pathspec: allow querying for attributes
[git/git.git] / Documentation / glossary-content.txt
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f562e6f3 1[[def_alternate_object_database]]alternate object database::
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2 Via the alternates mechanism, a <<def_repository,repository>>
3 can inherit part of its <<def_object_database,object database>>
3c735e07 4 from another object database, which is called an "alternate".
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5
6[[def_bare_repository]]bare repository::
343cad92 7 A bare repository is normally an appropriately
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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
2de9b711 10 revision control. That is, all of the Git
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11 administrative and control files that would normally be present in the
12 hidden `.git` sub-directory are directly present in the
cbd91922 13 `repository.git` directory instead,
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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::
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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
2de9b711 25 is done on the branch. A single Git
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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.
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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
a58f3c01 37 <<def_commit,commit>> could be one of its <<def_parent,parents>>).
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38
39[[def_changeset]]changeset::
2de9b711 40 BitKeeper/cvsps speak for "<<def_commit,commit>>". Since Git does not
f562e6f3 41 store changes, but states, it really does not make sense to use the term
2de9b711 42 "changesets" with Git.
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43
44[[def_checkout]]checkout::
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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>>.
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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
48a8c26c 55 as a new series of changes on top of a different codebase. In Git, this is
06ada152 56 performed by the "git cherry-pick" command to extract the change introduced
f562e6f3 57 by an existing <<def_commit,commit>> and to record it based on the tip
343cad92 58 of the current <<def_branch,branch>> as a new commit.
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59
60[[def_clean]]clean::
343cad92 61 A <<def_working_tree,working tree>> is clean, if it
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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::
343cad92 66 As a noun: A single point in the
2de9b711 67 Git history; the entire history of a project is represented as a
343cad92 68 set of interrelated commits. The word "commit" is often
2de9b711 69 used by Git in the same places other revision control systems
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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
2de9b711 74state in the Git history, by creating a new commit representing the current
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75state of the <<def_index,index>> and advancing <<def_HEAD,HEAD>>
76to point at the new commit.
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77
78[[def_commit_object]]commit object::
79 An <<def_object,object>> which contains the information about a
a58f3c01 80 particular <<def_revision,revision>>, such as <<def_parent,parents>>, committer,
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81 author, date and the <<def_tree_object,tree object>> which corresponds
82 to the top <<def_directory,directory>> of the stored
a58f3c01 83 revision.
f562e6f3 84
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85[[def_commit-ish]]commit-ish (also committish)::
86 A <<def_commit_object,commit object>> or an
87 <<def_object,object>> that can be recursively dereferenced to
88 a commit object.
89 The following are all commit-ishes:
90 a commit object,
91 a <<def_tag_object,tag object>> that points to a commit
92 object,
93 a tag object that points to a tag object that points to a
94 commit object,
95 etc.
96
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97[[def_core_git]]core Git::
98 Fundamental data structures and utilities of Git. Exposes only limited
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99 source code management tools.
100
101[[def_DAG]]DAG::
850d3a7c 102 Directed acyclic graph. The <<def_commit_object,commit objects>> form a
f562e6f3 103 directed acyclic graph, because they have parents (directed), and the
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104 graph of commit objects is acyclic (there is no <<def_chain,chain>>
105 which begins and ends with the same <<def_object,object>>).
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106
107[[def_dangling_object]]dangling object::
108 An <<def_unreachable_object,unreachable object>> which is not
109 <<def_reachable,reachable>> even from other unreachable objects; a
343cad92 110 dangling object has no references to it from any
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111 reference or <<def_object,object>> in the <<def_repository,repository>>.
112
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113[[def_detached_HEAD]]detached HEAD::
114 Normally the <<def_HEAD,HEAD>> stores the name of a
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115 <<def_branch,branch>>, and commands that operate on the
116 history HEAD represents operate on the history leading to the
117 tip of the branch the HEAD points at. However, Git also
118 allows you to <<def_checkout,check out>> an arbitrary
119 <<def_commit,commit>> that isn't necessarily the tip of any
120 particular branch. The HEAD in such a state is called
121 "detached".
122+
123Note that commands that operate on the history of the current branch
124(e.g. `git commit` to build a new history on top of it) still work
125while the HEAD is detached. They update the HEAD to point at the tip
126of the updated history without affecting any branch. Commands that
127update or inquire information _about_ the current branch (e.g. `git
d6ac1d21 128branch --set-upstream-to` that sets what remote-tracking branch the
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129current branch integrates with) obviously do not work, as there is no
130(real) current branch to ask about in this state.
343cad92 131
f562e6f3 132[[def_directory]]directory::
aa9b1573 133 The list you get with "ls" :-)
da139813 134
f562e6f3 135[[def_dirty]]dirty::
343cad92 136 A <<def_working_tree,working tree>> is said to be "dirty" if
a58f3c01 137 it contains modifications which have not been <<def_commit,committed>> to the current
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138 <<def_branch,branch>>.
139
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140[[def_evil_merge]]evil merge::
141 An evil merge is a <<def_merge,merge>> that introduces changes that
142 do not appear in any <<def_parent,parent>>.
143
a75d7b54 144[[def_fast_forward]]fast-forward::
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145 A fast-forward is a special type of <<def_merge,merge>> where you have a
146 <<def_revision,revision>> and you are "merging" another
147 <<def_branch,branch>>'s changes that happen to be a descendant of what
2e39a246 148 you have. In such a case, you do not make a new <<def_merge,merge>>
f562e6f3 149 <<def_commit,commit>> but instead just update to his
343cad92 150 revision. This will happen frequently on a
8b3f3f84 151 <<def_remote_tracking_branch,remote-tracking branch>> of a remote
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152 <<def_repository,repository>>.
153
154[[def_fetch]]fetch::
155 Fetching a <<def_branch,branch>> means to get the
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156 branch's <<def_head_ref,head ref>> from a remote
157 <<def_repository,repository>>, to find out which objects are
158 missing from the local <<def_object_database,object database>>,
5162e697 159 and to get them, too. See also linkgit:git-fetch[1].
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160
161[[def_file_system]]file system::
2de9b711 162 Linus Torvalds originally designed Git to be a user space file system,
f562e6f3 163 i.e. the infrastructure to hold files and directories. That ensured the
2de9b711 164 efficiency and speed of Git.
f562e6f3 165
2de9b711 166[[def_git_archive]]Git archive::
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167 Synonym for <<def_repository,repository>> (for arch people).
168
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169[[def_gitfile]]gitfile::
170 A plain file `.git` at the root of a working tree that
171 points at the directory that is the real repository.
172
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173[[def_grafts]]grafts::
174 Grafts enables two otherwise different lines of development to be joined
175 together by recording fake ancestry information for commits. This way
2de9b711 176 you can make Git pretend the set of <<def_parent,parents>> a <<def_commit,commit>> has
343cad92 177 is different from what was recorded when the commit was
cbd91922 178 created. Configured via the `.git/info/grafts` file.
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180Note that the grafts mechanism is outdated and can lead to problems
181transferring objects between repositories; see linkgit:git-replace[1]
182for a more flexible and robust system to do the same thing.
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183
184[[def_hash]]hash::
3ab50120 185 In Git's context, synonym for <<def_object_name,object name>>.
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186
187[[def_head]]head::
a58f3c01 188 A <<def_ref,named reference>> to the <<def_commit,commit>> at the tip of a
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189 <<def_branch,branch>>. Heads are stored in a file in
190 `$GIT_DIR/refs/heads/` directory, except when using packed refs. (See
5162e697 191 linkgit:git-pack-refs[1].)
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192
193[[def_HEAD]]HEAD::
a58f3c01 194 The current <<def_branch,branch>>. In more detail: Your <<def_working_tree,
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195 working tree>> is normally derived from the state of the tree
196 referred to by HEAD. HEAD is a reference to one of the
197 <<def_head,heads>> in your repository, except when using a
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198 <<def_detached_HEAD,detached HEAD>>, in which case it directly
199 references an arbitrary commit.
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200
201[[def_head_ref]]head ref::
343cad92 202 A synonym for <<def_head,head>>.
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203
204[[def_hook]]hook::
2de9b711 205 During the normal execution of several Git commands, call-outs are made
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206 to optional scripts that allow a developer to add functionality or
207 checking. Typically, the hooks allow for a command to be pre-verified
208 and potentially aborted, and allow for a post-notification after the
343cad92 209 operation is done. The hook scripts are found in the
a58f3c01 210 `$GIT_DIR/hooks/` directory, and are enabled by simply
d1983677 211 removing the `.sample` suffix from the filename. In earlier versions
2de9b711 212 of Git you had to make them executable.
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213
214[[def_index]]index::
215 A collection of files with stat information, whose contents are stored
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216 as objects. The index is a stored version of your
217 <<def_working_tree,working tree>>. Truth be told, it can also contain a second, and even
218 a third version of a working tree, which are used
219 when <<def_merge,merging>>.
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220
221[[def_index_entry]]index entry::
222 The information regarding a particular file, stored in the
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223 <<def_index,index>>. An index entry can be unmerged, if a
224 <<def_merge,merge>> was started, but not yet finished (i.e. if
225 the index contains multiple versions of that file).
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226
227[[def_master]]master::
343cad92 228 The default development <<def_branch,branch>>. Whenever you
2de9b711 229 create a Git <<def_repository,repository>>, a branch named
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230 "master" is created, and becomes the active branch. In most
231 cases, this contains the local development, though that is
232 purely by convention and is not required.
da139813 233
f562e6f3 234[[def_merge]]merge::
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235 As a verb: To bring the contents of another
236 <<def_branch,branch>> (possibly from an external
237 <<def_repository,repository>>) into the current branch. In the
238 case where the merged-in branch is from a different repository,
239 this is done by first <<def_fetch,fetching>> the remote branch
240 and then merging the result into the current branch. This
241 combination of fetch and merge operations is called a
242 <<def_pull,pull>>. Merging is performed by an automatic process
243 that identifies changes made since the branches diverged, and
244 then applies all those changes together. In cases where changes
245 conflict, manual intervention may be required to complete the
246 merge.
247+
a75d7b54 248As a noun: unless it is a <<def_fast_forward,fast-forward>>, a
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249successful merge results in the creation of a new <<def_commit,commit>>
250representing the result of the merge, and having as
251<<def_parent,parents>> the tips of the merged <<def_branch,branches>>.
252This commit is referred to as a "merge commit", or sometimes just a
253"merge".
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254
255[[def_object]]object::
2de9b711 256 The unit of storage in Git. It is uniquely identified by the
3ab50120 257 <<def_SHA1,SHA-1>> of its contents. Consequently, an
343cad92 258 object can not be changed.
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259
260[[def_object_database]]object database::
261 Stores a set of "objects", and an individual <<def_object,object>> is
262 identified by its <<def_object_name,object name>>. The objects usually
263 live in `$GIT_DIR/objects/`.
264
265[[def_object_identifier]]object identifier::
266 Synonym for <<def_object_name,object name>>.
267
268[[def_object_name]]object name::
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269 The unique identifier of an <<def_object,object>>. The
270 object name is usually represented by a 40 character
271 hexadecimal string. Also colloquially called <<def_SHA1,SHA-1>>.
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272
273[[def_object_type]]object type::
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274 One of the identifiers "<<def_commit_object,commit>>",
275 "<<def_tree_object,tree>>", "<<def_tag_object,tag>>" or
276 "<<def_blob_object,blob>>" describing the type of an
277 <<def_object,object>>.
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278
279[[def_octopus]]octopus::
79de4558 280 To <<def_merge,merge>> more than two <<def_branch,branches>>.
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281
282[[def_origin]]origin::
283 The default upstream <<def_repository,repository>>. Most projects have
284 at least one upstream project which they track. By default
343cad92 285 'origin' is used for that purpose. New upstream updates
d6ac1d21 286 will be fetched into <<def_remote_tracking_branch,remote-tracking branches>> named
cbd91922 287 origin/name-of-upstream-branch, which you can see using
dcb11263 288 `git branch -r`.
f1671ecb 289
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290[[def_pack]]pack::
291 A set of objects which have been compressed into one file (to save space
292 or to transmit them efficiently).
da139813 293
f562e6f3 294[[def_pack_index]]pack index::
aa9b1573 295 The list of identifiers, and other information, of the objects in a
f562e6f3 296 <<def_pack,pack>>, to assist in efficiently accessing the contents of a
343cad92 297 pack.
f562e6f3 298
3bd2bcfa 299[[def_pathspec]]pathspec::
57148ebb 300 Pattern used to limit paths in Git commands.
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301+
302Pathspecs are used on the command line of "git ls-files", "git
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303ls-tree", "git add", "git grep", "git diff", "git checkout",
304and many other commands to
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305limit the scope of operations to some subset of the tree or
306worktree. See the documentation of each command for whether
307paths are relative to the current directory or toplevel. The
308pathspec syntax is as follows:
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309+
310--
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311
312* any path matches itself
313* the pathspec up to the last slash represents a
314 directory prefix. The scope of that pathspec is
315 limited to that subtree.
316* the rest of the pathspec is a pattern for the remainder
317 of the pathname. Paths relative to the directory
318 prefix will be matched against that pattern using fnmatch(3);
319 in particular, '*' and '?' _can_ match directory separators.
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320
321--
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322+
323For example, Documentation/*.jpg will match all .jpg files
324in the Documentation subtree,
325including Documentation/chapter_1/figure_1.jpg.
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326+
327A pathspec that begins with a colon `:` has special meaning. In the
328short form, the leading colon `:` is followed by zero or more "magic
329signature" letters (which optionally is terminated by another colon `:`),
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330and the remainder is the pattern to match against the path.
331The "magic signature" consists of ASCII symbols that are neither
f745acb0 332alphanumeric, glob, regex special characters nor colon.
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333The optional colon that terminates the "magic signature" can be
334omitted if the pattern begins with a character that does not belong to
335"magic signature" symbol set and is not a colon.
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336+
337In the long form, the leading colon `:` is followed by a open
338parenthesis `(`, a comma-separated list of zero or more "magic words",
339and a close parentheses `)`, and the remainder is the pattern to match
340against the path.
341+
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342A pathspec with only a colon means "there is no pathspec". This form
343should not be combined with other pathspec.
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344+
345--
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346top;;
347 The magic word `top` (magic signature: `/`) makes the pattern
348 match from the root of the working tree, even when you are
349 running the command from inside a subdirectory.
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350
351literal;;
352 Wildcards in the pattern such as `*` or `?` are treated
353 as literal characters.
bd30c2e4 354
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355icase;;
356 Case insensitive match.
357
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358glob;;
359 Git treats the pattern as a shell glob suitable for
360 consumption by fnmatch(3) with the FNM_PATHNAME flag:
361 wildcards in the pattern will not match a / in the pathname.
362 For example, "Documentation/{asterisk}.html" matches
363 "Documentation/git.html" but not "Documentation/ppc/ppc.html"
364 or "tools/perf/Documentation/perf.html".
365+
366Two consecutive asterisks ("`**`") in patterns matched against
367full pathname may have special meaning:
368
369 - A leading "`**`" followed by a slash means match in all
370 directories. For example, "`**/foo`" matches file or directory
746be68d 371 "`foo`" anywhere, the same as pattern "`foo`". "`**/foo/bar`"
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372 matches file or directory "`bar`" anywhere that is directly
373 under directory "`foo`".
374
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375 - A trailing "`/**`" matches everything inside. For example,
376 "`abc/**`" matches all files inside directory "abc", relative
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377 to the location of the `.gitignore` file, with infinite depth.
378
379 - A slash followed by two consecutive asterisks then a slash
380 matches zero or more directories. For example, "`a/**/b`"
381 matches "`a/b`", "`a/x/b`", "`a/x/y/b`" and so on.
382
383 - Other consecutive asterisks are considered invalid.
384+
385Glob magic is incompatible with literal magic.
ef79b1f8 386
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387attr;;
388After `attr:` comes a space separated list of "attribute
389requirements", all of which must be met in order for the
390path to be considered a match; this is in addition to the
391usual non-magic pathspec pattern matching.
392See linkgit:gitattributes[5].
393+
394Each of the attribute requirements for the path takes one of
395these forms:
396
397- "`ATTR`" requires that the attribute `ATTR` be set.
398
399- "`-ATTR`" requires that the attribute `ATTR` be unset.
400
401- "`ATTR=VALUE`" requires that the attribute `ATTR` be
402 set to the string `VALUE`.
403
404- "`!ATTR`" requires that the attribute `ATTR` be
405 unspecified.
406+
407
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408exclude;;
409 After a path matches any non-exclude pathspec, it will be run
42ebeb9d 410 through all exclude pathspec (magic signature: `!` or its
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411 synonym `^`). If it matches, the path is ignored. When there
412 is no non-exclude pathspec, the exclusion is applied to the
413 result set as if invoked without any pathspec.
5c6933d2 414--
8a42c985 415
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416[[def_parent]]parent::
417 A <<def_commit_object,commit object>> contains a (possibly empty) list
418 of the logical predecessor(s) in the line of development, i.e. its
419 parents.
420
421[[def_pickaxe]]pickaxe::
422 The term <<def_pickaxe,pickaxe>> refers to an option to the diffcore
423 routines that help select changes that add or delete a given text
b6cbca38 424 string. With the `--pickaxe-all` option, it can be used to view the full
f562e6f3 425 <<def_changeset,changeset>> that introduced or removed, say, a
5162e697 426 particular line of text. See linkgit:git-diff[1].
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427
428[[def_plumbing]]plumbing::
2de9b711 429 Cute name for <<def_core_git,core Git>>.
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430
431[[def_porcelain]]porcelain::
432 Cute name for programs and program suites depending on
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433 <<def_core_git,core Git>>, presenting a high level access to
434 core Git. Porcelains expose more of a <<def_SCM,SCM>>
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435 interface than the <<def_plumbing,plumbing>>.
436
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437[[def_per_worktree_ref]]per-worktree ref::
438 Refs that are per-<<def_working_tree,worktree>>, rather than
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439 global. This is presently only <<def_HEAD,HEAD>> and any refs
440 that start with `refs/bisect/`, but might later include other
441 unusual refs.
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442
443[[def_pseudoref]]pseudoref::
444 Pseudorefs are a class of files under `$GIT_DIR` which behave
445 like refs for the purposes of rev-parse, but which are treated
446 specially by git. Pseudorefs both have names that are all-caps,
447 and always start with a line consisting of a
448 <<def_SHA1,SHA-1>> followed by whitespace. So, HEAD is not a
449 pseudoref, because it is sometimes a symbolic ref. They might
450 optionally contain some additional data. `MERGE_HEAD` and
451 `CHERRY_PICK_HEAD` are examples. Unlike
452 <<def_per_worktree_ref,per-worktree refs>>, these files cannot
453 be symbolic refs, and never have reflogs. They also cannot be
454 updated through the normal ref update machinery. Instead,
455 they are updated by directly writing to the files. However,
456 they can be read as if they were refs, so `git rev-parse
457 MERGE_HEAD` will work.
458
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459[[def_pull]]pull::
460 Pulling a <<def_branch,branch>> means to <<def_fetch,fetch>> it and
5162e697 461 <<def_merge,merge>> it. See also linkgit:git-pull[1].
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462
463[[def_push]]push::
343cad92 464 Pushing a <<def_branch,branch>> means to get the branch's
f562e6f3 465 <<def_head_ref,head ref>> from a remote <<def_repository,repository>>,
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466 find out if it is a direct ancestor to the branch's local
467 head ref, and in that case, putting all
f562e6f3 468 objects, which are <<def_reachable,reachable>> from the local
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469 head ref, and which are missing from the remote
470 repository, into the remote
f562e6f3 471 <<def_object_database,object database>>, and updating the remote
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472 head ref. If the remote <<def_head,head>> is not an
473 ancestor to the local head, the push fails.
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474
475[[def_reachable]]reachable::
476 All of the ancestors of a given <<def_commit,commit>> are said to be
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477 "reachable" from that commit. More
478 generally, one <<def_object,object>> is reachable from
f562e6f3 479 another if we can reach the one from the other by a <<def_chain,chain>>
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480 that follows <<def_tag,tags>> to whatever they tag,
481 <<def_commit_object,commits>> to their parents or trees, and
482 <<def_tree_object,trees>> to the trees or <<def_blob_object,blobs>>
483 that they contain.
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484
485[[def_rebase]]rebase::
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486 To reapply a series of changes from a <<def_branch,branch>> to a
487 different base, and reset the <<def_head,head>> of that branch
488 to the result.
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489
490[[def_ref]]ref::
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491 A name that begins with `refs/` (e.g. `refs/heads/master`)
492 that points to an <<def_object_name,object name>> or another
493 ref (the latter is called a <<def_symref,symbolic ref>>).
494 For convenience, a ref can sometimes be abbreviated when used
495 as an argument to a Git command; see linkgit:gitrevisions[7]
496 for details.
497 Refs are stored in the <<def_repository,repository>>.
498+
499The ref namespace is hierarchical.
500Different subhierarchies are used for different purposes (e.g. the
501`refs/heads/` hierarchy is used to represent local branches).
502+
503There are a few special-purpose refs that do not begin with `refs/`.
504The most notable example is `HEAD`.
f562e6f3 505
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506[[def_reflog]]reflog::
507 A reflog shows the local "history" of a ref. In other words,
508 it can tell you what the 3rd last revision in _this_ repository
509 was, and what was the current state in _this_ repository,
5162e697 510 yesterday 9:14pm. See linkgit:git-reflog[1] for details.
f8d69576 511
f562e6f3 512[[def_refspec]]refspec::
a58f3c01 513 A "refspec" is used by <<def_fetch,fetch>> and
343cad92 514 <<def_push,push>> to describe the mapping between remote
57148ebb 515 <<def_ref,ref>> and local ref.
f562e6f3 516
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517[[def_remote]]remote repository::
518 A <<def_repository,repository>> which is used to track the same
519 project but resides somewhere else. To communicate with remotes,
520 see <<def_fetch,fetch>> or <<def_push,push>>.
521
8b3f3f84 522[[def_remote_tracking_branch]]remote-tracking branch::
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523 A <<def_ref,ref>> that is used to follow changes from another
524 <<def_repository,repository>>. It typically looks like
525 'refs/remotes/foo/bar' (indicating that it tracks a branch named
526 'bar' in a remote named 'foo'), and matches the right-hand-side of
527 a configured fetch <<def_refspec,refspec>>. A remote-tracking
528 branch should not contain direct modifications or have local
529 commits made to it.
8b3f3f84 530
f562e6f3 531[[def_repository]]repository::
a58f3c01 532 A collection of <<def_ref,refs>> together with an
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533 <<def_object_database,object database>> containing all objects
534 which are <<def_reachable,reachable>> from the refs, possibly
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535 accompanied by meta data from one or more <<def_porcelain,porcelains>>. A
536 repository can share an object database with other repositories
537 via <<def_alternate_object_database,alternates mechanism>>.
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538
539[[def_resolve]]resolve::
540 The action of fixing up manually what a failed automatic
541 <<def_merge,merge>> left behind.
542
543[[def_revision]]revision::
dfb44106 544 Synonym for <<def_commit,commit>> (the noun).
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545
546[[def_rewind]]rewind::
547 To throw away part of the development, i.e. to assign the
548 <<def_head,head>> to an earlier <<def_revision,revision>>.
549
550[[def_SCM]]SCM::
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551 Source code management (tool).
552
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553[[def_SHA1]]SHA-1::
554 "Secure Hash Algorithm 1"; a cryptographic hash function.
555 In the context of Git used as a synonym for <<def_object_name,object name>>.
f562e6f3 556
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557[[def_shallow_clone]]shallow clone::
558 Mostly a synonym to <<def_shallow_repository,shallow repository>>
559 but the phrase makes it more explicit that it was created by
560 running `git clone --depth=...` command.
561
f562e6f3 562[[def_shallow_repository]]shallow repository::
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563 A shallow <<def_repository,repository>> has an incomplete
564 history some of whose <<def_commit,commits>> have <<def_parent,parents>> cauterized away (in other
2de9b711 565 words, Git is told to pretend that these commits do not have the
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566 parents, even though they are recorded in the <<def_commit_object,commit
567 object>>). This is sometimes useful when you are interested only in the
568 recent history of a project even though the real history recorded in the
343cad92 569 upstream is much larger. A shallow repository
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570 is created by giving the `--depth` option to linkgit:git-clone[1], and
571 its history can be later deepened with linkgit:git-fetch[1].
428ddc5d 572
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573[[def_submodule]]submodule::
574 A <<def_repository,repository>> that holds the history of a
575 separate project inside another repository (the latter of
576 which is called <<def_superproject, superproject>>).
577
578[[def_superproject]]superproject::
579 A <<def_repository,repository>> that references repositories
580 of other projects in its working tree as <<def_submodule,submodules>>.
581 The superproject knows about the names of (but does not hold
582 copies of) commit objects of the contained submodules.
583
f562e6f3 584[[def_symref]]symref::
3ab50120 585 Symbolic reference: instead of containing the <<def_SHA1,SHA-1>>
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586 id itself, it is of the format 'ref: refs/some/thing' and when
587 referenced, it recursively dereferences to this reference.
588 '<<def_HEAD,HEAD>>' is a prime example of a symref. Symbolic
5162e697 589 references are manipulated with the linkgit:git-symbolic-ref[1]
343cad92 590 command.
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591
592[[def_tag]]tag::
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593 A <<def_ref,ref>> under `refs/tags/` namespace that points to an
594 object of an arbitrary type (typically a tag points to either a
595 <<def_tag_object,tag>> or a <<def_commit_object,commit object>>).
596 In contrast to a <<def_head,head>>, a tag is not updated by
2de9b711 597 the `commit` command. A Git tag has nothing to do with a Lisp
487b0441 598 tag (which would be called an <<def_object_type,object type>>
2de9b711 599 in Git's context). A tag is most typically used to mark a particular
487b0441 600 point in the commit ancestry <<def_chain,chain>>.
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601
602[[def_tag_object]]tag object::
603 An <<def_object,object>> containing a <<def_ref,ref>> pointing to
343cad92 604 another object, which can contain a message just like a
f562e6f3 605 <<def_commit_object,commit object>>. It can also contain a (PGP)
a58f3c01 606 signature, in which case it is called a "signed tag object".
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607
608[[def_topic_branch]]topic branch::
2de9b711 609 A regular Git <<def_branch,branch>> that is used by a developer to
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610 identify a conceptual line of development. Since branches are very easy
611 and inexpensive, it is often desirable to have several small branches
612 that each contain very well defined concepts or small incremental yet
613 related changes.
614
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615[[def_tree]]tree::
616 Either a <<def_working_tree,working tree>>, or a <<def_tree_object,tree
a58f3c01 617 object>> together with the dependent <<def_blob_object,blob>> and tree objects
343cad92 618 (i.e. a stored representation of a working tree).
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619
620[[def_tree_object]]tree object::
621 An <<def_object,object>> containing a list of file names and modes along
cbd91922 622 with refs to the associated blob and/or tree objects. A
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623 <<def_tree,tree>> is equivalent to a <<def_directory,directory>>.
624
36a2a54d 625[[def_tree-ish]]tree-ish (also treeish)::
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626 A <<def_tree_object,tree object>> or an <<def_object,object>>
627 that can be recursively dereferenced to a tree object.
628 Dereferencing a <<def_commit_object,commit object>> yields the
629 tree object corresponding to the <<def_revision,revision>>'s
630 top <<def_directory,directory>>.
631 The following are all tree-ishes:
632 a <<def_commit-ish,commit-ish>>,
633 a tree object,
634 a <<def_tag_object,tag object>> that points to a tree object,
635 a tag object that points to a tag object that points to a tree
636 object,
637 etc.
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638
639[[def_unmerged_index]]unmerged index::
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640 An <<def_index,index>> which contains unmerged
641 <<def_index_entry,index entries>>.
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642
643[[def_unreachable_object]]unreachable object::
644 An <<def_object,object>> which is not <<def_reachable,reachable>> from a
645 <<def_branch,branch>>, <<def_tag,tag>>, or any other reference.
646
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647[[def_upstream_branch]]upstream branch::
648 The default <<def_branch,branch>> that is merged into the branch in
649 question (or the branch in question is rebased onto). It is configured
650 via branch.<name>.remote and branch.<name>.merge. If the upstream branch
651 of 'A' is 'origin/B' sometimes we say "'A' is tracking 'origin/B'".
652
f562e6f3 653[[def_working_tree]]working tree::
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654 The tree of actual checked out files. The working tree normally
655 contains the contents of the <<def_HEAD,HEAD>> commit's tree,
656 plus any local changes that you have made but not yet committed.