git-sparse-checkout(1)
======================

NAME
----
git-sparse-checkout - Initialize and modify the sparse-checkout
configuration, which reduces the checkout to a set of paths
given by a list of patterns.


SYNOPSIS
--------
[verse]
'git sparse-checkout <subcommand> [options]'


DESCRIPTION
-----------

Initialize and modify the sparse-checkout configuration, which reduces
the checkout to a set of paths given by a list of patterns.

THIS COMMAND IS EXPERIMENTAL. ITS BEHAVIOR, AND THE BEHAVIOR OF OTHER
COMMANDS IN THE PRESENCE OF SPARSE-CHECKOUTS, WILL LIKELY CHANGE IN
THE FUTURE.


COMMANDS
--------
'list'::
	Describe the patterns in the sparse-checkout file.

'init'::
	Enable the `core.sparseCheckout` setting. If the
	sparse-checkout file does not exist, then populate it with
	patterns that match every file in the root directory and
	no other directories, then will remove all directories tracked
	by Git. Add patterns to the sparse-checkout file to
	repopulate the working directory.
+
To avoid interfering with other worktrees, it first enables the
`extensions.worktreeConfig` setting and makes sure to set the
`core.sparseCheckout` setting in the worktree-specific config file.
+
When `--cone` is provided, the `core.sparseCheckoutCone` setting is
also set, allowing for better performance with a limited set of
patterns (see 'CONE PATTERN SET' below).
+
Use the `--[no-]sparse-index` option to toggle the use of the sparse
index format. This reduces the size of the index to be more closely
aligned with your sparse-checkout definition. This can have significant
performance advantages for commands such as `git status` or `git add`.
This feature is still experimental. Some commands might be slower with
a sparse index until they are properly integrated with the feature.
+
**WARNING:** Using a sparse index requires modifying the index in a way
that is not completely understood by external tools. If you have trouble
with this compatibility, then run `git sparse-checkout init --no-sparse-index`
to rewrite your index to not be sparse. Older versions of Git will not
understand the sparse directory entries index extension and may fail to
interact with your repository until it is disabled.

'set'::
	Write a set of patterns to the sparse-checkout file, as given as
	a list of arguments following the 'set' subcommand. Update the
	working directory to match the new patterns. Enable the
	core.sparseCheckout config setting if it is not already enabled.
+
When the `--stdin` option is provided, the patterns are read from
standard in as a newline-delimited list instead of from the arguments.
+
When `core.sparseCheckoutCone` is enabled, the input list is considered a
list of directories instead of sparse-checkout patterns. The command writes
patterns to the sparse-checkout file to include all files contained in those
directories (recursively) as well as files that are siblings of ancestor
directories. The input format matches the output of `git ls-tree --name-only`.
This includes interpreting pathnames that begin with a double quote (") as
C-style quoted strings.

'add'::
	Update the sparse-checkout file to include additional patterns.
	By default, these patterns are read from the command-line arguments,
	but they can be read from stdin using the `--stdin` option. When
	`core.sparseCheckoutCone` is enabled, the given patterns are interpreted
	as directory names as in the 'set' subcommand.

'reapply'::
	Reapply the sparsity pattern rules to paths in the working tree.
	Commands like merge or rebase can materialize paths to do their
	work (e.g. in order to show you a conflict), and other
	sparse-checkout commands might fail to sparsify an individual file
	(e.g. because it has unstaged changes or conflicts).  In such
	cases, it can make sense to run `git sparse-checkout reapply` later
	after cleaning up affected paths (e.g. resolving conflicts, undoing
	or committing changes, etc.).

'disable'::
	Disable the `core.sparseCheckout` config setting, and restore the
	working directory to include all files. Leaves the sparse-checkout
	file intact so a later 'git sparse-checkout init' command may
	return the working directory to the same state.

SPARSE CHECKOUT
---------------

"Sparse checkout" allows populating the working directory sparsely.
It uses the skip-worktree bit (see linkgit:git-update-index[1]) to tell
Git whether a file in the working directory is worth looking at. If
the skip-worktree bit is set, then the file is ignored in the working
directory. Git will not populate the contents of those files, which
makes a sparse checkout helpful when working in a repository with many
files, but only a few are important to the current user.

The `$GIT_DIR/info/sparse-checkout` file is used to define the
skip-worktree reference bitmap. When Git updates the working
directory, it updates the skip-worktree bits in the index based
on this file. The files matching the patterns in the file will
appear in the working directory, and the rest will not.

To enable the sparse-checkout feature, run `git sparse-checkout init` to
initialize a simple sparse-checkout file and enable the `core.sparseCheckout`
config setting. Then, run `git sparse-checkout set` to modify the patterns in
the sparse-checkout file.

To repopulate the working directory with all files, use the
`git sparse-checkout disable` command.


FULL PATTERN SET
----------------

By default, the sparse-checkout file uses the same syntax as `.gitignore`
files.

While `$GIT_DIR/info/sparse-checkout` is usually used to specify what
files are included, you can also specify what files are _not_ included,
using negative patterns. For example, to remove the file `unwanted`:

----------------
/*
!unwanted
----------------


CONE PATTERN SET
----------------

The full pattern set allows for arbitrary pattern matches and complicated
inclusion/exclusion rules. These can result in O(N*M) pattern matches when
updating the index, where N is the number of patterns and M is the number
of paths in the index. To combat this performance issue, a more restricted
pattern set is allowed when `core.sparseCheckoutCone` is enabled.

The accepted patterns in the cone pattern set are:

1. *Recursive:* All paths inside a directory are included.

2. *Parent:* All files immediately inside a directory are included.

In addition to the above two patterns, we also expect that all files in the
root directory are included. If a recursive pattern is added, then all
leading directories are added as parent patterns.

By default, when running `git sparse-checkout init`, the root directory is
added as a parent pattern. At this point, the sparse-checkout file contains
the following patterns:

----------------
/*
!/*/
----------------

This says "include everything in root, but nothing two levels below root."

When in cone mode, the `git sparse-checkout set` subcommand takes a list of
directories instead of a list of sparse-checkout patterns. In this mode,
the command `git sparse-checkout set A/B/C` sets the directory `A/B/C` as
a recursive pattern, the directories `A` and `A/B` are added as parent
patterns. The resulting sparse-checkout file is now

----------------
/*
!/*/
/A/
!/A/*/
/A/B/
!/A/B/*/
/A/B/C/
----------------

Here, order matters, so the negative patterns are overridden by the positive
patterns that appear lower in the file.

If `core.sparseCheckoutCone=true`, then Git will parse the sparse-checkout file
expecting patterns of these types. Git will warn if the patterns do not match.
If the patterns do match the expected format, then Git will use faster hash-
based algorithms to compute inclusion in the sparse-checkout.

In the cone mode case, the `git sparse-checkout list` subcommand will list the
directories that define the recursive patterns. For the example sparse-checkout
file above, the output is as follows:

--------------------------
$ git sparse-checkout list
A/B/C
--------------------------

If `core.ignoreCase=true`, then the pattern-matching algorithm will use a
case-insensitive check. This corrects for case mismatched filenames in the
'git sparse-checkout set' command to reflect the expected cone in the working
directory.

When changing the sparse-checkout patterns in cone mode, Git will inspect each
tracked directory that is not within the sparse-checkout cone to see if it
contains any untracked files. If all of those files are ignored due to the
`.gitignore` patterns, then the directory will be deleted. If any of the
untracked files within that directory is not ignored, then no deletions will
occur within that directory and a warning message will appear. If these files
are important, then reset your sparse-checkout definition so they are included,
use `git add` and `git commit` to store them, then remove any remaining files
manually to ensure Git can behave optimally.


SUBMODULES
----------

If your repository contains one or more submodules, then submodules
are populated based on interactions with the `git submodule` command.
Specifically, `git submodule init -- <path>` will ensure the submodule
at `<path>` is present, while `git submodule deinit [-f] -- <path>`
will remove the files for the submodule at `<path>` (including any
untracked files, uncommitted changes, and unpushed history).  Similar
to how sparse-checkout removes files from the working tree but still
leaves entries in the index, deinitialized submodules are removed from
the working directory but still have an entry in the index.

Since submodules may have unpushed changes or untracked files,
removing them could result in data loss.  Thus, changing sparse
inclusion/exclusion rules will not cause an already checked out
submodule to be removed from the working copy.  Said another way, just
as `checkout` will not cause submodules to be automatically removed or
initialized even when switching between branches that remove or add
submodules, using `sparse-checkout` to reduce or expand the scope of
"interesting" files will not cause submodules to be automatically
deinitialized or initialized either.

Further, the above facts mean that there are multiple reasons that
"tracked" files might not be present in the working copy: sparsity
pattern application from sparse-checkout, and submodule initialization
state.  Thus, commands like `git grep` that work on tracked files in
the working copy may return results that are limited by either or both
of these restrictions.


SEE ALSO
--------

linkgit:git-read-tree[1]
linkgit:gitignore[5]

GIT
---
Part of the linkgit:git[1] suite
