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 <tree-ish>::
 131         Tree to checkout from (when paths are given). If not specified,
 132         the index will be used.
 133
 134 <branch>::
 135         Branch to checkout (when no paths are given); may be any object
 136         ID that resolves to a commit.  Defaults to HEAD.
 137 +
 138 When this parameter names a non-branch (but still a valid commit object),
 139 your HEAD becomes 'detached'.
 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 a file out of another commit
 195 <3> restore hello.c from the index
 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