--------
[verse]
'git checkout' [-q] [-f] [-m] [<branch>]
-'git checkout' [-q] [-f] [-m] [-b <new_branch>] [<start_point>]
+'git checkout' [-q] [-f] [-m] [[-b|-B|--orphan] <new_branch>] [<start_point>]
'git checkout' [-f|--ours|--theirs|-m|--conflict=<style>] [<tree-ish>] [--] <paths>...
'git checkout' --patch [<tree-ish>] [--] [<paths>...]
DESCRIPTION
-----------
-
-When <paths> are not given, this command switches branches by
-updating the index, working tree, and HEAD to reflect the specified
+Updates files in the working tree to match the version in the index
+or the specified tree. If no paths are given, 'git checkout' will
+also update `HEAD` to set the specified branch as the current
branch.
-If `-b` is given, a new branch is created and checked out, as if
-linkgit:git-branch[1] were called; in this case you can
-use the --track or --no-track options, which will be passed to `git
-branch`. As a convenience, --track without `-b` implies branch
-creation; see the description of --track below.
-
-When <paths> or --patch are given, this command does *not* switch
-branches. It updates the named paths in the working tree from
-the index file, or from a named <tree-ish> (most often a commit). In
-this case, the `-b` and `--track` options are meaningless and giving
-either of them results in an error. The <tree-ish> argument can be
-used to specify a specific tree-ish (i.e. commit, tag or tree)
-to update the index for the given paths before updating the
-working tree.
-
-The index may contain unmerged entries after a failed merge. By
-default, if you try to check out such an entry from the index, the
+'git checkout' [<branch>]::
+'git checkout' -b|-B <new_branch> [<start point>]::
+
+ This form switches branches by updating the index, working
+ tree, and HEAD to reflect the specified branch.
++
+If `-b` is given, a new branch is created as if linkgit:git-branch[1]
+were called and then checked out; in this case you can
+use the `--track` or `--no-track` options, which will be passed to
+'git branch'. As a convenience, `--track` without `-b` implies branch
+creation; see the description of `--track` below.
++
+If `-B` is given, <new_branch> is created if it doesn't exist; otherwise, it
+is reset. This is the transactional equivalent of
++
+------------
+$ git branch -f <branch> [<start point>]
+$ git checkout <branch>
+------------
++
+that is to say, the branch is not reset/created unless "git checkout" is
+successful.
+
+'git checkout' [--patch] [<tree-ish>] [--] <pathspec>...::
+
+ When <paths> or `--patch` are given, 'git checkout' does *not*
+ switch branches. It updates the named paths in the working tree
+ from the index file or from a named <tree-ish> (most often a
+ commit). In this case, the `-b` and `--track` options are
+ meaningless and giving either of them results in an error. The
+ <tree-ish> argument can be used to specify a specific tree-ish
+ (i.e. commit, tag or tree) to update the index for the given
+ paths before updating the working tree.
++
+The index may contain unmerged entries because of a previous failed merge.
+By default, if you try to check out such an entry from the index, the
checkout operation will fail and nothing will be checked out.
-Using -f will ignore these unmerged entries. The contents from a
+Using `-f` will ignore these unmerged entries. The contents from a
specific side of the merge can be checked out of the index by
-using --ours or --theirs. With -m, changes made to the working tree
-file can be discarded to recreate the original conflicted merge result.
+using `--ours` or `--theirs`. With `-m`, changes made to the working tree
+file can be discarded to re-create the original conflicted merge result.
OPTIONS
-------
Create a new branch named <new_branch> and start it at
<start_point>; see linkgit:git-branch[1] for details.
+-B::
+ Creates the branch <new_branch> and start it at <start_point>;
+ if it already exists, then reset it to <start_point>. This is
+ equivalent to running "git branch" with "-f"; see
+ linkgit:git-branch[1] for details.
+
-t::
--track::
When creating a new branch, set up "upstream" configuration. See
Create the new branch's reflog; see linkgit:git-branch[1] for
details.
+--orphan::
+ Create a new 'orphan' branch, named <new_branch>, started from
+ <start_point> and switch to it. The first commit made on this
+ new branch will have no parents and it will be the root of a new
+ history totally disconnected from all the other branches and
+ commits.
++
+The index and the working tree are adjusted as if you had previously run
+"git checkout <start_point>". This allows you to start a new history
+that records a set of paths similar to <start_point> by easily running
+"git commit -a" to make the root commit.
++
+This can be useful when you want to publish the tree from a commit
+without exposing its full history. You might want to do this to publish
+an open source branch of a project whose current tree is "clean", but
+whose full history contains proprietary or otherwise encumbered bits of
+code.
++
+If you want to start a disconnected history that records a set of paths
+that is totally different from the one of <start_point>, then you should
+clear the index and the working tree right after creating the orphan
+branch by running "git rm -rf ." from the top level of the working tree.
+Afterwards you will be ready to prepare your new files, repopulating the
+working tree, by copying them from elsewhere, extracting a tarball, etc.
+
-m::
--merge::
When switching branches,
checks out the branch (instead of detaching). You may also specify
`-` which is synonymous with `"@\{-1\}"`.
+
-As a further special case, you may use `"A...B"` as a shortcut for the
+As a further special case, you may use `"A\...B"` as a shortcut for the
merge base of `A` and `B` if there is exactly one merge base. You can
leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
+
------------
$ git checkout mytopic
-fatal: Entry 'frotz' not uptodate. Cannot merge.
+error: You have local changes to 'frotz'; not switching branches.
------------
+
You can give the `-m` flag to the command, which would try a