# info > GITGLOSSARY --- type: CommandReference command: gitglossary mode: man section: 7 source: man-pages --- ## Quick Reference - `commit` — A single point in Git history; a snapshot of the project’s state. - `branch` — A line of development; its tip is the most recent commit. - `HEAD` — The current branch or detached commit; basis for the working tree. - `index` — Staging area containing a stored version of the working tree. - `merge` — Bringing changes from another branch into the current branch, creating a merge commit if not fast-forward. - `remote` — A repository elsewhere that tracks the same project; default name `origin`. - `repository` — Collection of refs and object database holding project history. - `rebase` — Reapply a series of changes from a branch to a different base, rewriting history. ## Name gitglossary - A Git Glossary ## Synopsis * ## Glossary - `alternate object database` — Via the alternates mechanism, a repository can inherit part of its object database from another. - `bare repository` — A repository directory with `.git` suffix, containing Git administrative files directly, with no checked-out working tree. - `blob object` — Untyped object, e.g. the contents of a file. - `branch` — A line of development; the most recent commit is its tip, referenced by a branch head. A repository can track many branches; the working tree is associated with the current branch, and `HEAD` points to it. - `cache` — Obsolete for `index`. - `chain` — A list of objects, each containing a reference to its successor. - `changeset` — BitKeeper/cvsps term for "commit". Git does not store changes, so the term does not apply. - `checkout` — The action of updating the working tree, index, and `HEAD` from the object database. - `cherry-picking` — Selecting a subset of changes from a series of commits and recording them on a different base. Performed by `git cherry-pick`. - `clean` — A working tree that corresponds to the revision referenced by the current `HEAD`. - `commit` — Noun: a single point in Git history; the entire history is a set of interrelated commits. Also used as a short hand for `commit object`. Verb: creating a new commit representing the current index and advancing `HEAD`. - `commit object` — An object containing revision information: parents, author, committer, date, and the tree object of the top directory of the stored revision. - `commit-ish` (also `committish`) — A commit object, or an object that can be recursively dereferenced to a commit (e.g. a tag that points to a commit). - `core Git` — Fundamental data structures and utilities of Git, exposing limited source code management tools. - `DAG` — Directed acyclic graph. The commit objects form a DAG because they have parents (directed) and there is no cycle. - `dangling object` — An unreachable object that is not reachable even from other unreachable objects; no references to it exist in the repository. - `detached HEAD` — State where `HEAD` points directly to a commit, not a branch. Commands that update history work, but branch-related commands (e.g. setting upstream) do not. - `directory` — The list you get with `ls` :-) - `dirty` — A working tree that contains uncommitted modifications. - `evil merge` — A merge that introduces changes not present in any parent. - `fast-forward` — A merge where the branch being merged is a descendant of the current branch; no new merge commit is created, only the branch pointer is updated. Common on remote-tracking branches. - `fetch` — Retrieving a branch’s head ref from a remote repository and fetching missing objects. See [git-fetch(1)](http://localhost/phpMan.php/man/git-fetch/1/markdown). - `file system` — Git was originally designed as a user-space file system to hold files and directories. - `Git archive` — Synonym for `repository` (used by arch people). - `gitfile` — A plain `.git` file at the root of a working tree that points to the real repository directory. - `grafts` — Outdated mechanism to record fake ancestry information for commits. Replaced by [git-replace(1)](http://localhost/phpMan.php/man/git-replace/1/markdown). - `hash` — Synonym for `object name`. - `head` — A named reference to the commit at the tip of a branch. Stored in `$GIT_DIR/refs/heads/`, except when using packed refs. See [git-pack-refs(1)](http://localhost/phpMan.php/man/git-pack-refs/1/markdown). - `HEAD` — The current branch; normally a reference to one of the heads. In detached HEAD state, it directly references an arbitrary commit. The working tree is derived from the tree referred to by `HEAD`. - `head ref` — Synonym for `head`. - `hook` — Optional scripts called during execution of Git commands, located in `$GIT_DIR/hooks/`. Enabled by removing the `.sample` suffix. - `index` — A collection of files with stat information, whose contents are stored as objects. It is a stored version of the working tree and can contain multiple versions during a merge. - `index entry` — Information about a file in the index. Can be unmerged if a merge is in progress. - `master` — The default development branch. Created automatically when a repository is initialized. - `merge` — Verb: to bring the contents of another branch into the current branch. If the merged-in branch is from a different repository, fetching is done first; the combination of fetch and merge is called a pull. Automatic, but conflicts may require manual resolution. Noun: unless fast-forward, the new commit resulting from a merge, with multiple parents (a merge commit). - `object` — The unit of storage in Git, uniquely identified by the SHA-1 of its contents. Immutable. - `object database` — Stores objects, usually in `$GIT_DIR/objects/`. - `object identifier` — Synonym for `object name`. - `object name` — The unique identifier of an object, represented by a 40-character hexadecimal string. Also called SHA-1. - `object type` — One of `commit`, `tree`, `tag`, or `blob`. - `octopus` — Merging more than two branches. - `origin` — The default upstream repository. Fetched into remote-tracking branches named `origin/`. - `overlay` — Only update and add files to the working directory, but do not delete them. Default checkout mode. The opposite, no-overlay, also deletes tracked files not present in the source. - `pack` — A set of objects compressed into one file to save space or to transmit efficiently. - `pack index` — List of identifiers and other information of objects in a pack, to assist access. - `pathspec` — Pattern used to limit paths in Git commands. Syntax: directory prefix up to the last slash, then a pattern matched via [fnmatch(3)](http://localhost/phpMan.php/man/fnmatch/3/markdown). Magic signatures: `top` (root-relative), `literal` (no wildcards), `icase` (case-insensitive), `glob` (shell glob with `**` for recursion; `**/foo` matches anywhere, `abc/**` matches everything inside `abc`, `a/**/b` matches `a/b`, `a/x/b`, etc.), `attr:` (attribute requirements; see [gitattributes(5)](http://localhost/phpMan.php/man/gitattributes/5/markdown)), `exclude` (ignore matching paths). Short form: `::pattern`; long form: `:()pattern`. A lone colon means “no pathspec”. Glob and literal magic are incompatible. - `parent` — A commit object’s logical predecessor(s) in the line of development. - `pickaxe` — Diffcore option to select changes that add or delete a given text string. See [git-diff(1)](http://localhost/phpMan.php/man/git-diff/1/markdown). - `plumbing` — Cute name for core Git. - `porcelain` — High-level programs and suites that depend on core Git, presenting a more SCM-like interface. - `per-worktree ref` — Refs that are per-working-tree, such as `HEAD` and refs starting with `refs/bisect/`. - `pseudoref` — Files under `$GIT_DIR` (e.g. `MERGE_HEAD`, `CHERRY_PICK_HEAD`) that behave like refs but have all-caps names, contain a SHA-1, cannot be symbolic, and are updated by direct file writes. Readable via `git rev-parse`. - `pull` — Fetching a branch and merging it. See [git-pull(1)](http://localhost/phpMan.php/man/git-pull/1/markdown). - `push` — Updating a remote branch’s head ref with local objects, if the remote head is an ancestor. Otherwise fails. - `reachable` — An object is reachable from another if it can be reached via a chain of tags, commits, or trees. All ancestors of a commit are reachable from it. - `rebase` — Reapplying a series of changes from a branch to a different base and resetting the head of that branch. - `ref` — A name beginning with `refs/` (e.g. `refs/heads/master`) that points to an object name or another ref (symbolic ref). Special refs like `HEAD` do not start with `refs/`. See [gitrevisions(7)](http://localhost/phpMan.php/man/gitrevisions/7/markdown). - `reflog` — The local “history” of a ref, showing what the ref pointed to at various times. See [git-reflog(1)](http://localhost/phpMan.php/man/git-reflog/1/markdown). - `refspec` — A mapping between remote ref and local ref used by fetch and push. - `remote repository` — A repository that tracks the same project but resides elsewhere. - `remote-tracking branch` — A ref like `refs/remotes//` that follows changes from another repository. Should not be directly modified. - `repository` — A collection of refs together with an object database containing all reachable objects, possibly with metadata from porcelains. Can share an object database via alternates. - `resolve` — Fixing up a failed automatic merge manually. - `revision` — Synonym for `commit` (noun). - `rewind` — Assigning the head to an earlier revision, discarding later commits. - `SCM` — Source code management (tool). - `SHA-1` — Secure Hash Algorithm 1; a cryptographic hash function. In Git, synonym for `object name`. - `shallow clone` — A clone created with `--depth`, resulting in a shallow repository. - `shallow repository` — A repository with incomplete history where some parent edges are cauterized. Created with `git clone --depth` and deepened with [git-fetch(1)](http://localhost/phpMan.php/man/git-fetch/1/markdown). - `stash entry` — An object used to temporarily store the contents of a dirty working directory and index for future reuse. - `submodule` — A repository that holds the history of a separate project inside another repository (the superproject). - `superproject` — A repository that references submodules in its working tree. - `symref` — Symbolic reference of the form `ref: refs/some/thing`; dereferences recursively to the target. `HEAD` is a prime example. Manipulated with [git-symbolic-ref(1)](http://localhost/phpMan.php/man/git-symbolic-ref/1/markdown). - `tag` — A ref under `refs/tags/` pointing to an object (typically a commit or tag). Not updated by commit. Used to mark specific points in history. - `tag object` — An object containing a ref pointing to another object, possibly with a message and a (PGP) signature (signed tag object). - `topic branch` — A regular branch used by a developer to isolate a conceptual line of development. - `tree` — Either a working tree, or a tree object together with the dependent blob and tree objects (a stored representation of a working tree). - `tree object` — An object containing a list of file names, modes, and refs to associated blob and tree objects. Equivalent to a directory. - `tree-ish` (also `treeish`) — A tree object or an object that can be recursively dereferenced to a tree (e.g. a commit-ish). - `unmerged index` — An index containing unmerged index entries. - `unreachable object` — An object not reachable from any branch, tag, or other reference. - `upstream branch` — The default branch merged into the branch in question (or the branch rebased onto). Configured via `branch..remote` and `branch..merge`. - `working tree` — The tree of actually checked-out files. Contains the contents of the `HEAD` commit’s tree plus any local uncommitted changes. ## See Also - [gittutorial(7)](http://localhost/phpMan.php/man/gittutorial/7/markdown) - [gittutorial-2(7)](http://localhost/phpMan.php/man/gittutorial-2/7/markdown) - [gitcvs-migration(7)](http://localhost/phpMan.php/man/gitcvs-migration/7/markdown) - [giteveryday(7)](http://localhost/phpMan.php/man/giteveryday/7/markdown) - [The Git User’s Manual](file:///usr/share/doc/git/html/user-manual.html)