1alternate object database:: 2 Via the alternates mechanism, a repository can inherit part of its 3 object database from another object database, which is called 4 "alternate". 5 6bare repository:: 7 A bare repository is normally an appropriately named 8 directory with a `.git` suffix that does not have a 9 locally checked-out copy of any of the files under revision 10 control. That is, all of the `git` administrative and 11 control files that would normally be present in the 12 hidden `.git` sub-directory are directly present in 13 the `repository.git` directory instead, and no other files 14 are present and checked out. Usually publishers of public 15 repositories make bare repositories available. 16 17blob object:: 18 Untyped object, e.g. the contents of a file. 19 20branch:: 21 A non-cyclical graph of revisions, i.e. the complete history of 22 a particular revision, which is called the branch head. The 23 branch heads are stored in `$GIT_DIR/refs/heads/`. 24 25cache:: 26 Obsolete for: index. 27 28chain:: 29 A list of objects, where each object in the list contains a 30 reference to its successor (for example, the successor of a commit 31 could be one of its parents). 32 33changeset:: 34 BitKeeper/cvsps speak for "commit". Since git does not store 35 changes, but states, it really does not make sense to use 36 the term "changesets" with git. 37 38checkout:: 39 The action of updating the working tree to a revision which was 40 stored in the object database. 41 42cherry-picking:: 43 In SCM jargon, "cherry pick" means to choose a subset of 44 changes out of a series of changes (typically commits) 45 and record them as a new series of changes on top of 46 different codebase. In GIT, this is performed by 47 "git cherry-pick" command to extract the change 48 introduced by an existing commit and to record it based 49 on the tip of the current branch as a new commit. 50 51clean:: 52 A working tree is clean, if it corresponds to the revision 53 referenced by the current head. Also see "dirty". 54 55commit:: 56 As a verb: The action of storing the current state of the index in the 57 object database. The result is a revision. 58 As a noun: Short hand for commit object. 59 60commit object:: 61 An object which contains the information about a particular 62 revision, such as parents, committer, author, date and the 63 tree object which corresponds to the top directory of the 64 stored revision. 65 66core git:: 67 Fundamental data structures and utilities of git. Exposes only 68 limited source code management tools. 69 70DAG:: 71 Directed acyclic graph. The commit objects form a directed acyclic 72 graph, because they have parents (directed), and the graph of commit 73 objects is acyclic (there is no chain which begins and ends with the 74 same object). 75 76dangling object:: 77 An unreachable object which is not reachable even from other 78 unreachable objects; a dangling object has no references to it 79 from any reference or object in the repository. 80 81dircache:: 82 You are *waaaaay* behind. 83 84dirty:: 85 A working tree is said to be dirty if it contains modifications 86 which have not been committed to the current branch. 87 88directory:: 89 The list you get with "ls" :-) 90 91ent:: 92 Favorite synonym to "tree-ish" by some total geeks. See 93 `http://en.wikipedia.org/wiki/Ent_(Middle-earth)` for an in-depth 94 explanation. Avoid this term, not to confuse people. 95 96fast forward:: 97 A fast-forward is a special type of merge where you have 98 a revision and you are "merging" another branch's changes 99 that happen to be a descendant of what you have. 100 In such these cases, you do not make a new merge commit but 101 instead just update to his revision. This will happen 102 frequently on a tracking branch of a remote repository. 103 104fetch:: 105 Fetching a branch means to get the branch's head ref from a 106 remote repository, to find out which objects are missing from 107 the local object database, and to get them, too. 108 109file system:: 110 Linus Torvalds originally designed git to be a user space file 111 system, i.e. the infrastructure to hold files and directories. 112 That ensured the efficiency and speed of git. 113 114git archive:: 115 Synonym for repository (for arch people). 116 117grafts:: 118 Grafts enables two otherwise different lines of development to be 119 joined together by recording fake ancestry information for commits. 120 This way you can make git pretend the set of parents a commit 121 has is different from what was recorded when the commit was created. 122 Configured via the `.git/info/grafts` file. 123 124hash:: 125 In git's context, synonym to object name. 126 127head:: 128 The top of a branch. It contains a ref to the corresponding 129 commit object. 130 131head ref:: 132 A ref pointing to a head. Often, this is abbreviated to "head". 133 Head refs are stored in `$GIT_DIR/refs/heads/`. 134 135hook:: 136 During the normal execution of several git commands, 137 call-outs are made to optional scripts that allow 138 a developer to add functionality or checking. 139 Typically, the hooks allow for a command to be pre-verified 140 and potentially aborted, and allow for a post-notification 141 after the operation is done. 142 The hook scripts are found in the `$GIT_DIR/hooks/` directory, 143 and are enabled by simply making them executable. 144 145index:: 146 A collection of files with stat information, whose contents are 147 stored as objects. The index is a stored version of your working 148 tree. Truth be told, it can also contain a second, and even a third 149 version of a working tree, which are used when merging. 150 151index entry:: 152 The information regarding a particular file, stored in the index. 153 An index entry can be unmerged, if a merge was started, but not 154 yet finished (i.e. if the index contains multiple versions of 155 that file). 156 157master:: 158 The default development branch. Whenever you create a git 159 repository, a branch named "master" is created, and becomes 160 the active branch. In most cases, this contains the local 161 development, though that is purely conventional and not required. 162 163merge:: 164 To merge branches means to try to accumulate the changes since a 165 common ancestor and apply them to the first branch. An automatic 166 merge uses heuristics to accomplish that. Evidently, an automatic 167 merge can fail. 168 169object:: 170 The unit of storage in git. It is uniquely identified by 171 the SHA1 of its contents. Consequently, an object can not 172 be changed. 173 174object database:: 175 Stores a set of "objects", and an individual object is identified 176 by its object name. The objects usually live in `$GIT_DIR/objects/`. 177 178object identifier:: 179 Synonym for object name. 180 181object name:: 182 The unique identifier of an object. The hash of the object's contents 183 using the Secure Hash Algorithm 1 and usually represented by the 40 184 character hexadecimal encoding of the hash of the object (possibly 185 followed by a white space). 186 187object type:: 188 One of the identifiers "commit","tree","tag" and "blob" describing 189 the type of an object. 190 191octopus:: 192 To merge more than two branches. Also denotes an intelligent 193 predator. 194 195origin:: 196 The default upstream repository. Most projects have at 197 least one upstream project which they track. By default 198 'origin' is used for that purpose. New upstream updates 199 will be fetched into remote tracking branches named 200 origin/name-of-upstream-branch, which you can see using 201 "git branch -r". 202 203pack:: 204 A set of objects which have been compressed into one file (to save 205 space or to transmit them efficiently). 206 207pack index:: 208 The list of identifiers, and other information, of the objects in a 209 pack, to assist in efficiently accessing the contents of a pack. 210 211parent:: 212 A commit object contains a (possibly empty) list of the logical 213 predecessor(s) in the line of development, i.e. its parents. 214 215pickaxe:: 216 The term pickaxe refers to an option to the diffcore routines 217 that help select changes that add or delete a given text string. 218 With the --pickaxe-all option, it can be used to view the 219 full changeset that introduced or removed, say, a particular 220 line of text. See gitlink:git-diff[1]. 221 222plumbing:: 223 Cute name for core git. 224 225porcelain:: 226 Cute name for programs and program suites depending on core git, 227 presenting a high level access to core git. Porcelains expose 228 more of a SCM interface than the plumbing. 229 230pull:: 231 Pulling a branch means to fetch it and merge it. 232 233push:: 234 Pushing a branch means to get the branch's head ref from a remote 235 repository, find out if it is an ancestor to the branch's local 236 head ref is a direct, and in that case, putting all objects, which 237 are reachable from the local head ref, and which are missing from 238 the remote repository, into the remote object database, and updating 239 the remote head ref. If the remote head is not an ancestor to the 240 local head, the push fails. 241 242reachable:: 243 All of the ancestors of a given commit are said to be reachable from 244 that commit. More generally, one object is reachable from another if 245 we can reach the one from the other by a chain that follows tags to 246 whatever they tag, commits to their parents or trees, and trees to the 247 trees or blobs that they contain. 248 249rebase:: 250 To clean a branch by starting from the head of the main line of 251 development ("master"), and reapply the (possibly cherry-picked) 252 changes from that branch. 253 254ref:: 255 A 40-byte hex representation of a SHA1 or a name that denotes 256 a particular object. These may be stored in `$GIT_DIR/refs/`. 257 258refspec:: 259 A refspec is used by fetch and push to describe the mapping 260 between remote ref and local ref. They are combined with 261 a colon in the format <src>:<dst>, preceded by an optional 262 plus sign, +. For example: 263 `git fetch $URL refs/heads/master:refs/heads/origin` 264 means "grab the master branch head from the $URL and store 265 it as my origin branch head". 266 And `git push $URL refs/heads/master:refs/heads/to-upstream` 267 means "publish my master branch head as to-upstream branch 268 at $URL". See also gitlink:git-push[1] 269 270repository:: 271 A collection of refs together with an object database containing 272 all objects, which are reachable from the refs, possibly accompanied 273 by meta data from one or more porcelains. A repository can 274 share an object database with other repositories. 275 276resolve:: 277 The action of fixing up manually what a failed automatic merge 278 left behind. 279 280revision:: 281 A particular state of files and directories which was stored in 282 the object database. It is referenced by a commit object. 283 284rewind:: 285 To throw away part of the development, i.e. to assign the head to 286 an earlier revision. 287 288SCM:: 289 Source code management (tool). 290 291SHA1:: 292 Synonym for object name. 293 294shallow repository:: 295 A shallow repository has an incomplete history some of 296 whose commits have parents cauterized away (in other 297 words, git is told to pretend that these commits do not 298 have the parents, even though they are recorded in the 299 commit object). This is sometimes useful when you are 300 interested only in the recent history of a project even 301 though the real history recorded in the upstream is 302 much larger. A shallow repository is created by giving 303 `--depth` option to gitlink:git-clone[1], and its 304 history can be later deepened with gitlink:git-fetch[1]. 305 306symref:: 307 Symbolic reference: instead of containing the SHA1 id itself, it 308 is of the format 'ref: refs/some/thing' and when referenced, it 309 recursively dereferences to this reference. 'HEAD' is a prime 310 example of a symref. Symbolic references are manipulated with 311 the gitlink:git-symbolic-ref[1] command. 312 313topic branch:: 314 A regular git branch that is used by a developer to 315 identify a conceptual line of development. Since branches 316 are very easy and inexpensive, it is often desirable to 317 have several small branches that each contain very well 318 defined concepts or small incremental yet related changes. 319 320tracking branch:: 321 A regular git branch that is used to follow changes from 322 another repository. A tracking branch should not contain 323 direct modifications or have local commits made to it. 324 A tracking branch can usually be identified as the 325 right-hand-side ref in a Pull: refspec. 326 327tree object:: 328 An object containing a list of file names and modes along with refs 329 to the associated blob and/or tree objects. A tree is equivalent 330 to a directory. 331 332tree:: 333 Either a working tree, or a tree object together with the 334 dependent blob and tree objects (i.e. a stored representation 335 of a working tree). 336 337tree-ish:: 338 A ref pointing to either a commit object, a tree object, or a 339 tag object pointing to a tag or commit or tree object. 340 341tag object:: 342 An object containing a ref pointing to another object, which can 343 contain a message just like a commit object. It can also 344 contain a (PGP) signature, in which case it is called a "signed 345 tag object". 346 347tag:: 348 A ref pointing to a tag or commit object. In contrast to a head, 349 a tag is not changed by a commit. Tags (not tag objects) are 350 stored in `$GIT_DIR/refs/tags/`. A git tag has nothing to do with 351 a Lisp tag (which is called object type in git's context). 352 A tag is most typically used to mark a particular point in the 353 commit ancestry chain. 354 355unmerged index:: 356 An index which contains unmerged index entries. 357 358unreachable object:: 359 An object which is not reachable from a branch, tag, or any 360 other reference. 361 362working tree:: 363 The set of files and directories currently being worked on, 364 i.e. you can work in your working tree without using git at all. 365