path: root/Documentation/git-checkout.txt
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Diffstat (limited to 'Documentation/git-checkout.txt')
1 files changed, 78 insertions, 0 deletions
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index d504108..d263a56 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -225,6 +225,19 @@ This means that you can use `git checkout -p` to selectively discard
edits from your current working tree. See the ``Interactive Mode''
section of linkgit:git-add[1] to learn how to operate the `--patch` mode.
+ Check out a branch in a separate working directory at
+ `<path>`. A new working directory is linked to the current
+ repository, sharing everything except working directory
+ specific files such as HEAD, index... See "MULTIPLE WORKING
+ TREES" section for more information.
+ `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 to checkout; if it refers to a branch (i.e., a name that,
when prepended with "refs/heads/", is a valid ref), then that
@@ -388,6 +401,71 @@ $ git reflog -2 HEAD # or
$ git log -g -2 HEAD
+A git repository can support multiple working trees, allowing you to check
+out more than one branch at a time. With `git checkout --to` a new working
+tree is associated with the repository. This new working tree is called a
+"linked working tree" as opposed to the "main working tree" prepared by "git
+init" or "git clone". A repository has one main working tree (if it's not a
+bare repository) and zero or more linked working trees.
+Each linked working tree has a private sub-directory in the repository's
+$GIT_DIR/worktrees directory. The private sub-directory's name is usually
+the base name of the linked working tree's path, possibly appended with a
+number to make it unique. For example, when `$GIT_DIR=/path/main/.git` the
+command `git checkout --to /path/other/test-next next` creates the linked
+working tree in `/path/other/test-next` and also creates a
+`$GIT_DIR/worktrees/test-next` directory (or `$GIT_DIR/worktrees/test-next1`
+if `test-next` is already taken).
+Within a linked working tree, $GIT_DIR is set to point to this private
+directory (e.g. `/path/main/.git/worktrees/test-next` in the example) and
+$GIT_COMMON_DIR is set to point back to the main working tree's $GIT_DIR
+(e.g. `/path/main/.git`). These settings are made in a `.git` file located at
+the top directory of the linked working tree.
+Path resolution via `git rev-parse --git-path` uses either
+$GIT_DIR or $GIT_COMMON_DIR depending on the path. For example, in the
+linked working tree `git rev-parse --git-path HEAD` returns
+`/path/main/.git/worktrees/test-next/HEAD` (not
+`/path/other/test-next/.git/HEAD` or `/path/main/.git/HEAD`) while `git
+rev-parse --git-path refs/heads/master` uses
+$GIT_COMMON_DIR and returns `/path/main/.git/refs/heads/master`,
+since refs are shared across all working trees.
+See linkgit:gitrepository-layout[5] for more information. The rule of
+thumb is do not make any assumption about whether a path belongs to
+$GIT_DIR or $GIT_COMMON_DIR when you need to directly access something
+inside $GIT_DIR. Use `git rev-parse --git-path` to get the final path.
+When you are done with a linked working tree you can simply delete it.
+The working tree's entry in the repository's $GIT_DIR/worktrees
+directory will eventually be removed automatically (see
+`gc.pruneworktreesexpire` in linkgit::git-config[1]), or you can run
+`git prune --worktrees` in the main or any linked working tree to
+clean up any stale entries in $GIT_DIR/worktrees.
+If you move a linked working directory to another file system, or
+within a file system that does not support hard links, you need to run
+at least one git command inside the linked working directory
+(e.g. `git status`) in order to update its entry in $GIT_DIR/worktrees
+so that it does not get automatically removed.
+To prevent a $GIT_DIR/worktrees entry from from being pruned (which
+can be useful in some situations, such as when the
+entry's working tree is stored on a portable device), add a file named
+'locked' to the entry's directory. The file contains the reason in
+plain text. For example, if a linked working tree's `.git` file points
+to `/path/main/.git/worktrees/test-next` then a file named
+`/path/main/.git/worktrees/test-next/locked` will prevent the
+`test-next` entry from being pruned. See
+linkgit:gitrepository-layout[5] for details.
+Multiple checkout support for submodules is incomplete. It is NOT
+recommended to make multiple checkouts of a superproject.