SYNOPSIS
--------
-'git-checkout' [-f] [-b <new_branch>] [<branch>]
+'git-checkout' [-f] [-b <new_branch>] [-m] [<branch>] [<paths>...]
DESCRIPTION
-----------
-Updates the index and working tree to reflect the specified branch,
-<branch>. Updates HEAD to be <branch> or, if specified, <new_branch>.
+
+When <paths> are not given, this command switches branches, by
+updating the index and working tree to reflect the specified
+branch, <branch>, and updating HEAD to be <branch> or, if
+specified, <new_branch>.
+
+When <paths> are given, this command does *not* switch
+branches. It updates the named paths in the working tree from
+the index file (i.e. it runs `git-checkout-index -f -u`). In
+this case, `-f` and `-b` options are meaningless and giving
+either of them results in an error. <branch> argument can be
+used to specify a specific tree-ish to update the index for the
+given paths before updating the working tree.
+
OPTIONS
-------
-b::
Create a new branch and start it at <branch>.
+-m::
+ If you have local modifications to a file that is
+ different between the current branch and the branch you
+ are switching to, the command refuses to switch
+ branches, to preserve your modifications in context.
+ With this option, a three-way merge between the current
+ branch, your working tree contents, and the new branch
+ is done, and you will be on the new branch.
++
+When a merge conflict happens, the index entries for conflicting
+paths are left unmerged, and you need to resolve the conflicts
+and mark the resolved paths with `git update-index`.
+
<new_branch>::
Name for the new branch.
Branch to checkout; may be any object ID that resolves to a
commit. Defaults to HEAD.
+
+EXAMPLES
+--------
+
+. The following sequence checks out the `master` branch, reverts
+the `Makefile` to two revisions back, deletes hello.c by
+mistake, and gets it back from the index.
++
+------------
+$ git checkout master <1>
+$ git checkout master~2 Makefile <2>
+$ rm -f hello.c
+$ git checkout hello.c <3>
+
+<1> switch branch
+<2> take out a file out of other commit
+<3> or "git checkout -- hello.c", as in the next example.
+------------
++
+If you have an unfortunate branch that is named `hello.c`, the
+last step above would be confused as an instruction to switch to
+that branch. You should instead write:
++
+------------
+$ git checkout -- hello.c
+------------
+
+. After working in a wrong branch, switching to the correct
+branch you would want to is done with:
++
+------------
+$ git checkout mytopic
+------------
++
+However, your "wrong" branch and correct "mytopic" branch may
+differ in files that you have locally modified, in which case,
+the above checkout would fail like this:
++
+------------
+$ git checkout mytopic
+fatal: Entry 'frotz' not uptodate. Cannot merge.
+------------
++
+You can give the `-m` flag to the command, which would try a
+three-way merge:
++
+------------
+$ git checkout -m mytopic
+Auto-merging frotz
+------------
++
+After this three-way merge, the local modifications are _not_
+registered in your index file, so `git diff` would show you what
+changes you made since the tip of the new branch.
+
+. When a merge conflict happens during switching branches with
+the `-m` option, you would see something like this:
++
+------------
+$ git checkout -m mytopic
+Auto-merging frotz
+merge: warning: conflicts during merge
+ERROR: Merge conflict in frotz
+fatal: merge program failed
+------------
++
+At this point, `git diff` shows the changes cleanly merged as in
+the previous example, as well as the changes in the conflicted
+files. Edit and resolve the conflict and mark it resolved with
+`git update-index` as usual:
++
+------------
+$ edit frotz
+$ git update-index frotz
+------------
+
+
Author
------
Written by Linus Torvalds <torvalds@osdl.org>