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>>, and commands that operate on the 104 history HEAD represents operate on the history leading to the 105 tip of the branch the HEAD points at. However, Git also 106 allows you to <<def_checkout,check out>> an arbitrary 107 <<def_commit,commit>> that isn't necessarily the tip of any 108 particular branch. The HEAD in such a state is called 109 "detached". 110+ 111Note that commands that operate on the history of the current branch 112(e.g. `git commit` to build a new history on top of it) still work 113while the HEAD is detached. They update the HEAD to point at the tip 114of the updated history without affecting any branch. Commands that 115update or inquire information _about_ the current branch (e.g. `git 116branch --set-upstream-to` that sets what remote tracking branch the 117current branch integrates with) obviously do not work, as there is no 118(real) current branch to ask about in this state. 119 120[[def_dircache]]dircache:: 121 You are *waaaaay* behind. See <<def_index,index>>. 122 123[[def_directory]]directory:: 124 The list you get with "ls" :-) 125 126[[def_dirty]]dirty:: 127 A <<def_working_tree,working tree>> is said to be "dirty" if 128 it contains modifications which have not been <<def_commit,committed>> to the current 129 <<def_branch,branch>>. 130 131[[def_ent]]ent:: 132 Favorite synonym to "<<def_tree-ish,tree-ish>>" by some total geeks. See 133 http://en.wikipedia.org/wiki/Ent_(Middle-earth) for an in-depth 134 explanation. Avoid this term, not to confuse people. 135 136[[def_evil_merge]]evil merge:: 137 An evil merge is a <<def_merge,merge>> that introduces changes that 138 do not appear in any <<def_parent,parent>>. 139 140[[def_fast_forward]]fast-forward:: 141 A fast-forward is a special type of <<def_merge,merge>> where you have a 142 <<def_revision,revision>> and you are "merging" another 143 <<def_branch,branch>>'s changes that happen to be a descendant of what 144 you have. In such these cases, you do not make a new <<def_merge,merge>> 145 <<def_commit,commit>> but instead just update to his 146 revision. This will happen frequently on a 147 <<def_remote_tracking_branch,remote-tracking branch>> of a remote 148 <<def_repository,repository>>. 149 150[[def_fetch]]fetch:: 151 Fetching a <<def_branch,branch>> means to get the 152 branch's <<def_head_ref,head ref>> from a remote 153 <<def_repository,repository>>, to find out which objects are 154 missing from the local <<def_object_database,object database>>, 155 and to get them, too. See also linkgit:git-fetch[1]. 156 157[[def_file_system]]file system:: 158 Linus Torvalds originally designed Git to be a user space file system, 159 i.e. the infrastructure to hold files and directories. That ensured the 160 efficiency and speed of Git. 161 162[[def_git_archive]]Git archive:: 163 Synonym for <<def_repository,repository>> (for arch people). 164 165[[def_gitfile]]gitfile:: 166 A plain file `.git` at the root of a working tree that 167 points at the directory that is the real repository. 168 169[[def_grafts]]grafts:: 170 Grafts enables two otherwise different lines of development to be joined 171 together by recording fake ancestry information for commits. This way 172 you can make Git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has 173 is different from what was recorded when the commit was 174 created. Configured via the `.git/info/grafts` file. 175 176[[def_hash]]hash:: 177 In Git's context, synonym to <<def_object_name,object name>>. 178 179[[def_head]]head:: 180 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a 181 <<def_branch,branch>>. Heads are stored in a file in 182 `$GIT_DIR/refs/heads/` directory, except when using packed refs. (See 183 linkgit:git-pack-refs[1].) 184 185[[def_HEAD]]HEAD:: 186 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree, 187 working tree>> is normally derived from the state of the tree 188 referred to by HEAD. HEAD is a reference to one of the 189 <<def_head,heads>> in your repository, except when using a 190 <<def_detached_HEAD,detached HEAD>>, in which case it directly 191 references an arbitrary commit. 192 193[[def_head_ref]]head ref:: 194 A synonym for <<def_head,head>>. 195 196[[def_hook]]hook:: 197 During the normal execution of several Git commands, call-outs are made 198 to optional scripts that allow a developer to add functionality or 199 checking. Typically, the hooks allow for a command to be pre-verified 200 and potentially aborted, and allow for a post-notification after the 201 operation is done. The hook scripts are found in the 202 `$GIT_DIR/hooks/` directory, and are enabled by simply 203 removing the `.sample` suffix from the filename. In earlier versions 204 of Git you had to make them executable. 205 206[[def_index]]index:: 207 A collection of files with stat information, whose contents are stored 208 as objects. The index is a stored version of your 209 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even 210 a third version of a working tree, which are used 211 when <<def_merge,merging>>. 212 213[[def_index_entry]]index entry:: 214 The information regarding a particular file, stored in the 215 <<def_index,index>>. An index entry can be unmerged, if a 216 <<def_merge,merge>> was started, but not yet finished (i.e. if 217 the index contains multiple versions of that file). 218 219[[def_master]]master:: 220 The default development <<def_branch,branch>>. Whenever you 221 create a Git <<def_repository,repository>>, a branch named 222 "master" is created, and becomes the active branch. In most 223 cases, this contains the local development, though that is 224 purely by convention and is not required. 225 226[[def_merge]]merge:: 227 As a verb: To bring the contents of another 228 <<def_branch,branch>> (possibly from an external 229 <<def_repository,repository>>) into the current branch. In the 230 case where the merged-in branch is from a different repository, 231 this is done by first <<def_fetch,fetching>> the remote branch 232 and then merging the result into the current branch. This 233 combination of fetch and merge operations is called a 234 <<def_pull,pull>>. Merging is performed by an automatic process 235 that identifies changes made since the branches diverged, and 236 then applies all those changes together. In cases where changes 237 conflict, manual intervention may be required to complete the 238 merge. 239+ 240As a noun: unless it is a <<def_fast_forward,fast-forward>>, a 241successful merge results in the creation of a new <<def_commit,commit>> 242representing the result of the merge, and having as 243<<def_parent,parents>> the tips of the merged <<def_branch,branches>>. 244This commit is referred to as a "merge commit", or sometimes just a 245"merge". 246 247[[def_object]]object:: 248 The unit of storage in Git. It is uniquely identified by the 249 <<def_SHA1,SHA1>> of its contents. Consequently, an 250 object can not be changed. 251 252[[def_object_database]]object database:: 253 Stores a set of "objects", and an individual <<def_object,object>> is 254 identified by its <<def_object_name,object name>>. The objects usually 255 live in `$GIT_DIR/objects/`. 256 257[[def_object_identifier]]object identifier:: 258 Synonym for <<def_object_name,object name>>. 259 260[[def_object_name]]object name:: 261 The unique identifier of an <<def_object,object>>. The <<def_hash,hash>> 262 of the object's contents using the Secure Hash Algorithm 263 1 and usually represented by the 40 character hexadecimal encoding of 264 the <<def_hash,hash>> of the object. 265 266[[def_object_type]]object type:: 267 One of the identifiers "<<def_commit_object,commit>>", 268 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or 269 "<<def_blob_object,blob>>" describing the type of an 270 <<def_object,object>>. 271 272[[def_octopus]]octopus:: 273 To <<def_merge,merge>> more than two <<def_branch,branches>>. Also denotes an 274 intelligent predator. 275 276[[def_origin]]origin:: 277 The default upstream <<def_repository,repository>>. Most projects have 278 at least one upstream project which they track. By default 279 'origin' is used for that purpose. New upstream updates 280 will be fetched into remote <<def_remote_tracking_branch,remote-tracking branches>> named 281 origin/name-of-upstream-branch, which you can see using 282 `git branch -r`. 283 284[[def_pack]]pack:: 285 A set of objects which have been compressed into one file (to save space 286 or to transmit them efficiently). 287 288[[def_pack_index]]pack index:: 289 The list of identifiers, and other information, of the objects in a 290 <<def_pack,pack>>, to assist in efficiently accessing the contents of a 291 pack. 292 293[[def_pathspec]]pathspec:: 294 Pattern used to specify paths. 295+ 296Pathspecs are used on the command line of "git ls-files", "git 297ls-tree", "git add", "git grep", "git diff", "git checkout", 298and many other commands to 299limit the scope of operations to some subset of the tree or 300worktree. See the documentation of each command for whether 301paths are relative to the current directory or toplevel. The 302pathspec syntax is as follows: 303 304* any path matches itself 305* the pathspec up to the last slash represents a 306 directory prefix. The scope of that pathspec is 307 limited to that subtree. 308* the rest of the pathspec is a pattern for the remainder 309 of the pathname. Paths relative to the directory 310 prefix will be matched against that pattern using fnmatch(3); 311 in particular, '*' and '?' _can_ match directory separators. 312+ 313For example, Documentation/*.jpg will match all .jpg files 314in the Documentation subtree, 315including Documentation/chapter_1/figure_1.jpg. 316 317+ 318A pathspec that begins with a colon `:` has special meaning. In the 319short form, the leading colon `:` is followed by zero or more "magic 320signature" letters (which optionally is terminated by another colon `:`), 321and the remainder is the pattern to match against the path. The optional 322colon that terminates the "magic signature" can be omitted if the pattern 323begins with a character that cannot be a "magic signature" and is not a 324colon. 325+ 326In the long form, the leading colon `:` is followed by a open 327parenthesis `(`, a comma-separated list of zero or more "magic words", 328and a close parentheses `)`, and the remainder is the pattern to match 329against the path. 330+ 331The "magic signature" consists of an ASCII symbol that is not 332alphanumeric. 333+ 334-- 335top `/`;; 336 The magic word `top` (mnemonic: `/`) makes the pattern match 337 from the root of the working tree, even when you are running 338 the command from inside a subdirectory. 339-- 340+ 341Currently only the slash `/` is recognized as the "magic signature", 342but it is envisioned that we will support more types of magic in later 343versions of Git. 344+ 345A pathspec with only a colon means "there is no pathspec". This form 346should not be combined with other pathspec. 347 348[[def_parent]]parent:: 349 A <<def_commit_object,commit object>> contains a (possibly empty) list 350 of the logical predecessor(s) in the line of development, i.e. its 351 parents. 352 353[[def_pickaxe]]pickaxe:: 354 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore 355 routines that help select changes that add or delete a given text 356 string. With the `--pickaxe-all` option, it can be used to view the full 357 <<def_changeset,changeset>> that introduced or removed, say, a 358 particular line of text. See linkgit:git-diff[1]. 359 360[[def_plumbing]]plumbing:: 361 Cute name for <<def_core_git,core Git>>. 362 363[[def_porcelain]]porcelain:: 364 Cute name for programs and program suites depending on 365 <<def_core_git,core Git>>, presenting a high level access to 366 core Git. Porcelains expose more of a <<def_SCM,SCM>> 367 interface than the <<def_plumbing,plumbing>>. 368 369[[def_pull]]pull:: 370 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and 371 <<def_merge,merge>> it. See also linkgit:git-pull[1]. 372 373[[def_push]]push:: 374 Pushing a <<def_branch,branch>> means to get the branch's 375 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>, 376 find out if it is a direct ancestor to the branch's local 377 head ref, and in that case, putting all 378 objects, which are <<def_reachable,reachable>> from the local 379 head ref, and which are missing from the remote 380 repository, into the remote 381 <<def_object_database,object database>>, and updating the remote 382 head ref. If the remote <<def_head,head>> is not an 383 ancestor to the local head, the push fails. 384 385[[def_reachable]]reachable:: 386 All of the ancestors of a given <<def_commit,commit>> are said to be 387 "reachable" from that commit. More 388 generally, one <<def_object,object>> is reachable from 389 another if we can reach the one from the other by a <<def_chain,chain>> 390 that follows <<def_tag,tags>> to whatever they tag, 391 <<def_commit_object,commits>> to their parents or trees, and 392 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>> 393 that they contain. 394 395[[def_rebase]]rebase:: 396 To reapply a series of changes from a <<def_branch,branch>> to a 397 different base, and reset the <<def_head,head>> of that branch 398 to the result. 399 400[[def_ref]]ref:: 401 A 40-byte hex representation of a <<def_SHA1,SHA1>> or a name that 402 denotes a particular <<def_object,object>>. They may be stored in 403 a file under `$GIT_DIR/refs/` directory, or 404 in the `$GIT_DIR/packed-refs` file. 405 406[[def_reflog]]reflog:: 407 A reflog shows the local "history" of a ref. In other words, 408 it can tell you what the 3rd last revision in _this_ repository 409 was, and what was the current state in _this_ repository, 410 yesterday 9:14pm. See linkgit:git-reflog[1] for details. 411 412[[def_refspec]]refspec:: 413 A "refspec" is used by <<def_fetch,fetch>> and 414 <<def_push,push>> to describe the mapping between remote 415 <<def_ref,ref>> and local ref. They are combined with a colon in 416 the format <src>:<dst>, preceded by an optional plus sign, +. 417 For example: `git fetch $URL 418 refs/heads/master:refs/heads/origin` means "grab the master 419 <<def_branch,branch>> <<def_head,head>> from the $URL and store 420 it as my origin branch head". And `git push 421 $URL refs/heads/master:refs/heads/to-upstream` means "publish my 422 master branch head as to-upstream branch at $URL". See also 423 linkgit:git-push[1]. 424 425[[def_remote_tracking_branch]]remote-tracking branch:: 426 A <<def_ref,ref>> that is used to follow changes from another 427 <<def_repository,repository>>. It typically looks like 428 'refs/remotes/foo/bar' (indicating that it tracks a branch named 429 'bar' in a remote named 'foo'), and matches the right-hand-side of 430 a configured fetch <<def_refspec,refspec>>. A remote-tracking 431 branch should not contain direct modifications or have local 432 commits made to it. 433 434[[def_repository]]repository:: 435 A collection of <<def_ref,refs>> together with an 436 <<def_object_database,object database>> containing all objects 437 which are <<def_reachable,reachable>> from the refs, possibly 438 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A 439 repository can share an object database with other repositories 440 via <<def_alternate_object_database,alternates mechanism>>. 441 442[[def_resolve]]resolve:: 443 The action of fixing up manually what a failed automatic 444 <<def_merge,merge>> left behind. 445 446[[def_revision]]revision:: 447 A particular state of files and directories which was stored in the 448 <<def_object_database,object database>>. It is referenced by a 449 <<def_commit_object,commit object>>. 450 451[[def_rewind]]rewind:: 452 To throw away part of the development, i.e. to assign the 453 <<def_head,head>> to an earlier <<def_revision,revision>>. 454 455[[def_SCM]]SCM:: 456 Source code management (tool). 457 458[[def_SHA1]]SHA1:: 459 Synonym for <<def_object_name,object name>>. 460 461[[def_shallow_repository]]shallow repository:: 462 A shallow <<def_repository,repository>> has an incomplete 463 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other 464 words, Git is told to pretend that these commits do not have the 465 parents, even though they are recorded in the <<def_commit_object,commit 466 object>>). This is sometimes useful when you are interested only in the 467 recent history of a project even though the real history recorded in the 468 upstream is much larger. A shallow repository 469 is created by giving the `--depth` option to linkgit:git-clone[1], and 470 its history can be later deepened with linkgit:git-fetch[1]. 471 472[[def_symref]]symref:: 473 Symbolic reference: instead of containing the <<def_SHA1,SHA1>> 474 id itself, it is of the format 'ref: refs/some/thing' and when 475 referenced, it recursively dereferences to this reference. 476 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic 477 references are manipulated with the linkgit:git-symbolic-ref[1] 478 command. 479 480[[def_tag]]tag:: 481 A <<def_ref,ref>> under `refs/tags/` namespace that points to an 482 object of an arbitrary type (typically a tag points to either a 483 <<def_tag_object,tag>> or a <<def_commit_object,commit object>>). 484 In contrast to a <<def_head,head>>, a tag is not updated by 485 the `commit` command. A Git tag has nothing to do with a Lisp 486 tag (which would be called an <<def_object_type,object type>> 487 in Git's context). A tag is most typically used to mark a particular 488 point in the commit ancestry <<def_chain,chain>>. 489 490[[def_tag_object]]tag object:: 491 An <<def_object,object>> containing a <<def_ref,ref>> pointing to 492 another object, which can contain a message just like a 493 <<def_commit_object,commit object>>. It can also contain a (PGP) 494 signature, in which case it is called a "signed tag object". 495 496[[def_topic_branch]]topic branch:: 497 A regular Git <<def_branch,branch>> that is used by a developer to 498 identify a conceptual line of development. Since branches are very easy 499 and inexpensive, it is often desirable to have several small branches 500 that each contain very well defined concepts or small incremental yet 501 related changes. 502 503[[def_tree]]tree:: 504 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree 505 object>> together with the dependent <<def_blob_object,blob>> and tree objects 506 (i.e. a stored representation of a working tree). 507 508[[def_tree_object]]tree object:: 509 An <<def_object,object>> containing a list of file names and modes along 510 with refs to the associated blob and/or tree objects. A 511 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>. 512 513[[def_tree-ish]]tree-ish:: 514 A <<def_ref,ref>> pointing to either a <<def_commit_object,commit 515 object>>, a <<def_tree_object,tree object>>, or a <<def_tag_object,tag 516 object>> pointing to a tag or commit or tree object. 517 518[[def_unmerged_index]]unmerged index:: 519 An <<def_index,index>> which contains unmerged 520 <<def_index_entry,index entries>>. 521 522[[def_unreachable_object]]unreachable object:: 523 An <<def_object,object>> which is not <<def_reachable,reachable>> from a 524 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference. 525 526[[def_upstream_branch]]upstream branch:: 527 The default <<def_branch,branch>> that is merged into the branch in 528 question (or the branch in question is rebased onto). It is configured 529 via branch.<name>.remote and branch.<name>.merge. If the upstream branch 530 of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'". 531 532[[def_working_tree]]working tree:: 533 The tree of actual checked out files. The working tree normally 534 contains the contents of the <<def_HEAD,HEAD>> commit's tree, 535 plus any local changes that you have made but not yet committed.