X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=Documentation%2Fglossary.txt;h=3f7b1e42b502e1cc87305167ffcb99486132caca;hb=9644ffdd65f10970d54ab56ae128cde6f3fe1b96;hp=2465514e461a4a6c4e61f04ced18d6229eae0f51;hpb=0220f1ebdee113e02031de0dba2d5e2c8623d6bb;p=git.git diff --git a/Documentation/glossary.txt b/Documentation/glossary.txt index 2465514e4..3f7b1e42b 100644 --- a/Documentation/glossary.txt +++ b/Documentation/glossary.txt @@ -2,15 +2,15 @@ GIT Glossary ============ [[def_alternate_object_database]]alternate object database:: - Via the alternates mechanism, a <> can - inherit part of its <> from another - <>, which is called "alternate". + Via the alternates mechanism, a <> + can inherit part of its <> + from another object database, which is called "alternate". [[def_bare_repository]]bare repository:: - A <> is normally an appropriately + A bare repository is normally an appropriately named <> with a `.git` suffix that does not have a locally checked-out copy of any of the files under - <> control. That is, all of the `git` + 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, @@ -21,10 +21,15 @@ GIT Glossary Untyped <>, e.g. the contents of a file. [[def_branch]]branch:: - A non-cyclical graph of revisions, i.e. the complete history of a - particular <>, which is called the - branch <>. The heads - are stored in `$GIT_DIR/refs/heads/`. + A "branch" is an active line of development. The most recent + <> on a branch is referred to as the tip of + that branch. The tip of the branch is referenced by a branch + <>, which moves forward as additional development + is done on the branch. A single git + <> can track an arbitrary number of + branches, but your <> is + associated with just one of them (the "current" or "checked out" + branch), and <> points to that branch. [[def_cache]]cache:: Obsolete for: <>. @@ -32,7 +37,7 @@ GIT Glossary [[def_chain]]chain:: A list of objects, where each <> in the list contains a reference to its successor (for example, the successor of a - <> could be one of its parents). + <> could be one of its <>). [[def_changeset]]changeset:: BitKeeper/cvsps speak for "<>". Since git does not @@ -50,25 +55,32 @@ GIT Glossary 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 <> and to record it based on the tip - of the current <> as a new <>. + of the current <> as a new commit. [[def_clean]]clean:: - A <> is <>, if it + A <> is clean, if it corresponds to the <> referenced by the current <>. Also see "<>". [[def_commit]]commit:: - As a verb: The action of storing the current state of the - <> in the <>. The - result is a <>. As a noun: Short hand for - <>. + 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 <>. ++ +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 <> and advancing <> +to point at the new commit. [[def_commit_object]]commit object:: An <> which contains the information about a - particular <>, such as parents, committer, + particular <>, such as <>, committer, author, date and the <> which corresponds to the top <> of the stored - <>. + revision. [[def_core_git]]core git:: Fundamental data structures and utilities of git. Exposes only limited @@ -77,25 +89,31 @@ GIT Glossary [[def_DAG]]DAG:: Directed acyclic graph. The <> objects form a directed acyclic graph, because they have parents (directed), and the - graph of <> objects is acyclic (there is no + graph of commit objects is acyclic (there is no <> which begins and ends with the same <>). [[def_dangling_object]]dangling object:: An <> which is not <> even from other unreachable objects; a - <> has no references to it from any + dangling object has no references to it from any reference or <> in the <>. +[[def_detached_HEAD]]detached HEAD:: + Normally the <> stores the name of a + <>. However, git also allows you to <> + an arbitrary <> 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. + You are *waaaaay* behind. See <>. [[def_directory]]directory:: The list you get with "ls" :-) [[def_dirty]]dirty:: - A <> is said to be <> if - it contains modifications which have not been committed to the current + A <> is said to be "dirty" if + it contains modifications which have not been <> to the current <>. [[def_ent]]ent:: @@ -103,22 +121,26 @@ GIT Glossary `http://en.wikipedia.org/wiki/Ent_(Middle-earth)` for an in-depth explanation. Avoid this term, not to confuse people. +[[def_evil_merge]]evil merge:: + An evil merge is a <> that introduces changes that + do not appear in any <>. + [[def_fast_forward]]fast forward:: A fast-forward is a special type of <> where you have a <> and you are "merging" another <>'s changes that happen to be a descendant of what you have. In such these cases, you do not make a new <> <> but instead just update to his - <>. This will happen frequently on a + revision. This will happen frequently on a <> of a remote <>. [[def_fetch]]fetch:: Fetching a <> means to get the - <>'s <> from a remote - <>, to find out which objects are missing - from the local <>, and to get them, - too. + branch's <> from a remote + <>, to find out which objects are + missing from the local <>, + 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, @@ -131,62 +153,84 @@ GIT Glossary [[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 <> has - is different from what was recorded when the <> was + you can make git pretend the set of <> a <> 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_head]]head:: - The top of a <>. It contains a <> to the - corresponding <>. + A <> to the <> at the tip of a + <>. Heads are stored in + `$GIT_DIR/refs/heads/`, except when using packed refs. (See + gitlink:git-pack-refs[1].) + +[[def_HEAD]]HEAD:: + The current <>. In more detail: Your <> is normally derived from the state of the tree + referred to by HEAD. HEAD is a reference to one of the + <> in your repository, except when using a + <>, in which case it may + reference an arbitrary commit. [[def_head_ref]]head ref:: - A <> pointing to a <>. Often, this is - abbreviated to "<>". Head refs are stored in - `$GIT_DIR/refs/heads/`. + A synonym for <>. [[def_hook]]hook:: During the normal execution of several git commands, call-outs are made to optional scripts that allow a developer to add functionality or checking. Typically, the hooks allow for a command to be pre-verified and potentially aborted, and allow for a post-notification after the - operation is done. The <> scripts are found in the - `$GIT_DIR/hooks/` <>, and are enabled by simply + operation is done. The hook scripts are found in the + `$GIT_DIR/hooks/` 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 <> is a stored version of your working - <>. Truth be told, it can also contain a second, and even - a third version of a <>, which are used - when merging. + as objects. The index is a stored version of your + <>. Truth be told, it can also contain a second, and even + a third version of a working tree, which are used + when <>. [[def_index_entry]]index entry:: The information regarding a particular file, stored in the - <>. An <> can be unmerged, - if a <> was started, but not yet finished (i.e. if the - <> contains multiple versions of that file). + <>. An index entry can be unmerged, if a + <> was started, but not yet finished (i.e. if + the index contains multiple versions of that file). [[def_master]]master:: - The default development <>. Whenever you create a git - <>, a <> named - "<>" is created, and becomes the active - <>. In most cases, this contains the local - development, though that is purely conventional and not required. + The default development <>. Whenever you + create a git <>, 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:: - To <> branches means to try to accumulate the changes - since a common ancestor and apply them to the first - <>. An automatic <> uses heuristics - to accomplish that. Evidently, an automatic <> can - fail. + As a verb: To bring the contents of another + <> (possibly from an external + <>) into the current branch. In the + case where the merged-in branch is from a different repository, + this is done by first <> the remote branch + and then merging the result into the current branch. This + combination of fetch and merge operations is called a + <>. 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 <>, a +successful merge results in the creation of a new <> +representing the result of the merge, and having as +<> the tips of the merged <>. +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 <> of its contents. Consequently, an - <> can not be changed. + object can not be changed. [[def_object_database]]object database:: Stores a set of "objects", and an individual <> is @@ -198,9 +242,9 @@ GIT Glossary [[def_object_name]]object name:: The unique identifier of an <>. The <> - of the <>'s contents using the Secure Hash Algorithm + of the object's contents using the Secure Hash Algorithm 1 and usually represented by the 40 character hexadecimal encoding of - the <> of the <> (possibly followed by + the <> of the object (possibly followed by a white space). [[def_object_type]]object type:: @@ -209,16 +253,16 @@ GIT Glossary describing the type of an <>. [[def_octopus]]octopus:: - To <> more than two branches. Also denotes an + To <> more than two <>. Also denotes an intelligent predator. [[def_origin]]origin:: The default upstream <>. Most projects have at least one upstream project which they track. By default - '<>' is used for that purpose. New upstream updates - will be fetched into remote tracking branches named + 'origin' is used for that purpose. New upstream updates + will be fetched into remote <> named origin/name-of-upstream-branch, which you can see using - "git <> -r". + "`git branch -r`". [[def_pack]]pack:: A set of objects which have been compressed into one file (to save space @@ -227,7 +271,7 @@ GIT Glossary [[def_pack_index]]pack index:: The list of identifiers, and other information, of the objects in a <>, to assist in efficiently accessing the contents of a - <>. + pack. [[def_parent]]parent:: A <> contains a (possibly empty) list @@ -247,29 +291,29 @@ GIT Glossary [[def_porcelain]]porcelain:: Cute name for programs and program suites depending on <>, presenting a high level access to - <>. Porcelains expose more of a <> + core git. Porcelains expose more of a <> interface than the <>. [[def_pull]]pull:: Pulling a <> means to <> it and - <> it. + <> it. See also gitlink:git-pull[1]. [[def_push]]push:: - Pushing a <> means to get the <>'s + Pushing a <> means to get the branch's <> from a remote <>, - find out if it is an ancestor to the <>'s local - <> is a direct, and in that case, putting all + 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 <> from the local - <>, and which are missing from the remote - <>, into the remote + head ref, and which are missing from the remote + repository, into the remote <>, and updating the remote - <>. If the remote <> is not an - ancestor to the local <>, the <> fails. + head ref. If the remote <> is not an + ancestor to the local head, the push fails. [[def_reachable]]reachable:: All of the ancestors of a given <> are said to be - <> from that <>. More - generally, one <> is <> from + "reachable" from that commit. More + generally, one <> is reachable from another if we can reach the one from the other by a <> that follows <> to whatever they tag, <> to their parents or trees, and @@ -286,26 +330,32 @@ GIT Glossary denotes a particular <>. These may be stored in `$GIT_DIR/refs/`. +[[def_reflog]]reflog:: + A reflog shows the local "history" of a ref. In other words, + it can tell you what the 3rd last revision in _this_ repository + was, and what was the current state in _this_ repository, + yesterday 9:14pm. See gitlink:git-reflog[1] for details. + [[def_refspec]]refspec:: - A <> is used by <> and - <> to describe the mapping between remote <> - and local <>. They are combined with a colon in the format - :, preceded by an optional plus sign, +. For example: `git - fetch $URL refs/heads/master:refs/heads/origin` means - "grab the master <> <> - from the $URL and store it as my origin - <> <>". And `git <> - $URL refs/heads/master:refs/heads/to-upstream` means - "publish my master <> - <> as to-upstream <> at $URL". See - also gitlink:git-push[1] + A "refspec" is used by <> and + <> to describe the mapping between remote + <> and local ref. They are combined with a colon in + the format :, preceded by an optional plus sign, +. + For example: `git fetch $URL + refs/heads/master:refs/heads/origin` means "grab the master + <> <> 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 <> containing all objects which are <> - from the refs, possibly accompanied by meta data from one or more - porcelains. A <> can share an - <> with other repositories. + A collection of <> together with an + <> containing all objects + which are <> from the refs, possibly + accompanied by meta data from one or more <>. A + repository can share an object database with other repositories + via <>. [[def_resolve]]resolve:: The action of fixing up manually what a failed automatic @@ -327,39 +377,39 @@ GIT Glossary Synonym for <>. [[def_shallow_repository]]shallow repository:: - A <> has an incomplete - history some of whose commits have parents cauterized away (in other + A shallow <> has an incomplete + history some of whose <> have <> 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 <>). 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 <> + 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 <> id - itself, it is of the format 'ref: refs/some/thing' and when - referenced, it recursively dereferences to this reference. 'HEAD' is a - prime example of a <>. Symbolic references are - manipulated with the gitlink:git-symbolic-ref[1] command. + Symbolic reference: instead of containing the <> + id itself, it is of the format 'ref: refs/some/thing' and when + referenced, it recursively dereferences to this reference. + '<>' is a prime example of a symref. Symbolic + references are manipulated with the gitlink:git-symbolic-ref[1] + command. [[def_tag]]tag:: - A <> pointing to a <> or + A <> pointing to a <> or <>. In contrast to a <>, a tag is not changed by a <>. Tags (not <>) are stored in `$GIT_DIR/refs/tags/`. A git tag has nothing to do with a Lisp tag (which would be called an <> in git's context). A tag is most typically used to mark a particular point in the - <> ancestry <>. + commit ancestry <>. [[def_tag_object]]tag object:: An <> containing a <> pointing to - another <>, which can contain a message just like a + another object, which can contain a message just like a <>. It can also contain a (PGP) - signature, in which case it is called a "signed <>". + signature, in which case it is called a "signed tag object". [[def_topic_branch]]topic branch:: A regular git <> that is used by a developer to @@ -370,16 +420,16 @@ GIT Glossary [[def_tracking_branch]]tracking branch:: A regular git <> that is used to follow changes from - another <>. A <> should not contain direct modifications or have local commits - made to it. A <> can usually be + another <>. 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 <> in a Pull: <>. [[def_tree]]tree:: Either a <>, or a <> together with the dependent blob and <> objects - (i.e. a stored representation of a <>). + object>> together with the dependent <> and tree objects + (i.e. a stored representation of a working tree). [[def_tree_object]]tree object:: An <> containing a list of file names and modes along @@ -389,8 +439,7 @@ GIT Glossary [[def_tree-ish]]tree-ish:: A <> pointing to either a <>, a <>, or a <> pointing to a <> or <> or - <>. + object>> pointing to a tag or commit or tree object. [[def_unmerged_index]]unmerged index:: An <> which contains unmerged @@ -401,5 +450,6 @@ GIT Glossary <>, <>, or any other reference. [[def_working_tree]]working tree:: - The set of files and directories currently being worked on, i.e. you can - work in your <> without using git at all. + The tree of actual checked out files. The working tree is + normally equal to the <> plus any local changes + that you have made but not yet committed.