of files with stat information, whose contents are
203           stored as objects. The index is a stored version of your working
204           tree. Truth be told, it can also contain a second, and even a third
205           version of a working tree, which are used when merging.
207       index entry
208           The information regarding a particular file, stored in the index.
209           An index entry can be unmerged, if a merge was started, but not yet
210           finished (i.e. if the index contains multiple versions of that
211           file).
213       master
214           The default development branch. Whenever you create a Git
215           repository, a branch named "master" is created, and becomes the
216           active branch. In most cases, this contains the local development,
217           though that is purely by convention and is not required.
219       merge
220           As a verb: To bring the contents of another branch (possibly from
221           an external repository) into the current branch. In the case where
222           the merged-in branch is from a different repository, this is done
223           by first fetching the remote branch and then merging the result
224           into the current branch. This combination of fetch and merge
225           operations is called a pull. Merging is performed by an automatic
226           process that identifies changes made since the branches diverged,
227           and then applies all those changes together. In cases where changes
228           conflict, manual intervention may be required to complete the
229           merge.
231           As a noun: unless it is a fast-forward, a successful merge results
232           in the creation of a new commit representing the result of the
233           merge, and having as parents the tips of the merged branches. This
234           commit is referred to as a "merge commit", or sometimes just a
235           "merge".
237       object
238           The unit of storage in Git. It is uniquely identified by the SHA-1
239           of its contents. Consequently, an object can not be changed.
241       object database
242           Stores a set of "objects", and an individual object is identified
243           by its object name. The objects usually live in $GIT_DIR/objects/.
245       object identifier
246           Synonym for object name.
248       object name
249           The unique identifier of an object. The object name is usually
250           represented by a 40 character hexadecimal string. Also colloquially
251           called SHA-1.
253       object type
254           One of the identifiers "commit", "tree", "tag" or "blob" describing
255           the type of an object.
257       octopus
258           To merge more than two branches.
260       origin
261           The default upstream repository. Most projects have at least one
262           upstream project which they track. By default origin is used for
263           that purpose. New upstream updates will be fetched into
264           remote-tracking branches named origin/name-of-upstream-branch,
265           which you can see using git branch -r.
267       pack
268           A set of objects which have been compressed into one file (to save
269           space or to transmit them efficiently).
271       pack index
272           The list of identifiers, and other information, of the objects in a
273           pack, to assist in efficiently accessing the contents of a pack.
275       pathspec
276           Pattern used to limit paths in Git commands.
278           Pathspecs are used on the command line of "git ls-files", "git
279           ls-tree", "git add", "git grep", "git diff", "git checkout", and
280           many other commands to limit the scope of operations to some subset
281           of the tree or worktree. See the documentation of each command for
282           whether paths are relative to the current directory or toplevel.
283           The pathspec syntax is as follows:
285           ·   any path matches itself
287           ·   the pathspec up to the last slash represents a directory
288               prefix. The scope of that pathspec is limited to that subtree.
290           ·   the rest of the pathspec is a pattern for the remainder of the
291               pathname. Paths relative to the directory prefix will be
292               matched against that pattern using fnmatch(3); in particular, *
293               and ?  can match directory separators.
295           For example, Documentation/*.jpg will match all .jpg files in the
296           Documentation subtree, including
297           Documentation/chapter_1/figure_1.jpg.
299           A pathspec that begins with a colon : has special meaning. In the
300           short form, the leading colon : is followed by zero or more "magic
301           signature" letters (which optionally is terminated by another colon
302           :), and the remainder is the pattern to match against the path. The
303           "magic signature" consists of ASCII symbols that are neither
304           alphanumeric, glob, regex special characters nor colon. The
305           optional colon that terminates the "magic signature" can be omitted
306           if the pattern begins with a character that does not belong to
307           "magic signature" symbol set and is not a colon.
309           In the long form, the leading colon : is followed by a open
310           parenthesis (, a comma-separated list of zero or more "magic
311           words", and a close parentheses ), and the remainder is the pattern
312           to match against the path.
314           A pathspec with only a colon means "there is no pathspec". This
315           form should not be combined with other pathspec.
317           top
318               The magic word top (magic signature: /) makes the pattern match
319               from the root of the working tree, even when you are running
320               the command from inside a subdirectory.
322           literal
323               Wildcards in the pattern such as * or ?  are treated as literal
324               characters.
326           icase
327               Case insensitive match.
329           glob
330               Git treats the pattern as a shell glob suitable for consumption
331               by fnmatch(3) with the FNM_PATHNAME flag: wildcards in the
332               pattern will not match a / in the pathname. For example,
333               "Documentation/*.html" matches "Documentation/git.html" but not
334               "Documentation/ppc/ppc.html" or
335               "tools/perf/Documentation/perf.html".
337               Two consecutive asterisks ("**") in patterns matched against
338               full pathname may have special meaning:
340               ·   A leading "**" followed by a slash means match in all
341                   directories. For example, "**/foo" matches file or
342                   directory "foo" anywhere, the same as pattern "foo".
343                   "**/foo/bar" matches file or directory "bar" anywhere that
344                   is directly under directory "foo".
346               ·   A trailing "/**" matches everything inside. For example,
347                   "abc/**" matches all files inside directory "abc", relative
348                   to the location of the .gitignore file, with infinite
349                   depth.
351               ·   A slash followed by two consecutive asterisks then a slash
352                   matches zero or more directories. For example, "a/**/b"
353                   matches "a/b", "a/x/b", "a/x/y/b" and so on.
355               ·   Other consecutive asterisks are considered invalid.
357                   Glob magic is incompatible with literal magic.
359           attr
360               After attr: comes a space separated list of "attribute
361               requirements", all of which must be met in order for the path
362               to be considered a match; this is in addition to the usual
363               non-magic pathspec pattern matching. See gitattributes(5).
365               Each of the attribute requirements for the path takes one of
366               these forms:
368               ·   "ATTR" requires that the attribute ATTR be set.
370               ·   "-ATTR" requires that the attribute ATTR be unset.
372               ·   "ATTR=VALUE" requires that the attribute ATTR be set to the
373                   string VALUE.
375               ·   "!ATTR" requires that the attribute ATTR be unspecified.
377           exclude
378               After a path matches any non-exclude pathspec, it will be run
379               through all exclude pathspecs (magic signature: !  or its
380               synonym ^). If it matches, the path is ignored. When there is
381               no non-exclude pathspec, the exclusion is applied to the result
382               set as if invoked without any pathspec.
384       parent
385           A commit object contains a (possibly empty) list of the logical
386           predecessor(s) in the line of development, i.e. its parents.
388       pickaxe
389           The term pickaxe refers to an option to the diffcore routines that
390           help select changes that add or delete a given text string. With
391           the --pickaxe-all option, it can be used to view the full changeset
392           that introduced or removed, say, a particular line of text. See
393           git-diff(1).
395       plumbing
396           Cute name for core Git.
398       porcelain
399           Cute name for programs and program suites depending on core Git,
400           presenting a high level access to core Git. Porcelains expose more
401           of a SCM interface than the plumbing.
403       per-worktree ref
404           Refs that are per-worktree, rather than global. This is presently
405           only HEAD and any refs that start with refs/bisect/, but might
406           later include other unusual refs.
408       pseudoref
409           Pseudorefs are a class of files under $GIT_DIR which behave like
410           refs for the purposes of rev-parse, but which are treated specially
411           by git. Pseudorefs both have names that are all-caps, and always
412           start with a line consisting of a SHA-1 followed by whitespace. So,
413           HEAD is not a pseudoref, because it is sometimes a symbolic ref.
414           They might optionally contain some additional data.  MERGE_HEAD and
415           CHERRY_PICK_HEAD are examples. Unlike per-worktree refs, these
416           files cannot be symbolic refs, and never have reflogs. They also
417           cannot be updated through the normal ref update machinery. Instead,
418           they are updated by directly writing to the files. However, they
419           can be read as if they were refs, so git rev-parse MERGE_HEAD will
420           work.
422       pull
423           Pulling a branch means to fetch it and merge it. See also git-
424           pull(1).
426       push
427           Pushing a branch means to get the branch’s head ref from a remote
428           repository, find out if it is an ancestor to the branch’s local
429           head ref, and in that case, putting all objects, which are
430           reachable from the local head ref, and which are missing from the
431           remote repository, into the remote object database, and updating
432           the remote head ref. If the remote head is not an ancestor to the
433           local head, the push fails.
435       reachable
436           All of the ancestors of a given commit are said to be "reachable"
437           from that commit. More generally, one object is reachable from
438           another if we can reach the one from the other by a chain that
439           follows tags to whatever they tag, commits to their parents or
440           trees, and trees to the trees or blobs that they contain.
442       rebase
443           To reapply a series of changes from a branch to a different base,
444           and reset the head of that branch to the result.
446       ref
447           A name that begins with refs/ (e.g.  refs/heads/master) that points
448           to an object name or another ref (the latter is called a symbolic
449           ref). For convenience, a ref can sometimes be abbreviated when used
450           as an argument to a Git command; see gitrevisions(7) for details.
451           Refs are stored in the repository.
453           The ref namespace is hierarchical. Different subhierarchies are
454           used for different purposes (e.g. the refs/heads/ hierarchy is used
455           to represent local branches).
457           There are a few special-purpose refs that do not begin with refs/.
458           The most notable example is HEAD.
460       reflog
461           A reflog shows the local "history" of a ref. In other words, it can
462           tell you what the 3rd last revision in this repository was, and
463           what was the current state in this repository, yesterday 9:14pm.
464           See git-reflog(1) for details.
466       refspec
467           A "refspec" is used by fetch and push to describe the mapping
468           between remote ref and local ref.
470       remote repository
471           A repository which is used to track the same project but resides
472           somewhere else. To communicate with remotes, see fetch or push.
474       remote-tracking branch
475           A ref that is used to follow changes from another repository. It
476           typically looks like refs/remotes/foo/bar (indicating that it
477           tracks a branch named bar in a remote named foo), and matches the
478           right-hand-side of a configured fetch refspec. A remote-tracking
479           branch should not contain direct modifications or have local
480           commits made to it.
482       repository
483           A collection of refs together with an object database containing
484           all objects which are reachable from the refs, possibly accompanied
485           by meta data from one or more porcelains. A repository can share an
486           object database with other repositories via alternates mechanism.
488       resolve
489           The action of fixing up manually what a failed automatic merge left
490           behind.
492       revision
493           Synonym for commit (the noun).
495       rewind
496           To throw away part of the development, i.e. to assign the head to
497           an earlier revision.
499       SCM
500           Source code management (tool).
502       SHA-1
503           "Secure Hash Algorithm 1"; a cryptographic hash function. In the
504           context of Git used as a synonym for object name.
506       shallow clone
507           Mostly a synonym to shallow repository but the phrase makes it more
508           explicit that it was created by running git clone --depth=...
509           command.
511       shallow repository
512           A shallow repository has an incomplete history some of whose
513           commits have parents cauterized away (in other words, Git is told
514           to pretend that these commits do not have the parents, even though
515           they are recorded in the commit object). This is sometimes useful
516           when you are interested only in the recent history of a project
517           even though the real history recorded in the upstream is much
518           larger. A shallow repository is created by giving the --depth
519           option to git-clone(1), and its history can be later deepened with
520           git-fetch(1).
522       stash entry
523           An object used to temporarily store the contents of a dirty working
524           directory and the index for future reuse.
526       submodule
527           A repository that holds the history of a separate project inside
528           another repository (the latter of which is called superproject).
530       superproject
531           A repository that references repositories of other projects in its
532           working tree as submodules. The superproject knows about the names
533           of (but does not hold copies of) commit objects of the contained
534           submodules.
536       symref
537           Symbolic reference: instead of containing the SHA-1 id itself, it
538           is of the format ref: refs/some/thing and when referenced, it
539           recursively dereferences to this reference.  HEAD is a prime
540           example of a symref. Symbolic references are manipulated with the
541           git-symbolic-ref(1) command.
543       tag
544           A ref under refs/tags/ namespace that points to an object of an
545           arbitrary type (typically a tag points to either a tag or a commit
546           object). In contrast to a head, a tag is not updated by the commit
547           command. A Git tag has nothing to do with a Lisp tag (which would
548           be called an object type in Git’s context). A tag is most typically
549           used to mark a particular point in the commit ancestry chain.
551       tag object
552           An object containing a ref pointing to another object, which can
553           contain a message just like a commit object. It can also contain a
554           (PGP) signature, in which case it is called a "signed tag object".
556       topic branch
557           A regular Git branch that is used by a developer to identify a
558           conceptual line of development. Since branches are very easy and
559           inexpensive, it is often desirable to have several small branches
560           that each contain very well defined concepts or small incremental
561           yet related changes.
563       tree
564           Either a working tree, or a tree object together with the dependent
565           blob and tree objects (i.e. a stored representation of a working
566           tree).
568       tree object
569           An object containing a list of file names and modes along with refs
570           to the associated blob and/or tree objects. A tree is equivalent to
571           a directory.
573       tree-ish (also treeish)
574           A tree object or an object that can be recursively dereferenced to
575           a tree object. Dereferencing a commit object yields the tree object
576           corresponding to the revision's top directory. The following are
577           all tree-ishes: a commit-ish, a tree object, a tag object that
578           points to a tree object, a tag object that points to a tag object
579           that points to a tree object, etc.
581       unmerged index
582           An index which contains unmerged index entries.
584       unreachable object
585           An object which is not reachable from a branch, tag, or any other
586           reference.
588       upstream branch
589           The default branch that is merged into the branch in question (or
590           the branch in question is rebased onto). It is configured via
591           branch.<name>.remote and branch.<name>.merge. If the upstream
592           branch of A is origin/B sometimes we say "A is tracking origin/B".
594       working tree
595           The tree of actual checked out files. The working tree normally
596           contains the contents of the HEAD commit’s tree, plus any local
597           changes that you have made but not yet committed.


600       gittutorial(7), gittutorial-2(7), gitcvs-migration(7), giteveryday(7),
601       The Git User’s Manual[1]


604       Part of the git(1) suite


607        1. The Git User’s Manual
608           file:///usr/share/doc/git/user-manual.html
612Git 2.18.1                        05/14/2019                    GITGLOSSARY(7)