1[[def_alternate_object_database]]alternate object database:: 2 Via the alternates mechanism, a <<def_repository,repository>> 3 can inherit part of its <<def_object_database,object database>> 4 from another object database, which is called "alternate". 5 6[[def_bare_repository]]bare repository:: 7 A bare repository is normally an appropriately 8 named <<def_directory,directory>> with a `.git` suffix that does not 9 have a locally checked-out copy of any of the files under 10 revision control. That is, all of the `git` 11 administrative and control files that would normally be present in the 12 hidden `.git` sub-directory are directly present in the 13 `repository.git` directory instead, 14 and no other files are present and checked out. Usually publishers of 15 public repositories make bare repositories available. 16 17[[def_blob_object]]blob object:: 18 Untyped <<def_object,object>>, e.g. the contents of a file. 19 20[[def_branch]]branch:: 21 A "branch" is an active line of development. The most recent 22 <<def_commit,commit>> on a branch is referred to as the tip of 23 that branch. The tip of the branch is referenced by a branch 24 <<def_head,head>>, which moves forward as additional development 25 is done on the branch. A single git 26 <<def_repository,repository>> can track an arbitrary number of 27 branches, but your <<def_working_tree,working tree>> is 28 associated with just one of them (the "current" or "checked out" 29 branch), and <<def_HEAD,HEAD>> points to that branch. 30 31[[def_cache]]cache:: 32 Obsolete for: <<def_index,index>>. 33 34[[def_chain]]chain:: 35 A list of objects, where each <<def_object,object>> in the list contains 36 a reference to its successor (for example, the successor of a 37 <<def_commit,commit>> could be one of its <<def_parent,parents>>). 38 39[[def_changeset]]changeset:: 40 BitKeeper/cvsps speak for "<<def_commit,commit>>". Since git does not 41 store changes, but states, it really does not make sense to use the term 42 "changesets" with git. 43 44[[def_checkout]]checkout:: 45 The action of updating all or part of the 46 <<def_working_tree,working tree>> with a <<def_tree_object,tree object>> 47 or <<def_blob_object,blob>> from the 48 <<def_object_database,object database>>, and updating the 49 <<def_index,index>> and <<def_HEAD,HEAD>> if the whole working tree has 50 been pointed at a new <<def_branch,branch>>. 51 52[[def_cherry-picking]]cherry-picking:: 53 In <<def_SCM,SCM>> jargon, "cherry pick" means to choose a subset of 54 changes out of a series of changes (typically commits) and record them 55 as a new series of changes on top of a different codebase. In GIT, this is 56 performed by the "git cherry-pick" command to extract the change introduced 57 by an existing <<def_commit,commit>> and to record it based on the tip 58 of the current <<def_branch,branch>> as a new commit. 59 60[[def_clean]]clean:: 61 A <<def_working_tree,working tree>> is clean, if it 62 corresponds to the <<def_revision,revision>> referenced by the current 63 <<def_head,head>>. Also see "<<def_dirty,dirty>>". 64 65[[def_commit]]commit:: 66 As a noun: A single point in the 67 git history; the entire history of a project is represented as a 68 set of interrelated commits. The word "commit" is often 69 used by git in the same places other revision control systems 70 use the words "revision" or "version". Also used as a short 71 hand for <<def_commit_object,commit object>>. 72+ 73As a verb: The action of storing a new snapshot of the project's 74state in the git history, by creating a new commit representing the current 75state of the <<def_index,index>> and advancing <<def_HEAD,HEAD>> 76to point at the new commit. 77 78[[def_commit_object]]commit object:: 79 An <<def_object,object>> which contains the information about a 80 particular <<def_revision,revision>>, such as <<def_parent,parents>>, committer, 81 author, date and the <<def_tree_object,tree object>> which corresponds 82 to the top <<def_directory,directory>> of the stored 83 revision. 84 85[[def_core_git]]core git:: 86 Fundamental data structures and utilities of git. Exposes only limited 87 source code management tools. 88 89[[def_DAG]]DAG:: 90 Directed acyclic graph. The <<def_commit_object,commit objects>> form a 91 directed acyclic graph, because they have parents (directed), and the 92 graph of commit objects is acyclic (there is no <<def_chain,chain>> 93 which begins and ends with the same <<def_object,object>>). 94 95[[def_dangling_object]]dangling object:: 96 An <<def_unreachable_object,unreachable object>> which is not 97 <<def_reachable,reachable>> even from other unreachable objects; a 98 dangling object has no references to it from any 99 reference or <<def_object,object>> in the <<def_repository,repository>>. 100 101[[def_detached_HEAD]]detached HEAD:: 102 Normally the <<def_HEAD,HEAD>> stores the name of a 103 <<def_branch,branch>>. However, git also allows you to <<def_checkout,check out>> 104 an arbitrary <<def_commit,commit>> that isn't necessarily the tip of any 105 particular branch. In this case HEAD is said to be "detached". 106 107[[def_dircache]]dircache:: 108 You are *waaaaay* behind. See <<def_index,index>>. 109 110[[def_directory]]directory:: 111 The list you get with "ls" :-) 112 113[[def_dirty]]dirty:: 114 A <<def_working_tree,working tree>> is said to be "dirty" if 115 it contains modifications which have not been <<def_commit,committed>> to the current 116 <<def_branch,branch>>. 117 118[[def_ent]]ent:: 119 Favorite synonym to "<<def_tree-ish,tree-ish>>" by some total geeks. See 120 `http://en.wikipedia.org/wiki/Ent_(Middle-earth)` for an in-depth 121 explanation. Avoid this term, not to confuse people. 122 123[[def_evil_merge]]evil merge:: 124 An evil merge is a <<def_merge,merge>> that introduces changes that 125 do not appear in any <<def_parent,parent>>. 126 127[[def_fast_forward]]fast forward:: 128 A fast-forward is a special type of <<def_merge,merge>> where you have a 129 <<def_revision,revision>> and you are "merging" another 130 <<def_branch,branch>>'s changes that happen to be a descendant of what 131 you have. In such these cases, you do not make a new <<def_merge,merge>> 132 <<def_commit,commit>> but instead just update to his 133 revision. This will happen frequently on a 134 <<def_tracking_branch,tracking branch>> of a remote 135 <<def_repository,repository>>. 136 137[[def_fetch]]fetch:: 138 Fetching a <<def_branch,branch>> means to get the 139 branch's <<def_head_ref,head ref>> from a remote 140 <<def_repository,repository>>, to find out which objects are 141 missing from the local <<def_object_database,object database>>, 142 and to get them, too. See also linkgit:git-fetch[1]. 143 144[[def_file_system]]file system:: 145 Linus Torvalds originally designed git to be a user space file system, 146 i.e. the infrastructure to hold files and directories. That ensured the 147 efficiency and speed of git. 148 149[[def_git_archive]]git archive:: 150 Synonym for <<def_repository,repository>> (for arch people). 151 152[[def_grafts]]grafts:: 153 Grafts enables two otherwise different lines of development to be joined 154 together by recording fake ancestry information for commits. This way 155 you can make git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has 156 is different from what was recorded when the commit was 157 created. Configured via the `.git/info/grafts` file. 158 159[[def_hash]]hash:: 160 In git's context, synonym to <<def_object_name,object name>>. 161 162[[def_head]]head:: 163 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a 164 <<def_branch,branch>>. Heads are stored in 165 `$GIT_DIR/refs/heads/`, except when using packed refs. (See 166 linkgit:git-pack-refs[1].) 167 168[[def_HEAD]]HEAD:: 169 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree, 170 working tree>> is normally derived from the state of the tree 171 referred to by HEAD. HEAD is a reference to one of the 172 <<def_head,heads>> in your repository, except when using a 173 <<def_detached_HEAD,detached HEAD>>, in which case it may 174 reference an arbitrary commit. 175 176[[def_head_ref]]head ref:: 177 A synonym for <<def_head,head>>. 178 179[[def_hook]]hook:: 180 During the normal execution of several git commands, call-outs are made 181 to optional scripts that allow a developer to add functionality or 182 checking. Typically, the hooks allow for a command to be pre-verified 183 and potentially aborted, and allow for a post-notification after the 184 operation is done. The hook scripts are found in the 185 `$GIT_DIR/hooks/` directory, and are enabled by simply 186 making them executable. 187 188[[def_index]]index:: 189 A collection of files with stat information, whose contents are stored 190 as objects. The index is a stored version of your 191 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even 192 a third version of a working tree, which are used 193 when <<def_merge,merging>>. 194 195[[def_index_entry]]index entry:: 196 The information regarding a particular file, stored in the 197 <<def_index,index>>. An index entry can be unmerged, if a 198 <<def_merge,merge>> was started, but not yet finished (i.e. if 199 the index contains multiple versions of that file). 200 201[[def_master]]master:: 202 The default development <<def_branch,branch>>. Whenever you 203 create a git <<def_repository,repository>>, a branch named 204 "master" is created, and becomes the active branch. In most 205 cases, this contains the local development, though that is 206 purely by convention and is not required. 207 208[[def_merge]]merge:: 209 As a verb: To bring the contents of another 210 <<def_branch,branch>> (possibly from an external 211 <<def_repository,repository>>) into the current branch. In the 212 case where the merged-in branch is from a different repository, 213 this is done by first <<def_fetch,fetching>> the remote branch 214 and then merging the result into the current branch. This 215 combination of fetch and merge operations is called a 216 <<def_pull,pull>>. Merging is performed by an automatic process 217 that identifies changes made since the branches diverged, and 218 then applies all those changes together. In cases where changes 219 conflict, manual intervention may be required to complete the 220 merge. 221+ 222As a noun: unless it is a <<def_fast_forward,fast forward>>, a 223successful merge results in the creation of a new <<def_commit,commit>> 224representing the result of the merge, and having as 225<<def_parent,parents>> the tips of the merged <<def_branch,branches>>. 226This commit is referred to as a "merge commit", or sometimes just a 227"merge". 228 229[[def_object]]object:: 230 The unit of storage in git. It is uniquely identified by the 231 <<def_SHA1,SHA1>> of its contents. Consequently, an 232 object can not be changed. 233 234[[def_object_database]]object database:: 235 Stores a set of "objects", and an individual <<def_object,object>> is 236 identified by its <<def_object_name,object name>>. The objects usually 237 live in `$GIT_DIR/objects/`. 238 239[[def_object_identifier]]object identifier:: 240 Synonym for <<def_object_name,object name>>. 241 242[[def_object_name]]object name:: 243 The unique identifier of an <<def_object,object>>. The <<def_hash,hash>> 244 of the object's contents using the Secure Hash Algorithm 245 1 and usually represented by the 40 character hexadecimal encoding of 246 the <<def_hash,hash>> of the object. 247 248[[def_object_type]]object type:: 249 One of the identifiers "<<def_commit_object,commit>>", 250 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or 251 "<<def_blob_object,blob>>" describing the type of an 252 <<def_object,object>>. 253 254[[def_octopus]]octopus:: 255 To <<def_merge,merge>> more than two <<def_branch,branches>>. Also denotes an 256 intelligent predator. 257 258[[def_origin]]origin:: 259 The default upstream <<def_repository,repository>>. Most projects have 260 at least one upstream project which they track. By default 261 'origin' is used for that purpose. New upstream updates 262 will be fetched into remote <<def_tracking_branch,tracking branches>> named 263 origin/name-of-upstream-branch, which you can see using 264 "`git branch -r`". 265 266[[def_pack]]pack:: 267 A set of objects which have been compressed into one file (to save space 268 or to transmit them efficiently). 269 270[[def_pack_index]]pack index:: 271 The list of identifiers, and other information, of the objects in a 272 <<def_pack,pack>>, to assist in efficiently accessing the contents of a 273 pack. 274 275[[def_parent]]parent:: 276 A <<def_commit_object,commit object>> contains a (possibly empty) list 277 of the logical predecessor(s) in the line of development, i.e. its 278 parents. 279 280[[def_pickaxe]]pickaxe:: 281 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore 282 routines that help select changes that add or delete a given text 283 string. With the `--pickaxe-all` option, it can be used to view the full 284 <<def_changeset,changeset>> that introduced or removed, say, a 285 particular line of text. See linkgit:git-diff[1]. 286 287[[def_plumbing]]plumbing:: 288 Cute name for <<def_core_git,core git>>. 289 290[[def_porcelain]]porcelain:: 291 Cute name for programs and program suites depending on 292 <<def_core_git,core git>>, presenting a high level access to 293 core git. Porcelains expose more of a <<def_SCM,SCM>> 294 interface than the <<def_plumbing,plumbing>>. 295 296[[def_pull]]pull:: 297 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and 298 <<def_merge,merge>> it. See also linkgit:git-pull[1]. 299 300[[def_push]]push:: 301 Pushing a <<def_branch,branch>> means to get the branch's 302 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>, 303 find out if it is a direct ancestor to the branch's local 304 head ref, and in that case, putting all 305 objects, which are <<def_reachable,reachable>> from the local 306 head ref, and which are missing from the remote 307 repository, into the remote 308 <<def_object_database,object database>>, and updating the remote 309 head ref. If the remote <<def_head,head>> is not an 310 ancestor to the local head, the push fails. 311 312[[def_reachable]]reachable:: 313 All of the ancestors of a given <<def_commit,commit>> are said to be 314 "reachable" from that commit. More 315 generally, one <<def_object,object>> is reachable from 316 another if we can reach the one from the other by a <<def_chain,chain>> 317 that follows <<def_tag,tags>> to whatever they tag, 318 <<def_commit_object,commits>> to their parents or trees, and 319 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>> 320 that they contain. 321 322[[def_rebase]]rebase:: 323 To reapply a series of changes from a <<def_branch,branch>> to a 324 different base, and reset the <<def_head,head>> of that branch 325 to the result. 326 327[[def_ref]]ref:: 328 A 40-byte hex representation of a <<def_SHA1,SHA1>> or a name that 329 denotes a particular <<def_object,object>>. These may be stored in 330 `$GIT_DIR/refs/`. 331 332[[def_reflog]]reflog:: 333 A reflog shows the local "history" of a ref. In other words, 334 it can tell you what the 3rd last revision in _this_ repository 335 was, and what was the current state in _this_ repository, 336 yesterday 9:14pm. See linkgit:git-reflog[1] for details. 337 338[[def_refspec]]refspec:: 339 A "refspec" is used by <<def_fetch,fetch>> and 340 <<def_push,push>> to describe the mapping between remote 341 <<def_ref,ref>> and local ref. They are combined with a colon in 342 the format <src>:<dst>, preceded by an optional plus sign, +. 343 For example: `git fetch $URL 344 refs/heads/master:refs/heads/origin` means "grab the master 345 <<def_branch,branch>> <<def_head,head>> from the $URL and store 346 it as my origin branch head". And `git push 347 $URL refs/heads/master:refs/heads/to-upstream` means "publish my 348 master branch head as to-upstream branch at $URL". See also 349 linkgit:git-push[1]. 350 351[[def_repository]]repository:: 352 A collection of <<def_ref,refs>> together with an 353 <<def_object_database,object database>> containing all objects 354 which are <<def_reachable,reachable>> from the refs, possibly 355 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A 356 repository can share an object database with other repositories 357 via <<def_alternate_object_database,alternates mechanism>>. 358 359[[def_resolve]]resolve:: 360 The action of fixing up manually what a failed automatic 361 <<def_merge,merge>> left behind. 362 363[[def_revision]]revision:: 364 A particular state of files and directories which was stored in the 365 <<def_object_database,object database>>. It is referenced by a 366 <<def_commit_object,commit object>>. 367 368[[def_rewind]]rewind:: 369 To throw away part of the development, i.e. to assign the 370 <<def_head,head>> to an earlier <<def_revision,revision>>. 371 372[[def_SCM]]SCM:: 373 Source code management (tool). 374 375[[def_SHA1]]SHA1:: 376 Synonym for <<def_object_name,object name>>. 377 378[[def_shallow_repository]]shallow repository:: 379 A shallow <<def_repository,repository>> has an incomplete 380 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other 381 words, git is told to pretend that these commits do not have the 382 parents, even though they are recorded in the <<def_commit_object,commit 383 object>>). This is sometimes useful when you are interested only in the 384 recent history of a project even though the real history recorded in the 385 upstream is much larger. A shallow repository 386 is created by giving the `--depth` option to linkgit:git-clone[1], and 387 its history can be later deepened with linkgit:git-fetch[1]. 388 389[[def_symref]]symref:: 390 Symbolic reference: instead of containing the <<def_SHA1,SHA1>> 391 id itself, it is of the format 'ref: refs/some/thing' and when 392 referenced, it recursively dereferences to this reference. 393 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic 394 references are manipulated with the linkgit:git-symbolic-ref[1] 395 command. 396 397[[def_tag]]tag:: 398 A <<def_ref,ref>> pointing to a <<def_tag_object,tag>> or 399 <<def_commit_object,commit object>>. In contrast to a <<def_head,head>>, 400 a tag is not changed by a <<def_commit,commit>>. Tags (not 401 <<def_tag_object,tag objects>>) are stored in `$GIT_DIR/refs/tags/`. A 402 git tag has nothing to do with a Lisp tag (which would be 403 called an <<def_object_type,object type>> in git's context). A 404 tag is most typically used to mark a particular point in the 405 commit ancestry <<def_chain,chain>>. 406 407[[def_tag_object]]tag object:: 408 An <<def_object,object>> containing a <<def_ref,ref>> pointing to 409 another object, which can contain a message just like a 410 <<def_commit_object,commit object>>. It can also contain a (PGP) 411 signature, in which case it is called a "signed tag object". 412 413[[def_topic_branch]]topic branch:: 414 A regular git <<def_branch,branch>> that is used by a developer to 415 identify a conceptual line of development. Since branches are very easy 416 and inexpensive, it is often desirable to have several small branches 417 that each contain very well defined concepts or small incremental yet 418 related changes. 419 420[[def_tracking_branch]]tracking branch:: 421 A regular git <<def_branch,branch>> that is used to follow changes from 422 another <<def_repository,repository>>. A tracking 423 branch should not contain direct modifications or have local commits 424 made to it. A tracking branch can usually be 425 identified as the right-hand-side <<def_ref,ref>> in a Pull: 426 <<def_refspec,refspec>>. 427 428[[def_tree]]tree:: 429 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree 430 object>> together with the dependent <<def_blob_object,blob>> and tree objects 431 (i.e. a stored representation of a working tree). 432 433[[def_tree_object]]tree object:: 434 An <<def_object,object>> containing a list of file names and modes along 435 with refs to the associated blob and/or tree objects. A 436 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>. 437 438[[def_tree-ish]]tree-ish:: 439 A <<def_ref,ref>> pointing to either a <<def_commit_object,commit 440 object>>, a <<def_tree_object,tree object>>, or a <<def_tag_object,tag 441 object>> pointing to a tag or commit or tree object. 442 443[[def_unmerged_index]]unmerged index:: 444 An <<def_index,index>> which contains unmerged 445 <<def_index_entry,index entries>>. 446 447[[def_unreachable_object]]unreachable object:: 448 An <<def_object,object>> which is not <<def_reachable,reachable>> from a 449 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference. 450 451[[def_working_tree]]working tree:: 452 The tree of actual checked out files. The working tree is 453 normally equal to the <<def_HEAD,HEAD>> plus any local changes 454 that you have made but not yet committed.