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[thirdparty/git.git] / Documentation / git-pack-objects.txt

git-pack-objects(1)
===================

NAME
----
git-pack-objects - Create a packed archive of objects


SYNOPSIS
--------
[verse]
'git-pack-objects' [-q] [--no-reuse-delta] [--delta-base-offset] [--non-empty]
	[--local] [--incremental] [--window=N] [--depth=N] [--all-progress]
	[--revs [--unpacked | --all]*] [--stdout | base-name] < object-list


DESCRIPTION
-----------
Reads list of objects from the standard input, and writes a packed
archive with specified base-name, or to the standard output.

A packed archive is an efficient way to transfer set of objects
between two repositories, and also is an archival format which
is efficient to access.  The packed archive format (.pack) is
designed to be unpackable without having anything else, but for
random access, accompanied with the pack index file (.idx).

Placing both in the pack/ subdirectory of $GIT_OBJECT_DIRECTORY (or
any of the directories on $GIT_ALTERNATE_OBJECT_DIRECTORIES)
enables git to read from such an archive.

'git-unpack-objects' command can read the packed archive and
expand the objects contained in the pack into "one-file
one-object" format; this is typically done by the smart-pull
commands when a pack is created on-the-fly for efficient network
transport by their peers.

In a packed archive, an object is either stored as a compressed
whole, or as a difference from some other object.  The latter is
often called a delta.


OPTIONS
-------
base-name::
	Write into a pair of files (.pack and .idx), using
	<base-name> to determine the name of the created file.
	When this option is used, the two files are written in
	<base-name>-<SHA1>.{pack,idx} files.  <SHA1> is a hash
	of the sorted object names to make the resulting filename
	based on the pack content, and written to the standard
	output of the command.

--stdout::
	Write the pack contents (what would have been written to
	.pack file) out to the standard output.

--revs::
	Read the revision arguments from the standard input, instead of
	individual object names.  The revision arguments are processed
	the same way as linkgit:git-rev-list[1] with `--objects` flag
	uses its `commit` arguments to build the list of objects it
	outputs.  The objects on the resulting list are packed.

--unpacked::
	This implies `--revs`.  When processing the list of
	revision arguments read from the standard input, limit
	the objects packed to those that are not already packed.

--all::
	This implies `--revs`.  In addition to the list of
	revision arguments read from the standard input, pretend
	as if all refs under `$GIT_DIR/refs` are specified to be
	included.

--window=[N], --depth=[N]::
	These two options affect how the objects contained in
	the pack are stored using delta compression.  The
	objects are first internally sorted by type, size and
	optionally names and compared against the other objects
	within --window to see if using delta compression saves
	space.  --depth limits the maximum delta depth; making
	it too deep affects the performance on the unpacker
	side, because delta data needs to be applied that many
	times to get to the necessary object.
	The default value for --window is 10 and --depth is 50.

--window-memory=[N]::
	This option provides an additional limit on top of `--window`;
	the window size will dynamically scale down so as to not take
	up more than N bytes in memory.  This is useful in
	repositories with a mix of large and small objects to not run
	out of memory with a large window, but still be able to take
	advantage of the large window for the smaller objects.  The
	size can be suffixed with "k", "m", or "g".
	`--window-memory=0` makes memory usage unlimited, which is the
	default.

--max-pack-size=<n>::
	Maximum size of each output packfile, expressed in MiB.
	If specified,  multiple packfiles may be created.
	The default is unlimited, unless the config variable
	`pack.packSizeLimit` is set.

--incremental::
	This flag causes an object already in a pack ignored
	even if it appears in the standard input.

--local::
	This flag is similar to `--incremental`; instead of
	ignoring all packed objects, it only ignores objects
	that are packed and not in the local object store
	(i.e. borrowed from an alternate).

--non-empty::
        Only create a packed archive if it would contain at
        least one object.

--progress::
	Progress status is reported on the standard error stream
	by default when it is attached to a terminal, unless -q
	is specified. This flag forces progress status even if
	the standard error stream is not directed to a terminal.

--all-progress::
	When --stdout is specified then progress report is
	displayed during the object count and deltification phases
	but inhibited during the write-out phase. The reason is
	that in some cases the output stream is directly linked
	to another command which may wish to display progress
	status of its own as it processes incoming pack data.
	This flag is like --progress except that it forces progress
	report for the write-out phase as well even if --stdout is
	used.

-q::
	This flag makes the command not to report its progress
	on the standard error stream.

--no-reuse-delta::
	When creating a packed archive in a repository that
	has existing packs, the command reuses existing deltas.
	This sometimes results in a slightly suboptimal pack.
	This flag tells the command not to reuse existing deltas
	but compute them from scratch.

--no-reuse-object::
	This flag tells the command not to reuse existing object data at all,
	including non deltified object, forcing recompression of everything.
	This implies --no-reuse-delta. Useful only in the obscure case where
	wholesale enforcement of a different compression level on the
	packed data is desired.

--compression=[N]::
	Specifies compression level for newly-compressed data in the
	generated pack.  If not specified,  pack compression level is
	determined first by pack.compression,  then by core.compression,
	and defaults to -1,  the zlib default,  if neither is set.
	Add \--no-reuse-object if you want to force a uniform compression
	level on all data no matter the source.

--delta-base-offset::
	A packed archive can express base object of a delta as
	either 20-byte object name or as an offset in the
	stream, but older version of git does not understand the
	latter.  By default, git-pack-objects only uses the
	former format for better compatibility.  This option
	allows the command to use the latter format for
	compactness.  Depending on the average delta chain
	length, this option typically shrinks the resulting
	packfile by 3-5 per-cent.

--threads=<n>::
	Specifies the number of threads to spawn when searching for best
	delta matches.  This requires that pack-objects be compiled with
	pthreads otherwise this option is ignored with a warning.
	This is meant to reduce packing time on multiprocessor machines.
	The required amount of memory for the delta search window is
	however multiplied by the number of threads.

--index-version=<version>[,<offset>]::
	This is intended to be used by the test suite only. It allows
	to force the version for the generated pack index, and to force
	64-bit index entries on objects located above the given offset.


Author
------
Written by Linus Torvalds <torvalds@osdl.org>

Documentation
-------------
Documentation by Junio C Hamano

See Also
--------
linkgit:git-rev-list[1]
linkgit:git-repack[1]
linkgit:git-prune-packed[1]

GIT
---
Part of the linkgit:git[7] suite