path: root/Documentation/git.txt

git(7)
======

NAME
----
git - the stupid content tracker


SYNOPSIS
--------
[verse]
'git' [--version] [--exec-path[=GIT_EXEC_PATH]] [-p|--paginate]
    [--bare] [--git-dir=GIT_DIR] [--help] COMMAND [ARGS]

DESCRIPTION
-----------
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.

See this link:tutorial.html[tutorial] to get started, then see
link:everyday.html[Everyday Git] for a useful minimum set of commands, and
"man git-commandname" for documentation of each command.  CVS users may
also want to read link:cvs-migration.html[CVS migration].

The COMMAND is either a name of a Git command (see below) or an alias
as defined in the configuration file (see gitlink:git-repo-config[1]).

OPTIONS
-------
--version::
	Prints the git suite version that the 'git' program came from.

--help::
	Prints the synopsis and a list of the most commonly used
	commands.  If a git command is named this option will bring up
	the man-page for that command. If the option '--all' or '-a' is
	given then all available commands are printed.

--exec-path::
	Path to wherever your core git programs are installed.
	This can also be controlled by setting the GIT_EXEC_PATH
	environment variable. If no path is given 'git' will print
	the current setting and then exit.

-p|--paginate::
	Pipe all output into 'less' (or if set, $PAGER).

--git-dir=<path>::
	Set the path to the repository. This can also be controlled by
	setting the GIT_DIR environment variable.

--bare::
	Same as --git-dir=`pwd`.

FURTHER DOCUMENTATION
---------------------

See the references above to get started using git.  The following is
probably more detail than necessary for a first-time user.

The <<Discussion,Discussion>> section below and the
link:core-tutorial.html[Core tutorial] both provide introductions to the
underlying git architecture.

See also the link:howto-index.html[howto] documents for some useful
examples.

GIT COMMANDS
------------

We divide git into high level ("porcelain") commands and low level
("plumbing") commands.

High-level commands (porcelain)
-------------------------------

We separate the porcelain commands into the main commands and some
ancillary user utilities.

Main porcelain commands
~~~~~~~~~~~~~~~~~~~~~~~

gitlink:git-add[1]::
	Add paths to the index.

gitlink:git-am[1]::
	Apply patches from a mailbox, but cooler.

gitlink:git-applymbox[1]::
	Apply patches from a mailbox, original version by Linus.

gitlink:git-archive[1]::
	Creates an archive of files from a named tree.

gitlink:git-bisect[1]::
	Find the change that introduced a bug by binary search.

gitlink:git-branch[1]::
	Create and Show branches.

gitlink:git-checkout[1]::
	Checkout and switch to a branch.

gitlink:git-cherry-pick[1]::
	Cherry-pick the effect of an existing commit.

gitlink:git-clean[1]::
	Remove untracked files from the working tree.

gitlink:git-clone[1]::
	Clones a repository into a new directory.

gitlink:git-commit[1]::
	Record changes to the repository.

gitlink:git-diff[1]::
	Show changes between commits, commit and working tree, etc.

gitlink:git-fetch[1]::
	Download from a remote repository via various protocols.

gitlink:git-format-patch[1]::
	Prepare patches for e-mail submission.

gitlink:git-grep[1]::
	Print lines matching a pattern.

gitlink:gitk[1]::
	The git repository browser.

gitlink:git-log[1]::
	Shows commit logs.

gitlink:git-ls-remote[1]::
	Shows references in a remote or local repository.

gitlink:git-merge[1]::
	Grand unified merge driver.

gitlink:git-mv[1]::
	Move or rename a file, a directory, or a symlink.

gitlink:git-pack-refs[1]::
	Pack heads and tags for efficient repository access.

gitlink:git-pull[1]::
	Fetch from and merge with a remote repository or a local branch.

gitlink:git-push[1]::
	Update remote refs along with associated objects.

gitlink:git-rebase[1]::
	Rebase local commits to the updated upstream head.

gitlink:git-repack[1]::
	Pack unpacked objects in a repository.

gitlink:git-rerere[1]::
	Reuse recorded resolution of conflicted merges.

gitlink:git-reset[1]::
	Reset current HEAD to the specified state.

gitlink:git-resolve[1]::
	Merge two commits.

gitlink:git-revert[1]::
	Revert an existing commit.

gitlink:git-rm[1]::
	Remove files from the working tree and from the index.

gitlink:git-shortlog[1]::
	Summarizes 'git log' output.

gitlink:git-show[1]::
	Show one commit log and its diff.

gitlink:git-show-branch[1]::
	Show branches and their commits.

gitlink:git-status[1]::
	Shows the working tree status.

gitlink:git-verify-tag[1]::
	Check the GPG signature of tag.

gitlink:git-whatchanged[1]::
	Shows commit logs and differences they introduce.


Ancillary Commands
~~~~~~~~~~~~~~~~~~
Manipulators:

gitlink:git-applypatch[1]::
	Apply one patch extracted from an e-mail.

gitlink:git-archimport[1]::
	Import an arch repository into git.

gitlink:git-convert-objects[1]::
	Converts old-style git repository.

gitlink:git-cvsimport[1]::
	Salvage your data out of another SCM people love to hate.

gitlink:git-cvsexportcommit[1]::
	Export a single commit to a CVS checkout.

gitlink:git-cvsserver[1]::
	A CVS server emulator for git.

gitlink:git-gc[1]::
	Cleanup unnecessary files and optimize the local repository.

gitlink:git-lost-found[1]::
	Recover lost refs that luckily have not yet been pruned.

gitlink:git-merge-one-file[1]::
	The standard helper program to use with `git-merge-index`.

gitlink:git-prune[1]::
	Prunes all unreachable objects from the object database.

gitlink:git-quiltimport[1]::
	Applies a quilt patchset onto the current branch.

gitlink:git-reflog[1]::
	Manage reflog information.

gitlink:git-relink[1]::
	Hardlink common objects in local repositories.

gitlink:git-svn[1]::
	Bidirectional operation between a single Subversion branch and git.

gitlink:git-svnimport[1]::
	Import a SVN repository into git.

gitlink:git-sh-setup[1]::
	Common git shell script setup code.

gitlink:git-symbolic-ref[1]::
	Read and modify symbolic refs.

gitlink:git-tag[1]::
	An example script to create a tag object signed with GPG.

gitlink:git-update-ref[1]::
	Update the object name stored in a ref safely.


Interrogators:

gitlink:git-annotate[1]::
	Annotate file lines with commit info.

gitlink:git-blame[1]::
	Find out where each line in a file came from.

gitlink:git-check-ref-format[1]::
	Make sure ref name is well formed.

gitlink:git-cherry[1]::
	Find commits not merged upstream.

gitlink:git-count-objects[1]::
	Count unpacked number of objects and their disk consumption.

gitlink:git-daemon[1]::
	A really simple server for git repositories.

gitlink:git-fmt-merge-msg[1]::
	Produce a merge commit message.

gitlink:git-get-tar-commit-id[1]::
	Extract commit ID from an archive created using git-tar-tree.

gitlink:git-imap-send[1]::
	Dump a mailbox from stdin into an imap folder.

gitlink:git-instaweb[1]::
	Instantly browse your working repository in gitweb.

gitlink:git-mailinfo[1]::
	Extracts patch and authorship information from a single
	e-mail message, optionally transliterating the commit
	message into utf-8.

gitlink:git-mailsplit[1]::
	A stupid program to split UNIX mbox format mailbox into
	individual pieces of e-mail.

gitlink:git-merge-tree[1]::
	Show three-way merge without touching index.

gitlink:git-patch-id[1]::
	Compute unique ID for a patch.

gitlink:git-parse-remote[1]::
	Routines to help parsing `$GIT_DIR/remotes/` files.

gitlink:git-request-pull[1]::
	git-request-pull.

gitlink:git-rev-parse[1]::
	Pick out and massage parameters.

gitlink:git-runstatus[1]::
	A helper for git-status and git-commit.

gitlink:git-send-email[1]::
	Send patch e-mails out of "format-patch --mbox" output.

gitlink:git-symbolic-ref[1]::
	Read and modify symbolic refs.

gitlink:git-stripspace[1]::
	Filter out empty lines.


Low-level commands (plumbing)
-----------------------------

Although git includes its
own porcelain layer, its low-level commands are sufficient to support
development of alternative porcelains.  Developers of such porcelains
might start by reading about gitlink:git-update-index[1] and
gitlink:git-read-tree[1].

We divide the low-level commands into commands that manipulate objects (in
the repository, index, and working tree), commands that interrogate and
compare objects, and commands that move objects and references between
repositories.

Manipulation commands
~~~~~~~~~~~~~~~~~~~~~
gitlink:git-apply[1]::
	Reads a "diff -up1" or git generated patch file and
	applies it to the working tree.

gitlink:git-checkout-index[1]::
	Copy files from the index to the working tree.

gitlink:git-commit-tree[1]::
	Creates a new commit object.

gitlink:git-hash-object[1]::
	Computes the object ID from a file.

gitlink:git-index-pack[1]::
	Build pack idx file for an existing packed archive.

gitlink:git-init[1]::
gitlink:git-init-db[1]::
	Creates an empty git object database, or reinitialize an
	existing one.

gitlink:git-merge-file[1]::
	Runs a threeway merge.

gitlink:git-merge-index[1]::
	Runs a merge for files needing merging.

gitlink:git-mktag[1]::
	Creates a tag object.

gitlink:git-mktree[1]::
	Build a tree-object from ls-tree formatted text.

gitlink:git-pack-objects[1]::
	Creates a packed archive of objects.

gitlink:git-prune-packed[1]::
	Remove extra objects that are already in pack files.

gitlink:git-read-tree[1]::
	Reads tree information into the index.

gitlink:git-repo-config[1]::
	Get and set options in .git/config.

gitlink:git-unpack-objects[1]::
	Unpacks objects out of a packed archive.

gitlink:git-update-index[1]::
	Registers files in the working tree to the index.

gitlink:git-write-tree[1]::
	Creates a tree from the index.


Interrogation commands
~~~~~~~~~~~~~~~~~~~~~~

gitlink:git-cat-file[1]::
	Provide content or type/size information for repository objects.

gitlink:git-describe[1]::
	Show the most recent tag that is reachable from a commit.

gitlink:git-diff-index[1]::
	Compares content and mode of blobs between the index and repository.

gitlink:git-diff-files[1]::
	Compares files in the working tree and the index.

gitlink:git-diff-stages[1]::
	Compares two "merge stages" in the index.

gitlink:git-diff-tree[1]::
	Compares the content and mode of blobs found via two tree objects.

gitlink:git-for-each-ref[1]::
	Output information on each ref.

gitlink:git-fsck-objects[1]::
	Verifies the connectivity and validity of the objects in the database.

gitlink:git-ls-files[1]::
	Information about files in the index and the working tree.

gitlink:git-ls-tree[1]::
	Displays a tree object in human readable form.

gitlink:git-merge-base[1]::
	Finds as good common ancestors as possible for a merge.

gitlink:git-name-rev[1]::
	Find symbolic names for given revs.

gitlink:git-pack-redundant[1]::
	Find redundant pack files.

gitlink:git-rev-list[1]::
	Lists commit objects in reverse chronological order.

gitlink:git-show-index[1]::
	Displays contents of a pack idx file.

gitlink:git-show-ref[1]::
	List references in a local repository.

gitlink:git-tar-tree[1]::
	Creates a tar archive of the files in the named tree object.

gitlink:git-unpack-file[1]::
	Creates a temporary file with a blob's contents.

gitlink:git-var[1]::
	Displays a git logical variable.

gitlink:git-verify-pack[1]::
	Validates packed git archive files.

In general, the interrogate commands do not touch the files in
the working tree.


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

gitlink:git-fetch-pack[1]::
	Updates from a remote repository (engine for ssh and
	local transport).

gitlink:git-http-fetch[1]::
	Downloads a remote git repository via HTTP by walking
	commit chain.

gitlink:git-local-fetch[1]::
	Duplicates another git repository on a local system by
	walking commit chain.

gitlink:git-peek-remote[1]::
	Lists references on a remote repository using
	upload-pack protocol (engine for ssh and local
	transport).

gitlink:git-receive-pack[1]::
	Invoked by 'git-send-pack' to receive what is pushed to it.

gitlink:git-send-pack[1]::
	Pushes to a remote repository, intelligently.

gitlink:git-http-push[1]::
	Push missing objects using HTTP/DAV.

gitlink:git-shell[1]::
	Restricted shell for GIT-only SSH access.

gitlink:git-ssh-fetch[1]::
	Pulls from a remote repository over ssh connection by
	walking commit chain.

gitlink:git-ssh-upload[1]::
	Helper "server-side" program used by git-ssh-fetch.

gitlink:git-update-server-info[1]::
	Updates auxiliary information on a dumb server to help
	clients discover references and packs on it.

gitlink:git-upload-archive[1]::
	Invoked by 'git-archive' to send a generated archive.

gitlink:git-upload-pack[1]::
	Invoked by 'git-fetch-pack' to push
	what are asked for.


Configuration Mechanism
-----------------------

Starting from 0.99.9 (actually mid 0.99.8.GIT), `.git/config` file
is used to hold per-repository configuration options.  It is a
simple text file modeled after `.ini` format familiar to some
people.  Here is an example:

------------
#
# A '#' or ';' character indicates a comment.
#

; core variables
[core]
	; Don't trust file modes
	filemode = false

; user identity
[user]
	name = "Junio C Hamano"
	email = "junkio@twinsun.com"

------------

Various commands read from the configuration file and adjust
their operation accordingly.


Identifier Terminology
----------------------
<object>::
	Indicates the object name for any type of object.

<blob>::
	Indicates a blob object name.

<tree>::
	Indicates a tree object name.

<commit>::
	Indicates a commit object name.

<tree-ish>::
	Indicates a tree, commit or tag object name.  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`, or `tag`.

<file>::
	Indicates a filename - almost 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 current branch (i.e. the
	contents of `$GIT_DIR/HEAD`).

<tag>::
	a valid tag 'name'
	(i.e. the contents of `$GIT_DIR/refs/tags/<tag>`).

<head>::
	a valid head 'name'
	(i.e. the contents of `$GIT_DIR/refs/heads/<head>`).

For a more complete list of ways to spell object names, see
"SPECIFYING REVISIONS" section in gitlink:git-rev-parse[1].


File/Directory Structure
------------------------

Please see link:repository-layout.html[repository layout] document.

Read link:hooks.html[hooks] for more details about each hook.

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
	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 the default `.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 gitlink:git-commit-tree[1]

git Diffs
~~~~~~~~~
'GIT_DIFF_OPTS'::
	Only valid setting is "--unified=??" or "-u??" to set the
	number of context lines shown when a unified diff is created.
	This takes precedence over any "-U" or "--unified" option
	value passed on the git diff command line.

'GIT_EXTERNAL_DIFF'::
	When the environment variable 'GIT_EXTERNAL_DIFF' is set, the
	program named by it is called, instead of the diff invocation
	described above.  For a path that is added, removed, or modified,
        'GIT_EXTERNAL_DIFF' is called with 7 parameters:

	path old-file old-hex old-mode new-file new-hex new-mode
+
where:

	<old|new>-file:: are files GIT_EXTERNAL_DIFF can use to read the
                         contents of <old|new>,
	<old|new>-hex:: are the 40-hexdigit SHA1 hashes,
	<old|new>-mode:: are the octal representation of the file modes.

+
The file parameters can point at the user's working file
(e.g. `new-file` in "git-diff-files"), `/dev/null` (e.g. `old-file`
when a new file is added), or a temporary file (e.g. `old-file` in the
index).  'GIT_EXTERNAL_DIFF' should not worry about unlinking the
temporary file --- it is removed when 'GIT_EXTERNAL_DIFF' exits.
+
For a path that is unmerged, 'GIT_EXTERNAL_DIFF' is called with 1
parameter, <path>.

other
~~~~~
'GIT_PAGER'::
	This environment variable overrides `$PAGER`.

'GIT_TRACE'::
	If this variable is set to "1", "2" or "true" (comparison
	is case insensitive), git will print `trace:` messages on
	stderr telling about alias expansion, built-in command
	execution and external command execution.
	If this variable is set to an integer value greater than 1
	and lower than 10 (strictly) then git will interpret this
	value as an open file descriptor and will try to write the
	trace messages into this file descriptor.
	Alternatively, if this variable is set to an absolute path
	(starting with a '/' character), git will interpret this
	as a file path and will try to write the trace messages
	into it.

Discussion[[Discussion]]
------------------------
include::README[]

Authors
-------
* git's founding father is Linus Torvalds <torvalds@osdl.org>.
* The current git nurse is Junio C Hamano <junkio@cox.net>.
* The git potty was written by Andres Ericsson <ae@op5.se>.
* General upbringing is handled by the git-list <git@vger.kernel.org>.

Documentation
--------------
The documentation for git suite was started by David Greaves
<david@dgreaves.com>, and later enhanced greatly by the
contributors on the git-list <git@vger.kernel.org>.

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