Documentation / git-checkout.txton commit checkout -f: allow ignoring unmerged paths when checking out of the index (db94109)
   1git-checkout(1)
   2===============
   3
   4NAME
   5----
   6git-checkout - Checkout a branch or paths to the working tree
   7
   8SYNOPSIS
   9--------
  10[verse]
  11'git checkout' [-q] [-f] [[--track | --no-track] -b <new_branch> [-l]] [-m] [<branch>]
  12'git checkout' [-f] [<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, or from a named commit.  In
  27this case, the `-b` options is meaningless and giving
  28either of them results in an error.  <tree-ish> argument can be
  29used to specify a specific tree-ish (i.e. commit, tag or tree)
  30to update the index for the given paths before updating the
  31working tree.
  32
  33The index may contain unmerged entries after a failed merge.  By
  34default, if you try to check out such an entry from the index, the
  35checkout operation will fail and nothing will be checked out.
  36Using -f will ignore these unmerged entries.
  37
  38OPTIONS
  39-------
  40-q::
  41        Quiet, suppress feedback messages.
  42
  43-f::
  44        When switching branches, proceed even if the index or the
  45        working tree differs from HEAD.  This is used to throw away
  46        local changes.
  47+
  48When checking out paths from the index, do not fail upon unmerged
  49entries; instead, unmerged entries are ignored.
  50
  51-b::
  52        Create a new branch named <new_branch> and start it at
  53        <branch>.  The new branch name must pass all checks defined
  54        by linkgit:git-check-ref-format[1].  Some of these checks
  55        may restrict the characters allowed in a branch name.
  56
  57-t::
  58--track::
  59        When creating a new branch, set up configuration so that 'git-pull'
  60        will automatically retrieve data from the start point, which must be
  61        a branch. Use this if you always pull from the same upstream branch
  62        into the new branch, and if you don't want to use "git pull
  63        <repository> <refspec>" explicitly. This behavior is the default
  64        when the start point is a remote branch. Set the
  65        branch.autosetupmerge configuration variable to `false` if you want
  66        'git-checkout' and 'git-branch' to always behave as if '--no-track' were
  67        given. Set it to `always` if you want this behavior when the
  68        start-point is either a local or remote branch.
  69
  70--no-track::
  71        Ignore the branch.autosetupmerge configuration variable.
  72
  73-l::
  74        Create the new branch's reflog.  This activates recording of
  75        all changes made to the branch ref, enabling use of date
  76        based sha1 expressions such as "<branchname>@\{yesterday}".
  77
  78-m::
  79        If you have local modifications to one or more files that
  80        are different between the current branch and the branch to
  81        which you are switching, the command refuses to switch
  82        branches in order to preserve your modifications in context.
  83        However, with this option, a three-way merge between the current
  84        branch, your working tree contents, and the new branch
  85        is done, and you will be on the new branch.
  86+
  87When a merge conflict happens, the index entries for conflicting
  88paths are left unmerged, and you need to resolve the conflicts
  89and mark the resolved paths with `git add` (or `git rm` if the merge
  90should result in deletion of the path).
  91
  92<new_branch>::
  93        Name for the new branch.
  94
  95<branch>::
  96        Branch to checkout; may be any object ID that resolves to a
  97        commit.  Defaults to HEAD.
  98+
  99When this parameter names a non-branch (but still a valid commit object),
 100your HEAD becomes 'detached'.
 101
 102
 103Detached HEAD
 104-------------
 105
 106It is sometimes useful to be able to 'checkout' a commit that is
 107not at the tip of one of your branches.  The most obvious
 108example is to check out the commit at a tagged official release
 109point, like this:
 110
 111------------
 112$ git checkout v2.6.18
 113------------
 114
 115Earlier versions of git did not allow this and asked you to
 116create a temporary branch using `-b` option, but starting from
 117version 1.5.0, the above command 'detaches' your HEAD from the
 118current branch and directly point at the commit named by the tag
 119(`v2.6.18` in the above example).
 120
 121You can use usual git commands while in this state.  You can use
 122`git reset --hard $othercommit` to further move around, for
 123example.  You can make changes and create a new commit on top of
 124a detached HEAD.  You can even create a merge by using `git
 125merge $othercommit`.
 126
 127The state you are in while your HEAD is detached is not recorded
 128by any branch (which is natural --- you are not on any branch).
 129What this means is that you can discard your temporary commits
 130and merges by switching back to an existing branch (e.g. `git
 131checkout master`), and a later `git prune` or `git gc` would
 132garbage-collect them.  If you did this by mistake, you can ask
 133the reflog for HEAD where you were, e.g.
 134
 135------------
 136$ git log -g -2 HEAD
 137------------
 138
 139
 140EXAMPLES
 141--------
 142
 143. The following sequence checks out the `master` branch, reverts
 144the `Makefile` to two revisions back, deletes hello.c by
 145mistake, and gets it back from the index.
 146+
 147------------
 148$ git checkout master             <1>
 149$ git checkout master~2 Makefile  <2>
 150$ rm -f hello.c
 151$ git checkout hello.c            <3>
 152------------
 153+
 154<1> switch branch
 155<2> take out a file out of other commit
 156<3> restore hello.c from HEAD of current branch
 157+
 158If you have an unfortunate branch that is named `hello.c`, this
 159step would be confused as an instruction to switch to that branch.
 160You should instead write:
 161+
 162------------
 163$ git checkout -- hello.c
 164------------
 165
 166. After working in a wrong branch, switching to the correct
 167branch would be done using:
 168+
 169------------
 170$ git checkout mytopic
 171------------
 172+
 173However, your "wrong" branch and correct "mytopic" branch may
 174differ in files that you have locally modified, in which case,
 175the above checkout would fail like this:
 176+
 177------------
 178$ git checkout mytopic
 179fatal: Entry 'frotz' not uptodate. Cannot merge.
 180------------
 181+
 182You can give the `-m` flag to the command, which would try a
 183three-way merge:
 184+
 185------------
 186$ git checkout -m mytopic
 187Auto-merging frotz
 188------------
 189+
 190After this three-way merge, the local modifications are _not_
 191registered in your index file, so `git diff` would show you what
 192changes you made since the tip of the new branch.
 193
 194. When a merge conflict happens during switching branches with
 195the `-m` option, you would see something like this:
 196+
 197------------
 198$ git checkout -m mytopic
 199Auto-merging frotz
 200merge: warning: conflicts during merge
 201ERROR: Merge conflict in frotz
 202fatal: merge program failed
 203------------
 204+
 205At this point, `git diff` shows the changes cleanly merged as in
 206the previous example, as well as the changes in the conflicted
 207files.  Edit and resolve the conflict and mark it resolved with
 208`git add` as usual:
 209+
 210------------
 211$ edit frotz
 212$ git add frotz
 213------------
 214
 215
 216Author
 217------
 218Written by Linus Torvalds <torvalds@osdl.org>
 219
 220Documentation
 221--------------
 222Documentation by Junio C Hamano and the git-list <git@vger.kernel.org>.
 223
 224GIT
 225---
 226Part of the linkgit:git[1] suite