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git-checkout(1) [xfree86 man page]

GIT-CHECKOUT(1) 						    Git Manual							   GIT-CHECKOUT(1)

NAME
       git-checkout - Switch branches or restore working tree files

SYNOPSIS
       git checkout [-q] [-f] [-m] [<branch>]
       git checkout [-q] [-f] [-m] --detach [<branch>]
       git checkout [-q] [-f] [-m] [--detach] <commit>
       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 [<tree-ish>] [--] <pathspec>...
       git checkout (-p|--patch) [<tree-ish>] [--] [<paths>...]

DESCRIPTION
       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.

       git checkout <branch>
	   To prepare for working on <branch>, switch to it by updating the index and the files in the working tree, and by pointing HEAD at the
	   branch. Local modifications to the files in the working tree are kept, so that they can be committed to the <branch>.

	   If <branch> is not found but there does exist a tracking branch in exactly one remote (call it <remote>) with a matching name, treat as
	   equivalent to

	       $ git checkout -b <branch> --track <remote>/<branch>

	   You could omit <branch>, in which case the command degenerates to "check out the current branch", which is a glorified no-op with
	   rather expensive side-effects to show only the tracking information, if exists, for the current branch.

       git checkout -b|-B <new_branch> [<start point>]
	   Specifying -b causes a new branch to be created as if 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 --detach [<branch>], git checkout [--detach] <commit>
	   Prepare to work on top of <commit>, by detaching HEAD at it (see "DETACHED HEAD" section), and updating the index and the files in the
	   working tree. Local modifications to the files in the working tree are kept, so that the resulting working tree will be the state
	   recorded in the commit plus the local modifications.

	   When the <commit> argument is a branch name, the --detach option can be used to detach HEAD at the tip of the branch (git checkout
	   <branch> would check out that branch without detaching HEAD).

	   Omitting <branch> detaches HEAD at the tip of the current branch.

       git checkout [<tree-ish>] [--] <pathspec>...
	   Overwrite paths in the working tree by replacing with the contents in the index or in the <tree-ish> (most often a commit). When a
	   <tree-ish> is given, the paths that match the <pathspec> are updated both in the index and in 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 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 re-create the original conflicted merge result.

       git checkout (-p|--patch) [<tree-ish>] [--] [<pathspec>...]
	   This is similar to the "check out paths to the working tree from either the index or from a tree-ish" mode described above, but lets
	   you use the interactive interface to show the "diff" output and choose which hunks to use in the result. See below for the description
	   of --patch option.

OPTIONS
       -q, --quiet
	   Quiet, suppress feedback messages.

       --[no-]progress
	   Progress status is reported on the standard error stream by default when it is attached to a terminal, unless --quiet is specified.
	   This flag enables progress reporting even if not attached to a terminal, regardless of --quiet.

       -f, --force
	   When switching branches, proceed even if the index or the working tree differs from HEAD. This is used to throw away local changes.

	   When checking out paths from the index, do not fail upon unmerged entries; instead, unmerged entries are ignored.

       --ours, --theirs
	   When checking out paths from the index, check out stage #2 (ours) or #3 (theirs) for unmerged paths.

	   Note that during git rebase and git pull --rebase, ours and theirs may appear swapped; --ours gives the version from the branch the
	   changes are rebased onto, while --theirs gives the version from the branch that holds your work that is being rebased.

	   This is because rebase is used in a workflow that treats the history at the remote as the shared canonical one, and treats the work
	   done on the branch you are rebasing as the third-party work to be integrated, and you are temporarily assuming the role of the keeper
	   of the canonical history during the rebase. As the keeper of the canonical history, you need to view the history from the remote as
	   ours (i.e. "our shared canonical history"), while what you did on your side branch as theirs (i.e. "one contributor's work on top of
	   it").

       -b <new_branch>
	   Create a new branch named <new_branch> and start it at <start_point>; see git-branch(1) for details.

       -B <new_branch>
	   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 git-branch(1) for details.

       -t, --track
	   When creating a new branch, set up "upstream" configuration. See "--track" in git-branch(1) for details.

	   If no -b option is given, the name of the new branch will be derived from the remote-tracking branch, by looking at the local part of
	   the refspec configured for the corresponding remote, and then stripping the initial part up to the "*". This would tell us to use
	   "hack" as the local branch when branching off of "origin/hack" (or "remotes/origin/hack", or even "refs/remotes/origin/hack"). If the
	   given name has no slash, or the above guessing results in an empty name, the guessing is aborted. You can explicitly give a name with
	   -b in such a case.

       --no-track
	   Do not set up "upstream" configuration, even if the branch.autoSetupMerge configuration variable is true.

       -l
	   Create the new branch's reflog; see git-branch(1) for details.

       --detach
	   Rather than checking out a branch to work on it, check out a commit for inspection and discardable experiments. This is the default
	   behavior of "git checkout <commit>" when <commit> is not a branch name. See the "DETACHED HEAD" section below for details.

       --orphan <new_branch>
	   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.

       --ignore-skip-worktree-bits
	   In sparse checkout mode, git checkout -- <paths> would update only entries matched by <paths> and sparse patterns in
	   $GIT_DIR/info/sparse-checkout. This option ignores the sparse patterns and adds back any files in <paths>.

       -m, --merge
	   When switching branches, if you have local modifications to one or more files that are different between the current branch and the
	   branch to which you are switching, the command refuses to switch branches in order to preserve your modifications in context. However,
	   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 add (or git rm if the merge should result in deletion of the path).

	   When checking out paths from the index, this option lets you recreate the conflicted merge in the specified paths.

       --conflict=<style>
	   The same as --merge option above, but changes the way the conflicting hunks are presented, overriding the merge.conflictStyle
	   configuration variable. Possible values are "merge" (default) and "diff3" (in addition to what is shown by "merge" style, shows the
	   original contents).

       -p, --patch
	   Interactively select hunks in the difference between the <tree-ish> (or the index, if unspecified) and the working tree. The chosen
	   hunks are then applied in reverse to the working tree (and if a <tree-ish> was specified, the index).

	   This means that you can use git checkout -p to selectively discard edits from your current working tree. See the "Interactive Mode"
	   section of git-add(1) to learn how to operate the --patch mode.

       --ignore-other-worktrees
	   git checkout refuses when the wanted ref is already checked out by another worktree. This option makes it check the ref out anyway. In
	   other words, the ref can be held by more than one worktree.

       --[no-]recurse-submodules
	   Using --recurse-submodules will update the content of all initialized submodules according to the commit recorded in the superproject.
	   If local modifications in a submodule would be overwritten the checkout will fail unless -f is used. If nothing (or
	   --no-recurse-submodules) is used, the work trees of submodules will not be updated. Just like git-submodule(1), this will detach the
	   submodules HEAD.

       <branch>
	   Branch to checkout; if it refers to a branch (i.e., a name that, when prepended with "refs/heads/", is a valid ref), then that branch
	   is checked out. Otherwise, if it refers to a valid commit, your HEAD becomes "detached" and you are no longer on any branch (see below
	   for details).

	   You can use the "@{-N}" syntax to refer to the N-th last branch/commit checked out using "git checkout" operation. You may also specify
	   - which is synonymous to "@{-1}.

	   As a 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.

       <new_branch>
	   Name for the new branch.

       <start_point>
	   The name of a commit at which to start the new branch; see git-branch(1) for details. Defaults to HEAD.

       <tree-ish>
	   Tree to checkout from (when paths are given). If not specified, the index will be used.

DETACHED HEAD
       HEAD normally refers to a named branch (e.g. master). Meanwhile, each branch refers to a specific commit. Let's look at a repo with three
       commits, one of them tagged, and with branch master checked out:

		      HEAD (refers to branch 'master')
		       |
		       v
	   a---b---c  branch 'master' (refers to commit 'c')
	       ^
	       |
	     tag 'v2.0' (refers to commit 'b')

       When a commit is created in this state, the branch is updated to refer to the new commit. Specifically, git commit creates a new commit d,
       whose parent is commit c, and then updates branch master to refer to new commit d. HEAD still refers to branch master and so indirectly now
       refers to commit d:

	   $ edit; git add; git commit

			  HEAD (refers to branch 'master')
			   |
			   v
	   a---b---c---d  branch 'master' (refers to commit 'd')
	       ^
	       |
	     tag 'v2.0' (refers to commit 'b')

       It is sometimes useful to be able to checkout a commit that is not at the tip of any named branch, or even to create a new commit that is
       not referenced by a named branch. Let's look at what happens when we checkout commit b (here we show two ways this may be done):

	   $ git checkout v2.0	# or
	   $ git checkout master^^

	      HEAD (refers to commit 'b')
	       |
	       v
	   a---b---c---d  branch 'master' (refers to commit 'd')
	       ^
	       |
	     tag 'v2.0' (refers to commit 'b')

       Notice that regardless of which checkout command we use, HEAD now refers directly to commit b. This is known as being in detached HEAD
       state. It means simply that HEAD refers to a specific commit, as opposed to referring to a named branch. Let's see what happens when we
       create a commit:

	   $ edit; git add; git commit

		HEAD (refers to commit 'e')
		 |
		 v
		 e
		/
	   a---b---c---d  branch 'master' (refers to commit 'd')
	       ^
	       |
	     tag 'v2.0' (refers to commit 'b')

       There is now a new commit e, but it is referenced only by HEAD. We can of course add yet another commit in this state:

	   $ edit; git add; git commit

		    HEAD (refers to commit 'f')
		     |
		     v
		 e---f
		/
	   a---b---c---d  branch 'master' (refers to commit 'd')
	       ^
	       |
	     tag 'v2.0' (refers to commit 'b')

       In fact, we can perform all the normal Git operations. But, let's look at what happens when we then checkout master:

	   $ git checkout master

			  HEAD (refers to branch 'master')
		 e---f	   |
		/	   v
	   a---b---c---d  branch 'master' (refers to commit 'd')
	       ^
	       |
	     tag 'v2.0' (refers to commit 'b')

       It is important to realize that at this point nothing refers to commit f. Eventually commit f (and by extension commit e) will be deleted
       by the routine Git garbage collection process, unless we create a reference before that happens. If we have not yet moved away from commit
       f, any of these will create a reference to it:

	   $ git checkout -b foo   (1)
	   $ git branch foo	   (2)
	   $ git tag foo	   (3)

       1. creates a new branch foo, which refers to commit f, and then updates HEAD to refer to branch foo. In other words, we'll no longer be in
       detached HEAD state after this command.
       2. similarly creates a new branch foo, which refers to commit f, but leaves HEAD detached.
       3. creates a new tag foo, which refers to commit f, leaving HEAD detached.

       If we have moved away from commit f, then we must first recover its object name (typically by using git reflog), and then we can create a
       reference to it. For example, to see the last two commits to which HEAD referred, we can use either of these commands:

	   $ git reflog -2 HEAD # or
	   $ git log -g -2 HEAD

ARGUMENT DISAMBIGUATION
       When there is only one argument given and it is not -- (e.g. "git checkout abc"), and when the argument is both a valid <tree-ish> (e.g. a
       branch "abc" exists) and a valid <pathspec> (e.g. a file or a directory whose name is "abc" exists), Git would usually ask you to
       disambiguate. Because checking out a branch is so common an operation, however, "git checkout abc" takes "abc" as a <tree-ish> in such a
       situation. Use git checkout -- <pathspec> if you want to checkout these paths out of the index.

EXAMPLES
	1. 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 a file out of another commit
	   3. restore hello.c from the index

	   If you want to check out all C source files out of the index, you can say

	       $ git checkout -- '*.c'

	   Note the quotes around *.c. The file hello.c will also be checked out, even though it is no longer in the working tree, because the
	   file globbing is used to match entries in the index (not in the working tree by the shell).

	   If you have an unfortunate branch that is named hello.c, this step would be confused as an instruction to switch to that branch. You
	   should instead write:

	       $ git checkout -- hello.c

	2. After working in the wrong branch, switching to the correct branch would be done using:

	       $ git checkout mytopic

	   However, your "wrong" branch and correct "mytopic" branch may differ in files that you have modified locally, in which case the above
	   checkout would fail like this:

	       $ git checkout mytopic
	       error: You have local changes to 'frotz'; not switching branches.

	   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.

	3. 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
	       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 add as usual:

	       $ edit frotz
	       $ git add frotz

GIT
       Part of the git(1) suite

Git 2.17.1							    10/05/2018							   GIT-CHECKOUT(1)
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