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