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+git-sparse-checkout(1)
+======================
+
+NAME
+----
+git-sparse-checkout - Reduce your working tree to a subset of tracked files
+
+
+SYNOPSIS
+--------
+[verse]
+'git sparse-checkout' (init | list | set | add | reapply | disable) [<options>]
+
+
+DESCRIPTION
+-----------
+
+This command is used to create sparse checkouts, which change the
+working tree from having all tracked files present to only having a
+subset of those files. It can also switch which subset of files are
+present, or undo and go back to having all tracked files present in
+the working copy.
+
+The subset of files is chosen by providing a list of directories in
+cone mode (the default), or by providing a list of patterns in
+non-cone mode.
+
+When in a sparse-checkout, other Git commands behave a bit differently.
+For example, switching branches will not update paths outside the
+sparse-checkout directories/patterns, and `git commit -a` will not record
+paths outside the sparse-checkout directories/patterns as deleted.
+
+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 directories or patterns in the sparse-checkout file.
+
+'set'::
+ Enable the necessary sparse-checkout config settings
+ (`core.sparseCheckout`, `core.sparseCheckoutCone`, and
+ `index.sparse`) if they are not already set to the desired values,
+ populate the sparse-checkout file from the list of arguments
+ following the 'set' subcommand, and update the working directory to
+ match.
++
+To ensure that adjusting the sparse-checkout settings within a worktree
+does not alter the sparse-checkout settings in other worktrees, the 'set'
+subcommand will upgrade your repository config to use worktree-specific
+config if not already present. The sparsity defined by the arguments to
+the 'set' subcommand are stored in the worktree-specific sparse-checkout
+file. See linkgit:git-worktree[1] and the documentation of
+`extensions.worktreeConfig` in linkgit:git-config[1] for more details.
++
+When the `--stdin` option is provided, the directories or patterns are
+read from standard in as a newline-delimited list instead of from the
+arguments.
++
+By default, the input list is considered a list of directories, matching
+the output of `git ls-tree -d --name-only`. This includes interpreting
+pathnames that begin with a double quote (") as C-style quoted strings.
+Note that all files under the specified directories (at any depth) will
+be included in the sparse checkout, as well as files that are siblings
+of either the given directory or any of its ancestors (see 'CONE PATTERN
+SET' below for more details). In the past, this was not the default,
+and `--cone` needed to be specified or `core.sparseCheckoutCone` needed
+to be enabled.
++
+When `--no-cone` is passed, the input list is considered a list of
+patterns. This mode has a number of drawbacks, including not working
+with some options like `--sparse-index`. As explained in the
+"Non-cone Problems" section below, we do not recommend using it.
++
+Use the `--[no-]sparse-index` option to use a sparse index (the
+default is to not use it). A sparse index 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.
+
+'add'::
+ Update the sparse-checkout file to include additional directories
+ (in cone mode) or patterns (in non-cone mode). By default, these
+ directories or patterns are read from the command-line arguments,
+ but they can be read from stdin using the `--stdin` option.
+
+'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.).
++
+The `reapply` command can also take `--[no-]cone` and `--[no-]sparse-index`
+flags, with the same meaning as the flags from the `set` command, in order
+to change which sparsity mode you are using without needing to also respecify
+all sparsity paths.
+
+'disable'::
+ Disable the `core.sparseCheckout` config setting, and restore the
+ working directory to include all files.
+
+'init'::
+ Deprecated command that behaves like `set` with no specified paths.
+ May be removed in the future.
++
+Historically, `set` did not handle all the necessary config settings,
+which meant that both `init` and `set` had to be called. Invoking
+both meant the `init` step would first remove nearly all tracked files
+(and in cone mode, ignored files too), then the `set` step would add
+many of the tracked files (but not ignored files) back. In addition
+to the lost files, the performance and UI of this combination was
+poor.
++
+Also, historically, `init` would not actually initialize the
+sparse-checkout file if it already existed. This meant it was
+possible to return to a sparse-checkout without remembering which
+paths to pass to a subsequent 'set' or 'add' command. However,
+`--cone` and `--sparse-index` options would not be remembered across
+the disable command, so the easy restore of calling a plain `init`
+decreased in utility.
+
+EXAMPLES
+--------
+`git sparse-checkout set MY/DIR1 SUB/DIR2`::
+
+ Change to a sparse checkout with all files (at any depth) under
+ MY/DIR1/ and SUB/DIR2/ present in the working copy (plus all
+ files immediately under MY/ and SUB/ and the toplevel
+ directory). If already in a sparse checkout, change which files
+ are present in the working copy to this new selection. Note
+ that this command will also delete all ignored files in any
+ directory that no longer has either tracked or
+ non-ignored-untracked files present.
+
+`git sparse-checkout disable`::
+
+ Repopulate the working directory with all files, disabling sparse
+ checkouts.
+
+`git sparse-checkout add SOME/DIR/ECTORY`::
+
+ Add all files under SOME/DIR/ECTORY/ (at any depth) to the
+ sparse checkout, as well as all files immediately under
+ SOME/DIR/ and immediately under SOME/. Must already be in a
+ sparse checkout before using this command.
+
+`git sparse-checkout reapply`::
+
+ It is possible for commands to update the working tree in a
+ way that does not respect the selected sparsity directories.
+ This can come from tools external to Git writing files, or
+ even affect Git commands because of either special cases (such
+ as hitting conflicts when merging/rebasing), or because some
+ commands didn't fully support sparse checkouts (e.g. the old
+ `recursive` merge backend had only limited support). This
+ command reapplies the existing sparse directory specifications
+ to make the working directory match.
+
+INTERNALS -- 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, and the file is not present in the working tree,
+then its absence is ignored. Git will avoid populating 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 `$GIT_DIR/info/sparse-checkout` file is used to define the
+skip-worktree reference bitmap. When Git updates the working
+directory, it updates the skip-worktree bits in the index based
+on this file. The files matching the patterns in the file will
+appear in the working directory, and the rest will not.
+
+INTERNALS -- NON-CONE PROBLEMS
+------------------------------
+
+The `$GIT_DIR/info/sparse-checkout` file populated by the `set` and
+`add` subcommands is defined to be a bunch of patterns (one per line)
+using the same syntax as `.gitignore` files. In cone mode, these
+patterns are restricted to matching directories (and users only ever
+need supply or see directory names), while in non-cone mode any
+gitignore-style pattern is permitted. Using the full gitignore-style
+patterns in non-cone mode has a number of shortcomings:
+
+ * Fundamentally, it makes various worktree-updating processes (pull,
+ merge, rebase, switch, reset, checkout, etc.) require O(N*M) pattern
+ matches, where N is the number of patterns and M is the number of
+ paths in the index. This scales poorly.
+
+ * Avoiding the scaling issue has to be done via limiting the number
+ of patterns via specifying leading directory name or glob.
+
+ * Passing globs on the command line is error-prone as users may
+ forget to quote the glob, causing the shell to expand it into all
+ matching files and pass them all individually along to
+ sparse-checkout set/add. While this could also be a problem with
+ e.g. "git grep -- *.c", mistakes with grep/log/status appear in
+ the immediate output. With sparse-checkout, the mistake gets
+ recorded at the time the sparse-checkout command is run and might
+ not be problematic until the user later switches branches or rebases
+ or merges, thus putting a delay between the user's error and when
+ they have a chance to catch/notice it.
+
+ * Related to the previous item, sparse-checkout has an 'add'
+ subcommand but no 'remove' subcommand. Even if a 'remove'
+ subcommand were added, undoing an accidental unquoted glob runs
+ the risk of "removing too much", as it may remove entries that had
+ been included before the accidental add.
+
+ * Non-cone mode uses gitignore-style patterns to select what to
+ *include* (with the exception of negated patterns), while
+ .gitignore files use gitignore-style patterns to select what to
+ *exclude* (with the exception of negated patterns). The
+ documentation on gitignore-style patterns usually does not talk in
+ terms of matching or non-matching, but on what the user wants to
+ "exclude". This can cause confusion for users trying to learn how
+ to specify sparse-checkout patterns to get their desired behavior.
+
+ * Every other git subcommand that wants to provide "special path
+ pattern matching" of some sort uses pathspecs, but non-cone mode
+ for sparse-checkout uses gitignore patterns, which feels
+ inconsistent.
+
+ * It has edge cases where the "right" behavior is unclear. Two examples:
+
+ First, two users are in a subdirectory, and the first runs
+ git sparse-checkout set '/toplevel-dir/*.c'
+ while the second runs
+ git sparse-checkout set relative-dir
+ Should those arguments be transliterated into
+ current/subdirectory/toplevel-dir/*.c
+ and
+ current/subdirectory/relative-dir
+ before inserting into the sparse-checkout file? The user who typed
+ the first command is probably aware that arguments to set/add are
+ supposed to be patterns in non-cone mode, and probably would not be
+ happy with such a transliteration. However, many gitignore-style
+ patterns are just paths, which might be what the user who typed the
+ second command was thinking, and they'd be upset if their argument
+ wasn't transliterated.
+
+ Second, what should bash-completion complete on for set/add commands
+ for non-cone users? If it suggests paths, is it exacerbating the
+ problem above? Also, if it suggests paths, what if the user has a
+ file or directory that begins with either a '!' or '#' or has a '*',
+ '\', '?', '[', or ']' in its name? And if it suggests paths, will
+ it complete "/pro" to "/proc" (in the root filesytem) rather than to
+ "/progress.txt" in the current directory? (Note that users are
+ likely to want to start paths with a leading '/' in non-cone mode,
+ for the same reason that .gitignore files often have one.)
+ Completing on files or directories might give nasty surprises in
+ all these cases.
+
+ * The excessive flexibility made other extensions essentially
+ impractical. `--sparse-index` is likely impossible in non-cone
+ mode; even if it is somehow feasible, it would have been far more
+ work to implement and may have been too slow in practice. Some
+ ideas for adding coupling between partial clones and sparse
+ checkouts are only practical with a more restricted set of paths
+ as well.
+
+For all these reasons, non-cone mode is deprecated. Please switch to
+using cone mode.
+
+
+INTERNALS -- CONE MODE HANDLING
+-------------------------------
+
+The "cone mode", which is the default, lets you specify only what
+directories to include. For any directory specified, all paths below
+that directory will be included, and any paths immediately under
+leading directories (including the toplevel directory) will also be
+included. Thus, if you specified the directory
+ Documentation/technical/
+then your sparse checkout would contain:
+
+ * all files in the toplevel-directory
+ * all files immediately under Documentation/
+ * all files at any depth under Documentation/technical/
+
+Also, in cone mode, even if no directories are specified, then the
+files in the toplevel directory will be included.
+
+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.
+
+See also the "Internals -- Cone Pattern Set" section to learn how the
+directories are transformed under the hood into a subset of the
+Full Pattern Set of sparse-checkout.
+
+
+INTERNALS -- FULL 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 sparse-checkout file uses the same syntax as `.gitignore` files;
+see linkgit:gitignore[5] for details. Here, though, the patterns are
+usually being used to select which files to include rather than which
+files to exclude. (However, it can get a bit confusing since
+gitignore-style patterns have negations defined by patterns which
+begin with a '!', so you can also select files to _not_ include.)
+
+For example, to select everything, and then to remove the file
+`unwanted` (so that every file will appear in your working tree except
+the file named `unwanted`):
+
+ git sparse-checkout set --no-cone '/*' '!unwanted'
+
+These patterns are just placed into the
+`$GIT_DIR/info/sparse-checkout` as-is, so the contents of that file
+at this point would be
+
+----------------
+/*
+!unwanted
+----------------
+
+See also the "Sparse Checkout" section of linkgit:git-read-tree[1] to
+learn more about the gitignore-style patterns used in sparse
+checkouts.
+
+
+INTERNALS -- CONE PATTERN SET
+-----------------------------
+
+In cone mode, only directories are accepted, but they are translated into
+the same gitignore-style patterns used in the full pattern set. We refer
+to the particular patterns used in those mode as being of one of two types:
+
+1. *Recursive:* All paths inside a directory are included.
+
+2. *Parent:* All files immediately inside a directory are included.
+
+Since cone mode always includes files at the toplevel, when running
+`git sparse-checkout set` with no directories specified, the toplevel
+directory is added as a parent pattern. At this point, the
+sparse-checkout file contains the following patterns:
+
+----------------
+/*
+!/*/
+----------------
+
+This says "include everything immediately under the toplevel
+directory, but nothing at any level below that."
+
+When in cone mode, the `git sparse-checkout set` subcommand takes a
+list of directories. 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.
+
+Unless `core.sparseCheckoutCone` is explicitly set to `false`, 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. If they do not match, git will behave as though
+`core.sparseCheckoutCone` was false, regardless of its setting.
+
+In the cone mode case, despite the fact that full patterns are written
+to the $GIT_DIR/info/sparse-checkout file, the `git sparse-checkout
+list` subcommand will list the directories that define the recursive
+patterns. For the example sparse-checkout file above, the output is as
+follows:
+
+--------------------------
+$ 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.
+
+
+INTERNALS -- 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