git_checkout.txt

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 [-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 a
           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 [-p|--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.

           git checkout with <paths> or --patch is used to restore modified
           or deleted paths to their original contents from the index or
           replace paths with the contents from a named <tree-ish> (most
           often a commit-ish).

           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.

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.

       <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).

           As a special case, the "@{-N}" syntax for the N-th last
           branch/commit checks out branches (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 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

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 2.7.4                        10/04/2017                  GIT-CHECKOUT(1)