Documentation/git.txt - git - Git at Google

 git(7)
 ======
 v0.99.4, Aug 2005

 NAME
 ----
 git - the stupid content tracker


 SYNOPSIS
 --------
 'git-<command>' <args>

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

 This is reference information for the core git commands.

 Before reading this cover to cover, you may want to take a look
 at the link:tutorial.html[tutorial] document.

 The Discussion section below contains much useful definition and
 clarification info - read that first.  And of the commands, I suggest
 reading link:git-update-cache.html[git-update-cache] and
 link:git-read-tree.html[git-read-tree] first - I wish I had!

 David Greaves <david@dgreaves.com>
 08/05/05

 Updated by Junio C Hamano <junkio@cox.net> on 2005-05-05 to
 reflect recent changes.

 Commands Overview
 -----------------
 The git commands can helpfully be split into those that manipulate
 the repository, the cache and the working fileset, those that
 interrogate and compare them, and those that moves objects and
 references between repositories.

 In addition, git itself comes with a spartan set of porcelain
 commands.  They are usable but are not meant to compete with real
 Porcelains.

 There are also some ancillary programs that can be viewed as useful
 aids for using the core commands but which are unlikely to be used by
 SCMs layered over git.

 Manipulation commands
 ~~~~~~~~~~~~~~~~~~~~~
 link:git-checkout-cache.html[git-checkout-cache]::
 	Copy files from the cache to the working directory

 link:git-commit-tree.html[git-commit-tree]::
 	Creates a new commit object

 link:git-init-db.html[git-init-db]::
 	Creates an empty git object database

 link:git-merge-base.html[git-merge-base]::
 	Finds as good a common ancestor as possible for a merge

 link:git-mktag.html[git-mktag]::
 	Creates a tag object

 link:git-read-tree.html[git-read-tree]::
 	Reads tree information into the directory cache

 link:git-update-cache.html[git-update-cache]::
 	Modifies the index or directory cache

 link:git-hash-object.html[git-hash-object]::
 	Computes the object ID from a file.

 link:git-write-tree.html[git-write-tree]::
 	Creates a tree from the current cache

 link:git-pack-objects.html[git-pack-objects]::
 	Creates a packed archive of objects.

 link:git-unpack-objects.html[git-unpack-objects]::
 	Unpacks objects out of a packed archive.

 link:git-prune-packed.html[git-prune-packed]::
 	Remove extra objects that are already in pack files.

 link:git-apply.html[git-apply]::
 	Reads a "diff -up1" or git generated patch file and
 	applies it to the working tree.


 Interrogation commands
 ~~~~~~~~~~~~~~~~~~~~~~
 link:git-cat-file.html[git-cat-file]::
 	Provide content or type information for repository objects

 link:git-diff-cache.html[git-diff-cache]::
 	Compares content and mode of blobs between the cache and repository

 link:git-diff-files.html[git-diff-files]::
 	Compares files in the working tree and the cache

 link:git-diff-tree.html[git-diff-tree]::
 	Compares the content and mode of blobs found via two tree objects

 link:git-diff-stages.html[git-diff-stages]::
 	Compares two "merge stages" in the index file.

 link:git-export.html[git-export]::
 	Exports each commit and a diff against each of its parents

 link:git-fsck-cache.html[git-fsck-cache]::
 	Verifies the connectivity and validity of the objects in the database

 link:git-ls-files.html[git-ls-files]::
 	Information about files in the cache/working directory

 link:git-ls-tree.html[git-ls-tree]::
 	Displays a tree object in human readable form

 link:git-merge-cache.html[git-merge-cache]::
 	Runs a merge for files needing merging

 link:git-rev-list.html[git-rev-list]::
 	Lists commit objects in reverse chronological order

 link:git-rev-tree.html[git-rev-tree]::
 	Provides the revision tree for one or more commits

 link:git-tar-tree.html[git-tar-tree]::
 	Creates a tar archive of the files in the named tree

 link:git-unpack-file.html[git-unpack-file]::
 	Creates a temporary file with a blob's contents

 link:git-var.html[git-var]::
 	Displays a git logical variable

 link:git-show-index.html[git-show-index]::
 	Displays contents of a pack idx file.

 link:git-verify-pack.html[git-verify-pack]::
 	Validates packed GIT archive files

 The interrogate commands may create files - and you can force them to
 touch the working file set - but in general they don't


 Synching repositories
 ~~~~~~~~~~~~~~~~~~~~~

 link:git-clone-script.html[git-clone-script]::
 	Clones a repository into the current repository (user interface)

 link:git-clone-pack.html[git-clone-pack]::
 	Clones a repository into the current repository (engine
 	for ssh and local transport)

 link:git-http-pull.html[git-http-pull]::
 	Downloads a remote GIT repository via HTTP

 link:git-local-pull.html[git-local-pull]::
 	Duplicates another GIT repository on a local system

 link:git-ssh-pull.html[git-ssh-pull]::
 	Pulls from a remote repository over ssh connection

 link:git-send-pack.html[git-send-pack]::
 	Pushes to a remote repository, intelligently.

 link:git-receive-pack.html[git-receive-pack]::
 	Invoked by 'git-send-pack' to receive what is pushed to it.

 link:git-clone-pack.html[git-clone-pack]::
 	Clones from a remote repository.

 link:git-fetch-pack.html[git-fetch-pack]::
 	Updates from a remote repository.

 link:git-peek-remote.html[git-peek-remote]::
 	Lists references on a remote repository using upload-pack protocol.

 link:git-upload-pack.html[git-upload-pack]::
 	Invoked by 'git-clone-pack' and 'git-fetch-pack' to push
 	what are asked for.

 link:git-update-server-info.html[git-update-server-info]::
 	Updates auxiliary information on a dumb server to help
 	clients discover references and packs on it.


 Porcelain-ish Commands
 ----------------------
 link:git-whatchanged.html[git-whatchanged]::
 	Shows commit logs and differences they introduce.

 link:git-log-script.html[git-log-script]::
 	Shows commit logs.

 link:git-shortlog.html[git-shortlog]::
 	Summarizes 'git log' output.

 link:git-status-script.html[git-status-script]::
 	Shows the working tree status.

 link:git-fetch-script.html[git-fetch-script]::
 	Download from a remote repository via various protocols.

 link:git-pull-script.html[git-pull-script]::
 	Fetch from and merge with a remote repository.

 link:git-resolve-script.html[git-resolve-script]::
 	Merge two commits.

 link:git-octopus-script.html[git-octopus-script]::
 	Merge more than two commits.

 link:git-push-script.html[git-push-script]::
 	Update remote refs along with associated objects.

 link:git-commit-script.html[git-commit-script]::
 	Record changes to the repository.

 link:git-show-branch.html[git-show-branch]::
 	Show branches and their commits.

 link:git-repack-script.html[git-repack-script]::
 	Pack unpacked objects in a repository.

 link:git-rename-script.html[git-rename]::
 	Rename files and directories.

 link:git-ls-remote-script.html[git-ls-remote-script]::
 	Shows references in a remote or local repository.


 Ancillary Commands
 ------------------
 Manipulators:

 link:git-apply-patch-script.html[git-apply-patch-script]::
 	Sample script to apply the diffs from git-diff-*

 link:git-convert-cache.html[git-convert-cache]::
 	Converts old-style GIT repository

 link:git-merge-one-file-script.html[git-merge-one-file-script]::
 	The standard helper program to use with "git-merge-cache"

 link:git-prune-script.html[git-prune-script]::
 	Prunes all unreachable objects from the object database

 link:git-tag-script.html[git-tag-script]::
 	An example script to create a tag object signed with GPG

 link:git-cvsimport-script.html[git-cvsimport-script]::
 	Salvage your data out of another SCM people love to hate.


 Interrogators:

 link:git-diff-helper.html[git-diff-helper]::
 	Generates patch format output for git-diff-*

 link:git-ssh-push.html[git-ssh-push]::
 	Helper "server-side" program used by git-ssh-pull

 link:git-send-email-script.html[git-send-email]::
 	Send patch e-mails out of "format-patch --mbox" output.


 Commands not yet documented
 ---------------------------

 link:git-applymbox.html[git-applymbox]::
 	git-applymbox.

 link:git-applypatch.html[git-applypatch]::
 	git-applypatch.

 link:git-mailinfo.html[git-mailinfo]::
 	git-mailinfo.

 link:git-mailsplit.html[git-mailsplit]::
 	git-mailsplit.

 link:git-add-script.html[git-add-script]::
 	git-add-script.

 link:git-bisect-script.html[git-bisect-script]::
 	git-bisect-script.

 link:git-branch-script.html[git-branch-script]::
 	git-branch-script.

 link:git-build-rev-cache.html[git-build-rev-cache]::
 	git-build-rev-cache.

 link:git-checkout-script.html[git-checkout-script]::
 	git-checkout-script.

 link:git-cherry.html[git-cherry]::
 	git-cherry.

 link:git-clone-dumb-http.html[git-clone-dumb-http]::
 	git-clone-dumb-http.

 link:git-count-objects-script.html[git-count-objects-script]::
 	git-count-objects-script.

 link:git-daemon.html[git-daemon]::
 	git-daemon.

 link:git-diff-script.html[git-diff-script]::
 	git-diff-script.

 link:git-format-patch-script.html[git-format-patch-script]::
 	git-format-patch-script.

 link:git-get-tar-commit-id.html[git-get-tar-commit-id]::
 	git-get-tar-commit-id.

 link:git-patch-id.html[git-patch-id]::
 	git-patch-id.

 link:git-rebase-script.html[git-rebase-script]::
 	git-rebase-script.

 link:git-relink-script.html[git-relink-script]::
 	git-relink-script.

 link:git-request-pull-script.html[git-request-pull-script]::
 	git-request-pull-script.

 link:git-reset-script.html[git-reset-script]::
 	git-reset-script.

 link:git-rev-parse.html[git-rev-parse]::
 	git-rev-parse.

 link:git-revert-script.html[git-revert-script]::
 	git-revert-script.

 link:git-sh-setup-script.html[git-sh-setup-script]::
 	git-sh-setup-script.

 link:git-show-rev-cache.html[git-show-rev-cache]::
 	git-show-rev-cache.

 link:git-stripspace.html[git-stripspace]::
 	git-stripspace.

 link:git-verify-tag-script.html[git-verify-tag-script]::
 	git-verify-tag-script.

 link:gitk.html[gitk]::
 	gitk.


 Identifier Terminology
 ----------------------
 <object>::
 	Indicates the sha1 identifier for any type of object

 <blob>::
 	Indicates a blob object sha1 identifier

 <tree>::
 	Indicates a tree object sha1 identifier

 <commit>::
 	Indicates a commit object sha1 identifier

 <tree-ish>::
 	Indicates a tree, commit or tag object sha1 identifier.  A
 	command that takes a <tree-ish> argument ultimately wants to
 	operate on a <tree> object but automatically dereferences
 	<commit> and <tag> objects that point at a <tree>.

 <type>::
 	Indicates that an object type is required.
 	Currently one of: blob/tree/commit/tag

 <file>::
 	Indicates a filename - always relative to the root of
 	the tree structure GIT_INDEX_FILE describes.

 Symbolic Identifiers
 --------------------
 Any git command accepting any <object> can also use the following
 symbolic notation:

 HEAD::
 	indicates the head of the repository (ie the contents of
 	`$GIT_DIR/HEAD`)
 <tag>::
 	a valid tag 'name'+
 	(ie the contents of `$GIT_DIR/refs/tags/<tag>`)
 <head>::
 	a valid head 'name'+
 	(ie the contents of `$GIT_DIR/refs/heads/<head>`)
 <snap>::
 	a valid snapshot 'name'+
 	(ie the contents of `$GIT_DIR/refs/snap/<snap>`)


 File/Directory Structure
 ------------------------
 The git-core manipulates the following areas in the directory:

  .git/	       The base (overridden with $GIT_DIR)
    objects/    The object base (overridden with $GIT_OBJECT_DIRECTORY)
      ??/       'First 2 chars of object' directories.
      pack/     Packed archives.

    refs/       Directories containing symbolic names for objects
 	       (each file contains the hex SHA1 + newline)
      heads/    Commits which are heads of various sorts
      tags/     Tags, by the tag name (or some local renaming of it)
      */        Any other subdirectory of refs/ can be used to store
 	       files similar to what are under refs/heads/.
    HEAD        Symlink to refs/heads/<current-branch-name>

 Higher level SCMs may provide and manage additional information in the
 GIT_DIR.

 Terminology
 -----------
 Please see link:glossary.html[glossary] document.


 Environment Variables
 ---------------------
 Various git commands use the following environment variables:

 The git Repository
 ~~~~~~~~~~~~~~~~~~
 These environment variables apply to 'all' core git commands. Nb: it
 is worth noting that they may be used/overridden by SCMS sitting above
 git so take care if using Cogito etc

 'GIT_INDEX_FILE'::
 	This environment allows the specification of an alternate
 	cache/index file. If not specified, the default of
 	`$GIT_DIR/index` is used.

 'GIT_OBJECT_DIRECTORY'::
 	If the object storage directory is specified via this
 	environment variable then the sha1 directories are created
 	underneath - otherwise the default `$GIT_DIR/objects`
 	directory is used.

 'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
 	Due to the immutable nature of git objects, old objects can be
 	archived into shared, read-only directories. This variable
 	specifies a ":" separated list of git object directories which
 	can be used to search for git objects. New objects will not be
 	written to these directories.

 'GIT_DIR'::
 	If the 'GIT_DIR' environment variable is set then it specifies
 	a path to use instead of `./.git` for the base of the
 	repository.

 git Commits
 ~~~~~~~~~~~
 'GIT_AUTHOR_NAME'::
 'GIT_AUTHOR_EMAIL'::
 'GIT_AUTHOR_DATE'::
 'GIT_COMMITTER_NAME'::
 'GIT_COMMITTER_EMAIL'::
 	see link:git-commit-tree.html[git-commit-tree]

 git Diffs
 ~~~~~~~~~
 'GIT_DIFF_OPTS'::
 'GIT_EXTERNAL_DIFF'::
 	see the "generating patches" section in :
 	link:git-diff-cache.html[git-diff-cache];
 	link:git-diff-files.html[git-diff-files];
 	link:git-diff-tree.html[git-diff-tree]

 Discussion
 ----------
 include::../README[]

 Author
 ------
 Written by Linus Torvalds <torvalds@osdl.org> and the git-list <git@vger.kernel.org>.

 Documentation
 --------------
 Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.

 GIT
 ---
 Part of the link:git.html[git] suite
	git(7)
	======
	v0.99.4, Aug 2005

	NAME
	----
	git - the stupid content tracker


	SYNOPSIS
	--------
	'git-<command>' <args>

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

	This is reference information for the core git commands.

	Before reading this cover to cover, you may want to take a look
	at the link:tutorial.html[tutorial] document.

	The Discussion section below contains much useful definition and
	clarification info - read that first. And of the commands, I suggest
	reading link:git-update-cache.html[git-update-cache] and
	link:git-read-tree.html[git-read-tree] first - I wish I had!

	David Greaves <david@dgreaves.com>
	08/05/05

	Updated by Junio C Hamano <junkio@cox.net> on 2005-05-05 to
	reflect recent changes.

	Commands Overview
	-----------------
	The git commands can helpfully be split into those that manipulate
	the repository, the cache and the working fileset, those that
	interrogate and compare them, and those that moves objects and
	references between repositories.

	In addition, git itself comes with a spartan set of porcelain
	commands. They are usable but are not meant to compete with real
	Porcelains.

	There are also some ancillary programs that can be viewed as useful
	aids for using the core commands but which are unlikely to be used by
	SCMs layered over git.

	Manipulation commands
	~~~~~~~~~~~~~~~~~~~~~
	link:git-checkout-cache.html[git-checkout-cache]::
	Copy files from the cache to the working directory

	link:git-commit-tree.html[git-commit-tree]::
	Creates a new commit object

	link:git-init-db.html[git-init-db]::
	Creates an empty git object database

	link:git-merge-base.html[git-merge-base]::
	Finds as good a common ancestor as possible for a merge

	link:git-mktag.html[git-mktag]::
	Creates a tag object

	link:git-read-tree.html[git-read-tree]::
	Reads tree information into the directory cache

	link:git-update-cache.html[git-update-cache]::
	Modifies the index or directory cache

	link:git-hash-object.html[git-hash-object]::
	Computes the object ID from a file.

	link:git-write-tree.html[git-write-tree]::
	Creates a tree from the current cache

	link:git-pack-objects.html[git-pack-objects]::
	Creates a packed archive of objects.

	link:git-unpack-objects.html[git-unpack-objects]::
	Unpacks objects out of a packed archive.

	link:git-prune-packed.html[git-prune-packed]::
	Remove extra objects that are already in pack files.

	link:git-apply.html[git-apply]::
	Reads a "diff -up1" or git generated patch file and
	applies it to the working tree.


	Interrogation commands
	~~~~~~~~~~~~~~~~~~~~~~
	link:git-cat-file.html[git-cat-file]::
	Provide content or type information for repository objects

	link:git-diff-cache.html[git-diff-cache]::
	Compares content and mode of blobs between the cache and repository

	link:git-diff-files.html[git-diff-files]::
	Compares files in the working tree and the cache

	link:git-diff-tree.html[git-diff-tree]::
	Compares the content and mode of blobs found via two tree objects

	link:git-diff-stages.html[git-diff-stages]::
	Compares two "merge stages" in the index file.

	link:git-export.html[git-export]::
	Exports each commit and a diff against each of its parents

	link:git-fsck-cache.html[git-fsck-cache]::
	Verifies the connectivity and validity of the objects in the database

	link:git-ls-files.html[git-ls-files]::
	Information about files in the cache/working directory

	link:git-ls-tree.html[git-ls-tree]::
	Displays a tree object in human readable form

	link:git-merge-cache.html[git-merge-cache]::
	Runs a merge for files needing merging

	link:git-rev-list.html[git-rev-list]::
	Lists commit objects in reverse chronological order

	link:git-rev-tree.html[git-rev-tree]::
	Provides the revision tree for one or more commits

	link:git-tar-tree.html[git-tar-tree]::
	Creates a tar archive of the files in the named tree

	link:git-unpack-file.html[git-unpack-file]::
	Creates a temporary file with a blob's contents

	link:git-var.html[git-var]::
	Displays a git logical variable

	link:git-show-index.html[git-show-index]::
	Displays contents of a pack idx file.

	link:git-verify-pack.html[git-verify-pack]::
	Validates packed GIT archive files

	The interrogate commands may create files - and you can force them to
	touch the working file set - but in general they don't


	Synching repositories
	~~~~~~~~~~~~~~~~~~~~~

	link:git-clone-script.html[git-clone-script]::
	Clones a repository into the current repository (user interface)

	link:git-clone-pack.html[git-clone-pack]::
	Clones a repository into the current repository (engine
	for ssh and local transport)

	link:git-http-pull.html[git-http-pull]::
	Downloads a remote GIT repository via HTTP

	link:git-local-pull.html[git-local-pull]::
	Duplicates another GIT repository on a local system

	link:git-ssh-pull.html[git-ssh-pull]::
	Pulls from a remote repository over ssh connection

	link:git-send-pack.html[git-send-pack]::
	Pushes to a remote repository, intelligently.

	link:git-receive-pack.html[git-receive-pack]::
	Invoked by 'git-send-pack' to receive what is pushed to it.

	link:git-clone-pack.html[git-clone-pack]::
	Clones from a remote repository.

	link:git-fetch-pack.html[git-fetch-pack]::
	Updates from a remote repository.

	link:git-peek-remote.html[git-peek-remote]::
	Lists references on a remote repository using upload-pack protocol.

	link:git-upload-pack.html[git-upload-pack]::
	Invoked by 'git-clone-pack' and 'git-fetch-pack' to push
	what are asked for.

	link:git-update-server-info.html[git-update-server-info]::
	Updates auxiliary information on a dumb server to help
	clients discover references and packs on it.


	Porcelain-ish Commands
	----------------------
	link:git-whatchanged.html[git-whatchanged]::
	Shows commit logs and differences they introduce.

	link:git-log-script.html[git-log-script]::
	Shows commit logs.

	link:git-shortlog.html[git-shortlog]::
	Summarizes 'git log' output.

	link:git-status-script.html[git-status-script]::
	Shows the working tree status.

	link:git-fetch-script.html[git-fetch-script]::
	Download from a remote repository via various protocols.

	link:git-pull-script.html[git-pull-script]::
	Fetch from and merge with a remote repository.

	link:git-resolve-script.html[git-resolve-script]::
	Merge two commits.

	link:git-octopus-script.html[git-octopus-script]::
	Merge more than two commits.

	link:git-push-script.html[git-push-script]::
	Update remote refs along with associated objects.

	link:git-commit-script.html[git-commit-script]::
	Record changes to the repository.

	link:git-show-branch.html[git-show-branch]::
	Show branches and their commits.

	link:git-repack-script.html[git-repack-script]::
	Pack unpacked objects in a repository.

	link:git-rename-script.html[git-rename]::
	Rename files and directories.

	link:git-ls-remote-script.html[git-ls-remote-script]::
	Shows references in a remote or local repository.


	Ancillary Commands
	------------------
	Manipulators:

	link:git-apply-patch-script.html[git-apply-patch-script]::
	Sample script to apply the diffs from git-diff-*

	link:git-convert-cache.html[git-convert-cache]::
	Converts old-style GIT repository

	link:git-merge-one-file-script.html[git-merge-one-file-script]::
	The standard helper program to use with "git-merge-cache"

	link:git-prune-script.html[git-prune-script]::
	Prunes all unreachable objects from the object database

	link:git-tag-script.html[git-tag-script]::
	An example script to create a tag object signed with GPG

	link:git-cvsimport-script.html[git-cvsimport-script]::
	Salvage your data out of another SCM people love to hate.


	Interrogators:

	link:git-diff-helper.html[git-diff-helper]::
	Generates patch format output for git-diff-*

	link:git-ssh-push.html[git-ssh-push]::
	Helper "server-side" program used by git-ssh-pull

	link:git-send-email-script.html[git-send-email]::
	Send patch e-mails out of "format-patch --mbox" output.


	Commands not yet documented
	---------------------------

	link:git-applymbox.html[git-applymbox]::
	git-applymbox.

	link:git-applypatch.html[git-applypatch]::
	git-applypatch.

	link:git-mailinfo.html[git-mailinfo]::
	git-mailinfo.

	link:git-mailsplit.html[git-mailsplit]::
	git-mailsplit.

	link:git-add-script.html[git-add-script]::
	git-add-script.

	link:git-bisect-script.html[git-bisect-script]::
	git-bisect-script.

	link:git-branch-script.html[git-branch-script]::
	git-branch-script.

	link:git-build-rev-cache.html[git-build-rev-cache]::
	git-build-rev-cache.

	link:git-checkout-script.html[git-checkout-script]::
	git-checkout-script.

	link:git-cherry.html[git-cherry]::
	git-cherry.

	link:git-clone-dumb-http.html[git-clone-dumb-http]::
	git-clone-dumb-http.

	link:git-count-objects-script.html[git-count-objects-script]::
	git-count-objects-script.

	link:git-daemon.html[git-daemon]::
	git-daemon.

	link:git-diff-script.html[git-diff-script]::
	git-diff-script.

	link:git-format-patch-script.html[git-format-patch-script]::
	git-format-patch-script.

	link:git-get-tar-commit-id.html[git-get-tar-commit-id]::
	git-get-tar-commit-id.

	link:git-patch-id.html[git-patch-id]::
	git-patch-id.

	link:git-rebase-script.html[git-rebase-script]::
	git-rebase-script.

	link:git-relink-script.html[git-relink-script]::
	git-relink-script.

	link:git-request-pull-script.html[git-request-pull-script]::
	git-request-pull-script.

	link:git-reset-script.html[git-reset-script]::
	git-reset-script.

	link:git-rev-parse.html[git-rev-parse]::
	git-rev-parse.

	link:git-revert-script.html[git-revert-script]::
	git-revert-script.

	link:git-sh-setup-script.html[git-sh-setup-script]::
	git-sh-setup-script.

	link:git-show-rev-cache.html[git-show-rev-cache]::
	git-show-rev-cache.

	link:git-stripspace.html[git-stripspace]::
	git-stripspace.

	link:git-verify-tag-script.html[git-verify-tag-script]::
	git-verify-tag-script.

	link:gitk.html[gitk]::
	gitk.


	Identifier Terminology
	----------------------
	<object>::
	Indicates the sha1 identifier for any type of object

	<blob>::
	Indicates a blob object sha1 identifier

	<tree>::
	Indicates a tree object sha1 identifier

	<commit>::
	Indicates a commit object sha1 identifier

	<tree-ish>::
	Indicates a tree, commit or tag object sha1 identifier. A
	command that takes a <tree-ish> argument ultimately wants to
	operate on a <tree> object but automatically dereferences
	<commit> and <tag> objects that point at a <tree>.

	<type>::
	Indicates that an object type is required.
	Currently one of: blob/tree/commit/tag

	<file>::
	Indicates a filename - always relative to the root of
	the tree structure GIT_INDEX_FILE describes.

	Symbolic Identifiers
	--------------------
	Any git command accepting any <object> can also use the following
	symbolic notation:

	HEAD::
	indicates the head of the repository (ie the contents of
	`$GIT_DIR/HEAD`)
	<tag>::
	a valid tag 'name'+
	(ie the contents of `$GIT_DIR/refs/tags/<tag>`)
	<head>::
	a valid head 'name'+
	(ie the contents of `$GIT_DIR/refs/heads/<head>`)
	<snap>::
	a valid snapshot 'name'+
	(ie the contents of `$GIT_DIR/refs/snap/<snap>`)


	File/Directory Structure
	------------------------
	The git-core manipulates the following areas in the directory:

	.git/ The base (overridden with $GIT_DIR)
	objects/ The object base (overridden with $GIT_OBJECT_DIRECTORY)
	??/ 'First 2 chars of object' directories.
	pack/ Packed archives.

	refs/ Directories containing symbolic names for objects
	(each file contains the hex SHA1 + newline)
	heads/ Commits which are heads of various sorts
	tags/ Tags, by the tag name (or some local renaming of it)
	*/ Any other subdirectory of refs/ can be used to store
	files similar to what are under refs/heads/.
	HEAD Symlink to refs/heads/<current-branch-name>

	Higher level SCMs may provide and manage additional information in the
	GIT_DIR.

	Terminology
	-----------
	Please see link:glossary.html[glossary] document.


	Environment Variables
	---------------------
	Various git commands use the following environment variables:

	The git Repository
	~~~~~~~~~~~~~~~~~~
	These environment variables apply to 'all' core git commands. Nb: it
	is worth noting that they may be used/overridden by SCMS sitting above
	git so take care if using Cogito etc

	'GIT_INDEX_FILE'::
	This environment allows the specification of an alternate
	cache/index file. If not specified, the default of
	`$GIT_DIR/index` is used.

	'GIT_OBJECT_DIRECTORY'::
	If the object storage directory is specified via this
	environment variable then the sha1 directories are created
	underneath - otherwise the default `$GIT_DIR/objects`
	directory is used.

	'GIT_ALTERNATE_OBJECT_DIRECTORIES'::
	Due to the immutable nature of git objects, old objects can be
	archived into shared, read-only directories. This variable
	specifies a ":" separated list of git object directories which
	can be used to search for git objects. New objects will not be
	written to these directories.

	'GIT_DIR'::
	If the 'GIT_DIR' environment variable is set then it specifies
	a path to use instead of `./.git` for the base of the
	repository.

	git Commits
	~~~~~~~~~~~
	'GIT_AUTHOR_NAME'::
	'GIT_AUTHOR_EMAIL'::
	'GIT_AUTHOR_DATE'::
	'GIT_COMMITTER_NAME'::
	'GIT_COMMITTER_EMAIL'::
	see link:git-commit-tree.html[git-commit-tree]

	git Diffs
	~~~~~~~~~
	'GIT_DIFF_OPTS'::
	'GIT_EXTERNAL_DIFF'::
	see the "generating patches" section in :
	link:git-diff-cache.html[git-diff-cache];
	link:git-diff-files.html[git-diff-files];
	link:git-diff-tree.html[git-diff-tree]

	Discussion
	----------
	include::../README[]

	Author
	------
	Written by Linus Torvalds <torvalds@osdl.org> and the git-list <git@vger.kernel.org>.

	Documentation
	--------------
	Documentation by David Greaves, Junio C Hamano and the git-list <git@vger.kernel.org>.

	GIT
	---
	Part of the link:git.html[git] suite