Merge branch 'ks/maint-mailinfo-folded'
[git/git.git] / Documentation / git-checkout.txt
1 git-checkout(1)
2 ===============
3
4 NAME
5 ----
6 git-checkout - Checkout a branch or paths to the working tree
7
8 SYNOPSIS
9 --------
10 [verse]
11 'git checkout' [-q] [-f] [--track | --no-track] [-b <new_branch> [-l]] [-m] [<branch>]
12 'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
13
14 DESCRIPTION
15 -----------
16
17 When <paths> are not given, this command switches branches by
18 updating the index and working tree to reflect the specified
19 branch, <branch>, and updating HEAD to be <branch> or, if
20 specified, <new_branch>. Using -b will cause <new_branch> to
21 be created; in this case you can use the --track or --no-track
22 options, which will be passed to `git branch`.
23
24 As a convenience, --track will default to create a branch whose
25 name is constructed from the specified branch name by stripping
26 the first namespace level.
27
28 When <paths> are given, this command does *not* switch
29 branches. It updates the named paths in the working tree from
30 the index file, or from a named <tree-ish> (most often a commit). In
31 this case, the `-b` options is meaningless and giving
32 either of them results in an error. <tree-ish> argument can be
33 used to specify a specific tree-ish (i.e. commit, tag or tree)
34 to update the index for the given paths before updating the
35 working tree.
36
37 The index may contain unmerged entries after a failed merge. By
38 default, if you try to check out such an entry from the index, the
39 checkout operation will fail and nothing will be checked out.
40 Using -f will ignore these unmerged entries. The contents from a
41 specific side of the merge can be checked out of the index by
42 using --ours or --theirs. With -m, changes made to the working tree
43 file can be discarded to recreate the original conflicted merge result.
44
45 OPTIONS
46 -------
47 -q::
48 Quiet, suppress feedback messages.
49
50 -f::
51 When switching branches, proceed even if the index or the
52 working tree differs from HEAD. This is used to throw away
53 local changes.
54 +
55 When checking out paths from the index, do not fail upon unmerged
56 entries; instead, unmerged entries are ignored.
57
58 --ours::
59 --theirs::
60 When checking out paths from the index, check out stage #2
61 ('ours') or #3 ('theirs') for unmerged paths.
62
63 -b::
64 Create a new branch named <new_branch> and start it at
65 <branch>. The new branch name must pass all checks defined
66 by linkgit:git-check-ref-format[1]. Some of these checks
67 may restrict the characters allowed in a branch name.
68
69 -t::
70 --track::
71 When creating a new branch, set up configuration so that 'git-pull'
72 will automatically retrieve data from the start point, which must be
73 a branch. Use this if you always pull from the same upstream branch
74 into the new branch, and if you don't want to use "git pull
75 <repository> <refspec>" explicitly. This behavior is the default
76 when the start point is a remote branch. Set the
77 branch.autosetupmerge configuration variable to `false` if you want
78 'git-checkout' and 'git-branch' to always behave as if '--no-track' were
79 given. Set it to `always` if you want this behavior when the
80 start-point is either a local or remote branch.
81 +
82 If no '-b' option was given, the name of the new branch will be
83 derived from the remote branch, by attempting to guess the name
84 of the branch on remote system. If "remotes/" or "refs/remotes/"
85 are prefixed, it is stripped away, and then the part up to the
86 next slash (which would be the nickname of the remote) is removed.
87 This would tell us to use "hack" as the local branch when branching
88 off of "origin/hack" (or "remotes/origin/hack", or even
89 "refs/remotes/origin/hack"). If the given name has no slash, or the above
90 guessing results in an empty name, the guessing is aborted. You can
91 explicitly give a name with '-b' in such a case.
92
93 --no-track::
94 Ignore the branch.autosetupmerge configuration variable.
95
96 -l::
97 Create the new branch's reflog. This activates recording of
98 all changes made to the branch ref, enabling use of date
99 based sha1 expressions such as "<branchname>@\{yesterday}".
100
101 -m::
102 --merge::
103 When switching branches,
104 if you have local modifications to one or more files that
105 are different between the current branch and the branch to
106 which you are switching, the command refuses to switch
107 branches in order to preserve your modifications in context.
108 However, with this option, a three-way merge between the current
109 branch, your working tree contents, and the new branch
110 is done, and you will be on the new branch.
111 +
112 When a merge conflict happens, the index entries for conflicting
113 paths are left unmerged, and you need to resolve the conflicts
114 and mark the resolved paths with `git add` (or `git rm` if the merge
115 should result in deletion of the path).
116 +
117 When checking out paths from the index, this option lets you recreate
118 the conflicted merge in the specified paths.
119
120 --conflict=<style>::
121 The same as --merge option above, but changes the way the
122 conflicting hunks are presented, overriding the
123 merge.conflictstyle configuration variable. Possible values are
124 "merge" (default) and "diff3" (in addition to what is shown by
125 "merge" style, shows the original contents).
126
127 <new_branch>::
128 Name for the new branch.
129
130 <branch>::
131 Branch to checkout; may be any object ID that resolves to a
132 commit. Defaults to HEAD.
133 +
134 When this parameter names a non-branch (but still a valid commit object),
135 your HEAD becomes 'detached'.
136 +
137 As a special case, the "`@\{-N\}`" syntax for the N-th last branch
138 checks out the branch (instead of detaching). You may also specify
139 "`-`" which is synonymous with "`@\{-1\}`".
140
141
142 Detached HEAD
143 -------------
144
145 It is sometimes useful to be able to 'checkout' a commit that is
146 not at the tip of one of your branches. The most obvious
147 example is to check out the commit at a tagged official release
148 point, like this:
149
150 ------------
151 $ git checkout v2.6.18
152 ------------
153
154 Earlier versions of git did not allow this and asked you to
155 create a temporary branch using `-b` option, but starting from
156 version 1.5.0, the above command 'detaches' your HEAD from the
157 current branch and directly point at the commit named by the tag
158 (`v2.6.18` in the above example).
159
160 You can use usual git commands while in this state. You can use
161 `git reset --hard $othercommit` to further move around, for
162 example. You can make changes and create a new commit on top of
163 a detached HEAD. You can even create a merge by using `git
164 merge $othercommit`.
165
166 The state you are in while your HEAD is detached is not recorded
167 by any branch (which is natural --- you are not on any branch).
168 What this means is that you can discard your temporary commits
169 and merges by switching back to an existing branch (e.g. `git
170 checkout master`), and a later `git prune` or `git gc` would
171 garbage-collect them. If you did this by mistake, you can ask
172 the reflog for HEAD where you were, e.g.
173
174 ------------
175 $ git log -g -2 HEAD
176 ------------
177
178
179 EXAMPLES
180 --------
181
182 . The following sequence checks out the `master` branch, reverts
183 the `Makefile` to two revisions back, deletes hello.c by
184 mistake, and gets it back from the index.
185 +
186 ------------
187 $ git checkout master <1>
188 $ git checkout master~2 Makefile <2>
189 $ rm -f hello.c
190 $ git checkout hello.c <3>
191 ------------
192 +
193 <1> switch branch
194 <2> take out a file out of other commit
195 <3> restore hello.c from HEAD of current branch
196 +
197 If you have an unfortunate branch that is named `hello.c`, this
198 step would be confused as an instruction to switch to that branch.
199 You should instead write:
200 +
201 ------------
202 $ git checkout -- hello.c
203 ------------
204
205 . After working in a wrong branch, switching to the correct
206 branch would be done using:
207 +
208 ------------
209 $ git checkout mytopic
210 ------------
211 +
212 However, your "wrong" branch and correct "mytopic" branch may
213 differ in files that you have locally modified, in which case,
214 the above checkout would fail like this:
215 +
216 ------------
217 $ git checkout mytopic
218 fatal: Entry 'frotz' not uptodate. Cannot merge.
219 ------------
220 +
221 You can give the `-m` flag to the command, which would try a
222 three-way merge:
223 +
224 ------------
225 $ git checkout -m mytopic
226 Auto-merging frotz
227 ------------
228 +
229 After this three-way merge, the local modifications are _not_
230 registered in your index file, so `git diff` would show you what
231 changes you made since the tip of the new branch.
232
233 . When a merge conflict happens during switching branches with
234 the `-m` option, you would see something like this:
235 +
236 ------------
237 $ git checkout -m mytopic
238 Auto-merging frotz
239 ERROR: Merge conflict in frotz
240 fatal: merge program failed
241 ------------
242 +
243 At this point, `git diff` shows the changes cleanly merged as in
244 the previous example, as well as the changes in the conflicted
245 files. Edit and resolve the conflict and mark it resolved with
246 `git add` as usual:
247 +
248 ------------
249 $ edit frotz
250 $ git add frotz
251 ------------
252
253
254 Author
255 ------
256 Written by Linus Torvalds <torvalds@osdl.org>
257
258 Documentation
259 --------------
260 Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
261
262 GIT
263 ---
264 Part of the linkgit:git[1] suite