Documentation / git-checkout.txton commit Merge branch 'bc/reflog-fix' into js/reflog-delete (50f3ac2)
   1git-checkout(1)
   2===============
   3
   4NAME
   5----
   6git-checkout - Checkout and switch to a branch
   7
   8SYNOPSIS
   9--------
  10[verse]
  11'git-checkout' [-q] [-f] [[--track | --no-track] -b <new_branch> [-l]] [-m] [<branch>]
  12'git-checkout' [<tree-ish>] <paths>...
  13
  14DESCRIPTION
  15-----------
  16
  17When <paths> are not given, this command switches branches by
  18updating the index and working tree to reflect the specified
  19branch, <branch>, and updating HEAD to be <branch> or, if
  20specified, <new_branch>.  Using -b will cause <new_branch> to
  21be created; in this case you can use the --track or --no-track
  22options, which will be passed to `git branch`.
  23
  24When <paths> are given, this command does *not* switch
  25branches.  It updates the named paths in the working tree from
  26the index file (i.e. it runs `git-checkout-index -f -u`), or
  27from a named commit.  In
  28this case, the `-f` and `-b` options are meaningless and giving
  29either of them results in an error.  <tree-ish> argument can be
  30used to specify a specific tree-ish (i.e. commit, tag or tree)
  31to update the index for the given paths before updating the
  32working tree.
  33
  34
  35OPTIONS
  36-------
  37-q::
  38        Quiet, suppress feedback messages.
  39
  40-f::
  41        Proceed even if the index or the working tree differs
  42        from HEAD.  This is used to throw away local changes.
  43
  44-b::
  45        Create a new branch named <new_branch> and start it at
  46        <branch>.  The new branch name must pass all checks defined
  47        by linkgit:git-check-ref-format[1].  Some of these checks
  48        may restrict the characters allowed in a branch name.
  49
  50--track::
  51        When -b is given and a branch is created off a remote branch,
  52        set up configuration so that git-pull will automatically
  53        retrieve data from the remote branch.  Use this if you always
  54        pull from the same remote branch into the new branch, or if you
  55        don't want to use "git pull <repository> <refspec>" explicitly.
  56        This behavior is the default.  Set the
  57        branch.autosetupmerge configuration variable to false if you
  58        want git-checkout and git-branch to always behave as if
  59        '--no-track' were given.
  60
  61--no-track::
  62        When -b is given and a branch is created off a remote branch,
  63        set up configuration so that git-pull will not retrieve data
  64        from the remote branch, ignoring the branch.autosetupmerge
  65        configuration variable.
  66
  67-l::
  68        Create the new branch's reflog.  This activates recording of
  69        all changes made to the branch ref, enabling use of date
  70        based sha1 expressions such as "<branchname>@\{yesterday}".
  71
  72-m::
  73        If you have local modifications to one or more files that
  74        are different between the current branch and the branch to
  75        which you are switching, the command refuses to switch
  76        branches in order to preserve your modifications in context.
  77        However, with this option, a three-way merge between the current
  78        branch, your working tree contents, and the new branch
  79        is done, and you will be on the new branch.
  80+
  81When a merge conflict happens, the index entries for conflicting
  82paths are left unmerged, and you need to resolve the conflicts
  83and mark the resolved paths with `git add` (or `git rm` if the merge
  84should result in deletion of the path).
  85
  86<new_branch>::
  87        Name for the new branch.
  88
  89<branch>::
  90        Branch to checkout; may be any object ID that resolves to a
  91        commit.  Defaults to HEAD.
  92+
  93When this parameter names a non-branch (but still a valid commit object),
  94your HEAD becomes 'detached'.
  95
  96
  97Detached HEAD
  98-------------
  99
 100It is sometimes useful to be able to 'checkout' a commit that is
 101not at the tip of one of your branches.  The most obvious
 102example is to check out the commit at a tagged official release
 103point, like this:
 104
 105------------
 106$ git checkout v2.6.18
 107------------
 108
 109Earlier versions of git did not allow this and asked you to
 110create a temporary branch using `-b` option, but starting from
 111version 1.5.0, the above command 'detaches' your HEAD from the
 112current branch and directly point at the commit named by the tag
 113(`v2.6.18` in the above example).
 114
 115You can use usual git commands while in this state.  You can use
 116`git-reset --hard $othercommit` to further move around, for
 117example.  You can make changes and create a new commit on top of
 118a detached HEAD.  You can even create a merge by using `git
 119merge $othercommit`.
 120
 121The state you are in while your HEAD is detached is not recorded
 122by any branch (which is natural --- you are not on any branch).
 123What this means is that you can discard your temporary commits
 124and merges by switching back to an existing branch (e.g. `git
 125checkout master`), and a later `git prune` or `git gc` would
 126garbage-collect them.  If you did this by mistake, you can ask
 127the reflog for HEAD where you were, e.g.
 128
 129------------
 130$ git log -g -2 HEAD
 131------------
 132
 133
 134EXAMPLES
 135--------
 136
 137. The following sequence checks out the `master` branch, reverts
 138the `Makefile` to two revisions back, deletes hello.c by
 139mistake, and gets it back from the index.
 140+
 141------------
 142$ git checkout master             <1>
 143$ git checkout master~2 Makefile  <2>
 144$ rm -f hello.c
 145$ git checkout hello.c            <3>
 146------------
 147+
 148<1> switch branch
 149<2> take out a file out of other commit
 150<3> restore hello.c from HEAD of current branch
 151+
 152If you have an unfortunate branch that is named `hello.c`, this
 153step would be confused as an instruction to switch to that branch.
 154You should instead write:
 155+
 156------------
 157$ git checkout -- hello.c
 158------------
 159
 160. After working in a wrong branch, switching to the correct
 161branch would be done using:
 162+
 163------------
 164$ git checkout mytopic
 165------------
 166+
 167However, your "wrong" branch and correct "mytopic" branch may
 168differ in files that you have locally modified, in which case,
 169the above checkout would fail like this:
 170+
 171------------
 172$ git checkout mytopic
 173fatal: Entry 'frotz' not uptodate. Cannot merge.
 174------------
 175+
 176You can give the `-m` flag to the command, which would try a
 177three-way merge:
 178+
 179------------
 180$ git checkout -m mytopic
 181Auto-merging frotz
 182------------
 183+
 184After this three-way merge, the local modifications are _not_
 185registered in your index file, so `git diff` would show you what
 186changes you made since the tip of the new branch.
 187
 188. When a merge conflict happens during switching branches with
 189the `-m` option, you would see something like this:
 190+
 191------------
 192$ git checkout -m mytopic
 193Auto-merging frotz
 194merge: warning: conflicts during merge
 195ERROR: Merge conflict in frotz
 196fatal: merge program failed
 197------------
 198+
 199At this point, `git diff` shows the changes cleanly merged as in
 200the previous example, as well as the changes in the conflicted
 201files.  Edit and resolve the conflict and mark it resolved with
 202`git add` as usual:
 203+
 204------------
 205$ edit frotz
 206$ git add frotz
 207------------
 208
 209
 210Author
 211------
 212Written by Linus Torvalds <torvalds@osdl.org>
 213
 214Documentation
 215--------------
 216Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 217
 218GIT
 219---
 220Part of the linkgit:git[7] suite