-alternate object database::
- Via the alternates mechanism, a repository can inherit part of its
- object database from another object database, which is called
- "alternate".
-
-bare repository::
- A bare repository is normally an appropriately named
- directory with a `.git` suffix that does not have a
- locally checked-out copy of any of the files under revision
- control. That is, all of the `git` administrative and
- control files that would normally be present in the
- hidden `.git` sub-directory are directly present in
- the `repository.git` directory instead, and no other files
- are present and checked out. Usually publishers of public
- repositories make bare repositories available.
-
-blob object::
- Untyped object, e.g. the contents of a file.
-
-branch::
- A non-cyclical graph of revisions, i.e. the complete history of
- a particular revision, which is called the branch head. The
- branch heads are stored in `$GIT_DIR/refs/heads/`.
-
-cache::
- Obsolete for: index.
-
-chain::
- A list of objects, where each object in the list contains a
- reference to its successor (for example, the successor of a commit
- could be one of its parents).
-
-changeset::
- BitKeeper/cvsps speak for "commit". Since git does not store
- changes, but states, it really does not make sense to use
- the term "changesets" with git.
-
-checkout::
- The action of updating the working tree to a revision which was
- stored in the object database.
-
-cherry-picking::
- In SCM jargon, "cherry pick" means to choose a subset of
- changes out of a series of changes (typically commits)
- and record them as a new series of changes on top of
- different codebase. In GIT, this is performed by
- "git cherry-pick" command to extract the change
- introduced by an existing commit and to record it based
- on the tip of the current branch as a new commit.
-
-clean::
- A working tree is clean, if it corresponds to the revision
- referenced by the current head. Also see "dirty".
-
-commit::
- As a verb: The action of storing the current state of the index in the
- object database. The result is a revision.
- As a noun: Short hand for commit object.
-
-commit object::
- An object which contains the information about a particular
- revision, such as parents, committer, author, date and the
- tree object which corresponds to the top directory of the
- stored revision.
-
-core git::
- Fundamental data structures and utilities of git. Exposes only
- limited source code management tools.
-
-DAG::
- Directed acyclic graph. The commit objects form a directed acyclic
- graph, because they have parents (directed), and the graph of commit
- objects is acyclic (there is no chain which begins and ends with the
- same object).
-
-dircache::
+GIT Glossary
+============
+
+[[def_alternate_object_database]]alternate object database::
+ Via the alternates mechanism, a <<def_repository,repository>>
+ can inherit part of its <<def_object_database,object database>>
+ from another object database, which is called "alternate".
+
+[[def_bare_repository]]bare repository::
+ A bare repository is normally an appropriately
+ named <<def_directory,directory>> with a `.git` suffix that does not
+ have a locally checked-out copy of any of the files under
+ <<def_revision,revision>> control. That is, all of the `git`
+ administrative and control files that would normally be present in the
+ hidden `.git` sub-directory are directly present in the
+ `repository.git` directory instead,
+ and no other files are present and checked out. Usually publishers of
+ public repositories make bare repositories available.
+
+[[def_blob_object]]blob object::
+ Untyped <<def_object,object>>, e.g. the contents of a file.
+
+[[def_branch]]branch::
+ A "branch" is an active line of development. The most recent
+ <<def_commit,commit>> on a branch is referred to as the tip of
+ that branch. The tip of the branch is referenced by a branch
+ <<def_head,head>>, which moves forward as additional development
+ is done on the branch. A single git
+ <<def_repository,repository>> can track an arbitrary number of
+ branches, but your <<def_working_tree,working tree>> is
+ associated with just one of them (the "current" or "checked out"
+ branch), and <<def_HEAD,HEAD>> points to that branch.
+
+[[def_cache]]cache::
+ Obsolete for: <<def_index,index>>.
+
+[[def_chain]]chain::
+ A list of objects, where each <<def_object,object>> in the list contains
+ a reference to its successor (for example, the successor of a
+ <<def_commit,commit>> could be one of its parents).
+
+[[def_changeset]]changeset::
+ BitKeeper/cvsps speak for "<<def_commit,commit>>". Since git does not
+ store changes, but states, it really does not make sense to use the term
+ "changesets" with git.
+
+[[def_checkout]]checkout::
+ The action of updating the <<def_working_tree,working tree>> to a
+ <<def_revision,revision>> which was stored in the
+ <<def_object_database,object database>>.
+
+[[def_cherry-picking]]cherry-picking::
+ In <<def_SCM,SCM>> jargon, "cherry pick" means to choose a subset of
+ changes out of a series of changes (typically commits) and record them
+ as a new series of changes on top of different codebase. In GIT, this is
+ performed by "git cherry-pick" command to extract the change introduced
+ by an existing <<def_commit,commit>> and to record it based on the tip
+ of the current <<def_branch,branch>> as a new commit.
+
+[[def_clean]]clean::
+ A <<def_working_tree,working tree>> is clean, if it
+ corresponds to the <<def_revision,revision>> referenced by the current
+ <<def_head,head>>. Also see "<<def_dirty,dirty>>".
+
+[[def_commit]]commit::
+ As a noun: A single point in the
+ git history; the entire history of a project is represented as a
+ set of interrelated commits. The word "commit" is often
+ used by git in the same places other revision control systems
+ use the words "revision" or "version". Also used as a short
+ hand for <<def_commit_object,commit object>>.
++
+As a verb: The action of storing a new snapshot of the project's
+state in the git history, by creating a new commit representing the current
+state of the <<def_index,index>> and advancing <<def_HEAD,HEAD>>
+to point at the new commit.
+
+[[def_commit_object]]commit object::
+ An <<def_object,object>> which contains the information about a
+ particular <<def_revision,revision>>, such as parents, committer,
+ author, date and the <<def_tree_object,tree object>> which corresponds
+ to the top <<def_directory,directory>> of the stored
+ <<def_revision,revision>>.
+
+[[def_core_git]]core git::
+ Fundamental data structures and utilities of git. Exposes only limited
+ source code management tools.
+
+[[def_DAG]]DAG::
+ Directed acyclic graph. The <<def_commit,commit>> objects form a
+ directed acyclic graph, because they have parents (directed), and the
+ graph of commit objects is acyclic (there is no
+ <<def_chain,chain>> which begins and ends with the same
+ <<def_object,object>>).
+
+[[def_dangling_object]]dangling object::
+ An <<def_unreachable_object,unreachable object>> which is not
+ <<def_reachable,reachable>> even from other unreachable objects; a
+ dangling object has no references to it from any
+ reference or <<def_object,object>> in the <<def_repository,repository>>.
+
+[[def_detached_HEAD]]detached HEAD::
+ Normally the <<def_HEAD,HEAD>> stores the name of a
+ <<def_branch,branch>>. However, git also allows you to check
+ out an arbitrary commit that isn't necessarily the tip of any
+ particular branch. In this case HEAD is said to be "detached".
+
+[[def_dircache]]dircache::
You are *waaaaay* behind.
-dirty::
- A working tree is said to be dirty if it contains modifications
- which have not been committed to the current branch.
-
-directory::
+[[def_directory]]directory::
The list you get with "ls" :-)
-ent::
- Favorite synonym to "tree-ish" by some total geeks. See
+[[def_dirty]]dirty::
+ A <<def_working_tree,working tree>> is said to be "dirty" if
+ it contains modifications which have not been committed to the current
+ <<def_branch,branch>>.
+
+[[def_ent]]ent::
+ Favorite synonym to "<<def_tree-ish,tree-ish>>" by some total geeks. See
`http://en.wikipedia.org/wiki/Ent_(Middle-earth)` for an in-depth
- explanation. Avoid this term, not to confuse people.
-
-fast forward::
- A fast-forward is a special type of merge where you have
- a revision and you are "merging" another branch's changes
- that happen to be a descendant of what you have.
- In such these cases, you do not make a new merge commit but
- instead just update to his revision. This will happen
- frequently on a tracking branch of a remote repository.
-
-fetch::
- Fetching a branch means to get the branch's head ref from a
- remote repository, to find out which objects are missing from
- the local object database, and to get them, too.
-
-file system::
- Linus Torvalds originally designed git to be a user space file
- system, i.e. the infrastructure to hold files and directories.
- That ensured the efficiency and speed of git.
-
-git archive::
- Synonym for repository (for arch people).
-
-grafts::
- Grafts enables two otherwise different lines of development to be
- joined together by recording fake ancestry information for commits.
- This way you can make git pretend the set of parents a commit
- has is different from what was recorded when the commit was created.
- Configured via the `.git/info/grafts` file.
-
-hash::
- In git's context, synonym to object name.
-
-head::
- The top of a branch. It contains a ref to the corresponding
- commit object.
-
-head ref::
- A ref pointing to a head. Often, this is abbreviated to "head".
- Head refs are stored in `$GIT_DIR/refs/heads/`.
-
-hook::
- During the normal execution of several git commands,
- call-outs are made to optional scripts that allow
- a developer to add functionality or checking.
- Typically, the hooks allow for a command to be pre-verified
- and potentially aborted, and allow for a post-notification
- after the operation is done.
- The hook scripts are found in the `$GIT_DIR/hooks/` directory,
- and are enabled by simply making them executable.
-
-index::
- A collection of files with stat information, whose contents are
- stored as objects. The index is a stored version of your working
- tree. Truth be told, it can also contain a second, and even a third
- version of a working tree, which are used when merging.
-
-index entry::
- The information regarding a particular file, stored in the index.
- An index entry can be unmerged, if a merge was started, but not
- yet finished (i.e. if the index contains multiple versions of
- that file).
-
-master::
- The default development branch. Whenever you create a git
- repository, a branch named "master" is created, and becomes
- the active branch. In most cases, this contains the local
- development, though that is purely conventional and not required.
-
-merge::
- To merge branches means to try to accumulate the changes since a
- common ancestor and apply them to the first branch. An automatic
- merge uses heuristics to accomplish that. Evidently, an automatic
- merge can fail.
-
-object::
- The unit of storage in git. It is uniquely identified by
- the SHA1 of its contents. Consequently, an object can not
- be changed.
-
-object database::
- Stores a set of "objects", and an individual object is identified
- by its object name. The objects usually live in `$GIT_DIR/objects/`.
-
-object identifier::
- Synonym for object name.
-
-object name::
- The unique identifier of an object. The hash of the object's contents
- using the Secure Hash Algorithm 1 and usually represented by the 40
- character hexadecimal encoding of the hash of the object (possibly
- followed by a white space).
-
-object type:
- One of the identifiers "commit","tree","tag" and "blob" describing
- the type of an object.
-
-octopus::
- To merge more than two branches. Also denotes an intelligent
- predator.
-
-origin::
- The default upstream tracking branch. Most projects have at
- least one upstream project which they track. By default
- 'origin' is used for that purpose. New upstream updates
- will be fetched into this branch; you should never commit
- to it yourself.
-
-pack::
- A set of objects which have been compressed into one file (to save
- space or to transmit them efficiently).
-
-pack index::
+ explanation. Avoid this term, not to confuse people.
+
+[[def_fast_forward]]fast forward::
+ A fast-forward is a special type of <<def_merge,merge>> where you have a
+ <<def_revision,revision>> and you are "merging" another
+ <<def_branch,branch>>'s changes that happen to be a descendant of what
+ you have. In such these cases, you do not make a new <<def_merge,merge>>
+ <<def_commit,commit>> but instead just update to his
+ revision. This will happen frequently on a
+ <<def_tracking_branch,tracking branch>> of a remote
+ <<def_repository,repository>>.
+
+[[def_fetch]]fetch::
+ Fetching a <<def_branch,branch>> means to get the
+ branch's <<def_head_ref,head ref>> from a remote
+ <<def_repository,repository>>, to find out which objects are
+ missing from the local <<def_object_database,object database>>,
+ and to get them, too. See also gitlink:git-fetch[1].
+
+[[def_file_system]]file system::
+ Linus Torvalds originally designed git to be a user space file system,
+ i.e. the infrastructure to hold files and directories. That ensured the
+ efficiency and speed of git.
+
+[[def_git_archive]]git archive::
+ Synonym for <<def_repository,repository>> (for arch people).
+
+[[def_grafts]]grafts::
+ Grafts enables two otherwise different lines of development to be joined
+ together by recording fake ancestry information for commits. This way
+ you can make git pretend the set of parents a <<def_commit,commit>> has
+ is different from what was recorded when the commit was
+ created. Configured via the `.git/info/grafts` file.
+
+[[def_hash]]hash::
+ In git's context, synonym to <<def_object_name,object name>>.
+
+[[def_head]]head::
+ A named reference to the <<def_commit,commit>> at the tip of a
+ <<def_branch,branch>>. Heads are stored in
+ `$GIT_DIR/refs/heads/`, except when using packed refs. (See
+ gitlink:git-pack-refs[1].)
+
+[[def_HEAD]]HEAD::
+ The current branch. In more detail: Your <<def_working_tree,
+ working tree>> is normally derived from the state of the tree
+ referred to by HEAD. HEAD is a reference to one of the
+ <<def_head,heads>> in your repository, except when using a
+ <<def_detached_HEAD,detached HEAD>>, in which case it may
+ reference an arbitrary commit.
+
+[[def_head_ref]]head ref::
+ A synonym for <<def_head,head>>.
+
+[[def_hook]]hook::
+ During the normal execution of several git commands, call-outs are made
+ to optional scripts that allow a developer to add functionality or
+ checking. Typically, the hooks allow for a command to be pre-verified
+ and potentially aborted, and allow for a post-notification after the
+ operation is done. The hook scripts are found in the
+ `$GIT_DIR/hooks/` <<def_directory,directory>>, and are enabled by simply
+ making them executable.
+
+[[def_index]]index::
+ A collection of files with stat information, whose contents are stored
+ as objects. The index is a stored version of your working
+ <<def_tree,tree>>. Truth be told, it can also contain a second, and even
+ a third version of a <<def_working_tree,working tree>>, which are used
+ when merging.
+
+[[def_index_entry]]index entry::
+ The information regarding a particular file, stored in the
+ <<def_index,index>>. An index entry can be unmerged, if a
+ <<def_merge,merge>> was started, but not yet finished (i.e. if
+ the index contains multiple versions of that file).
+
+[[def_master]]master::
+ The default development <<def_branch,branch>>. Whenever you
+ create a git <<def_repository,repository>>, a branch named
+ "master" is created, and becomes the active branch. In most
+ cases, this contains the local development, though that is
+ purely by convention and is not required.
+
+[[def_merge]]merge::
+ As a verb: To bring the contents of another
+ <<def_branch,branch>> (possibly from an external
+ <<def_repository,repository>>) into the current branch. In the
+ case where the merged-in branch is from a different repository,
+ this is done by first <<def_fetch,fetching>> the remote branch
+ and then merging the result into the current branch. This
+ combination of fetch and merge operations is called a
+ <<def_pull,pull>>. Merging is performed by an automatic process
+ that identifies changes made since the branches diverged, and
+ then applies all those changes together. In cases where changes
+ conflict, manual intervention may be required to complete the
+ merge.
++
+As a noun: unless it is a <<def_fast_forward,fast forward>>, a
+successful merge results in the creation of a new <<def_commit,commit>>
+representing the result of the merge, and having as
+<<def_parent,parents>> the tips of the merged <<def_branch,branches>>.
+This commit is referred to as a "merge commit", or sometimes just a
+"merge".
+
+[[def_object]]object::
+ The unit of storage in git. It is uniquely identified by the
+ <<def_SHA1,SHA1>> of its contents. Consequently, an
+ object can not be changed.
+
+[[def_object_database]]object database::
+ Stores a set of "objects", and an individual <<def_object,object>> is
+ identified by its <<def_object_name,object name>>. The objects usually
+ live in `$GIT_DIR/objects/`.
+
+[[def_object_identifier]]object identifier::
+ Synonym for <<def_object_name,object name>>.
+
+[[def_object_name]]object name::
+ The unique identifier of an <<def_object,object>>. The <<def_hash,hash>>
+ of the object's contents using the Secure Hash Algorithm
+ 1 and usually represented by the 40 character hexadecimal encoding of
+ the <<def_hash,hash>> of the object (possibly followed by
+ a white space).
+
+[[def_object_type]]object type::
+ One of the identifiers
+ "<<def_commit,commit>>","<<def_tree,tree>>","<<def_tag,tag>>" or "<<def_blob_object,blob>>"
+ describing the type of an <<def_object,object>>.
+
+[[def_octopus]]octopus::
+ To <<def_merge,merge>> more than two branches. Also denotes an
+ intelligent predator.
+
+[[def_origin]]origin::
+ The default upstream <<def_repository,repository>>. Most projects have
+ at least one upstream project which they track. By default
+ 'origin' is used for that purpose. New upstream updates
+ will be fetched into remote tracking branches named
+ origin/name-of-upstream-branch, which you can see using
+ "git <<def_branch,branch>> -r".
+
+[[def_pack]]pack::
+ A set of objects which have been compressed into one file (to save space
+ or to transmit them efficiently).
+
+[[def_pack_index]]pack index::
The list of identifiers, and other information, of the objects in a
- pack, to assist in efficiently accessing the contents of a pack.
-
-parent::
- A commit object contains a (possibly empty) list of the logical
- predecessor(s) in the line of development, i.e. its parents.
-
-pickaxe::
- The term pickaxe refers to an option to the diffcore routines
- that help select changes that add or delete a given text string.
- With the --pickaxe-all option, it can be used to view the
- full changeset that introduced or removed, say, a particular
- line of text. See gitlink:git-diff[1].
-
-plumbing::
- Cute name for core git.
-
-porcelain::
- Cute name for programs and program suites depending on core git,
- presenting a high level access to core git. Porcelains expose
- more of a SCM interface than the plumbing.
-
-pull::
- Pulling a branch means to fetch it and merge it.
-
-push::
- Pushing a branch means to get the branch's head ref from a remote
- repository, find out if it is an ancestor to the branch's local
- head ref is a direct, and in that case, putting all objects, which
- are reachable from the local head ref, and which are missing from
- the remote repository, into the remote object database, and updating
- the remote head ref. If the remote head is not an ancestor to the
- local head, the push fails.
-
-reachable::
- An object is reachable from a ref/commit/tree/tag, if there is a
- chain leading from the latter to the former.
-
-rebase::
- To clean a branch by starting from the head of the main line of
- development ("master"), and reapply the (possibly cherry-picked)
- changes from that branch.
-
-ref::
- A 40-byte hex representation of a SHA1 or a name that denotes
- a particular object. These may be stored in `$GIT_DIR/refs/`.
-
-refspec::
- A refspec is used by fetch and push to describe the mapping
- between remote ref and local ref. They are combined with
- a colon in the format <src>:<dst>, preceded by an optional
- plus sign, +. For example:
- `git fetch $URL refs/heads/master:refs/heads/origin`
- means "grab the master branch head from the $URL and store
- it as my origin branch head".
- And `git push $URL refs/heads/master:refs/heads/to-upstream`
- means "publish my master branch head as to-upstream master head
- at $URL". See also gitlink:git-push[1]
-
-repository::
- A collection of refs together with an object database containing
- all objects, which are reachable from the refs, possibly accompanied
- by meta data from one or more porcelains. A repository can
- share an object database with other repositories.
-
-resolve::
- The action of fixing up manually what a failed automatic merge
- left behind.
-
-revision::
- A particular state of files and directories which was stored in
- the object database. It is referenced by a commit object.
-
-rewind::
- To throw away part of the development, i.e. to assign the head to
- an earlier revision.
-
-SCM::
+ <<def_pack,pack>>, to assist in efficiently accessing the contents of a
+ pack.
+
+[[def_parent]]parent::
+ A <<def_commit_object,commit object>> contains a (possibly empty) list
+ of the logical predecessor(s) in the line of development, i.e. its
+ parents.
+
+[[def_pickaxe]]pickaxe::
+ The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore
+ routines that help select changes that add or delete a given text
+ string. With the --pickaxe-all option, it can be used to view the full
+ <<def_changeset,changeset>> that introduced or removed, say, a
+ particular line of text. See gitlink:git-diff[1].
+
+[[def_plumbing]]plumbing::
+ Cute name for <<def_core_git,core git>>.
+
+[[def_porcelain]]porcelain::
+ Cute name for programs and program suites depending on
+ <<def_core_git,core git>>, presenting a high level access to
+ core git. Porcelains expose more of a <<def_SCM,SCM>>
+ interface than the <<def_plumbing,plumbing>>.
+
+[[def_pull]]pull::
+ Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
+ <<def_merge,merge>> it. See also gitlink:git-pull[1].
+
+[[def_push]]push::
+ Pushing a <<def_branch,branch>> means to get the branch's
+ <<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
+ find out if it is an ancestor to the branch's local
+ head ref is a direct, and in that case, putting all
+ objects, which are <<def_reachable,reachable>> from the local
+ head ref, and which are missing from the remote
+ repository, into the remote
+ <<def_object_database,object database>>, and updating the remote
+ head ref. If the remote <<def_head,head>> is not an
+ ancestor to the local head, the push fails.
+
+[[def_reachable]]reachable::
+ All of the ancestors of a given <<def_commit,commit>> are said to be
+ "reachable" from that commit. More
+ generally, one <<def_object,object>> is reachable from
+ another if we can reach the one from the other by a <<def_chain,chain>>
+ that follows <<def_tag,tags>> to whatever they tag,
+ <<def_commit_object,commits>> to their parents or trees, and
+ <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>>
+ that they contain.
+
+[[def_rebase]]rebase::
+ To reapply a series of changes from a <<def_branch,branch>> to a
+ different base, and reset the <<def_head,head>> of that branch
+ to the result.
+
+[[def_ref]]ref::
+ A 40-byte hex representation of a <<def_SHA1,SHA1>> or a name that
+ denotes a particular <<def_object,object>>. These may be stored in
+ `$GIT_DIR/refs/`.
+
+[[def_refspec]]refspec::
+ A <<def_refspec,refspec>> is used by <<def_fetch,fetch>> and
+ <<def_push,push>> to describe the mapping between remote
+ <<def_ref,ref>> and local ref. They are combined with a colon in
+ the format <src>:<dst>, preceded by an optional plus sign, +.
+ For example: `git fetch $URL
+ refs/heads/master:refs/heads/origin` means "grab the master
+ <<def_branch,branch>> <<def_head,head>> from the $URL and store
+ it as my origin branch head". And `git push
+ $URL refs/heads/master:refs/heads/to-upstream` means "publish my
+ master branch head as to-upstream branch at $URL". See also
+ gitlink:git-push[1]
+
+[[def_repository]]repository::
+ A collection of refs together with an
+ <<def_object_database,object database>> containing all objects
+ which are <<def_reachable,reachable>> from the refs, possibly
+ accompanied by meta data from one or more porcelains. A
+ repository can share an object database with other repositories.
+
+[[def_resolve]]resolve::
+ The action of fixing up manually what a failed automatic
+ <<def_merge,merge>> left behind.
+
+[[def_revision]]revision::
+ A particular state of files and directories which was stored in the
+ <<def_object_database,object database>>. It is referenced by a
+ <<def_commit_object,commit object>>.
+
+[[def_rewind]]rewind::
+ To throw away part of the development, i.e. to assign the
+ <<def_head,head>> to an earlier <<def_revision,revision>>.
+
+[[def_SCM]]SCM::
Source code management (tool).
-SHA1::
- Synonym for object name.
-
-topic branch::
- A regular git branch that is used by a developer to
- identify a conceptual line of development. Since branches
- are very easy and inexpensive, it is often desirable to
- have several small branches that each contain very well
- defined concepts or small incremental yet related changes.
-
-tracking branch::
- A regular git branch that is used to follow changes from
- another repository. A tracking branch should not contain
- direct modifications or have local commits made to it.
- A tracking branch can usually be identified as the
- right-hand-side ref in a Pull: refspec.
-
-tree object::
- An object containing a list of file names and modes along with refs
- to the associated blob and/or tree objects. A tree is equivalent
- to a directory.
-
-tree::
- Either a working tree, or a tree object together with the
- dependent blob and tree objects (i.e. a stored representation
- of a working tree).
-
-tree-ish::
- A ref pointing to either a commit object, a tree object, or a
- tag object pointing to a tag or commit or tree object.
-
-tag object::
- An object containing a ref pointing to another object, which can
- contain a message just like a commit object. It can also
- contain a (PGP) signature, in which case it is called a "signed
- tag object".
-
-tag::
- A ref pointing to a tag or commit object. In contrast to a head,
- a tag is not changed by a commit. Tags (not tag objects) are
- stored in `$GIT_DIR/refs/tags/`. A git tag has nothing to do with
- a Lisp tag (which is called object type in git's context).
- A tag is most typically used to mark a particular point in the
- commit ancestry chain.
-
-unmerged index:
- An index which contains unmerged index entries.
-
-working tree::
- The set of files and directories currently being worked on,
- i.e. you can work in your working tree without using git at all.
-
+[[def_SHA1]]SHA1::
+ Synonym for <<def_object_name,object name>>.
+
+[[def_shallow_repository]]shallow repository::
+ A shallow repository has an incomplete
+ history some of whose commits have parents cauterized away (in other
+ words, git is told to pretend that these commits do not have the
+ parents, even though they are recorded in the <<def_commit_object,commit
+ object>>). This is sometimes useful when you are interested only in the
+ recent history of a project even though the real history recorded in the
+ upstream is much larger. A shallow repository
+ is created by giving the `--depth` option to gitlink:git-clone[1], and
+ its history can be later deepened with gitlink:git-fetch[1].
+
+[[def_symref]]symref::
+ Symbolic reference: instead of containing the <<def_SHA1,SHA1>>
+ id itself, it is of the format 'ref: refs/some/thing' and when
+ referenced, it recursively dereferences to this reference.
+ '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic
+ references are manipulated with the gitlink:git-symbolic-ref[1]
+ command.
+
+[[def_tag]]tag::
+ A <<def_ref,ref>> pointing to a tag or
+ <<def_commit_object,commit object>>. In contrast to a <<def_head,head>>,
+ a tag is not changed by a <<def_commit,commit>>. Tags (not
+ <<def_tag_object,tag objects>>) are stored in `$GIT_DIR/refs/tags/`. A
+ git tag has nothing to do with a Lisp tag (which would be
+ called an <<def_object_type,object type>> in git's context). A
+ tag is most typically used to mark a particular point in the
+ commit ancestry <<def_chain,chain>>.
+
+[[def_tag_object]]tag object::
+ An <<def_object,object>> containing a <<def_ref,ref>> pointing to
+ another object, which can contain a message just like a
+ <<def_commit_object,commit object>>. It can also contain a (PGP)
+ signature, in which case it is called a "signed <<def_tag_object,tag
+ object>>".
+
+[[def_topic_branch]]topic branch::
+ A regular git <<def_branch,branch>> that is used by a developer to
+ identify a conceptual line of development. Since branches are very easy
+ and inexpensive, it is often desirable to have several small branches
+ that each contain very well defined concepts or small incremental yet
+ related changes.
+
+[[def_tracking_branch]]tracking branch::
+ A regular git <<def_branch,branch>> that is used to follow changes from
+ another <<def_repository,repository>>. A tracking
+ branch should not contain direct modifications or have local commits
+ made to it. A tracking branch can usually be
+ identified as the right-hand-side <<def_ref,ref>> in a Pull:
+ <<def_refspec,refspec>>.
+
+[[def_tree]]tree::
+ Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree
+ object>> together with the dependent blob and tree objects
+ (i.e. a stored representation of a working tree).
+
+[[def_tree_object]]tree object::
+ An <<def_object,object>> containing a list of file names and modes along
+ with refs to the associated blob and/or tree objects. A
+ <<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
+
+[[def_tree-ish]]tree-ish::
+ A <<def_ref,ref>> pointing to either a <<def_commit_object,commit
+ object>>, a <<def_tree_object,tree object>>, or a <<def_tag_object,tag
+ object>> pointing to a tag or commit or tree object.
+
+[[def_unmerged_index]]unmerged index::
+ An <<def_index,index>> which contains unmerged
+ <<def_index_entry,index entries>>.
+
+[[def_unreachable_object]]unreachable object::
+ An <<def_object,object>> which is not <<def_reachable,reachable>> from a
+ <<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
+
+[[def_working_tree]]working tree::
+ The tree of actual checked out files. The working tree is
+ normally equal to the <<def_HEAD,HEAD>> plus any local changes
+ that you have made but not yet committed.