Merge branch 'po/help-guides'
[git/git.git] / Documentation / git-checkout.txt
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1git-checkout(1)
2===============
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3
4NAME
5----
76ce9462 6git-checkout - Checkout a branch or paths to the working tree
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7
8SYNOPSIS
9--------
71bb1033 10[verse]
76cfadfc 11'git checkout' [-q] [-f] [-m] [<branch>]
32669671 12'git checkout' [-q] [-f] [-m] [--detach] [<commit>]
02ac9837 13'git checkout' [-q] [-f] [-m] [[-b|-B|--orphan] <new_branch>] [<start_point>]
eac5a401 14'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
a31538e2 15'git checkout' [-p|--patch] [<tree-ish>] [--] [<paths>...]
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16
17DESCRIPTION
18-----------
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19Updates files in the working tree to match the version in the index
20or the specified tree. If no paths are given, 'git checkout' will
21also update `HEAD` to set the specified branch as the current
76cfadfc 22branch.
4aaa7027 23
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24'git checkout' <branch>::
25 To prepare for working on <branch>, switch to it by updating
26 the index and the files in the working tree, and by pointing
27 HEAD at the branch. Local modifications to the files in the
28 working tree are kept, so that they can be committed to the
29 <branch>.
30+
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31If <branch> is not found but there does exist a tracking branch in
32exactly one remote (call it <remote>) with a matching name, treat as
33equivalent to
34+
35------------
36$ git checkout -b <branch> --track <remote>/<branch>
37------------
38+
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39You could omit <branch>, in which case the command degenerates to
40"check out the current branch", which is a glorified no-op with a
41rather expensive side-effects to show only the tracking information,
42if exists, for the current branch.
43
02ac9837 44'git checkout' -b|-B <new_branch> [<start point>]::
4aaa7027 45
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46 Specifying `-b` causes a new branch to be created as if
47 linkgit:git-branch[1] were called and then checked out. In
48 this case you can use the `--track` or `--no-track` options,
49 which will be passed to 'git branch'. As a convenience,
50 `--track` without `-b` implies branch creation; see the
51 description of `--track` below.
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52+
53If `-B` is given, <new_branch> is created if it doesn't exist; otherwise, it
54is reset. This is the transactional equivalent of
55+
56------------
57$ git branch -f <branch> [<start point>]
58$ git checkout <branch>
59------------
60+
61that is to say, the branch is not reset/created unless "git checkout" is
62successful.
bb0ceb62 63
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64'git checkout' --detach [<branch>]::
65'git checkout' <commit>::
66
67 Prepare to work on top of <commit>, by detaching HEAD at it
68 (see "DETACHED HEAD" section), and updating the index and the
69 files in the working tree. Local modifications to the files
70 in the working tree are kept, so that the resulting working
71 tree will be the state recorded in the commit plus the local
72 modifications.
73+
74Passing `--detach` forces this behavior in the case of a <branch> (without
75the option, giving a branch name to the command would check out the branch,
76instead of detaching HEAD at it), or the current commit,
77if no <branch> is specified.
78
a31538e2 79'git checkout' [-p|--patch] [<tree-ish>] [--] <pathspec>...::
4aaa7027 80
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81 When <paths> or `--patch` are given, 'git checkout' does *not*
82 switch branches. It updates the named paths in the working tree
83 from the index file or from a named <tree-ish> (most often a
84 commit). In this case, the `-b` and `--track` options are
85 meaningless and giving either of them results in an error. The
86 <tree-ish> argument can be used to specify a specific tree-ish
87 (i.e. commit, tag or tree) to update the index for the given
88 paths before updating the working tree.
c5b41519 89+
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90The index may contain unmerged entries because of a previous failed merge.
91By default, if you try to check out such an entry from the index, the
db941099 92checkout operation will fail and nothing will be checked out.
b831deda 93Using `-f` will ignore these unmerged entries. The contents from a
38901a48 94specific side of the merge can be checked out of the index by
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95using `--ours` or `--theirs`. With `-m`, changes made to the working tree
96file can be discarded to re-create the original conflicted merge result.
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97
98OPTIONS
99-------
6124aee5 100-q::
f7aec129 101--quiet::
2be7fcb4 102 Quiet, suppress feedback messages.
6124aee5 103
0270f7c5 104-f::
f7aec129 105--force::
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106 When switching branches, proceed even if the index or the
107 working tree differs from HEAD. This is used to throw away
108 local changes.
109+
110When checking out paths from the index, do not fail upon unmerged
111entries; instead, unmerged entries are ignored.
0270f7c5 112
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113--ours::
114--theirs::
115 When checking out paths from the index, check out stage #2
116 ('ours') or #3 ('theirs') for unmerged paths.
0270f7c5 117
45aaf031 118-b <new_branch>::
2b1f4247 119 Create a new branch named <new_branch> and start it at
76cfadfc 120 <start_point>; see linkgit:git-branch[1] for details.
7fc9d69f 121
45aaf031 122-B <new_branch>::
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123 Creates the branch <new_branch> and start it at <start_point>;
124 if it already exists, then reset it to <start_point>. This is
125 equivalent to running "git branch" with "-f"; see
126 linkgit:git-branch[1] for details.
127
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128-t::
129--track::
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130 When creating a new branch, set up "upstream" configuration. See
131 "--track" in linkgit:git-branch[1] for details.
bb0ceb62 132+
c7cb12b8 133If no '-b' option is given, the name of the new branch will be
29b9a66f 134derived from the remote-tracking branch. If "remotes/" or "refs/remotes/"
c7cb12b8 135is prefixed it is stripped away, and then the part up to the
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136next slash (which would be the nickname of the remote) is removed.
137This would tell us to use "hack" as the local branch when branching
138off of "origin/hack" (or "remotes/origin/hack", or even
139"refs/remotes/origin/hack"). If the given name has no slash, or the above
140guessing results in an empty name, the guessing is aborted. You can
971e8352 141explicitly give a name with '-b' in such a case.
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142
143--no-track::
167d7445 144 Do not set up "upstream" configuration, even if the
70e96647 145 branch.autosetupmerge configuration variable is true.
0746d19a 146
969d326d 147-l::
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148 Create the new branch's reflog; see linkgit:git-branch[1] for
149 details.
969d326d 150
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151--detach::
152 Rather than checking out a branch to work on it, check out a
153 commit for inspection and discardable experiments.
154 This is the default behavior of "git checkout <commit>" when
155 <commit> is not a branch name. See the "DETACHED HEAD" section
156 below for details.
157
45aaf031 158--orphan <new_branch>::
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159 Create a new 'orphan' branch, named <new_branch>, started from
160 <start_point> and switch to it. The first commit made on this
161 new branch will have no parents and it will be the root of a new
162 history totally disconnected from all the other branches and
163 commits.
9db5ebf4 164+
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165The index and the working tree are adjusted as if you had previously run
166"git checkout <start_point>". This allows you to start a new history
167that records a set of paths similar to <start_point> by easily running
168"git commit -a" to make the root commit.
9db5ebf4 169+
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170This can be useful when you want to publish the tree from a commit
171without exposing its full history. You might want to do this to publish
172an open source branch of a project whose current tree is "clean", but
173whose full history contains proprietary or otherwise encumbered bits of
174code.
175+
176If you want to start a disconnected history that records a set of paths
177that is totally different from the one of <start_point>, then you should
178clear the index and the working tree right after creating the orphan
179branch by running "git rm -rf ." from the top level of the working tree.
180Afterwards you will be ready to prepare your new files, repopulating the
181working tree, by copying them from elsewhere, extracting a tarball, etc.
9db5ebf4 182
1be0659e 183-m::
eac5a401 184--merge::
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185 When switching branches,
186 if you have local modifications to one or more files that
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187 are different between the current branch and the branch to
188 which you are switching, the command refuses to switch
189 branches in order to preserve your modifications in context.
190 However, with this option, a three-way merge between the current
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191 branch, your working tree contents, and the new branch
192 is done, and you will be on the new branch.
193+
194When a merge conflict happens, the index entries for conflicting
195paths are left unmerged, and you need to resolve the conflicts
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196and mark the resolved paths with `git add` (or `git rm` if the merge
197should result in deletion of the path).
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198+
199When checking out paths from the index, this option lets you recreate
200the conflicted merge in the specified paths.
1be0659e 201
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202--conflict=<style>::
203 The same as --merge option above, but changes the way the
204 conflicting hunks are presented, overriding the
205 merge.conflictstyle configuration variable. Possible values are
206 "merge" (default) and "diff3" (in addition to what is shown by
207 "merge" style, shows the original contents).
1be0659e 208
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209-p::
210--patch::
211 Interactively select hunks in the difference between the
212 <tree-ish> (or the index, if unspecified) and the working
213 tree. The chosen hunks are then applied in reverse to the
214 working tree (and if a <tree-ish> was specified, the index).
215+
216This means that you can use `git checkout -p` to selectively discard
a31538e2 217edits from your current working tree. See the ``Interactive Mode''
6cf378f0 218section of linkgit:git-add[1] to learn how to operate the `--patch` mode.
4f353658 219
0270f7c5 220<branch>::
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221 Branch to checkout; if it refers to a branch (i.e., a name that,
222 when prepended with "refs/heads/", is a valid ref), then that
223 branch is checked out. Otherwise, if it refers to a valid
224 commit, your HEAD becomes "detached" and you are no longer on
225 any branch (see below for details).
696acf45 226+
6cf378f0 227As a special case, the `"@{-N}"` syntax for the N-th last branch
696acf45 228checks out the branch (instead of detaching). You may also specify
6cf378f0 229`-` which is synonymous with `"@{-1}"`.
873c3472 230+
6cf378f0 231As a further special case, you may use `"A...B"` as a shortcut for the
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232merge base of `A` and `B` if there is exactly one merge base. You can
233leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
5e1a2e8c 234
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235<new_branch>::
236 Name for the new branch.
237
238<start_point>::
239 The name of a commit at which to start the new branch; see
240 linkgit:git-branch[1] for details. Defaults to HEAD.
241
242<tree-ish>::
243 Tree to checkout from (when paths are given). If not specified,
244 the index will be used.
245
246
5e1a2e8c 247
32669671 248DETACHED HEAD
5e1a2e8c 249-------------
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250HEAD normally refers to a named branch (e.g. 'master'). Meanwhile, each
251branch refers to a specific commit. Let's look at a repo with three
252commits, one of them tagged, and with branch 'master' checked out:
5e1a2e8c 253
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254------------
255 HEAD (refers to branch 'master')
256 |
257 v
258a---b---c branch 'master' (refers to commit 'c')
259 ^
260 |
261 tag 'v2.0' (refers to commit 'b')
262------------
263
264When a commit is created in this state, the branch is updated to refer to
265the new commit. Specifically, 'git commit' creates a new commit 'd', whose
266parent is commit 'c', and then updates branch 'master' to refer to new
267commit 'd'. HEAD still refers to branch 'master' and so indirectly now refers
268to commit 'd':
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269
270------------
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271$ edit; git add; git commit
272
273 HEAD (refers to branch 'master')
274 |
275 v
276a---b---c---d branch 'master' (refers to commit 'd')
277 ^
278 |
279 tag 'v2.0' (refers to commit 'b')
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280------------
281
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282It is sometimes useful to be able to checkout a commit that is not at
283the tip of any named branch, or even to create a new commit that is not
284referenced by a named branch. Let's look at what happens when we
285checkout commit 'b' (here we show two ways this may be done):
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286
287------------
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288$ git checkout v2.0 # or
289$ git checkout master^^
290
291 HEAD (refers to commit 'b')
292 |
293 v
294a---b---c---d branch 'master' (refers to commit 'd')
295 ^
296 |
297 tag 'v2.0' (refers to commit 'b')
298------------
5e1a2e8c 299
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300Notice that regardless of which checkout command we use, HEAD now refers
301directly to commit 'b'. This is known as being in detached HEAD state.
302It means simply that HEAD refers to a specific commit, as opposed to
303referring to a named branch. Let's see what happens when we create a commit:
cec8d146 304
cec8d146 305------------
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306$ edit; git add; git commit
307
308 HEAD (refers to commit 'e')
309 |
310 v
311 e
312 /
313a---b---c---d branch 'master' (refers to commit 'd')
314 ^
315 |
316 tag 'v2.0' (refers to commit 'b')
cec8d146 317------------
7fc9d69f 318
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319There is now a new commit 'e', but it is referenced only by HEAD. We can
320of course add yet another commit in this state:
7fc9d69f 321
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322------------
323$ edit; git add; git commit
324
325 HEAD (refers to commit 'f')
326 |
327 v
328 e---f
329 /
330a---b---c---d branch 'master' (refers to commit 'd')
331 ^
332 |
333 tag 'v2.0' (refers to commit 'b')
334------------
335
2de9b711 336In fact, we can perform all the normal Git operations. But, let's look
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337at what happens when we then checkout master:
338
339------------
340$ git checkout master
341
342 HEAD (refers to branch 'master')
343 e---f |
344 / v
345a---b---c---d branch 'master' (refers to commit 'd')
346 ^
347 |
348 tag 'v2.0' (refers to commit 'b')
349------------
350
351It is important to realize that at this point nothing refers to commit
352'f'. Eventually commit 'f' (and by extension commit 'e') will be deleted
2de9b711 353by the routine Git garbage collection process, unless we create a reference
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354before that happens. If we have not yet moved away from commit 'f',
355any of these will create a reference to it:
356
357------------
358$ git checkout -b foo <1>
359$ git branch foo <2>
360$ git tag foo <3>
361------------
362
363<1> creates a new branch 'foo', which refers to commit 'f', and then
364updates HEAD to refer to branch 'foo'. In other words, we'll no longer
365be in detached HEAD state after this command.
366
367<2> similarly creates a new branch 'foo', which refers to commit 'f',
368but leaves HEAD detached.
369
370<3> creates a new tag 'foo', which refers to commit 'f',
371leaving HEAD detached.
372
373If we have moved away from commit 'f', then we must first recover its object
374name (typically by using git reflog), and then we can create a reference to
375it. For example, to see the last two commits to which HEAD referred, we
376can use either of these commands:
377
378------------
379$ git reflog -2 HEAD # or
380$ git log -g -2 HEAD
381------------
4aaa7027 382
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383EXAMPLES
384--------
4aaa7027 385
1be0659e 386. The following sequence checks out the `master` branch, reverts
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387the `Makefile` to two revisions back, deletes hello.c by
388mistake, and gets it back from the index.
1be0659e 389+
4aaa7027 390------------
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391$ git checkout master <1>
392$ git checkout master~2 Makefile <2>
4aaa7027 393$ rm -f hello.c
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394$ git checkout hello.c <3>
395------------
396+
1e2ccd3a 397<1> switch branch
c7cb12b8 398<2> take a file out of another commit
ce8936c3 399<3> restore hello.c from the index
1be0659e 400+
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401If you want to check out _all_ C source files out of the index,
402you can say
403+
404------------
405$ git checkout -- '*.c'
406------------
407+
408Note the quotes around `*.c`. The file `hello.c` will also be
409checked out, even though it is no longer in the working tree,
410because the file globbing is used to match entries in the index
411(not in the working tree by the shell).
412+
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413If you have an unfortunate branch that is named `hello.c`, this
414step would be confused as an instruction to switch to that branch.
415You should instead write:
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417------------
418$ git checkout -- hello.c
419------------
420
c7cb12b8 421. After working in the wrong branch, switching to the correct
71bb1033 422branch would be done using:
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423+
424------------
425$ git checkout mytopic
426------------
427+
428However, your "wrong" branch and correct "mytopic" branch may
c7cb12b8 429differ in files that you have modified locally, in which case
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430the above checkout would fail like this:
431+
432------------
433$ git checkout mytopic
142183d0 434error: You have local changes to 'frotz'; not switching branches.
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435------------
436+
437You can give the `-m` flag to the command, which would try a
438three-way merge:
439+
440------------
441$ git checkout -m mytopic
442Auto-merging frotz
443------------
444+
445After this three-way merge, the local modifications are _not_
446registered in your index file, so `git diff` would show you what
447changes you made since the tip of the new branch.
448
449. When a merge conflict happens during switching branches with
450the `-m` option, you would see something like this:
451+
452------------
453$ git checkout -m mytopic
454Auto-merging frotz
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455ERROR: Merge conflict in frotz
456fatal: merge program failed
457------------
458+
459At this point, `git diff` shows the changes cleanly merged as in
460the previous example, as well as the changes in the conflicted
461files. Edit and resolve the conflict and mark it resolved with
d7f078b8 462`git add` as usual:
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463+
464------------
465$ edit frotz
d7f078b8 466$ git add frotz
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467------------
468
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469GIT
470---
9e1f0a85 471Part of the linkgit:git[1] suite